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    • EL7554IREZ图

    • 深圳市炎凯科技有限公司

       该会员已使用本站7年以上
    • EL7554IREZ 现货库存
    • 数量7728 
    • 厂家INTERSIL 
    • 封装TSSOP 
    • 批号24+ 
    • 全新原装现货 假一罚十！
    • QQ:354696650QQ：354696650 复制
      QQ:2850471056QQ：2850471056 复制
    • 0755-89587732 QQ:354696650QQ:2850471056
    • EL7554IRE图

    • 深圳市科雨电子有限公司

       该会员已使用本站8年以上
    • EL7554IRE
    • 数量1001 
    • 厂家INTERSIL 
    • 封装SSOP-28 
    • 批号21+ 
    • ★体验愉快问购元件！！就找我吧!《停产物料》
    • QQ:97671959QQ：97671959 复制
    • 171-4729-9698（微信同号） QQ:97671959
    • EL7554IRE-T7图

    • 深圳市科雨电子有限公司

       该会员已使用本站8年以上
    • EL7554IRE-T7
    • 数量1001 
    • 厂家INTERSIL 
    • 封装SSOP-28 
    • 批号21+ 
    • ★体验愉快问购元件！！就找我吧!《停产物料》
    • QQ:97877805QQ：97877805 复制
    • 171-4729-0036(微信同号） QQ:97877805
    • EL7554IREZ图

    • 深圳市得捷芯城科技有限公司

       该会员已使用本站11年以上
    • EL7554IREZ
    • 数量4573 
    • 厂家INTERSIL 
    • 封装NA/ 
    • 批号23+ 
    • 原装现货，当天可交货，原型号开票
    • QQ:3007977934QQ：3007977934 复制
      QQ:3007947087QQ：3007947087 复制
    • 0755-82546830 QQ:3007977934QQ:3007947087
    • EL7554IREZ 其他被动元件图

    • 深圳市集创讯科技有限公司

       该会员已使用本站5年以上
    • EL7554IREZ 其他被动元件
    • 数量15000 
    • 厂家INTERSIL 
    • 封装TSSOP28 
    • 批号24+ 
    • 原装进口正品现货，假一罚十价格优势
    • QQ:2885393494QQ：2885393494 复制
      QQ:2885393495QQ：2885393495 复制
    • 0755-83244680 QQ:2885393494QQ:2885393495
    • EL7554IRE图

    • 深圳市羿芯诚电子有限公司

       该会员已使用本站7年以上
    • EL7554IRE
    • 数量8500 
    • 厂家原厂品牌 
    • 封装原厂封装 
    • 批号新年份 
    • 羿芯诚只做原装长期供，支持实单
    • QQ:2880123150QQ：2880123150 复制
    • 0755-82570600 QQ:2880123150
    • EL7554IREZ图

    • 深圳市正纳电子有限公司

       该会员已使用本站15年以上
    • EL7554IREZ
    • 数量35898 
    • 厂家INTERSIL 
    • 封装28-HTSSOP 
    • 批号21+ 
    • ■原装现货长期供应电子元器件代理经销WWW.ZN-IC.COM
    • QQ:2881664480QQ：2881664480 复制
    • 0755-83532193 QQ:2881664480
    • EL7554IRE-T13图

    • 北京首天国际有限公司

       该会员已使用本站16年以上
    • EL7554IRE-T13
    • 数量1500 
    • 厂家INTERSIL 
    • 封装 
    • 批号16+ 
    • 百分百原装正品，现货库存
    • QQ:528164397QQ：528164397 复制
      QQ:1318502189QQ：1318502189 复制
    • 010-62565447 QQ:528164397QQ:1318502189
    • EL7554IRE图

    • 深圳市硅诺电子科技有限公司

       该会员已使用本站8年以上
    • EL7554IRE
    • 数量38279 
    • 厂家ELANTEC 
    • 封装HTSSOP28 
    • 批号17+ 
    • 原厂指定分销商，有意请来电或QQ洽谈
    • QQ:1091796029QQ：1091796029 复制
      QQ:916896414QQ：916896414 复制
    • 0755-82772151 QQ:1091796029QQ:916896414
    • EL7554IRE-T7图

    • 北京首天国际有限公司

       该会员已使用本站16年以上
    • EL7554IRE-T7
    • 数量0 
    • 厂家INTERSIL 
    • 封装0.00 
    • 批号16+ 
    • 百分百原装正品，现货库存
    • QQ:528164397QQ：528164397 复制
      QQ:1318502189QQ：1318502189 复制
    • 010-62565447 QQ:528164397QQ:1318502189
    • EL7554IREZ图

    • 北京齐天芯科技有限公司

       该会员已使用本站15年以上
    • EL7554IREZ
    • 数量100000 
    • 厂家Intersil 
    • 封装N/A 
    • 批号16+ 
    • 原装正品，假一罚十
    • QQ:2880824479QQ：2880824479 复制
      QQ:1344056792QQ：1344056792 复制
    • 010-62104931 QQ:2880824479QQ:1344056792
    • EL7554IRE图

    • 深圳市欧立现代科技有限公司

       该会员已使用本站12年以上
    • EL7554IRE
    • 数量3800 
    • 厂家Intersil 
    • 封装28-SOIC 
    • 批号24+ 
    • 授权分销 现货热卖
    • QQ:1950791264QQ：1950791264 复制
      QQ:2216987084QQ：2216987084 复制
    • 0755-83222787 QQ:1950791264QQ:2216987084
    • EL7554IRE图

    • 深圳市博正芯科技有限公司

       该会员已使用本站6年以上
    • EL7554IRE
    • 数量11500 
    • 厂家Elantec 
    • 封装正品 
    • 批号21+ 
    • ★★正品专卖,进口原装深圳现货★★
    • QQ:639834857QQ：639834857 复制
      QQ:1487625604QQ：1487625604 复制
    • 0755-82545278 QQ:639834857QQ:1487625604
    • EL7554IREZ图

    • 万三科技(深圳)有限公司

       该会员已使用本站2年以上
    • EL7554IREZ
    • 数量660000 
    • 厂家RENESAS（瑞萨电子） 
    • 封装 
    • 批号23+ 
    • 支持实单/只做原装
    • QQ:3008961398QQ：3008961398 复制
    • 0755-21006672 QQ:3008961398
    • EL7554IREZ图

    • 深圳市芯福林电子有限公司

       该会员已使用本站15年以上
    • EL7554IREZ
    • 数量98500 
    • 厂家 
    • 封装原厂封装 
    • 批号23+ 
    • 真实库存全新原装正品！代理此型号
    • QQ:2881495751QQ：2881495751 复制
    • 0755-88917743 QQ:2881495751
    • EL7554IREZ图

    • 深圳市瑞天芯科技有限公司

       该会员已使用本站7年以上
    • EL7554IREZ
    • 数量20000 
    • 厂家INTERSIL 
    • 封装TSSOP28 
    • 批号22+ 
    • 深圳现货库存，保证原装正品
    • QQ:1940213521QQ：1940213521 复制
    • 15973558688 QQ:1940213521
    • EL7554IREZ-T7图

    • 万三科技(深圳)有限公司

       该会员已使用本站2年以上
    • EL7554IREZ-T7
    • 数量6500000 
    • 厂家RENESAS（瑞萨电子） 
    • 封装原厂原装 
    • 批号22+ 
    • 万三科技 秉承原装 实单可议
    • QQ:3008962483QQ：3008962483 复制
    • 0755-23763516 QQ:3008962483
    • EL7554IRE-T13图

    • 深圳市一线半导体有限公司

       该会员已使用本站11年以上
    • EL7554IRE-T13
    • 数量25000 
    • 厂家Renesas Electronics America Inc 
    • 封装 
    • 批号 
    • 全新原装部分现货其他订货
    • QQ:2881493920QQ：2881493920 复制
      QQ:2881493921QQ：2881493921 复制
    • 0755-88608801多线 QQ:2881493920QQ:2881493921
    • EL7554IREZ-T7图

    • 深圳市隆鑫创展电子有限公司

       该会员已使用本站15年以上
    • EL7554IREZ-T7
    • 数量30000 
    • 厂家ON 
    • 封装NEWINORIGINAL 
    • 批号2022+ 
    • 电子元器件一站式配套服务QQ:122350038
    • QQ:2355878626QQ：2355878626 复制
      QQ:2850299242QQ：2850299242 复制
    • 0755-82812278 QQ:2355878626QQ:2850299242
    • EL7554IREZ-T7图

    • 深圳市特拉特科技有限公司

       该会员已使用本站2年以上
    • EL7554IREZ-T7
    • 数量10000 
    • 厂家INTERSIL 
    • 封装TSSOP 
    • 批号22+ 
    • 原厂指定分销商，有意请来电或QQ洽谈
    • QQ:709809857QQ：709809857 复制
    • 0755-82531732 QQ:709809857
    • EL7554IRE图

    • 深圳市创思克科技有限公司

       该会员已使用本站2年以上
    • EL7554IRE
    • 数量7800 
    • 厂家INTERSIL 
    • 封装TSSOP-28 
    • 批号20+ 
    • 全新原装原厂实力挺实单欢迎来撩
    • QQ:1092793871QQ：1092793871 复制
    • -0755-88910020 QQ:1092793871
    • EL7554IREZ图

    • 深圳市正纳电子有限公司

       该会员已使用本站15年以上
    • EL7554IREZ
    • 数量26700 
    • 厂家Intersil(英特矽尔) 
    • 封装▊原厂封装▊ 
    • 批号▊ROHS环保▊ 
    • 十年以上分销商原装进口件服务型企业0755-83790645
    • QQ:2881664479QQ：2881664479 复制
    • 755-83790645 QQ:2881664479
    • EL7554IREZ-T7图

    • 上海意淼电子科技有限公司

       该会员已使用本站14年以上
    • EL7554IREZ-T7
    • 数量20000 
    • 厂家INTERSIL 
    • 封装TSSOP 
    • 批号23+ 
    • 原装现货热卖！请联系吴先生 13681678667
    • QQ:617677003QQ：617677003 复制
    • 15618836863 QQ:617677003
    • EL7554IREZ图

    • 深圳威尔运电子有限公司

       该会员已使用本站10年以上
    • EL7554IREZ
    • 数量750 
    • 厂家N/A 
    • 封装N/A 
    • 批号16+ 
    • 正品原装，假一罚十！
    • QQ:276537593QQ：276537593 复制
    • 86-0755-83826550 QQ:276537593
    • EL7554IRE图

    • 深圳市晨豪科技有限公司

       该会员已使用本站12年以上
    • EL7554IRE
    • 数量89630 
    • 厂家ELANTEC 
    • 封装HTSSOP-28 
    • 批号23+ 
    • 当天发货全新原装现货
    • QQ:1743149803QQ：1743149803 复制
      QQ:1852346906QQ：1852346906 复制
    • 0755-82732291 QQ:1743149803QQ:1852346906
    • EL7554IRE图

    • 深圳市华来深电子有限公司

       该会员已使用本站13年以上
    • EL7554IRE
    • 数量8560 
    • 厂家INTERSI 
    • 封装TSSOP-2 
    • 批号17+ 
    • 受权代理！全新原装现货特价热卖！
    • QQ:1258645397QQ：1258645397 复制
      QQ:876098337QQ：876098337 复制
    • 0755-83238902 QQ:1258645397QQ:876098337
    • EL7554IRE图

    • 深圳市顺鑫诚电子科技有限公司

       该会员已使用本站14年以上
    • EL7554IRE
    • 数量5000 
    • 厂家INTELRSIL 
    • 封装SOIC 
    • 批号18+ 
    • 保证原装正品，欢迎来电咨询
    • QQ:1533095505QQ：1533095505 复制
      QQ:449551876QQ：449551876 复制
    • 0755-29486608 QQ:1533095505QQ:449551876
    • EL7554IREZ图

    • 深圳德田科技有限公司

       该会员已使用本站7年以上
    • EL7554IREZ
    • 数量0 
    • 厂家新年份 
    • 封装9600 
    • 批号 
    • 原装正品现货，可出样品！！！
    • QQ:229754250QQ：229754250 复制
    • 0755-83254070 QQ:229754250
    • EL7554IREZ图

    • 深圳市中杰盛科技有限公司

       该会员已使用本站14年以上
    • EL7554IREZ
    • 数量12000 
    • 厂家Intersil 
    • 封装HTSSOP EP 
    • 批号24+ 
    • 【原装优势★★★绝对有货】
    • QQ:409801605QQ：409801605 复制
    • 0755-22968359 QQ:409801605
    • EL7554IREZ图

    • 深圳市凯信扬科技有限公司

       该会员已使用本站7年以上
    • EL7554IREZ
    • 数量9820 
    • 厂家INTERSIL 
    • 封装TSSOP28 
    • 批号21+ 
    • 原则深圳现货，优势价格
    • QQ:872328909QQ：872328909 复制
    • 0755-82518059 QQ:872328909
    • EL7554IRE图

    • 深圳市能元时代电子有限公司

       该会员已使用本站10年以上
    • EL7554IRE
    • 数量50000 
    • 厂家ELANTEC 
    • 封装HTSSOP28 
    • 批号24+ 
    • 公司原装现货可含税！假一罚十！
    • QQ:2885637848QQ：2885637848 复制
      QQ:2885658492QQ：2885658492 复制
    • 0755-84502810 QQ:2885637848QQ:2885658492
    • EL7554IRE图

    • 现代芯城（深圳）科技有限公司

       该会员已使用本站15年以上
    • EL7554IRE
    • 数量67000 
    • 厂家一级代理 
    • 封装一级代理 
    • 批号一级代理 
    • 一级代理正品采购
    • QQ:3007226851QQ：3007226851 复制
      QQ:3007226849QQ：3007226849 复制
    • 0755-82542579 QQ:3007226851QQ:3007226849
    • EL7554IRE图

    • 深圳市晶美隆科技有限公司

       该会员已使用本站15年以上
    • EL7554IRE
    • 数量60000 
    • 厂家ELANTEC 
    • 封装HTSSOP28 
    • 批号24+ 
    • 假一罚十，原装进口正品现货供应，价格优势。
    • QQ:198857245QQ：198857245 复制
    • 0755-82865294 QQ:198857245
    • EL7554IRE图

    • 集好芯城

       该会员已使用本站13年以上
    • EL7554IRE
    • 数量1068 
    • 厂家Renesas Electronics America Inc 
    • 封装 
    • 批号最新批次 
    • 原厂原装公司现货
    • QQ:3008092965QQ：3008092965 复制
      QQ:3008092965QQ：3008092965 复制
    • 0755-83239307 QQ:3008092965QQ:3008092965
    • EL7554IREZ图

    • 深圳市华斯顿电子科技有限公司

       该会员已使用本站16年以上
    • EL7554IREZ
    • 数量57155 
    • 厂家INTERSIL 
    • 封装TSSOP28 
    • 批号2023+ 
    • 绝对原装全新正品现货/优势渠道商、原盘原包原盒
    • QQ:364510898QQ：364510898 复制
      QQ:515102657QQ：515102657 复制
    • 0755-83777708“进口原装正品专供” QQ:364510898QQ:515102657
    • EL7554IREZ-T7图

    • 深圳市华斯顿电子科技有限公司

       该会员已使用本站16年以上
    • EL7554IREZ-T7
    • 数量45621 
    • 厂家INTERSIL 
    • 封装TSSOP28 
    • 批号2023+ 
    • 绝对原装正品现货，全新深圳原装进口现货
    • QQ:1002316308QQ：1002316308 复制
      QQ:515102657QQ：515102657 复制
    • 美驻深办0755-83777708“进口原装正品专供” QQ:1002316308QQ:515102657
    • EL7554IREZ图

    • 深圳市晶美隆科技有限公司

       该会员已使用本站14年以上
    • EL7554IREZ
    • 数量11530 
    • 厂家Intersil 
    • 封装28-TSSOP曝露式焊盤，28-eTSSOP，28-HTSSOP 
    • 批号23+ 
    • 全新原装现货热卖
    • QQ:2885348317QQ：2885348317 复制
      QQ:2885348339QQ：2885348339 复制
    • 0755-83209630 QQ:2885348317QQ:2885348339
    • EL7554IREZ-T7图

    • 深圳市赛尔通科技有限公司

       该会员已使用本站12年以上
    • EL7554IREZ-T7
    • 数量65400 
    • 厂家INTERSIL 
    • 封装TSSOP 
    • 批号NEW 
    • 【◆全新原装现货◆绝对价格优势◆质量保证◆】
    • QQ:1134344845QQ：1134344845 复制
      QQ:847984313QQ：847984313 复制
    • 86-0755-83536093 QQ:1134344845QQ:847984313
    • EL7554IREZ-T7图

    • 深圳市宏世佳电子科技有限公司

       该会员已使用本站13年以上
    • EL7554IREZ-T7
    • 数量3543 
    • 厂家INTERSIL 
    • 封装TSSOP 
    • 批号2023+ 
    • 全新原厂原装产品、公司现货销售
    • QQ:2881894392QQ：2881894392 复制
      QQ:2881894393QQ：2881894393 复制
    • 0755- QQ:2881894392QQ:2881894393

    产品型号EL7554IRE的概述

    芯片EL7554IRE的概述 EL7554IRE是一款由Elantec Semiconductor公司设计和制造的高性能运算放大器。运算放大器在电子电路中扮演着至关重要的角色，广泛应用于信号处理、滤波器、放大器、比较器等多种应用场景。EL7554IRE以其卓越的性能和灵活的应用能力，成为业界认可的重要组成部分。 EL7554IRE的详细参数 EL7554IRE基于双极性工艺，具有优异的线性特性及低噪声性能。其主要技术参数如下： - 工作电压范围：±2.5V至±15V - 增益带宽产品：4MHz - 输入失调电压：最大50mV - 输入失调电流：最大100nA - 输出电流：最大50mA - 共模抑制比（CMRR）：最大80dB - 热失调：典型20μV/°C - 相位裕度：大于60° 此外，EL7554IRE的输入和输出端口均能有效地支持宽频段的操作，使其适用于多种高频信号处理场景。 ...

    产品型号EL7554IRE的Datasheet PDF文件预览

    EL7554  
    ®
    Data Sheet  
    January 31, 2005  
    FN7360.2  
    Monolithic 4 Amp DC-DC Step-Down  
    Regulator  
    Features  
    • Integrated MOSFETs  
    The EL7554 is a full-feature synchronous 4A step-down  
    regulator capable of up to 96% efficiency. This device  
    • 4A continuous output current  
    • Up to 96% efficiency  
    operates from 3V to 6V V input supply. With internal  
    IN  
    CMOS power FETs, the device can operate at up to 100%  
    duty ratio, allowing for output voltage range from 0.8V up to  
    • All ceramic capacitors  
    • Multiple supply start-up tracking  
    • Built-in ±5% voltage margining  
    nearly V .The adjustable high switching frequency of up to  
    IN  
    1MHz enables the use of small components, making the  
    whole converter occupy less than 0.58 square inch with  
    components on one side of the PCB. The EL7554 operates  
    at constant frequency PWM mode, making external  
    synchronization possible. The EL7554 features soft-start  
    and full start-up control, which eliminates the in-rush current  
    and enables users to control the start-up of multiple  
    converters to any configuration with ease. The EL7554 also  
    offers a ±5% voltage margining capability that allows raising  
    and lowering of the supplies derived from the EL7554 to  
    validate the performance and reliability of system cards  
    quickly and easily during manufacturing testing. A junction  
    temperature indicator conveniently monitors the silicon die  
    temperature, saving designers time in the tedious thermal  
    characterization.  
    • 3V to 6V input voltage  
    2
    • 0.58 in footprint with components on one side of PCB  
    • Adjustable switching frequency to 1MHz  
    • Oscillator synchronization possible  
    • 100% duty ratio  
    • Junction temperature indicator  
    • Over-temperature protection  
    • Internal soft-start  
    • Variable output voltage down to 0.8V  
    • Power-good indicator  
    An easy-to-use simulation tool is available for download and  
    can be used to modify design parameters such as switching  
    frequency, voltage ripple, ambient temperature, as well as  
    view schematics waveforms, efficiency graphs, and  
    complete BOM with Gerber layout.  
    • 28-pin HTSSOP package  
    • Pb-free available (RoHS compliant)  
    Applications  
    • Point-of-regulation power supplies  
    • FPGA Core and I/O supplies  
    • DSP, CPU Core, and IO supplies  
    • Logic/Bus supplies  
    The EL7554 is available in a 28-pin HTSSOP package and  
    is specified for operation over the -40°C to +85°C  
    temperature range.  
    Ordering Information  
    • Portable equipment  
    PART  
    TAPE &  
    REEL  
    NUMBER  
    PACKAGE  
    PKG. DWG. #  
    MDP0048  
    MDP0048  
    MDP0048  
    MDP0048  
    Related Documentation  
    • Technical Brief 418 - Using the EL7554 Demo Board  
    EL7554IRE  
    28-Pin HTSSOP  
    28-Pin HTSSOP  
    -
    7”  
    13”  
    -
    EL7554IRE-T7  
    • Easy to use applications software simulation tool available  
    at www.intersil.com/dc-dc  
    EL7554IRE-T13 28-Pin HTSSOP  
    EL7554IREZ  
    (See Note)  
    28-Pin HTSSOP  
    (Pb-free)  
    EL7554IREZ-T7 28-Pin HTSSOP  
    7”  
    MDP0048  
    MDP0048  
    (See Note)  
    (Pb-free)  
    EL7554IREZ-  
    28-Pin HTSSOP  
    (Pb-free)  
    13”  
    T13 (See Note)  
    NOTE: Intersil Pb-free products employ special Pb-free material sets; molding  
    compounds/die attach materials and 100% matte tin plate termination finish, which are  
    RoHS compliant and compatible with both SnPb and Pb-free soldering operations.  
    Intersil Pb-free products are MSL classified at Pb-free peak reflow temperatures that  
    meet or exceed the Pb-free requirements of IPC/JEDEC J STD-020.  
    CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.  
    1
    1-888-INTERSIL or 1-888-352-6832 | Intersil (and design) is a registered trademark of Intersil Americas Inc.  
    Copyright Intersil Americas Inc. 2004, 2005. All Rights Reserved  
    All other trademarks mentioned are the property of their respective owners.  
    EL7554  
    Typical Application Diagram  
    C
    C
    R
    C
    1
    2
    3
    4
    5
    6
    7
    8
    9
    COMP SGND 28  
    220pF  
    0.018µF 2.32K  
    0.018µF  
    R
    10.2K  
    2
    VREF  
    FB  
    COSC 27  
    STN 26  
    STP 25  
    EN 24  
    C
    OSC  
    R
    12.7K  
    1
    VO  
    0.22µF  
    VTJ  
    TM  
    PG 23  
    SEL  
    LX  
    VDD 22  
    VIN 21  
    V
    IN  
    (3V TO  
    6V)  
    2.2µH  
    OUT  
    LX  
    VIN 20  
    V
    OUT  
    (1.8V, 4A)  
    2x10µF  
    10 LX  
    11 LX  
    12 LX  
    13 LX  
    14 NC  
    VIN 19  
    C
    C
    IN  
    47µF  
    PGND 18  
    PGND 17  
    PGND 16  
    NC 15  
    FN7360.2  
    2
    January 31, 2005  
    EL7554  
    Absolute Maximum Ratings (T = 25°C)  
    A
    V
    , V  
    to SGND. . . . . . . . . . . . . . . . . . . . . . . . . . . -0.3V to +6.5V  
    Storage Temperature . . . . . . . . . . . . . . . . . . . . . . . .-65°C to +150°C  
    Junction Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . +135°C  
    Ambient Operating Temperature . . . . . . . . . . . . . . . .-40°C to +85°C  
    IN DD  
    VX to PGND. . . . . . . . . . . . . . . . . . . . . . . . . . . . . -0.3V to V +0.3V  
    IN  
    SGND to PGND . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -0.3V to +0.3V  
    COMP, V  
    , FB, V , V , TM,  
    REF TJ  
    O
    SEL, PG, EN, STP, STN, C  
    OSC  
    to SGND . . . . . -0.3V to V  
    +0.3V  
    DD  
    CAUTION: Stresses above those listed in “Absolute Maximum Ratings” may cause permanent damage to the device. This is a stress only rating and operation of the  
    device at these or any other conditions above those indicated in the operational sections of this specification is not implied.  
    IMPORTANT NOTE: All parameters having Min/Max specifications are guaranteed. Typ values are for information purposes only. Unless otherwise noted, all tests are  
    at the specified temperature and are pulsed tests, therefore: T = T = T  
    A
    J
    C
    DC Electrical Specifications  
    PARAMETER  
    V
    = V = 3.3V, T = T = 25°C, C  
    = 390pF, Unless Otherwise Specified  
    DD  
    DESCRIPTION  
    Input Voltage Range  
    Reference Accuracy  
    IN  
    A
    J
    OSC  
    CONDITIONS  
    MIN  
    3
    TYP  
    MAX  
    6
    UNIT  
    V
    V
    IN  
    V
    V
    V
    V
    1.24  
    1.26  
    50  
    1.28  
    V
    REF  
    Reference Temperature Coefficient  
    Reference Load Regulation  
    Oscillator Ramp Amplitude  
    Oscillator Charge Current  
    ppm/°C  
    %
    REFTC  
    REFLOAD  
    RAMP  
    0 < I  
    < 50µA  
    -1  
    REF  
    1.15  
    200  
    8
    V
    I
    I
    I
    I
    0.1V < V  
    0.1V < V  
    < 1.25V  
    µA  
    mA  
    mA  
    mA  
    V
    OSC_CHG  
    OSC_DIS  
    VDD  
    OSC  
    OSC  
    Oscillator Discharge Current  
    < 1.25V  
    V
    V
    V
    V
    Supply Current  
    Standby Current  
    for Shutdown  
    for Startup  
    V
    = 1 (L disconnected)  
    2
    2.7  
    1
    5
    DD  
    DD  
    DD  
    DD  
    EN  
    EN = 0  
    1.5  
    VDD_OFF  
    V
    V
    2.4  
    2.6  
    2.65  
    2.95  
    DD_OFF  
    DD_ON  
    OT  
    V
    T
    T
    Over-temperature Threshold  
    Over-temperature Hysteresis  
    Internal FET Leakage Current  
    Peak Current Limit  
    135  
    20  
    °C  
    °C  
    HYS  
    I
    I
    EN = 0, L = 6V (low FET), L = 0V (high FET)  
    10  
    µA  
    A
    LEAK  
    LMAX  
    X
    X
    6
    R
    R
    R
    PFET On Resistance  
    35  
    30  
    70  
    60  
    mΩ  
    mΩ  
    mΩ/°C  
    µA  
    µA  
    %
    DSON1  
    NFET On Resistance  
    DSONTC2  
    DSONTC  
    R
    Tempco  
    0.2  
    2.5  
    2.5  
    DSON  
    I
    I
    STP Pin Input Pull-down Current  
    STN Pin Input Pull-up Current  
    Positive Power Good Threshold  
    Negative Power Good Threshold  
    Power Good Drive High  
    V
    V
    = V /2  
    IN  
    -4  
    STP  
    STN  
    STP  
    STN  
    = V /2  
    IN  
    4
    V
    V
    V
    V
    V
    V
    V
    With respect to target output voltage  
    With respect to target output voltage  
    6
    14  
    -6  
    PGP  
    -14  
    2.6  
    %
    PGN  
    I
    I
    = 1mA  
    V
    PG_HI  
    PG_LO  
    OVP  
    PG  
    PG  
    Power Good Drive Low  
    = -1mA  
    0.5  
    V
    Output Over-voltage Protection  
    Output Initial Accuracy  
    10  
    0.8  
    0.2  
    125  
    ±1  
    %
    I
    = 0A  
    0.79  
    85  
    0.81  
    0.5  
    V
    FB  
    LOAD  
    Output Line Regulation  
    V
    V
    = 3.3V, ∆V = 10%, I  
    IN  
    = 0A  
    %
    FB_LINE  
    IN  
    LOAD  
    GM  
    Error Amplifier Transconductance  
    Output Temperature Stability  
    Switching Frequency  
    = 0.65V  
    165  
    µs  
    EA  
    FB_TC  
    S
    CC  
    V
    0°C < T < 85°C, I  
    LOAD  
    = 3A  
    %
    A
    F
    300  
    370  
    100  
    440  
    200  
    kHz  
    nA  
    I
    Feedback Input Pull-up Current  
    V
    = 0V  
    FB  
    FB  
    FN7360.2  
    3
    January 31, 2005  
    EL7554  
    DC Electrical Specifications  
    PARAMETER  
    V
    = V = 3.3V, T = T = 25°C, C  
    = 390pF, Unless Otherwise Specified  
    DD  
    DESCRIPTION  
    EN Input High Level  
    IN  
    A
    J
    OSC  
    CONDITIONS  
    MIN  
    TYP  
    MAX  
    UNIT  
    V
    V
    2.6  
    EN_HI  
    V
    EN Input Low Level  
    Enable Pull-up Current  
    Input High Level  
    1
    V
    EN_LO  
    I
    V
    = 0  
    EN  
    -4  
    -2.5  
    µA  
    V
    EN  
    TM, S  
    TM, S  
    2.6  
    EL_HI  
    Input Low Level  
    1
    V
    EL_LO  
    Pin Descriptions  
    PIN NUMBER  
    PIN NAME  
    COMP  
    VREF  
    PIN FUNCTION  
    Error amplifier output; place loop compensation components here  
    Bandgap reference bypass capacitor; typically 0.01µF to 0.047µF to SGND  
    1
    2
    3
    FB  
    Voltage feedback input; connected to external resistor divider between V and SGND for adjustable  
    OUT  
    output; also used for speed-up capacitor connection  
    4
    5
    6
    VO  
    VTJ  
    TM  
    Output sense for fixed output; also used for speed-up capacitor connection  
    Junction temperature monitor output, connected to a 0.01µF - 0.047µF to SGND  
    Stress test enable; allows ±5% output movement; needs a pull-down resistor (1K - 100K); connect to  
    SGND if function is not used  
    7
    SEL  
    Positive or negative voltage margining set pin; needs a pull-down resistor (1K - 100K); connect to  
    SGND if function is not used  
    8, 9, 10, 11, 12, 13  
    LX  
    NC  
    Inductor drive pin; high current output whose average voltage equals the regulator output voltage  
    Not used  
    14, 15  
    16, 17, 18  
    19, 20, 21  
    22  
    PGND  
    VIN  
    Ground return of the regulator; connected to the source of the low-side synchronous NMOS Power FET  
    Power supply input of the regulator; connected to the drain of the high-side PMOS Power FET  
    VDD  
    PG  
    Control circuit positive supply; connected to V through an internal 20Ω resistor  
    IN  
    23  
    Power-good window comparator output; logic 1 when regulator output is within ±10% of target output  
    voltage  
    24  
    25  
    26  
    EN  
    Chip enable, active high; a 2µA internal pull-up current enables the device if the pin is left open; a  
    capacitor can be added at this pin to delay the start of a converter  
    STP  
    STN  
    Auxilliary supply tracking positive input; tied to regulator output to synchronize start-up with a second  
    supply; leave open for standalone operation; 2µA internal pull-up current  
    Auxiliary supply tracking negative input; connect to output of a second supply to synchronize start-up;  
    leave open for standalone operation; 2µA internal pull-up current  
    27  
    28  
    COSC  
    SGND  
    Oscillator timing capacitor (see performance curves)  
    Control circuit negative supply or signal ground  
    FN7360.2  
    4
    January 31, 2005  
    EL7554  
    Block Diagram  
    TM  
    0.018µF  
    220pF  
    SEL  
    V
    C
    OSC  
    REF  
    V
    TJ  
    JUNCTION  
    VOLTAGE  
    OSCILLATOR  
    TEMPERATURE  
    REFERENCE  
    V
    DD  
    V
    V
    DD  
    IN  
    2.2nF  
    EN  
    20Ω  
    0.22µF  
    2x10µF  
    47µF  
    STP  
    STN  
    V
    V
    IN  
    POWER  
    TRACKING  
    POWER  
    FET  
    2.2µH  
    PWM  
    CONTROLLER  
    DRIVERS  
    OUT  
    (UP TO 4A)  
    POWER  
    FET  
    PGND  
    EA  
    CURRENT  
    SENSE  
    COMP  
    V
    DD  
    R
    C
    C
    C
    V
    REF  
    -
    +
    PG  
    SGND  
    FB  
    V
    O
    R
    2
    R
    1
    FN7360.2  
    January 31, 2005  
    5
    EL7554  
    Typical Performance Curves  
    V
    = V = 3.3V, V = 1.8V, I = 4A, L = 2.2µH, C = 2x10µF, C  
    = 47µF, C  
    OSC  
    = 220pF, T = 25°C unless otherwise noted.  
    A
    IN  
    D
    O
    O
    IN  
    OUT  
    1
    100  
    V
    =3.3V  
    V =2.5V  
    O
    O
    V
    =2.5V  
    O
    0.95  
    95  
    0.9  
    90  
    85  
    0.85  
    V
    =0.8V  
    O
    V
    =0.8V  
    O
    0.8  
    80  
    75  
    V
    =1V  
    V =1V  
    O
    O
    0.75  
    V
    =1.2V  
    O
    V
    =1.2V  
    O
    V
    =1.8V  
    V
    3
    =1.8V  
    O
    O
    0.7  
    0.65  
    0.6  
    70  
    65  
    60  
    0
    1
    2
    3
    4
    0
    1
    2
    4
    I
    (mA)  
    I (mA)  
    O
    O
    FIGURE 2. EFFICIENCY (V = 3.3V)  
    IN  
    FIGURE 1. EFFICIENCY (V = 5V)  
    IN  
    1.6  
    1.5  
    1.266  
    1.264  
    V
    =3.3V  
    DD  
    1.262  
    V
    =3.3V  
    DD  
    1.4  
    1.3  
    1.26  
    1.258  
    1.256  
    1.254  
    1.252  
    1.25  
    1.2  
    1.1  
    V
    =5V  
    50  
    DD  
    V
    =5V  
    50  
    DD  
    1
    1.248  
    0.9  
    1.246  
    100  
    -50  
    0
    150  
    100  
    -50  
    0
    150  
    JUNCTION TEMPERATURE  
    JUNCTION TEMPERATURE  
    FIGURE 4. V  
    vs TEMPERATURE  
    REF  
    FIGURE 3. V  
    REF  
    vs TEMPERATURE  
    1200  
    4
    3.5  
    1000  
    800  
    600  
    500  
    200  
    0
    V
    EN_HI  
    3
    2.5  
    2
    V
    =5V  
    DD  
    V
    =3.3V  
    DD  
    V
    EN_LOW  
    1.5  
    1
    100  
    200  
    300  
    400  
    (pF)  
    500  
    600  
    700  
    3
    3.5  
    4
    4.5  
    (V)  
    5
    5.5  
    DD  
    6
    C
    OSC  
    V
    DD  
    FIGURE 6. F vs C  
    FIGURE 5. V  
    & V  
    vs V  
    EN_LOW  
    S
    OSC  
    EN_HI  
    FN7360.2  
    6
    January 31, 2005  
    EL7554  
    Typical Performance Curves (Continued)  
    V
    = V = 3.3V, V = 1.8V, I = 4A, L = 2.2µH, C = 2x10µF, C  
    = 47µF, C  
    OSC  
    = 220pF, T = 25°C unless otherwise noted.  
    A
    IN  
    D
    O
    O
    IN  
    OUT  
    0.8  
    0.6  
    0.4  
    610  
    605  
    600  
    V
    =5V  
    IN  
    0.2  
    0.0  
    595  
    590  
    585  
    V
    1
    =3.3V  
    1.5  
    IN  
    -0.2  
    -0.4  
    0
    1
    2
    3
    4
    3
    0
    0.5  
    2
    2.5  
    3.5  
    4
    I
    (A)  
    I
    (A)  
    O
    O
    FIGURE 7. F vs I  
    S
    FIGURE 8. LOAD REGULATIONS  
    O
    JEDEC JESD51-3 LOW EFFECTIVE THERMAL  
    CONDUCTIVITY TEST BOARD HTSSOP EXPOSED  
    DIEPAD NOT SOLDERED TO PCB  
    50  
    45  
    40  
    35  
    30  
    25  
    1.2  
    1
    CONDITION:  
    28-Pin HTSSOP THERMAL PAD  
    SOLDERED TO 2-LAYER PCB  
    WITH 0.039" THICKNESS AND  
    1 OZ. COPPER ON BOTH SIDES  
    1.136W  
    0.8  
    0.6  
    0.4  
    0.2  
    0
    1
    2
    3
    4
    5
    6
    2
    7
    8
    9
    0
    25  
    50  
    75 85 100  
    125  
    150  
    PCB AREA (in )  
    AMBIENT TEMPERATURE (°C)  
    FIGURE 9. HTSSOP THERMAL RESISTANCE vs PCB AREA  
    (NO AIR FLOW)  
    FIGURE 10. PACKAGE POWER DISSIPATION vs AMBIENT  
    TEMPERATURE  
    JEDEC JESD51-7 HIGH EFFECTIVE THERMAL  
    CONDUCTIVITY TEST BOARD HTSSOP EXPOSED  
    DIEPAD SOLDERED TO PCB PER JESD51-5  
    4.5  
    4
    4.167W  
    3.5  
    3
    2.5  
    2
    1.5  
    1
    0.5  
    0
    0
    25  
    50  
    75 85 100  
    125  
    150  
    AMBIENT TEMPERATURE (°C)  
    FIGURE 11. PACKAGE POWER DISSIPATION vs AMBIENT TEMPERATURE  
    FN7360.2  
    7
    January 31, 2005  
    EL7554  
    Waveforms  
    V
    = V = 3.3V, V = 1.8V, I = 4A, L = 2.2µH, C = 2x10µF, C  
    = 47µF, C  
    OSC  
    = 220pF, T = 25°C unless otherwise noted.  
    A
    IN  
    D
    O
    O
    IN  
    OUT  
    V
    (2V/DIV)  
    IN  
    ∆V (100mV/DIV)  
    IN  
    I
    (1A/DIV)  
    IN  
    V
    (1V/DIV)  
    O
    V
    (2V/DIV)  
    LX  
    PG (2V/DIV)  
    ∆V (10mV/DIV)  
    O
    1µs/DIV  
    0.5ms/DIV  
    FIGURE 13. STEADY-STATE OPERATION  
    FIGURE 12. START-UP  
    3A  
    1.0A  
    V
    EN  
    I
    O
    I
    (2A/DIV)  
    (2V/DIV)  
    IN  
    ∆V (100mV/DIV)  
    O
    V
    O
    100µs/DIV  
    50µs/DIV  
    FIGURE 14. SHUT-DOWN  
    FIGURE 15. TRANSIENT RESPONSE  
    PG  
    TM  
    V
    (2V/DIV)  
    O
    SEL  
    ∆V (200mV/DIV)  
    O
    V
    (5V/DIV)  
    LX  
    0.5ms/DIV  
    1ms/DIV  
    FIGURE 17. OVER-VOLTAGE SHUT-DOWN  
    FIGURE 16. VOLTAGE MARGINING  
    FN7360.2  
    January 31, 2005  
    8
    EL7554  
    Waveforms (Continued)  
    V
    = V = 3.3V, V = 1.8V, I = 4A, L = 2.2µH, C = 2x10µF, C  
    = 47µF, C = 220pF, T = 25°C unless otherwise noted.  
    OSC A  
    IN  
    D
    O
    O
    IN  
    OUT  
    V
    (2V/DIV)  
    IN  
    V
    (5V/DIV)  
    IN  
    I
    (2A/DIV)  
    (1V/DIV)  
    IN  
    V
    V
    =2.5V  
    =1.8V  
    O1  
    O2  
    V
    O
    C
    C
    = 100µF,  
    IN  
    C
    C
    = 100µF,  
    IN  
    = 150µF  
    OUT  
    = 150µF  
    OUT  
    5ms/DIV  
    2ms/DIV  
    FIGURE 19. TRACKING START-UP  
    FIGURE 18. ADJUSTABLE START-UP  
    occur. Connecting a small capacitor at EN will delay the  
    Detailed Description  
    start-up. The delay time T can be calculated by:  
    D
    The EL7554 is a full-feature synchronous 6A step-down  
    regulator capable of up to 96% efficiency. This device  
    V
    EN_HI  
    -------------------  
    T
    = C  
    ×
    EN  
    D
    I
    operates from 3V to 6V V input supply. With internal  
    IN  
    EN  
    CMOS power FETs, the device can operate at up to 100%  
    where:  
    duty ratio, allowing for output voltage range from 0.8V up to  
    nearly V .The adjustable high switching frequency of up to  
    IN  
    • C  
    • V  
    is the capacitance at EN pin  
    EN  
    1MHz enables the use of small components, making the  
    whole converter occupy less than 0.58 square inch with  
    components on one side of the PCB. The EL7554 operates  
    at constant frequency PWM mode, making external  
    synchronization possible. Patented on-chip resistorless  
    current-sensing enables current mode control, which  
    provides over-current protection, and excellent step load  
    response. The EL7554 features soft-start and full start-up  
    control, which eliminate the in-rush current and enables  
    users to control the start-up of multiple converters to any  
    configuration with ease. The EL7554 also offers a ±5%  
    voltage margining capability that allows raising and lowering  
    of the supplies derived from the EL7554 to validate the  
    performance and reliability of system cards quickly and  
    easily during manufacturing testing. A junction temperature  
    indicator conveniently monitors the silicon die temperature,  
    saving designers time in the tedious thermal  
    is the EN input high level (function of V  
    voltage,  
    DD  
    EN_HI  
    see Figure 5)  
    • I  
    is the EN pin pull-up current, nominal 2.5µA  
    EN  
    If a slower than 2ms soft start-up is needed, please refer to  
    Full Start-Up Control section.  
    Steady-State Operation  
    The converter always operates at fixed frequency  
    continuous-conduction mode. For fast transient response,  
    peak current control method is employed. The inductor  
    current is sensed from the upper PFET. This current signal,  
    the slope compensation, and the compensated error signal  
    are fed to the PWM comparator to generate the PWM signal  
    for the internal power switches. When the upper PFET is on,  
    the low-side NFET is off and input voltage charges the  
    inductor. When PFET is off, the NFET is on and energy  
    stored in the inductor is dumped to the output to maintain  
    constant output voltage. Therefore, the LX waveform is  
    always a stable square waveform (see Figure 13) with peak  
    characterization.  
    Start-Up  
    The EL7554 employs a special soft-start to suppress the in-  
    rush current (see Figure 12). The start-up process takes  
    about 2ms and begins when the input voltage reaches about  
    2.8V and EN pin voltage 2V. When EN is released from  
    LOW, or the converter comes out of thermal shut-down  
    mode, the soft-start process repeats. When the input voltage  
    ramps up too slowly, slight over- current at the input can  
    close to V . So LX is a good indication that the converter is  
    IN  
    operating properly.  
    100% Duty Ratio  
    EL7554 uses CMOS as internal synchronous power  
    switches. The upper switch is a PMOS and the lower switch  
    an NMOS. This not only saves a boot capacitor, it also  
    FN7360.2  
    9
    January 31, 2005  
    EL7554  
    allows 100% turn-on of the upper PFET switch, achieving  
    switching frequency 20% lower than the sync frequency to  
    accommodate component variations.  
    V
    close to V . The maximum achievable V is:  
    O
    IN  
    O
    V
    = V – (R + R  
    ) × I  
    DSON1 O  
    O
    IN  
    L
    100pF  
    Where R is the DC resistance on the inductor and R  
    L
    is the PFET on-resistance, nominal 35mΩ at room  
    temperature with tempco of 0.2mΩ/°C.  
    EL7554  
    EXTERNAL SYNC  
    SOURCE  
    DSON1  
    C
    OSC  
    Output Voltage Selection  
    FIGURE 20. EXTERNAL SYNC CIRCUIT  
    The output voltage can be as high as the input voltage minus  
    Thermal Protection and Junction Temperature  
    Indicator  
    the PMOS and inductor voltage drops. Use R and R to set  
    the output voltage according to the following formula:  
    1
    2
    An internal temperature sensor continuously monitors the  
    junction temperature. In the event that the junction  
    temperature exceeds 135°C, the regulator is in a fault  
    condition and will shut down. When the temperature falls  
    back below 110°C, the regulator goes through the soft-start  
    procedure again.  
    R
    1
    V
    = 0.8 × 1 + ------  
    O
    R
    2
    Standard values of R and R are listed in Table 1.  
    1
    2
    TABLE 1.  
    The V pin is an accurate indicator of the internal silicon  
    TJ  
    V
    (V)  
    R
    (kΩ)  
    R (kΩ)  
    2
    O
    1
    junction temperature T , which can be determined by the  
    J
    following formula. This saves engineering time.  
    0.8  
    1
    2
    Open  
    10  
    2.49  
    4.99  
    10  
    1.2 – V  
    TJ  
    T
    = 75 + ------------------------  
    J
    0.00384  
    1.2  
    1.5  
    1.8  
    2.5  
    3.3  
    10  
    11.5  
    10.2  
    10  
    where VTJ is the voltage at VTJ pin.  
    12.7  
    21.5  
    36  
    Under-Voltage Lockout (UVLO)  
    When V  
    falls bellow 2.5V, the regulator shuts down. When  
    DD  
    11.5  
    V
    rises above 2.8V, converter goes through soft-start  
    DD  
    process again.  
    Voltage Margining  
    Power Good Indicator (PG) and Over-Voltage  
    Protection  
    The EL7554 has built-in 5% load stress test (commonly  
    called voltage margining) function. Combinations of TM and  
    SEL set the margins shown in Table 2. When this function is  
    not used, both pins should be connected to SGND, either  
    directly or through a 10kΩ resister. Figure 16 shows this  
    feature.  
    When the output reaches 10% of the preset voltage, the PG  
    pin outputs a HI signal as shown in the start-up waveform  
    (Figure 12). If the output voltage is higher than 10% of the  
    preset value for any reason, PG will go low and the regulator  
    will shut down. In addition to the indication power is good,  
    the PG pin can be used for multiple regulators’ start-up  
    control as described in the next section.  
    TABLE 2.  
    CONDITION  
    Normal  
    TM  
    0
    SEL  
    X
    V
    O
    Full Start-Up Control  
    Nominal  
    The EL7554 offers full start-up control. The core of this  
    control is a start-up comparator in front of the main PWM  
    controller. The STP and STN are the inputs to the  
    comparator, whose HI output forces the PWM comparator to  
    skip switching cycles. The user can choose any of the  
    following control configurations:  
    High Margin  
    Low Margin  
    1
    1
    Nominal + 5%  
    Nominal - 5%  
    1
    0
    Switching Frequency  
    The regulator operates from 200kHz to 1MHz. The switching  
    frequency is generated by a relaxation comparator and  
    adjusted by a C  
    ratio and runs from 0.2V to 1.2V. Please refer to Figure 6 for  
    a specific frequency.  
    1. ADJUSTABLE SOFT-START  
    . The triangle waveform has 95% duty  
    OSC  
    In this configuration, the ramp-up time is adjustable to any  
    time longer than the building soft-start time of 2ms. The  
    approximate ramp-up time, T , is:  
    ST  
    When external synchronization is required, use the following  
    circuit for connection. Always choose the converter self-  
    V
    O
    ---------  
    T
    = RC  
    ST  
    V
    IN  
    FN7360.2  
    10  
    January 31, 2005  
    EL7554  
    Figure 18 shows the waveforms.  
    goes HI, where V  
    REF  
    is the regulator reference voltage.  
    REF  
    V
    =1.26.  
    C
    0.1µF  
    STN  
    STP  
    -
    +
    V
    R
    B
    V
    O
    REF  
    R
    200K  
    -
    V
    O
    V
    +
    R
    A
    O2  
    V
    EL7554  
    V
    O1  
    IN  
    T
    EL7554  
    V
    IN  
    ST  
    EL7554  
    V
    IN  
    FIGURE 21. ADJUSTABLE START-UP  
    V
    (1+R /R  
    )
    REF  
    B
    A
    In this application, C and C  
    IN  
    may be increased to  
    OUT  
    V
    V
    reduce input/output ripple because the pulse skipping nature  
    of the method.  
    O1  
    O2  
    2. CASCADE START-UP  
    In this configuration, EN pin of Regulator 2 is connected to  
    FIGURE 24. OFFSET START-UP TRACKING  
    the PG pin of Regulator 1 (Figure 22). V will only start  
    O2  
    after V is good.  
    O1  
    Component Selection  
    INPUT CAPACITOR  
    The main functions of the input capacitor(s) are to maintain  
    the input voltage steady and to filter out the pulse current  
    passing through the upper switch. The root-mean-square  
    value of this current is:  
    EN  
    PG  
    V
    V
    V
    IN  
    O2  
    O1  
    EL7554  
    EL7554  
    V
    × (V – V )  
    IN O  
    O
    -----------------------------------------------  
    I
    =
    × I ≈ 1/2(I )  
    O
    IN,RMS  
    O
    V
    IN  
    V
    V
    O1  
    O2  
    for a wide range of V and V .  
    IN  
    O
    For long-term reliability, the input capacitor or combination of  
    capacitors must have the current rating higher than I  
    .
    IN,RMS  
    Use X5R or X7R type ceramic capacitors, or SPCAP or  
    POSCAP types of Polymer capacitors for their high current  
    handling capability.  
    FIGURE 22. CASCADE START-UP  
    3. LINEAR START-UP  
    In the linear start-up tracking configuration, the regulator with  
    lower output voltage, V , tracks the one with higher output  
    INDUCTOR  
    O2  
    voltage, V . The waveform is shown in Figure 19.  
    The NFET positive current limit is set at about 0.5A. For  
    optimal operation, the peak-to-peak inductor current ripple  
    O1  
    ∆I should be less than 1A. The following equation gives the  
    L
    C
    inductance value:  
    STN  
    STP  
    -
    +
    -
    +
    (V – V ) × V  
    O
    IN  
    O
    L = -------------------------------------------  
    V
    R
    V
    × ∆I × F  
    L S  
    O2  
    IN  
    V
    V
    O1  
    IN  
    EL7554  
    EL7554  
    V
    IN  
    The peak current the inductor sees is:  
    ∆I  
    L
    I
    = I + --------  
    LPK  
    O
    2
    V
    V
    O1  
    O2  
    When inductor is chosen, make sure the inductor can handle  
    this peak current and the average current of I .  
    O
    FIGURE 23. LINEAR START-UP TRACKING  
    OUTPUT CAPACITOR  
    If there is no holding time requirement for output; output  
    voltage ripple and transient response are the main deciding  
    factors in choosing the output capacitor. Initially, choose the  
    4. OFFSET START-UP  
    Compared with the cascade start-up, this configuration  
    allows Regulator 2 to begin the start-up process when V  
    O1  
    *(1+R /R ) before PG  
    reaches a particular value of V  
    REF  
    B
    A
    FN7360.2  
    11  
    January 31, 2005  
    EL7554  
    output capacitor with the ESR to satisfy the output ripple  
    Design Example  
    A 5V to 1.8V converter at 4A is needed.  
    ∆V requirement:  
    O
    ∆V = ∆I × ESR  
    O
    L
    1. Choose the input capacitor  
    The input capacitor or combination of capacitors has to be  
    able to take about 1/2 of the output current, e.g., 2A. TDK’s  
    C3216X5RIA106M is rated at 2.7A, 6.3V, meeting the above  
    criteria using 2 generators less input voltage ripple.  
    When output has a step load change ∆I , the initial voltage  
    O
    drop is ESR*∆I . Then V will drop even further before the  
    O
    O
    loop has the chance to respond. The higher the output  
    capacitance, the lower the voltage drop is. Also, higher loop  
    bandwidth will generate less voltage drop. Experiment with  
    the transient response (see Figure 15) to determine the final  
    values of output capacitance.  
    2. Choose the inductor. Set the converter switching  
    frequency at 600kHz:  
    (V – V ) × V  
    O
    IN  
    O
    L = -------------------------------------------  
    Like the input capacitor, it is recommended to use X5R or  
    X7R type of ceramic capacitors, or SPCAP or POSCAP type  
    of Polymer capacitors for the low ESR and high capacitance.  
    V
    × ∆I × F  
    L S  
    IN  
    ∆I = 1A yields 1.72µH. Leave some margin and choose  
    L
    L = 2.2µH. TDK RLF7030-2R2M5R4 has the required  
    current rating.  
    Generally, the AC current rating of the output capacitor is not  
    a concern because the RMS current is only 1/√12 of ∆I .  
    L
    This is easily satisfied.  
    3. Choose the output capacitor  
    L = 2.2µH yields about 0.9A inductor ripple current. 47µF  
    ceramic capacitor has less than 5mΩ of ESR easily  
    satisfying by the requirement. ESR is not the only factor  
    deciding the output capacitance. As discussed earlier, output  
    voltage droops less with more capacitance when converter is  
    in load transient. Multiple iterations may be needed before  
    final components are chosen.  
    LOOP COMPENSATION  
    Current mode converter forces the inductor current  
    proportional to the error signal, thus gets rid of the 2nd order  
    effect formed by the inductor and output capacitor. The PWM  
    comparator and the inductor form an equivalent  
    transconductance amplifier. So, a simple Type 1  
    compensator is good enough to generate a high bandwidth  
    stable converter. The compensation capacitor and resister  
    are decided by:  
    4. Loop compensation  
    50kHz is the intended crossover frequency. With the  
    conditions R and C are calculated as:  
    C
    C
    V
    × GM  
    × GM  
    PWM EA  
    FB  
    C
    = -----------------------------------------------------------------  
    C
    π × F × I  
    R
    = 2.32kΩ and C = 0.018pF  
    C
    C
    OUT  
    C
    For convenience, Table 3 lists the compensation values for  
    frequently used output voltages.  
    C
    OUT  
    ---------------  
    R
    = 2 × R  
    ×
    C
    OUT  
    C
    C
    TABLE 3. COMPENSATION VALUES  
    where:  
    V
    (V)  
    R
    (kΩ)  
    C (µF)  
    C
    O
    C
    • GM  
    GM  
    is the transconductance of the PWM comparator,  
    = 120s  
    PWM  
    PWM  
    3.3  
    2.5  
    1.8  
    1.5  
    1.2  
    1
    4.22  
    3.24  
    2.32  
    1.91  
    1.54  
    1.27  
    1.02  
    0.018  
    0.018  
    0.018  
    0.018  
    0.018  
    0.018  
    0.018  
    V
    OUT  
    R
    = ---------------  
    OUT  
    I
    OUT  
    • V  
    output voltage  
    output current  
    OUT  
    • I  
    OUT  
    • C  
    OUT  
    is output capacitance  
    • GM is the transconductance of the error amplifier,  
    EA  
    0.8  
    GM = 120µs  
    EA  
    • F is the intended crossover frequency of the loop. For  
    C
    best performance, set this value to about one-tenth of the  
    switching frequency.  
    FN7360.2  
    January 31, 2005  
    12  
    EL7554  
    Thermal Management  
    The EL7554IRE is packaged in a thermally-efficient  
    HTSSOP-28 package, which utilizes the exposed thermal  
    pad at the bottom to spread heat through PCB metal.  
    Layout Considerations  
    The layout is very important for the converter to function  
    properly. Follow these tips for best performance:  
    1. Separate the Power Ground ( ) and Signal Ground ( );  
    connect them only at one point right at the SGND pin  
    Therefore:  
    2. Place the input capacitor(s) as close to V and PGND  
    IN  
    1. The thermal pad must be soldered to the PCB  
    2. Maximize the PCB area  
    3. If a multiple layer PCB is used, thermal vias (13 to 25 mil)  
    must be placed underneath the thermal pad to connect to  
    ground plane(s). Do not place thermal reliefs on the vias.  
    Figure 25 shows a typical connection.  
    pins as possible  
    3. Make as small as possible the loop from LX pins to L to  
    C
    to PGND pins  
    O
    4. Place R and R pins as close to the FB pin as possible  
    1
    2
    5. Maximize the copper area around the PGND pins; do not  
    place thermal relief around them  
    The thermal resistance for this package is as low as 26°C/W  
    for 2 layer PCB of 0.39" thickness (see Figure 9). The actual  
    6. Thermal pad should be soldered to PCB. Place several  
    via holes under the chip to the ground plane to help heat  
    dissipation  
    junction temperature can be measured at V pin.  
    TJ  
    The thermal performance of the IC is heavily dependent on  
    the layout of the PCB. The user should exercise care during  
    the design phase to ensure the IC will operate within the  
    recommended environmental conditions.  
    The demo board is a good example of layout based on this  
    outline. Please refer to the EL7554 Application Brief.  
    COMPONENT SIDE  
    CONNECTION  
    GROUND PLANE  
    CONNECTION  
    FIGURE 25. PCB LAYOUT - 28-PIN HTSSOP PACKAGE  
    FN7360.2  
    13  
    January 31, 2005  
    EL7554  
    Package Outline Drawing  
    NOTE: The package drawing shown here may not be the latest version. To check the latest revision, please refer to the Intersil website at  
    http://www.intersil.com/design/packages/index.asp  
    All Intersil U.S. products are manufactured, assembled and tested utilizing ISO9000 quality systems.  
    Intersil Corporation’s quality certifications can be viewed at www.intersil.com/design/quality  
    Intersil products are sold by description only. Intersil Corporation reserves the right to make changes in circuit design, software and/or specifications at any time without  
    notice. Accordingly, the reader is cautioned to verify that data sheets are current before placing orders. Information furnished by Intersil is believed to be accurate and  
    reliable. However, no responsibility is assumed by Intersil or its subsidiaries for its use; nor for any infringements of patents or other rights of third parties which may result  
    from its use. No license is granted by implication or otherwise under any patent or patent rights of Intersil or its subsidiaries.  
    For information regarding Intersil Corporation and its products, see www.intersil.com  
    FN7360.2  
    14  
    January 31, 2005  
    配单直通车
    EL7554IRE产品参数
    型号:EL7554IRE
    是否Rohs认证： 不符合
    生命周期：Obsolete
    零件包装代码：TSSOP
    包装说明：HTSSOP, TSSOP28,.25
    针数：28
    Reach Compliance Code：not_compliant
    ECCN代码：EAR99
    HTS代码：8542.39.00.01
    风险等级：5.2
    模拟集成电路 - 其他类型：SWITCHING REGULATOR
    控制模式：CURRENT-MODE
    控制技术：PULSE WIDTH MODULATION
    最大输入电压：6 V
    最小输入电压：3 V
    标称输入电压：3.3 V
    JESD-30 代码：R-PDSO-G28
    JESD-609代码：e0
    长度：9.7 mm
    湿度敏感等级：3
    功能数量：1
    端子数量：28
    最高工作温度：85 °C
    最低工作温度：-40 °C
    最大输出电流：6 A
    封装主体材料：PLASTIC/EPOXY
    封装代码：HTSSOP
    封装等效代码：TSSOP28,.25
    封装形状：RECTANGULAR
    封装形式：SMALL OUTLINE, HEAT SINK/SLUG, THIN PROFILE, SHRINK PITCH
    峰值回流温度（摄氏度）：240
    认证状态：Not Qualified
    座面最大高度：1.2 mm
    子类别：Switching Regulator or Controllers
    表面贴装：YES
    切换器配置：BUCK
    最大切换频率：440 kHz
    温度等级：INDUSTRIAL
    端子面层：Tin/Lead (Sn/Pb)
    端子形式：GULL WING
    端子节距：0.65 mm
    端子位置：DUAL
    处于峰值回流温度下的最长时间：NOT SPECIFIED
    宽度：4.4 mm
    Base Number Matches：1
    •  
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