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LT1507CS8-3.3 参数 Datasheet PDF下载

LT1507CS8-3.3图片预览
型号: LT1507CS8-3.3
PDF下载: 下载PDF文件 查看货源
内容描述: 500kHz的单片式降压模式开关稳压器 [500kHz Monolithic Buck Mode Switching Regulator]
分类和应用: 稳压器开关式稳压器或控制器电源电路开关式控制器光电二极管
文件页数/大小: 20 页 / 346 K
品牌: LINER [ LINEAR TECHNOLOGY ]
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LT1507
500kHz Monolithic
Buck Mode Switching Regulator
FEATURES
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s
s
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Constant 500kHz Switching Frequency
Uses All Surface Mount Components
Operates with Inputs as Low as 4V
Saturated Switch Design (0.3Ω)
Cycle-by-Cycle Current Limiting
Easily Synchronizable
Inductor Size as Low as 2µH
Shutdown Current: 20µA
with all the necessary oscillator, control and logic cir-
cuitry. High switching frequency allows a considerable
reduction in the size of external components. The topology
is current mode for fast transient response and good loop
stability. Both fixed output voltage (3.3V) and adjustable
parts are available.
A special high speed bipolar process and new design
techniques allow this regulator to achieve high efficiency
at a high switching frequency. Efficiency is maintained
over a wide output current range by keeping quiescent
supply current to 4mA and by utilizing a supply boost
capacitor to allow the NPN power switch to saturate. A
shutdown signal will reduce supply current to 20µA. The
LT1507 can be externally synchronized from 570kHz to
1MHz with logic level inputs.
The LT1507 fits into standard 8-pin SO and PDIP pack-
ages. Temperature rise is kept to a minimum by the high
efficiency design. Full cycle-by-cycle short-circuit protec-
tion and thermal shutdown are provided. Standard surface
mount external parts are used including the inductor and
capacitors.
, LTC and LT are registered trademarks of Linear Technology Corporation.
APPLICATIONS
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Portable Computers
Battery-Powered Systems
Battery Charger
Distributed Power
DESCRIPTION
The LT
®
1507 is a 500kHz monolithic buck mode switching
regulator, functionally identical to the LT1375 but opti-
mized for lower input voltage applications. It will operate
over a 4V to 15V input range, compared with 5.5V to 25V
for the LT1375. A 1.5A switch is included on the die along
TYPICAL APPLICATION
5V to 3.3V Volt Down Converter
D2
1N914
C2
0.1µF
V
SW
LT1507-3.3
DEFAULT
(OPEN)
= ON
SHDN
GND
SENSE
V
C
C
C
3.3nF
D1
1N5818
L1***
5µH
5V
C3*
47µF
16V
TANTALUM
V
IN
EFFICIENCY (%)
BOOST
+
* AVX TPSD477M016R0150 OR SPRAGUE 593D EQUIVALENT.
RIPPLE CURRENT RATING
0.6A
** AVX TPSD108M010R0100 OR SPRAGUE 593D EQUIVALENT
*** COILTRONICS CTX5-1. SUBSTITUTION UNITS SHOULD BE RATED
AT
1.25A, USING LOW LOSS CORE MATERIAL
SEE BOOST PIN CONSIDERATIONS IN APPLICATIONS INFORMATION
SECTION FOR ALTERNATIVE D2 CONNECTION
U
U
U
5V to 3.3V Efficiency
100
V
IN
= 5V
V
OUT
= 3.3V
90
OUTPUT
3.3V
1.25A
80
70
+
C1**
100µF
10V
TANTALUM
60
50
0
0.25
0.75
1.00
0.50
LOAD CURRENT (A)
1.25
LT1507 • TA02
1