YB1680ST25XADJP中文资料应用文章市场行情现货热卖使用介绍-中国IC网-芯三七

YB1680

1.5MHz, 600mA Synchronous Step-Down Converter

Description

Features

High Efficiency : Up to 94%

1.5MHz Constant Switching Frequency

600mA Output Current at V_IN=3V

Integrated Main Switch and Synchronous

Rectifier. No Schottky Diode Required

2.5V to 5.5V Input Voltage Range

Output Voltage as Low as 0.6V

100% Duty Cycle in Dropout

Low Quiescent Current : 300μA

Slope Compensated Current Mode

Control for Excellent Line and Load

Transient Response

The YB1680 is a 1.5MHz constant

frequency, slope compensated current

mode PWM step-down converter. The

device integrates a main switch and a

synchronous rectifier for high efficiency

without an external Schottky diode. It is

ideal for powering portable equipment that

runs from a single cell lithium-Ion (Li+)

battery. The YB1680 can supply 600mA of

load current from a 2.5V to 5.5V input

voltage. The output voltage can be

regulated as low as 0.6V. The YB1680 can

also run at 100% duty cycle for low dropout

operation, extending battery life in portable

system. Idle mode operation at light loads

provides very low output ripple voltage for

noise sensitive applications.

Short Circuit Protection

Thermal Fault Protection

<1μA Shutdown Current

Space Saving 5-Pin SOT23 Package

Pb-free Package

Applications

The YB1680 is offered in a low profile 5-pin,

SOT package, and is available in an

adjustable version.

Cellular and Smart Phones

Microprocessors and DSP Core Supplies

Wireless and DSL Modems

PDAs

MP3 Player

Digital Still and Video Cameras

Portable Instruments

Typical Application Circuit

Figure 1: Typical Application Circuit

YB1680 Rev.1.0

www.yobon.com.tw

1

YB1680

1.5MHz, 600mA Synchronous Step-Down Converter

Pin Configuration

EN

FB

1

2

3

5

4

GND

SW

VIN

SOT23-5

Figure 2: Pin Configuration

Pin Description

Table 1

1

Name

EN

Description

Regulator Enable control input. Drive EN above 1.5V to turn on the

part. Drive EN below 0.3V to turn it off. In shutdown, all functions are

disabled drawing <1μA supply current. Do not leave EN floating.

2

GND

SW

Ground.

Power Switch Output. It is the Switch note connection to Inductor. This

pin connects to the drains of the internal P-CH and N-CH MOSFET

switches.

3

Supply Input Pin. Must be closely decoupled to GND, Pin 2, with a

2.2μF or greater ceramic capacitor.

4

5

VIN

FB

VFB (Adjustable Version) : Feedback Input Pin. Connect FB to the

center point of the external resistor divider. The feedback threshold

voltage is 0.6V.

Ordering Information

Order Number

Package Type

SOT23-5

Supplied As

Package Marking

YB1680ST25XADJP

3000 units Tape & Reel

A1XY (Note 1)

Note 1: XY = Manufacturing Date Code

YB1680 Rev.1.0

www.yobon.com.tw

2

YB1680

1.5MHz, 600mA Synchronous Step-Down Converter

Absolute Maximum Ratings

Input Supply Voltage................... -0.3V to 6V Operating Temperature Range.. -40°C to 85°C

EN, V_FBVoltage ................ -0.3V to V_IN+0.3V Junction Temperature....................... 125°C

SW, V_OUTVoltage.............. -0.3V to V_IN+0.3V Storage Temperature Range ...-65°C to 150°C

Peak SW Sink and Source Current........1.5A Lead Temperature (Soldering, 10s) .. 300°C

Electrical Characteristics

Table 2

(V_IN= V_RUN= 3.6V, T_A=25°C, Test Circuit Figure 1, unless otherwise noted.)

Description

Symbol

Test Conditions

MIN

TYP

MAX

Units

Input Voltage Range

V_IN

2.5

5.5

V

Input DC Supply Current

Active Mode

Shutdown Mode

I_Q

V

_FB= 0.5V

_FB= 0V, V_IN= 4.2V

270

0.08

400

1.0

μA

T_A= +25℃

0.5880 0.6000 0.6120

0.5865 0.6000 0.6135

0.5850 0.6000 0.6150

±30

Regulated Feedback Voltage

V_FB

V

T_A= 0℃ ≦ T_A≦ 85℃

T_A= -40℃ ≦ T_A≦ 85℃

V_FBInput Bias Current

I_FB

V_FB= 0.65V

nA

Reference Voltage Line

Regulation

V

_FB= 2.5V to 5.5V,

_OUT= V_FB(R2=0)

0.11

0.63

%/V

Output Voltage Line Regulation

Output Voltage Load Regulation

Maximum Output Current

Oscillator Frequency

V_IN= 2.5V to 5.5V, I_OUT= 10mA

I_OUTfrom 0 to 600mA

V_IN= 3.0V

0.11

%/V

%/mA

mA

MHz

Ω

0.0015

600

1.2

F_OSC

V_FB= 0.6V or V_OUT= 100%

1.5

1.8

R_DS(ON)of P-CH MOSFET

R_DS(ON)of N-CH MOSFET

I_SW= 300mA

0.30

0.20

0.50

0.45

I_SW= -300mA

Ω

V_IN= 3V, V_FB= 0.5V or

Peak Inductor Current

SW Leakage

V

_OUT= 90%

1.20

A

Duty Cycle < 35%

V_RUN= 0V, V_SW= 0V or 5V,

V_IN= 5V

±0.01

±1

μA

Output Over Voltage Lockout

EN Threshold

ΔV_OVL= V_OVL- V_FB

60

mV

V

V_EN

I_EN

-40℃ ≦ T_A≦ 85℃

0.3

0.45

±0.1

1.30

±1

EN Leakage Current

μA

YB1680 Rev.1.0

www.yobon.com.tw

3

YB1680

1.5MHz, 600mA Synchronous Step-Down Converter

Typical Performance Characteristics

YB1680 Rev.1.0

www.yobon.com.tw

4

YB1680

1.5MHz, 600mA Synchronous Step-Down Converter

YB1680 Rev.1.0

www.yobon.com.tw

5

YB1680

1.5MHz, 600mA Synchronous Step-Down Converter

YB1680 Rev.1.0

www.yobon.com.tw

6

YB1680

1.5MHz, 600mA Synchronous Step-Down Converter

Function Block

Figure 3: Function Block

Operation

the internal main switch (P-Ch MOSFET)

and synchronous rectifier (N-CH MOSFET).

YB1680 is a monolithic switching mode

Step-Down DC-DC converter. It utilizes

internal MOSFETs to achieve high

efficiency and can generate very low output

voltage by using internal reference at 0.6V.

It operates at a fixed switching frequency,

and uses the slope compensated current

mode architecture. This Step-Down DC-DC

Converter supplies 600mA output current at

V_IN= 3V with input voltage range from 2.5V

to 5.5V.

During normal operation, the internal P-Ch

MOSFET is turned on for a certain time to

ramp the inductor current at each rising

edge of the internal oscillator, and switched

off when the peak inductor current is above

the error voltage. The current comparator,

I_COMP, limits the peak inductor current.

When the main switch is off, the

synchronous rectifier will be turned on

immediately and stay on until either the

inductor current starts to reverse, as

Current Mode PWM Control

indicated

by

the

current

reversal

Slope compensated current mode PWM

control provides stable switching and

cycle-by-cycle current limit for excellent

load and line responses and protection of

comparator, I_ZERO, or the beginning of the

next clock cycle. The OVDET comparator

controls output transient overshoots by

YB1680 Rev.1.0

www.yobon.com.tw

7

YB1680

1.5MHz, 600mA Synchronous Step-Down Converter

turning the main switch off and keeping it

switch and synchronous rectifier. The slope

compensation signal reduces the peak

inductor current as a function of the duty

cycle to prevent sub-harmonic oscillations

at duty cycles greater than 50%.

Conversely the current limit increases as

the duty cycle decreases.

off until the fault is no longer present.

Idle Mode Operation

At very light loads, the YB1680

automatically enters Idle Mode. In the Idle

Mode, the inductor current may reach zero

or reverse on each pulse. The PWM control

loop will automatically skip pulses to

maintain output regulation. The bottom

MOSFET is turned off by the current

reversal comparator, I_ZERO, and the switch

voltage will ring. This is discontinuous

mode operation, and is normal behavior for

the switching regulator.

Application Information

Setting the Output Voltage

Figure 1 above shows the basic application

circuit with YB1680 adjustable output

version. The external resistor sets the

output voltage according to the following

equation:

Dropout Operation

When the input voltage decreases toward

the value of the output voltage, the YB1680

allows the main switch to remain on for

more than one switching cycle and

increases the duty cycle until it reaches

100%. The output voltage then is the input

voltage minus the voltage drop across the

main switch and the inductor. At low input

supply voltage, the R_DS(ON)of the

P-Channel MOSFET increases, and the

efficiency of the converter decreases.

Caution must be exercised to ensure the

heat dissipated not to exceed the maximum

junction temperature of the IC.

R1=300KΩ for all outputs; R2=300KΩ for

V

_OUT=1.2V, R2=200KΩ for V_OUT=1.5V,

R2=150KΩ for V_OUT=1.5V, and R=95.3KΩ

for V_OUT=2.5V.

Inductor Selection

For most designs, the YB1680 operates

with inductors of 1μH to 4.7μH. Low

inductance values are physically smaller

but require faster switching, which results in

some efficiency loss. The inductor value

can be derived from the following equation:

Maximum Load Current

Where ΔI_Lis inductor Ripple Current. Large

value inductors lower ripple current and

small value inductors result in high ripple

currents. Choose inductor ripple current

The YB1680 will operate with input supply

voltage as low as 2.5V, however, the

maximum load current decreases at lower

input due to large IR drop on the main

YB1680 Rev.1.0

www.yobon.com.tw

8

YB1680

1.5MHz, 600mA Synchronous Step-Down Converter

approximately 35% of the maximum load

switching frequency. Ceramic capacitors

with X5R or X7R dielectrics are

recommended due to their low ESR and

high ripple current. The output ripple V_OUT

is determined by:

current 600mA, or ΔI_L= 210mA.

For output voltages above 2.0V, when

light-load efficiency is important, the

minimum recommended inductor is 2.2μH.

For optimum voltage-positioning load

transients, choose an inductor with DC

series resistance in the 50mΩ to 150mΩ

range. For higher efficiency at heavy loads

(above 200mA), or minimal load regulation

(but some transient overshoot), the

resistance should be kept below 100mΩ.

The DC current rating of the inductor

should be at least equal to the maximum

load current plus half the ripple current to

prevent core saturation (600mA+105mA).

Input Capacitor Selection

The input capacitor reduces the surge

current drawn from the input and switching

noise from the device. The input capacitor

impedance at the switching frequency shall

be less than input source impedance to

prevent high frequency switching current

passing to the input. A low ESR input

capacitor sized for maximum RMS current

must be used. Ceramic capacitors with

X5R or X7R dielectrics are highly

recommended because of their low ESR

and small temperature coefficients. A 4.7μF

ceramic capacitor for most applications is

sufficient.

Output Capacitor Selection

The output capacitor is required to keep the

output voltage ripple small and to ensure

regulation loop stability. The output

capacitor must have low impedance at the

YB1680 Rev.1.0

www.yobon.com.tw

9

YB1680

1.5MHz, 600mA Synchronous Step-Down Converter

Package Information (SOT23-5)

NOTICE:

y The information described herein is subject to change without notice.

y Yobon does not assume any responsibility for use of any circuitry or applications described herein, nor

does it convey any patent license.

YB1680 Rev.1.0

www.yobon.com.tw

10

电子百科

产品导航

产品型号YB1680ST25XADJP的概述

产品型号YB1680ST25XADJP的Datasheet PDF文件预览

YB1680ST25XADJP相关产品..

YB1680ST25XADJP相关文章

IC37:专业IC行业平台