SI9172 Vishay, SI9172 Datasheet

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SI9172

Manufacturer Part Number
SI9172
Description
Psm Buck Converter With Dynamic Adjustable Output And Bypass Capability
Manufacturer
Vishay
Datasheet
The Si9172 is a dual-mode power adjustable output converter.
When it is set to PSM mode, the Si9172 operates as a pulse-
skipping-modulation controlled step-down (buck) converter
with a dynamically adjustable output of 1.5 V to 3.6 V. It has an
integrated MOSFET, capable of supplying a minimum 170-mA
load current with a 1.5-mH inductor. The output voltage is
adjusted by the analog dc signal at the ADJ pin. The typical
conversion efficiency is above 90%. A logic high at the
BP/PSM pin puts the Si9172 in bypass mode. The main PMOS
buck switch is forced to turn on at 100% duty cycle, overriding
the FB signal. The voltage differential between input and
Document Number: 71379
S-02890—Rev. A, 21–Dec-00
D 2.7-V to 6-V Input Voltage Range
D Dynamic Adjustable 1.5-V to 3.6-V Output.
D Power Conversion Efficiency of 95% at 170-mA Load
D Selectable Pulse Skipping Modulation (PSM) or
D Bypass for up to 800-mA Load
D Integrated MOSFET with Low External Part Count
D Low Quiescent Current–110 mA/250 mA (BP/PSM)
D Shutdown Current <1 mA
D Integrated UVLO and POR
D Integrated Soft-Start
Bypass Mode (BP) Operation
PSM Buck Converter with Dynamic Adjustable Output and
3.6 V
1.5 V
V
OUT
0.4 V
ON/OFF
BP/PSM
V
IN
2.5 V
V
ADJ
Bypass Capability
2
3
4
5
1
New Product
V
V
ENABLE
BP/PSM
ADJ
IN
IN
SI9172
MSOP-10
output is the resistive voltage drop on the internal PMOS and
the inductor. The Si9172 guarantees to deliver 800-mA load in
bypass mode with a typical 95% efficiency.
The Si9172 is available in MSOP-10 package. In order to
satisfy the stringent ambient temperature requirements, the
Si9172 is rated to handle the industrial temperature range of
–25_C to 85_C.
D Over Temperature Protection
D MSOP-10 Package
D Cellular Phones, Cordless Phones
D Computer Point of Use, Notebook
D PDAs
D Battery Powered Devices
GND
REF
L
L
F
X
X
B
10
9
8
7
6
Vishay Siliconix
V
OUT
www.vishay.com
Si9172
1

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SI9172 Summary of contents

Page 1

... D Integrated UVLO and POR D Integrated Soft-Start The Si9172 is a dual-mode power adjustable output converter. When it is set to PSM mode, the Si9172 operates as a pulse- skipping-modulation controlled step-down (buck) converter with a dynamically adjustable output has an integrated MOSFET, capable of supplying a minimum 170-mA load current with a 1 ...

Page 2

... Si9172 Vishay Siliconix BP/PSM, ENABLE ADJ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Peak Output Current . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Continuous Output Current . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Storage Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Operating Junction Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied ...

Page 3

... GND 8 Si9172BH- REF 6 Eval Kit Si9172DB Function 90% V OUT DELAY SS FIGURE 1. Si9172 Vishay Siliconix Temperature Range Package _ _ –25_C to 85_C Tape and Reel Temperature Range Board Type Surface Mount –25_C to 85_C . t = Start-Up Delay Time DELAY t = Soft-Start Time SS www.vishay.com 3 ...

Page 4

... Si9172 Vishay Siliconix V IN Reference Generator REF BP/PSM ENABLE ADJ + – FB 1.1 V www.vishay.com 4 New Product UVLO POR BP PSM/BP Controller PSM Driver V ADJ Turn-On Zero Current Control Detect Turn off Control Peak Current Comparater GND – + – 0.3 A Document Number: 71379 ...

Page 5

... IC is decreased to less than shutting off most of the circuits. A logic high enables the controller and starts up as described in the “Start-Up” section above. Reference The reference voltage of the Si9172 is set to 1.215 internally connected to the non-inverting inputs of the error amplifier. A 0.1-mF decoupling capacitor is required at the V pin. ...

Page 6

... Si9172 Vishay Siliconix V Current vs 220 PSM Mode 200 180 160 140 120 100 Voltage ( vs. V DS(on) 220 85_C 180 25_C 140 –25_C 100 (V) IN www.vishay.com 6 New Product _ Voltage 3.6 2.9 2.2 BP Mode 1 100 Threshold vs. ADJ Voltage ...

Page 7

... Information contained herein is intended to provide a product description only. No license, express or implied, by estoppel or otherwise, to any intellectual property rights is granted by this document. Except as provided in Vishay's terms and conditions of sale for such products, Vishay assumes no liability whatsoever, and disclaims any express or implied warranty, relating to sale and/or use of Vishay products including liability or warranties relating to fitness for a particular purpose, merchantability, or infringement of any patent, copyright, or other intellectual property right ...

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