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| SC191 Datasheet, PDF (1/13 Pages) Semtech Corporation – Low Supply Ripple Synchronous Buck Conversion Regulator | |||
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SC191
Low Supply Ripple Synchronous
Buck Conversion Regulator
POWER MANAGEMENT
Description
Features
The SC191 is a synchronous step-down converter with
integrated power devices and an integrated front-end
LDO regulator to minimize input supply ripple. If supply
ripple is not a concern, the front-end LDO regulator can be
bypassed externally to maximize efï¬ciency.
The internal MOSFET switches provide peak current greater
than 550mA to achieve a DC output of at least 330mA over
the rated input voltage range, making the SC191 ideal for
single-cell Li-ion battery applications as well as ï¬xed 3.3V
and 5V ï¬xed input applications. The output is a ï¬xed 1.2V
- ideal for low-voltage microprocessors. Other voltage
options are available (consult the factory for details).
Additional features include internal soft-start to limit in-
rush current, over-current protection, over-temperature
protection, and over-voltage protection.
The 1MHz switching frequency allows the use of small
surface mount capacitors and inductors, and no other
external compensation components are needed. The
device is available in a low proï¬le (0.8mm max height)
2.3mm x 2.3mm MLPD 8-lead package, minimizing area
without compromising performance.
 Less than 1mV Supply Ripple
 2.7V to 5.5V Input Range
 330mA Guaranteed Output Current
 Fixed Frequency 1MHz Operation
 No Schottky Diode Required
 Over-Current Protection
 Over-Voltage Protection
 Over-Temperature Protection
 Soft-Start
 No External Compensation Required
 MLPD-8, 2.3mm x 2.3mm Package
 WEEE and RoHS Compliant
Applications
 Cell Phones
 Cordless Phones
 Notebook and Subnotebook Computers
 PDAs and Mobile Communicators
 WLAN Peripherals
 Wireless Modules
 1 Li-Ion or 3 NiMH/NiCd Powered Devices
Patent Pending
Typical Application Circuit
VIN
CIN
4.7μF
SC191
3 VIN
4 EN
2
PVIN
7 PGND
8
LX
5
VOUT
BP 1
GND 6
L
4.7μH
CBP
4.7μF
COUT
4.7μF
VOUT
April 12, 2006
1
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