SC194A
1A Synchronous Buck Converter
with Integrated Power Devices
POWER MANAGEMENT
Description
The SC194A is a synchronous step-down converter with
integrated power devices. The SC194A is designed for
single-cell Li-Ion battery applications, but can also be used
in
fi
xed 3.3V or 5V applications. The switching frequency is
nominally set to 1MHz, allowing the use of small inductors
and capacitors. The 1.3A maximum current rating of the
internal MOSFET switches allows a DC output current of
1A.
The SC194A has a
fl
exible clocking methodology that
allows it to be synchronized to an external oscillator or
controlled by the internal oscillator. The device can
operate in either forced PWM mode or in PSAVE mode. If
PSAVE mode is enabled the part will automatically enter
PFM at light loads to maintain maximum efficiency across
the full load range.
For noise sensitive applications, PSAVE mode can be
disabled by synchronizing to an external oscillator, or
pulling the SYNC/PWM pin high. Shutdown turns off all
the control circuitry to achieve a typical shutdown current
of 0.1μA.
Features
Up to 93% efficiency
Output current - 1A
Input range - 2.7V to 5.5V
Quiescent current - 17μA
Four selectable output voltages
Dynamic voltage positioning capability
Fixed 1MHz frequency or 750kHz to 1.25MHz
synchronized operation
PSAVE operation to maximize efficiency at light loads
Minimal external components
Fast transient response
100% duty cycle in dropout
Soft-start
Over-temperature and short-circuit protection
Space-saving lead-free package - MLP-10, 3 x 3mm
Applications
Cell phones
Wireless communication chipset power
Personal media player
Notebook and sub-notebook computers
PDAs and mobile communicators
WLAN peripherals
Typical Application Circuit
SC194A
V
IN
2.7V to 5.5V
C
IN
10μF
VIN
EN
SYNC/PWM
VID0
VID1
MODE
LX
VOUT
PGND
GND
L1
4.7μH
C
OUT
10μF
V
OUT
1.8V
1A
July 05, 2006
1
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SEMTECH [ SEMTECH CORPORATION ]
