SC196 Datasheet, PDF (1/18 Pages) Semtech Corporation – 1.5A Synchronous Buck Converter with Integrated Power Devices

POWER MANAGEMENT
SC196
1.5A Synchronous Buck Converter
with Integrated Power Devices
Description
The SC196 is a synchronous step-down converter with
integrated power devices designed for use in applications
using a single-cell Li-ion battery. Its wide input voltage
range also makes it suitable for use in systems with fixed
3.3V or 5V supply rails available. The switching frequency is
nominally set to 1MHz, allowing the use of small inductors
and capacitors. The current rating of the internal MOSFET
switches allows a DC output current of 1.5A.
The output voltage is set by connecting a resistor divider
from the filter inductor to the feedback pin. See the
SC196A for pin-programmable output voltages.
The SC196 has a flexible clocking methodology that
allows it to be synchronized to an external oscillator or
controlled by the internal oscillator. The device operates
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 95% efficiency
‹
‹
V_OUT adjustable from less than 0.8V to V_IN
Output current — 1.5A
‹ Input range — 2.5V to 5.5V
‹ Quiescent current — 17μA
‹ Fixed 1MHz frequency or 750kHz to 1.25MHz
synchronized operation
‹ PSAVE operation to maximize efficiency at light loads
‹ Shutdown current <1μA
‹ Fast transient response
‹ 100% duty cycle in dropout
‹ Soft-start
‹ Over-temperature and short-circuit protection
‹ Lead-free package — MLPD10-UT, 3 x 3 x 0.6 mm
Applications
‹ Cell phones
‹ Wireless communication chipset power
‹ Personal media players
‹ Microprocessor/DSP core/IO power
‹ PDAs and handheld computers
‹ WLAN peripherals
‹ USB powered modems
‹ 1 Li-Ion or 3 NiMH/NiCd powered devices
Typical Application Circuit
V_IN
2.5V to 5.5V
C_IN
10μF
VIN ^SC196 _LX
PVIN
VOUT
MODE
ADJ
EN
SYNC/PWM
PGND
GND
L1
4.7μH
R_FB1
R_FB2
V_OUT
<0.8V to V_IN
1.5A
C_FB1
10pF
C_OUT
22μF
February 8, 2007
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