Multi-Output, Low-Noise Power Supply
Controller for Notebook Computers
December 15, 2000
SC1402
TEL:805-498-2111 FAX:805-498-3804 WEB:http://www.semtech.com
DESCRIPTION
The SC1402 is pin compatible with the MAX1632 with
improved load regulation performance. The SC1402 is
a multiple-output power supply controller designed to
power logic supply components in battery operated
systems. The SC1402 utilizes synchronous rectified
buck topologies to generate two voltages, (3.3V and
5V) with up to 95% efficiency. It also provides two lin-
ear regulators for system housekeeping functions. The
12V linear regulator output is generated from a coupled
inductor of the 5V switching regulator.
Control functions include: power up sequencing, soft
start, power-good signaling, automatic bootstrapping
for high side MOSFETs, and frequency synchroniza-
tion. An internal precision 2.5V reference ensures ±2%
output voltage. The internal oscillator can be adjusted
to 200kHz, 300kHz or synchronized to an external
clock. The MOSFET drivers provide 1A peak drive
current for fast MOSFET switching.
The SC1402 includes a PSAVE enable input to select
a pulse skipping mode for high efficiency or a fixed fre-
quency mode for low noise operation.
FEATURES
•=
6V to 30V Input range
•=
3.3V and 5V dual synchronous rectified outputs
•=
Fixed frequency or PSAVE for maximum efficiency
•=
•=
•=
•=
•=
•=
•=
•=
•=
•=
over wide load current range
5V/50mA linear regulator
12V/120mA linear regulator
Precision 2.5V reference output
Programmable power-up sequence
Power good output (RESET)
Output over current protection
Output over voltage protection
Output under voltage shut down
4µA typical shut down current
7mW typical quiescent power
APPLICATIONS
•=
Notebook and subnotebook computers
•=
PDAs and Mobile communicators
•=
Desktop DC-DC converters
ORDERING INFORMATION:
DEVICE
SC1402ISS
PACKAGE
(1)
TEMP. (T
A
)
-40 - +85°C
SSOP-28
TYPICAL APPLICATION CIRCUIT
Note:
(1) Only available in tape and reel packaging. (Suffix ‘.TR’).
1
© 2000 SEMTECH CORP.
652 MITCHELL ROAD
NEWBURY PARK CA 91320
SEMTECH [ SEMTECH CORPORATION ]
