SC1401 Datasheet, PDF (1/17 Pages) Semtech Corporation – HIGH PERFORMANCE SYNCHRONOUS BUCK CONTROLLER WITH LDO FOR PORTABLE POWER

HIGH PERFORMANCE SYNCHRONOUS BUCK
CONTROLLER WITH LDO FOR PORTABLE
SC1401
POWER
November 21, 2000
TEL:[phone] FAX:[phone] WEB:http://www.semtech.com
DESCRIPTION
The SC1401 is a synchronous buck regulator designed
to power the latest generation microprocessors in
battery operated systems. The SC1401 may be used
to provide both the I/O and core voltages utilizing
synchronous rectification for the core supply voltage
and an LDO N-Channel MOSFET controller for the I/O
supply voltage. A 1.25 volt reference allows lower
output voltages required by today’s portable
microprocessors.
The synchronous buck regulator is capable of
achieving efficiencies up to 95%. The gate drive
circuitry can deliver 2.0A peak currents, allowing the
use of N-channel MOSFETs for lower switching and
conduction losses.
A digital soft start is provided to ensure orderly start up
of the power supply without the need for external
components. At light load in power save mode, the
controller changes mode of operation by missing gate
drive cycles, thus reducing gate drive current and
improving efficiency. A logic high on PSAVE disables
the power saving mode thus reducing noise. The
SC1401 is fabricated in a high performance BiCMOS
process. This process reduces the power dissipation
in low current and shutdown operation modes and
improves efficiency.
The LDO controller is a high performance positive
voltage regulator designed to provide a low noise
power source to the microprocessor peripherals by
driving a low cost external N-Channel MOSFET.
VIN
C1
C2
C3
C4
C5
FEATURES
• >90% Efficiency (SMPS)
• 6.0V to 30V Input range
• 1.25V to 5.5V Adjustable output (SMPS)
• PWM and LDO regulator outputs
• High output gate drive of 2 Amps (SMPS)
• Power save mode for light load operation
• 200kHz/300kHz fixed-frequency PWM operation
• 2mA Typical quiescent current
• 2µA Typical shutdown current
APPLICATIONS
• Notebook and palmtop computers
• LCD monitors
• Internet appliances
ORDERING INFORMATION
DEVICE
SC1401ISS
PACKAGE
SSOP-20
TEMP. (T_A)
-40°C - +85°C
Notes
(1) Add suffix “TR” for tape and reel.
TYPICAL APPLICATION CIRCUIT
ENABLE_IO
RESET
PSAVE
SYNC
SHDN
R3
+5V
C10
C11
U1
SC1401ISS
1 _SYNC
PSAVE ²⁰
2 _SHDN
RESET ¹⁹
3 _FB
ENABLEIO ¹⁸
4 _VDD1
IOS ¹⁷
5 _GND
GATEIO ¹⁶
6 _CSL
VDD2 ¹⁵
7 _CSH
BST ¹⁴
8 _V5V
DH ¹³
9 _DL
PHASE ¹²
10 _PGND
PGND ¹¹
VDD2
C6
Q1
VO_LINEAR
D1
R1
C7
C8
+5V
D2
C9
R2
Q2
D4
Q3
L1
R4
C15
R6
VO_SMPS
C12
C13
C14
D3
R5
R7
C16
© 2000 SEMTECH CORP.
1
652 MITCHELL ROAD NEWBURY PARK CA 91320