SC401B Datasheet, PDF (1/32 Pages) Semtech Corporation – 15A Integrated FET Regulator with Programmable LDO

POWER MANAGEMENT
Features
 Power System
• Input voltage — 3V to 17V
• Bias voltage — 3V to 5.5V LDO or external
• Up to 96% peak efficiency
• Integrated bootstrap switch
• Programmable LDO output — 200mA
• Reference tolerance — 1% T_J= -40 to +125 °C
• Programmable soft-start time
 Logic Input/Output Control
• Independent EN controls for LDO and switcher
• Programmable V_IN UVLO threshold
• Power good output
• Selectable PSAVE or FCM mode
 Protection
• Over-voltage and under-voltage
• TC compensated R_DS(ON) sensed current limit
• Thermal Shutdown
 Output Capacitor Types
• High ESR — SP, POSCAP, OSCON
• Ceramic capacitors
 Package
• Lead-free package — 5x5mm, 32-Pin MLPQ
• RoHS/WEEE compliant and Halogen free
Applications
 Networking and telecommunication equipment
 Printers, DSL, and STB applications
 Embedded systems and power supply modules
 Point of load power supplies
SC401B
15A Integrated FET Regulator
with Programmable LDO
Description
The SC401B is a stand-alone synchronous EcoSpeed^TM buck
power supply which incorporates Semtech’s advanced
patented adaptive on-time control architecture. This pro-
vides excellent light-load efficiency and fast transient
response. It features integrated power MOSFETs, a boot-
strap switch, and a programmable LDO in a 5x5mm
package. The device is highly efficient and uses minimal
PCB area. The SC401B has the same package and pin con-
figuration as the entire SC40xB series for compatibility.
The SC401B supports using standard capacitor types such
as electrolytic or specialty polymer, in addition to ceramic,
at switching frequencies up to 1MHz. The programmable
frequency, synchronous operation, and selectable power
save provide high efficiency operation over a wide load
range.
Additional features include a programmable soft-start,
programmable cycle-by-cycle over-current limit protec-
tion, under-voltage and over-voltage protection, soft
shutdown, and selectable power save. The device also
provides separate enable inputs for the PWM controller
and LDO as well as a power good output for the PWM
controller.
The wide input range and programmable frequency make
the device extremely flexible and easy to use in a broad
range of applications.
Typical Application Circuit
ENABLE/PSAVE
ENABLE LDO
VEXT/LDO
VIN
10Ω
1µF
CIN
EN/PSV
ILIM
RTON
ENL
TON
LXS
PGOOD
VOUT
VDD
SC401B
LX
CSOFT
SS
BST
VIN _LXBST
CBST
FB
AGND PGND
RILIM
L1
COUT
RFB1
+
RFB2
PGOOD
VOUT
Rev. 2.1
© 2011 Semtech Corporation