SC418 Datasheet, PDF (1/30 Pages) Semtech Corporation – EcoSpeedTM DC-DC Buck Controller with Programmable LDO

SC418
POWER MANAGEMENT
EcoSpeed^TM DC-DC Buck Controller
with Programmable LDO
Features
 Power system
• Input voltage — 3V to 28V
• Integrated bootstrap switch
• Programmable LDO output — 200mA
• 1% reference tolerance -40 to +85 °C
• Selectable internal/external bias power supply
• EcoSpeed^TM architecture with pseudo-fixed fre-
quency adaptive on-time control
 Logic input/output control
• Independent control EN for LDO and switcher
• Programmable V_IN UVLO threshold
• Power good output
• Selectable power save mode
• Programmable ultrasonic power save mode
 Protections
• Over-voltage/under-voltage
• TC compensated R_DS(ON) sensed current limit
• Thermal shutdown
• Smart power save
 Output capacitor types
• High ESR — SP, POSCAP, OSCON
• Ceramic capacitors
 Package — 3 x 3mm, 20-pin MLPQ
 Lead-free and halogen free
 RoHS and WEEE compliant
Applications
 Office automation and computing
 Networking and telecommunication equipment
 Point-of-load power supplies and module replacement
Description
The SC418 is a synchronous EcoSpeed^TM buck regulator
which incorporates Semtech’s advanced, patented adap-
tive on-time control architecture to provide excellent
light-load efficiency and fast transient response. It fea-
tures an integrated bootstrap switch and programmable
LDO in a 3 x 3mm package. The device is highly efficient
and uses minimal PCB area.
The SC418 supports using standard capacitor types such
as electrolytic or special polymer, in addition to ceramic, at
switching frequencies up to 1MHz. The programmable
frequency, synchronous operation, and programmable
power-save provide high efficiency operation over a wide
load range.
Additional features include cycle-by-cycle current limit,
soft-start, under and over-voltage protection, program-
mable over-current protection, soft shutdown, selectable
power-save modes, and programmable ultrasonic 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 input voltage can range from 3V to 28V. The wide
input voltage range, programmable frequency, and pro-
grammable LDO make the device extremely flexible and
easy to use in a broad range of applications. Support is
provided for single cell or multi-cell battery systems in
addition to traditional DC power supply applications.
Typical Application Circuit
PGOOD
ENABLE
VEXT or VLDO
ENABLE LDO
RTON
VEXT or VLDO
0.1µF
1µF
VLDO
1µF
PSV
PGOOD
EN
ENL
TON
VDDA
VDDP
SC418
VLDO
VIN
DH
LX
BST
ILIM _RILIM
DL
VOUT
FBL
PSV
AGND PGND ^FB
CIN
L1
VIN
+ _COUT
VOUT
July 27, 2010
© 2010 Semtech Corporation