SC508 Datasheet, PDF (1/32 Pages) Semtech Corporation – EcoSpeed® DC-DC Buck Controller with Integrated LDO

POWER MANAGEMENT
SC508/SC508A
EcoSpeed^® DC-DC Buck Controller
with Integrated LDO
Features
Description
 Power system
• Input voltage — 4.5V to 46V
• Integrated bootstrap switch
• Fixed 5V LDO output — 200mA
• 1% reference tolerance -40 to +85 °C
• Selectable internal/external bias power supply
• EcoSpeed^® architecture with pseudo-fixed fre-
quency adaptive on-time control
 Logic input and output control
• Independent control EN for LDO and switcher
• Programmable soft-start time
• Programmable V_IN UVLO threshold
• Power Good output
• Selectable power-save mode
• Programmable ultrasonic power-save mode
 Protections
• Automatic restart on fault shutdown
• Over-voltage and under-voltage
• TC compensated R_DS(ON) sensed current limit
• Thermal shutdown
• Smart power-save
• Pre-bias start-up
 Capacitor types: SP, POSCAP, OSCON, and ceramic
 Package — 3 x 3(mm), 20-pin MLPQ
 Lead-free and halogen-free
 RoHS and WEEE compliant
 AEC-Q100 Qualified available in SC508A
Applications
 Office automation and computing
 Networking and telecommunication equipment
 Point-of-load power supplies and module replacement
 Automotive applications
The SC508/SC508A is a synchronous EcoSpeed^® buck reg-
ulator which incorporates Semtech’s advanced, patented
adaptive `on-time control architecture to provide excel-
lent light-load efficiency and fast transient response. It
features an integrated bootstrap switch and a fixed 5V
LDO in a 3 x 3(mm) package. The device is highly efficient
and uses minimal PCB area. The SC508A is available for
automotive applications and is qualified to AEC-Q100.
The SC508 supports using standard capacitor types such as
electrolytic or special polymer, in addition to ceramic, at switch-
ing 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,
programmable soft-start, under and over-voltage protec-
tion, programmable over-current protection, start-up into
pre-biased output, automatic fault recovery (hiccup restart),
soft-shutdown, selectable power-save modes, and pro-
grammable 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. Output
voltage range is 0.6 to 5V, with output voltages greater than
5V supported using additional components.
The input voltage can range from 5V to 46V. The wide
input voltage range, programmable frequency, and inte-
grated 5V LDO make the device extremely flexible and
easy to use in a broad range of applications. Support is
provided for multi-cell battery systems in addition to tra-
ditional DC power supply applications.
Typical Application Circuit
PGOOD
ENABLE
VEXT or VLDO
ENABLE LDO
RTON
VEXT or VLDO
VLDO
0.1µF
1µF
1µF
10nF
PGOOD
EN
ENL
TON
VDDA
VDDP
SC508
SC508A
VLDO
SS
PSV
AGND
VIN
DH
LX
BST
ILIM
DL
VOUT
PGND ^FB
3.3O
RLIM
CIN
L1
VIN
+ _COUT
VOUT
PSV
Revision 4.1
© 2011 Semtech Corporation