POWER MANAGEMENT
Description
The SC4608 is a voltage mode step down (buck) regula-
tor controller that provides accurate high efficiency power
conversion from an input supply range of 2.7V to 5.5V. A
high level of integration reduces external component
count, and makes it suitable for low voltage applications
where cost, size and efficiency are critical. The SC4608
is capable of producing an output voltage as low as 0.5V.
It’s frequency of operation is programmable to 1MHz.
The SC4608 drives external, N-channel MOSFETs with a
peak gate current of 1A. A non-overlap protection is pro-
vided for the gate drive signals to prevent shoot through
of the MOSFET pair. The SC4608 features lossless cur-
rent sensing of the voltage drop across the drain to
source resistance of the high side MOSFET during its
conduction period.
The quiescent supply current in sleep mode is typically
lower than 1µA. A external soft start is provided to pre-
vent output voltage overshoot during start-up.
The SC4608 is an ideal choice for converting 3.3V, 5V or
other low input supply voltages. It’s available in 16 pin
MLP package.
Typical Application Circuit
SC4608
Low Input, MHz Operation,
High Efficiency Synchronous Buck
Features
Asynchronous start up
Programmable switching frequency up to 1MHz
BiCMOS voltage mode PWM controller
2.7V to 5.5V input voltage range
Output voltage as low as 0.5V
+/-1% reference accuracy
Sleep mode (Icc = 1µA max)
Adjustable lossless short circuit current limiting
Combination pulse by pulse & hiccup mode
current limit
High efficiency synchronous switching
1A peak current driver
External soft start
Power good signal
16-pin MLP Lead-free package. This product is fully
WEEE and RoHS compliant
Applications
Distributed power architecture
Servers/workstations
Local microprocessor core power supplies
DSP and I/O power supplies
Battery-powered applications
Telecommunications equipment
Data processing applications
R13
R3
1
SC4608
16
PVDD
BST 15
C3
1u
1 AVDD
2 ISET
DRVH 13
R6
1
3 COMP
PHASE 12
C16
4 FSET
DRVL 11
R5
C1
180p
C2 2.2n
560pF
R1
14.3k
5 EN
R2
10k
Css
6
7
PGOOD
SS
PGND 10
AGND 9
VSENSE 8
1
22n
D2
M11
C17
1u
M2
C10
220u
Vin=3V – 3.6V
C13
C14
22u
22u
L1
1.8u
C6
C5
330u
22u
Vout= 0.5V / 12A
C4
C9
22u
4.7n
R7
10k
R8
200
Revision: June 19, 2006
1
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