Very Low Input, MHz Operation,
High Efficiency Synchronous Buck
POWER MANAGEMENT
Description
The SC4607 is a voltage mode step down (buck) regula-
tor controller that provides accurate high efficiency power
conversion from an input supply range of 2.25V to 5.5V.
The SC4607 is capable of producing an output voltage
as low as 0.5V and has a maximum duty cycle of 97%. 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 SC4607 drives external, N-channel MOSFETs with a
peak gate current of 1A. The SC4607 prevents shoot
through currents by offering nonoverlap protection for
the gate drive signals of the external MOSFETs. The
SC4607 features lossless current 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 10µA. A 1.2ms soft start is internally provided
to prevent output voltage overshoot during start-up.
The SC4607 is an ideal choice for converting 2.5V, 3.3V,
5V or other low input supply voltages. It’s available in 10
pin MSOP package
SC4607
Features
Asynchronous start up
BiCMOS voltage mode PWM controller
Operation of frequency to 1MHz
2.25V to 5.5V input voltage range
Output voltages as low as 0.5V
+/-1% reference accuracy
Sleep mode (Icc = 10µA typ)
Adjustable lossless short circuit current limiting
Combination pulse by pulse & hiccup mode
current limit
High efficiency synchronous switching
Up to 97% duty cycle
1A peak current driver
10-pin MSOP package
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
Typical Application Circuit
Vin = 2.25V - 5.5V
D2
R13
1
1
C3
4.7u
2
3
4
C1
180p
R1
14.3k
C2 2.2n
C20
560pF
5
C10
1u
C71
R6
U1
BST
VCC
ISET
COMP
FS/SYNC
DRVH
PHASE
DRVL
GND
VSENSE
10
9
8
7
6
R5
0
M2
1.8u
C6
330u
C5
22u
C4
22u
0
L1
M1
220u
C11
22u
C12
22u
R3
C14
0.1u
Vout = 1.5V (as low as 0.5V * ) / 12A
C9
4.7n
R8
200
R7
10k
SC4607
*External components can be modified to provide a Vout as low as 0.5V
R9
4.99k
Revision: June 1, 2005
1
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