SC4607 Datasheet, PDF (1/17 Pages) Semtech Corporation – Very Low Input, MHz Operation, High Efficiency Synchronous Buck

SC4607
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
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
D2
1u
C71
R3
C14
R13
1
U1
R6
0.1u
1 _BST
DRVH ¹⁰
0
C3
4.7u
2 _VCC
3 _ISET
PHASE ⁹
DRVL ⁸
C20
4 _COMP
GND ⁷
C1 C2 ^2.2n
5 _{FS/SYNC VSENSE} 6
R5
180p
560pF
SC4607
0
R1
14.3k
Vin = 2.25V - 5.5V
C10
C11
C12
220u
22u
22u
M1
L1
1.8u
M2
Vout = 1.5V (as low as 0.5V * ) / 12A
C6
330u
C5
C4
C9
22u
22u
4.7n
R7
10k
R8
200
R9
*External components can be modified to provide a Vout as low as 0.5V
4.99k
Revision: June 1, 2005
1
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