SC4605 Datasheet, PDF (1/19 Pages) Semtech Corporation – Low Input, High Efficiency Synchronous, Step Down Controller

SC4605
Low Input, High Efficiency
Synchronous, Step Down Controller
POWER MANAGEMENT
Description
Features
The SC4605 is a voltage mode step down (buck) regula-
tor controller that provides accurate high efficiency power
conversion from a input supply range of 2.8V 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 SC4605 drives external N-channel MOSFETs with 1A
peak current. A non-overlap protection is provided for
the gate drive signals to prevent shoot through of the
MOSFET pair. The voltage drop across the high side
MOSFET during its conduction is sensed for lossless short
circuit current limiting.
‹ BICMOS voltage mode PWM controller
‹ 2.8V to 5.5V Input voltage range
‹ Output voltages as low as 0.8V
‹ +/-1% Reference accuracy
‹ Sleep mode (Icc = 10µA typ)
‹ Lossless adjustable short circuit current limiting
‹ Combination pulse by pulse & hiccup mode
current limit
‹ High efficiency synchronous switching
‹ 0% to 97% Duty cycle range
‹ 1A Peak current driver
‹ 10-Pin MSOP package
The quiescent supply current in sleep mode is typically
lower than 10µA. A 1.8ms soft start is internally provided
to prevent output voltage overshoot during start-up.
The SC4605 is an ideal choice for 3.3V, 5V or other low
input supply systems. It’s available in 10 pin MSOP pack-
age.
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
R3
C 14
0. 1u
C1
180p
C2 2.2n
R1
14.3k
R 13
1
C3
4. 7u
C 20
470pF
D2
1u
C 71
U1
1 _BST
2 _VCC
3 _ISET
4 _COMP
5 _FFSS/ESTYNC
DRVH ¹⁰
PHASE ⁹
DRVL ⁸
GND ⁷
VSENSE ⁶
SC4605
Vin = 2.8V - 5.5V
C 10
C 11
C 12
220u
22u
22u
M1
L1
Vout = 1.5V (as low as 0.8V * ) / 12A
1. 8u
C6
C5
C4
C9
M2
330u
22u
22u
4. 7n
R7
10k
R8
200
R9
11.5k
* External components can be modified to provide a Vout as low as 0.8V.
Revision: October 14, 2004
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