SC4608 Datasheet, PDF (1/19 Pages) Semtech Corporation – Low Input, MHz Operation, High Efficiency Synchronous Buck

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
V_in=3V – 3.6V
C13
C14
22u
22u
L1
1.8u
C6
C5
330u
22u
V_out= 0.5V / 12A
C4
C9
22u
4.7n
R7
10k
R8
200
Revision: June 19, 2006
1
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