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SC4601 Datasheet, PDF (1/18 Pages) Semtech Corporation – Low Input, High Efficiency Synchronous, Step Down Controller
POWER MANAGEMENT
SC4601
Low Input, High Efficiency
Synchronous, Step Down Controller
Description
Features
The SC4601 is a voltage mode step down (buck) regula-
tor controller that provides accurate high efficiency power
conversion from input supply range 2.75V 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 SC4601 drives external complementary power
MOSFETs; P-channel on the high side and N-channel on
the low side. The use of high side P-channel MOSFETs
eliminates the need for an external charge pump and
simplifies the high side gate driver. Non-overlap protec-
tion is provided for the gate drive signals to prevent shoot
through of the MOSFET pair. The voltage drop across the
P-channel MOSFET during its conduction is sensed for
lossless short circuit current limiting.
‹ Programmable switching frequency up to 600KHz
‹ BICMOS voltage mode PWM controller
‹ 2.75V to 5.5V Input voltage range
‹ Output voltage as low as 0.8V
‹ +/-1% Reference accuracy
‹ Sleep mode (Icc = 10µA typ)
‹ Lossless adjustable overcurrent protection
‹ Combination pulse by pulse & hiccup mode
current limit
‹ High efficiency synchronous switching
‹ Up to 100% Duty cycle range
‹ Synchronization to external clock
‹ 10-Pin MSOP surface mount package. Available in
Lead-free package, fully WEEE and RoHS compliant
Applications
A low power sleep mode can be achieved by forcing the
SYNC/SLEEP pin below 0.8V. A synchronous mode of op-
eration is activated as the SYNC/SLEEP pin is driven by
an external clock. The quiescent supply current in sleep
mode is typically lower than 10µA. A 2.4ms soft start is
internally provided to prevent output voltage overshoot
during start-up. A 100% maximum duty cycle allows the
SC4601 to operate as a low dropout regulator in the
event of a low battery condition. Its switching frequency
can be programmed up to 600KHz.
‹ Distributed power architecture
‹ Servers/workstations
‹ Local microprocessor core power supplies
‹ DSP and I/O power supplies
‹ Battery powered applications
‹ Telecommunication equipment
‹ Data processing applications
The SC4601 is an ideal choice for 3.3V, 5V or other low
input supply systems. It’s available in 10 pin MSOP
package.
Typical Application Circuit
RT
30.1K
C3 4.7u
C1 470p
R1
C2
5.11K 6.8n
R15
1
U1
5 FS
1 VCC
2 SYNC
3 COMP
4 VSENSE
R3
ISET 6
PDRV 10
PHASE 7
NDRV 9
GND 8
SC4601
C14
M1
33n
R6
1.0
M2
R5
1.0
Vin = 2.75V ~ 5.5V
C10
C11
C12 C13
22u
22u
22u 22u
L1
Vout = 1.5V (as low as 0.5V * ) /6A
1.6u
C7
C4
150u
22u
C9
3.9n
R7
4.53k
R8
147
* External components can be modified to provide a VOUT as low as 0.8V.
Revision: February 22, 2006
1
R9
5.11k
www.semtech.com