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SP6123/SP6123A
Low Voltage, Synchronous Step-Down PWM Controller
Ideal for 2A to 10A, Small Footprint, DC-DC Power Converters
FEATURES
■ Optimized for Single Supply, 3V - 5.5V Applications
GL 1
8
BST
■ High Efficiency: Greater Than 95% Possible
VCC 2
SP6123
7
GH
■ Accurate Fixed 300kHz (SP6123) or 500kHz
8 Pin nSOIC
(SP6123A) Frequency Operation
■ Fast Transient Response
GND 3
COMP 4
6
5
SWN
VFB
■ Internal Soft Start Circuit
■ Accurate 0.8V Reference Allows Low Output
Voltages
■ Resistor Programmable Output Voltage
■ Loss-less Current Limit with High Side R DS(ON)
Sensing
■ Hiccup Mode Current Limit Protection
■ Dual N-Channel MOSFET Synchronous Driver
■ Quiescent Current: 500 μ A, 30 μ A in Shutdown
■ 8-Pin Surface Mount Package
Now Available in Lead Free Packaging
APPLICATIONS
■ DSP
■ Microprocessor Core
■ I/O & Logic
■ Industrial Control
■ Distributed Power
■ Low Voltage Power
DESCRIPTION
The SP6123 is a fixed frequency, voltage mode, synchronous PWM controller designed to
work from a single 5V or 3.3V input supply, providing excellent AC and DC regulation for high
efficiency power conversion. Requiring only few external components, the SP6123 pack-
aged in an 8-pin NSOIC, is especially suited for low voltage applications where cost, small
size and high efficiency are critical. The operating frequency is internally set to 300kHz
(SP6123) or 500kHz (SP6123A), allowing small inductor values and minimizing PC board
space. The SP6123 drives an all N-channel synchronous power MOSFET stage for improved
efficiency and includes an accurate 0.8V reference for low output voltage applications.
TYPICAL APPLICATION CIRCUIT
3V to 5.5V
IN
MBR0530
V IN
GL
BST
CBST
1 μ F
C IN
680 μ F
0.8V to 5.0V
CB
2.2 μ F
V CC
GND
SP6123A
GH
SWN
FDS6890A
L1
2A to 10A
(1.6V, 4A shown)
V OUT
COMP
V FB
1.5 μ H
R1
10k
CP
56pF
RZ
15k
C OUT1
470 μ F
C OUT2
470 μ F
C OUT3
1 μ F
CC
4.7nF
FDS6890A
STPS2L25U
R2
10k
Date: 9/13/04
SP6123 Low Voltage, Synchronous Step Down PWM Controller
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? Copyright 2004 Sipex Corporation