SP6127
High-Voltage, Step-Down Controller in TSOT6
FEATURES
Wide 4.5V – 29V Input Voltage Range
Internal compensation
Built-in High-Current PMOS Driver
Adjustable Overcurrent Protection
Internal soft start
900kHz Constant Frequency Operation
0.6V Reference Voltage
1% output setpoint accuracy
Lead Free, RoHS Compliant Package:
Small 6-pin TSOT
LX
GND
FB
6
5
4
SP6127
6 PinTSOT
1
V
IN
2
GATE
3
VDR
__________________________________________________________
DESCRIPTION
The SP6127 is a PWM controlled step down (buck) voltage mode regulator with V
IN
feedforward and
internal Type-II compensation. It operates from 4.5V to 29V V
IN
, making it suitable for 5V, 12V and 24V
applications. By using a PMOS driver, this device is capable of operating at 100% duty cycle. The high-
side driver is designed to drive the gate 5V below V
IN
. The programmable overcurrent protection is
based on the high-side MOSFET’s ON resistance sensing and allows setting the overcurrent protection
value up to 300mV threshold (measured between VIN-LX). The SP6127 is available in a space-saving 6-
pin TSOT package making it the smallest controller available capable of operating from 24VDC supplies.
_______________________________________
TYPICAL APPLICATION CIRCUIT
VIN
Q1
Si2343DS
2
1
Vin
Rs=1k
LX
C7
0.1uF
6
L1, IHLP-2525CZ
3.3uH, 30mOhm, 6A
Gate
C1
4.7uF
12V
GND
VOUT
C4
22uF
R1
200k, 1%
4
CZ
33pF
R2
100k, 1%
D1 1N4148
SP6127
3
VDR
Ds
MBRA340T3G
RZ
2K
1.8V
0-2.0A
VFB
GND
5
SHDN
High=Of f
GND
Jan28-08 RevE
SP6127 TSOT-6 PFET Buck Controller
Page 1
2007 Exar Corporation
EXAR [ EXAR CORPORATION ]
