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NCP3235
Buck Converter - High Current, Synchronous
The NCP3235 is a high current, high efficiency voltage mode synchronous buck converter which operates from 4.5 V to 23 V input and generates output voltages down to 0.6 V at up to 15 A continuous current. It has two operation modes: FCCM and automatic CCM/DCM. In automatic CCM/DCM mode, the controller can switch smoothly between CCM and DCM, where converter runs at reduced switching frequency to achieve much higher efficiency at light load. The NCP3235 is available in 6 mm x 6 mm QFN−40 pin package.
Features
• Wide Input Voltage Range from 4.5 V to 23 V • 0.6 V Internal Reference Voltage • Switching Frequency Option: 550 kHz, 1.1 MHz • External Programmable Soft−Start • Lossless Low−side FET Current Sensing • Output Over−voltage Protection and Under−voltage Protection • Selective Hiccup/Latch Off Operation for All Faults • Pre−bias Start−up • Adjustable Output Voltage • Power Good Output • Internal Over−temperature Protection • Adjustable Input UVLO • This is a Pb−Free Device
Typical Application
• Industry PC Equipment • ASIC, FPGA, DSP and CPU Core and I/O Supplies • Server and Storage System • Telecom and Network Equipment
www.onsemi.com
1 40
QFN40 6x6, 0.5P CASE 485CM
MARKING DIAGRAM
1
NCP3235 AWLYYWWG
A = Assembly Location WL = Wafer Lot YY = Year WW = Work Week G = Pb−Free Package
PIN CONNECTIONS
SS 1 FB 2 COMP 3 ISET 4 AGND 5 MODE 6 PG 7 VIN 8 VIN 9 VIN 10
VIN 11 VIN 12 VIN 13 VIN 14 VSWH 15 PGND 16 PGND 17 PGND 18 PGND 19 PGND 20
VIN EP42
GND EP41
VSWH EP43
40 EN 39 VCC 38 VB 37 AGND 36 BST 35 VSW 34 VSWH 33 VSWH 32 VSWH 31 VSWH
PGND 21 PGND 22 PGND 23 PGND 24 PGND 25 PGND 26 PGND 27 PGND 28 VSWH 29 VSWH 30
© Semiconductor Components Industries, LLC, 2016
August, 2019 − Rev. 1
(Top View)
ORDERING INFORMATION
Device NCP3235MNTXG
Package
QFN−40 (Pb−Free)
Shipping†
2500 / Tape & Reel
†For information on tape and reel specifications, including part orientation and tape sizes, please refer to our Tape and Reel Packaging Specification Brochure, BRD8011/D.
1 Publication Order Number: NCP3235/D
VCC
VB COMP
FB
LDO
VB
OSC
VREF
VB
E/A
SS Soft Start VCC
2 mA
EN
1.2V
PG
VB
Enable Logic POR
NCP3235
VCC
VB
Control Logic Ramp Generator
PWM Logic −and− UVLO
OVP, UVP Power Good
OCP, TSD Protection
VB
VB
Mode Selection
BST VIN
VSWH VSW
PGND MODE
AGND
ISET
Figure 1. NCP3235 Block Diagram
Table 1. PIN DESCRIPTION
Pin No.
Symbol
Description
1 SS A capacitor from this pin to GND allows the user to adjust the soft−start ramp time.
2 FB Output voltage feedback.
3
COMP
Output of the error amplifier.
4
ISET
A resistor from this pin to ground sets the over−current protection (OCP) threshold.
5, 37
AGND
Analog ground.
6
MODE
Mode selection for FCCM mode and automatic CCM/DCM mode, switching frequency and hiccup/latch pro-
tection mode. See table I in the latter page.
7 PG Power good indicator of the output voltage. Open−drain output. Connect PG to VDD with an e.