NX2423 Datasheet, PDF (1/20 Pages) Microsemi Corporation – TWO PHASE SYNCHRONOUS PWM CONTROLLER WITH INTEGRATED FET DRIVER, DIFFERENTIAL CURRENT SENSE & 5V BIAS REGULATOR

NX2423
TWO PHASE SYNCHRONOUS PWM CONTROLLER WITH
INTEGRATED FET DRIVER, DIFFERENTIAL CURRENT SENSE
& 5V BIAS REGULATOR
PRELIMINARY DATA SHEET ^{Pb Free Product}
DESCRIPTION
FEATURES
The NX2423 is a two-phase PWM controller with inte- ^{n Differential inductor DCR sensing eliminates the}
grated FET driver designed for low voltage high current ^{problem with layout parasitic}
application. The two phase synchronous buck converter ^{n 5V bias regulator available}
offers ripple cancelation for both input and output. The ^{n Low Impedance On-board Drivers}
NX2423 uses differential remote sensing using either cur-
rent sense resistor or inductor DCR sensing to achieve
accurate current matching between the two channels.
n
n
n
Hiccup current limit and IOUT indication
Power Good for power sequencing
EN2_B pin allows the slave channel on and off while
Differential sensing eliminates the error caused by PCB ^{the master channel is working}
board trace resistance that otherwise presents when us- ^{n Programmable frequency}
ing a single ended voltage sensing.
n Prebias start up
In addition the NX2423 offers high drive current capabil- ^{n OVP without negative spike at output}
ity especially for keeping the synchronous MOSFET off ^{n Selectable between internal and external reference}
during SW node transition, can provide regulated 5V to ^{n Internal Schottky diode from PVCC to BST}
IC biasing and drivers via 5V bias regulator, allows the ^{n Pb-free and RoHS compliant}
slave channel on and off via EN2_B pin while the main
APPLICATIONS
channel is working. Other features: PGOOD output, pro- _{n Graphic card High Current Vcore Supply}
grammable switching frequency and hiccup current lim-_{n High Current on board DC to DC converter}
iting circuitry.
applications
TYPICAL APPLICATION
2N3904
R10
2N3904
VCCDRV
BST1
R13
5V R14
C31
R11
C30
R15
C29
PVCC
5VCC
REFIN
AGND
CSCOMP
HDRV1
SW1
LDRV1
CS+1
CS-1
R16
C28
R17
R18 C26
R19
C25
R20
VOUT
RT
IOUT/IMAX
C27
VCOMP
FB
EN2_B
BST2
HDRV2
SW2
LDRV2
CS+2
CS-2
PGND(PAD) INREFOUT/POK
C11
C10
C12
Q1
Q2
L1
R29
C15
C13 C14
R28
C17 C18
C19
Q3
L2
R27
Q4
C22
C20 C21
R26
R24
C24
Ref for external circuitry
12V BUS
VOUT
Figure1 - Typical application of NX2423
ORDERING INFORMATION
Device
NX2423CMTR
Temperature
Package
0 to 70^oC MLPQ 4x4 - 24L
Frequency
50kHz to 1MHz
Pb-Free
Yes
Rev. 2.1
1
12/01/08