NX2124 Datasheet, PDF (1/17 Pages) Microsemi Corporation – 300kHz SYNCHRONOUS PWM CONTROLLER

Evaluation board available.
NX2124/2124A
300kHz SYNCHRONOUS PWM CONTROLLER
PRELIMINARY DATA SHEET
Pb Free Product
DESCRIPTION
FEATURES
The NX2124/2124A controller IC is a synchronous Buck ^{n Bus voltage operation from 2V to 25V}
controller IC designed for step down DC to DC con- ^{n Fixed 300kHz voltage mode controller}
verter applications. It is optimized to convert bus volt- ^{n Internal Digital Soft Start Function}
ages from 2V to 25V to outputs as low as 0.8V voltage. ^{n Prebias Startup}
The NX2124/2124A operates at fixed 300kHz, employs ^{n Less than 50 nS adaptive deadband}
fixed loss-less current limiting by sensing the Rdson of ^{n Current limit triggers hiccup by sensing Rdson of}
synchronous MOSFET followed by hiccup feature. ^{Synchronous MOSFET}
NX2124A has higher current limit threshold than NX2124. ^{n No negative spike at Vout during startup and}
Feedback under voltage also triggers hiccup.
shutdown
Other features of the device are: 5V gate drive, Adaptive ^{n Pb-free and RoHS compliant}
deadband control, Internal digital soft start, Vcc
APPLICATIONS
undervoltage lock out and shutdown capability via the
comp pin.
n
n
Graphic Card on board converters
Memory Vddq Supply in mother board applications
n On board DC to DC such as
5V to 3.3V, 2.5V or 1.8V
n Hard Disk Drive
n Set Top Box
TYPICAL APPLICATION
Vin
+5V
M3
HI=SD
C7
27pF
L2 1uH
C4
100uF
R5
D1
10
MBR0530T1
C3
1uF
5
Vcc
R4
37.4k
7 _COMP
1
BST
Hdrv ²
SW ⁸
C6
0.1uF
C2
2.2nF
6 _FB
Ldrv ⁴
Gnd
3
C5
Cin
1uF
280uF
18mohm
M1
L1 1.5uH
M2
R1
4k
Vout
+1.8V 9A
Co
2 x (1500uF,13mohm)
R2
C1
4.7nF
10k
R3
8k
Figure1 - Typical application of 2124
ORDERING INFORMATION
Device
NX2124CSTR
NX2124ACSTR
Temperature
0 to 70^oC
0 to 70^o C
Package
SOIC-8L
SOIC-8L
Frequency
300kHz
300kHz
OCP Threshold
360mV
540mV
Pb-Free
Yes
Yes
Rev.1.8
1
02/28/08