NX2142 Datasheet, PDF (1/18 Pages) Microsemi Corporation – SINGLE CHANNEL PWM CONTROLLER WITH FEEDFORWARD AND 5V BIAS REGULATOR

NX2142/2142A
SINGLE CHANNEL PWM CONTROLLER WITH FEEDFORWARD
AND 5V BIAS REGULATOR
ADVANCE DATA SHEET
Pb Free Product
DESCRIPTION
The NX2142/2142A controller IC is a compact synchro-
nous Buck controller IC with 10 lead MSOP package
designed for step down DC to DC converter applica-
n
n
n
tions with voltage feedforward functionality. Voltage
feedforward provides fast response, good line regula-
tion and nearly constant power stage gain under wide
voltage input range. The NX2142/2142A controller is
optimized to convert single supply up to 24V bus volt-
age to as low as 0.8V output voltage. NX2142/2142A
can function as a single supply controller with its 5V
n
n
n
n
n
n
bias regulator. Internal UVLO keeps the regulator off
until the supply voltage exceeds 7V where internal digi-
tal soft starts get initiated to ramp up output. The
NX2142/2142A employs fixed current limiting and FB
UVLO followed by hiccup feature. Other features in-
n
n
n
cludes: 5V gate drive capability , Converter Shutdown
by pulling COMP pin to Gnd, Adaptive dead band con-
n
trol.
Vin
+8 to 20V
47uF
MMBT3904
FEATURES
Bus voltage operation from 7V to 24V
5V bias regulator available
Excellent dynamic response with input voltage
feed-forward and voltage mode control
Fixed 600kHz, 1MHz switching frequency
Internal Digital Soft Start Function
Fixed internal hiccup current limit
FB UVLO followed by hiccup feature
Shutdown by pulling COMP pin low
Pb-free and RoHS compliant
APPLICATIONS
Graphic Card on board converters
Vddq Supply in mother board applications
On board DC to DC such as
12V to 3.3V, 2.5V or 1.8V
Set Top Box and LCD Display
TYPICAL APPLICATION
1uF
25TQC33M
1uF
BAT54A
7
1
VCC ^BST
6 _{REGOUT Hdrv 2}
5 _VIN
0.1uF
9
COMP
SW ¹⁰
27pF
20k
5.2nF
Ldrv ⁴
8 _FB
Gnd
3
0.1uF
AO4800(half)
DO3316P-682
AO4800(half)
1k
Vout
+3.3V /3A
1000uF,30mohm
324
Figure1 - Typical application of NX2142
ORDERING INFORMATION
Device
Temperature
NX2142CUTR
0 to 70^o C
NX2142ACUTR 0 to 70^o C
Package
MSOP-10L
MSOP-10L
Frequency
600kHz
1MHz
Pb-Free
Yes
Yes
Rev. 1.1
1
10/28/07