NX2305 Datasheet, PDF (1/19 Pages) Microsemi Corporation – SINGLE SUPPLY 12V SYNCHRONOUS PWM CONTROLLER WITH NMOS LDO CONTROLLER, POWER GOOD & ENABLES

Evaluation board available.
NX2305
SINGLE SUPPLY 12V SYNCHRONOUS PWM CONTROLLER
WITH NMOS LDO CONTROLLER, POWER GOOD & ENABLES
PRELIMINARY DATA SHEET
Pb Free Product
DESCRIPTION
FEATURES
The NX2305 controller IC is a combination synchronous ^{n 12V PWM controller plus LDO controller}
Buck and LDO controller IC designed to convert single ^{n Hiccup current limit by sensing Rdson of MOSFET}
12V supply to low cost dual on board supply applica- ^{n 12V high side and low side driver}
tions. The synchronous controller is used for high cur- ^{n Fixed internal 300kHz for switching controller}
rent high efficiency step down DC to DC converter appli- ^{n Dual Independent Digital Soft Start Function}
cations while the LDO controller in conjunction with an ^{n Adaptive Deadband Control}
external low cost N ch MOSFET can be used as a very ^{n Enable pin available to program the Vbus UVLO}
low drop out regulator in applications such as converting ^{n Shut Down switching and LDO via pulling down}
3.3V to 2.5V output. Internal UVLO keeps both regula- ^{EnSW or ENLDO pins}
tors off until the supply voltage exceeds 9V where inde- ^{n Pb-free and RoHS compliant}
pendent internal digital soft starts get initiated to ramp
APPLICATIONS
up both outputs.The switching section has hiccup cur-
rent limit by sensing the Rdson of synchronous MOSFET. ⁿ
The LDO controller has Feedback Under Voltage Lock ⁿ
Out as a short circuit protection.Other features includes: ⁿ
PCI Graphic Card on board converters
Mother board On board DC to DC applications
On board Single Supply 12V DC to DC such as
12V gate drive capability , Adaptive dead band control, ^{12V to 3.3V, 2.5V or 1.8V}
Power good flag for the switcher controller and separate ^{n Set Top Box and LCD Display}
Enable pins for independent power sequencing.
TYPICAL APPLICATION
R14 10
C11
C12
open
1uF
VIN2
+3.3V
VOUT2
+1.6V/2A
VIN2
+3.3V
HI=SD
VIN1
+12V
HI=SD
R6 10k
C9 M5
47uF
C10 150pF
C8
150uF
25mohm
R8
5k
R9
5k
R10
0.75k
R11
1.4k
M3
R12
6.8k
R13
1.4k
M4
5V REG
PGOOD
LDO OUT
LDO FB
VCC _PVCC ^{C1 0.1uF}
1N4148
L1 1uH
BST
HDRV
SW
C4
0.1uF
C2
180uF
M1
IRFR3709Z
L2 2.2uH
C3
100uF
ENLDO
OCP
LDRV
PGND
ENSW
FB
COMP
AGND
R1 4k
R5
10k
M2
IRFR3709Z _R2
1.1k
C6
3.9nF
C5
5.6nF
R3
10k
R4
8k
C13 100pF
VIN1
+12V
C7
2 x 470uF
VOUT1
+1.8V/10A
Device
NX2305CMTR
NX2305CSTR
Figure1 - Typical application of NX2305
ORDERING INFORMATION
Temperature
0 to 70^oC
0 to 70^oC
Package
MLPQ-16L
SOIC -16L
Frequency
300kHz
300kHz
Pb-Free
Yes
Yes
Rev.5.0
1
08/19/08