Evaluation board available.
NX2124/2124A
300kHz SYNCHRONOUS PWM CONTROLLER
PRODUCTION DATA SHEET
Pb Free Product
FEATURES
DESCRIPTION
n Bus voltage operation from 2V to 25V
The NX2124/2124A controller IC is a synchronous Buck
n Fixed 300kHz voltage mode controller
controller IC designed for step down DC to DC con-
n Internal Digital Soft Start Function
verter applications. It is optimized to convert bus volt-
n Prebias Startup
ages from 2V to 25V to outputs as low as 0.8V voltage.
n Less than 50 nS adaptive deadband
The NX2124/2124A operates at fixed 300kHz, employs
n Current limit triggers hiccup by sensing Rdson of
fixed loss-less current limiting by sensing the Rdson of
Synchronous MOSFET
synchronous MOSFET followed by hiccup feature.
n No negative spike at Vout during startup and
NX2124A has higher current limit threshold than NX2124.
shutdown
Feedback under voltage also triggers hiccup.
n Pb-free and RoHS compliant
Other features of the device are: 5V gate drive, Adaptive
deadband control, Internal digital soft start, Vcc
APPLICATIONS
undervoltage lock out and shutdown capability via the
n Graphic Card on board converters
comp pin.
n 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
L2 1uH
Vin
+5V
C4 C5 Cin
100uF
1uF
280uF
R5
D1
18mohm
MBR0530T1
10
C3
5
1
1uF
C6
Vcc BST
0.1uF
M1
2
Hdrv
7
COMP
M3
L1 1.5uH
HI=SD
Vout
R4 8
SW
37.4k
+1.8V 9A
Co
C7
R1 2 x (1500uF,13mohm)
27pF M2
4
C2
4k
Ldrv
2.2nF
6
R2
FB
C1
10k
Gnd
4.7nF
3
R3
8k
Figure1 - Typical application of 2124
ORDERING INFORMATION
Device Temperature Package Frequency OCP Threshold Pb-Free
o
NX2124CSTR 0 to 70 C SOIC-8L 300kHz 360mV Yes
o
NX2124ACSTR 0 to 70 C SOIC-8L 300kHz 540mV Yes
Rev.1.9
1
06/12/12
NX2124NX2124/2124A
ABSOLUTE MAXIMUM RATINGS(NOTE1)
Vcc to GND & BST to SW voltage ................... 6.5V
BST to GND Voltage ...................................... 40V
SW to GND Voltage .......................................-3V to 35V
o o
Storage Temperature Range ............................. -65 C to 150 C
o o
Operating Junction Temperature Range ............. -40 C to 125 C
NOTE1: Stresses above those listed inABSOLUTE MAXIMUM RATING, may cause permanent
damage to the device. This is a stress only rating and operation of the device at these or any other
conditions above those indicated in the operational sections of this specification is not implied.
PACKAGE INFORMATION
8-PIN PLASTIC SOIC (S)
o
/130 CW
JA
BST 1 8
SW
HDrv 2 7
Comp
Gnd 3 6
Fb
LDrv 4 5
Vcc
ELECTRICAL SPECIFICATIONS
o
Unless otherwise specified, these specifications apply over Vcc = 5V, and T = 0 to 70 C. Typical values refer to T
A A
o
= 25 C. Low duty cycle pulse testing is used which keeps junction and case temperatures equal to the ambient
temperature.
PARAMETER SYM Test Condition Min TYP MAX Units
Reference Voltage
Ref Voltage V 4.5V<Vcc<5.5V 0.8 V
REF
Ref Voltage line regulation 0.4 %
Supply Voltage(Vcc)
V Voltage Range V 5 V
4.5 5.5
CC CC
V Supply Current (Static) I (Static) Outputs not switching 3 mA
CC CC
V Supply Current I C =3300pF F =300kHz 5 mA
CC CC LOAD S
(Dynamic) (Dynamic)
Supply Voltage(V )
BST
V Supply Current (Static) I (Static) Outputs not switching 0.15 mA
BST BST
V Supply Current I C =3300pF F =300kHz 5 mA
BST BST LOAD S
(Dynamic) (Dynamic)
Under Voltage Lockout
V -Threshold V _UVLO V Rising 4.2 V
CC CC CC
V -Hysteresis V _Hyst V Falling 0.22 V
CC CC CC
Rev.1.9
2
06/12/12