nx2119 Microsemi Corporation, nx2119 Datasheet - Page 4

• Manufacturer Part Number: nx2119
• Description: Synchronous Pwm Controller With Current Limit Protection
• Manufacturer: Microsemi Corporation

Rev.3.2
04/10/08
PIN DESCRIPTIONS
PIN #
5
1
3
6
7
8
2
4
PIN SYMBOL
COMP
HDRV
LDRV
VCC
GND
BST
SW
FB
Power supply voltage. A high freq 1uF ceramic capacitor is placed as close as
possible to and connected to this pin and ground pin.
This pin supplies voltage to high side FET driver. A high freq 0.1uF ceramic capaci-
tor is placed as close as possible to and connected to these pins and respected
SW pins.
Ground pin.
This pin is the error amplifier inverting input. This pin is connected via resistor divider
to the output of the switching regulator to set the output DC voltage. When FB pin
voltage is lower than 0.6V, hiccup circuit starts to recycle the soft start circuit after
2048 switching cycles.
This pin is the output of the error amplifier and together with FB pin is used to
compensate the voltage control feedback loop. This pin is also used as a shut down
pin. When this pin is pulled below 0.3V, both drivers are turned off and internal soft
start is reset.
This pin is connected to source of high side FET and provides return path for the
high side driver. It is also used to hold the low side driver low until this pin is brought
low by the action of high side turning off. LDRV can only go high if SW is below 1V
threshold .
High side gate driver output.
Low side gate driver output.
PIN DESCRIPTION
NX2119/2119A
4