NX7102

Microsemi

Analog Mixed Signal Group

11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570

Page 2

3A High Voltage Synchroous Buck Converter

TM

®

Copyright

© 2010

Rev.1.3, 2011-04-22

ABSOLUTE MAXIMUM RATINGS

Supply Input Voltage (VIN)............................................................................ -0.3V to 20V

Switch Voltage (SW) ............................................................................. -1V to (VIN + 1V)

EN ................................................................................................... -0.3V to (VIN + 0.3V)

BST ...................................................................................................-0.3V to (VSW + 6V)

COMP, FB, SS ................................................................................................. -0.3V to 6V

Maximum Operating Junction Temperature............................................................... 150

°C

Storage Temperature Range ........................................................................ -65

°C to 150°C

Package Peak Temp. for Solder Reflow (40 seconds maximum exposure)................ 260°C

Note: Exceeding these ratings could cause damage to the device. All voltages are with respect to

Ground. Currents are positive into, negative out of specified terminal

.

PACKAGE PIN OU T

4

3

2

1

5

6

7

8

BST

GND

SW

VIN

FB

COMP

EN

SS

(Top View)

“xxxx” Denote Date Code and Lot Identification

RoHS / Pb-free 100% Matte Tin Pin Finish

THERMAL DATA

THERMAL RESISTANCE

θ

JA

75

°C/W

The

θ

above assume no ambient airflow.

FUNCTIO N AL PIN DESCRIP T ION

Pin

Name

Description

1

BST

Bootstrap pin. A minimum 10nF bootstrap capacitor is connected between the BS pin and SW pin.

The voltage across the bootstrap capacitor drives the internal high side NMOS.

2

VIN

Supply input pin. A capacitor should be connected between the IN pin and GND pin to keep the

input voltage constant.

3

SW

Power switch output pin. This pin is connected to the inductor and bootstrap capacitor.

4

GND

Ground.

5

FB

Feedback pin. This pin is connected to an external resistor divider to program the system output

voltage. When the FB pin voltage exceeds 20% of the nominal regulation value of 0.925V, the over

voltage protection is triggered. When the FB pin voltage is below 0.3V, the oscillator frequency is

lowered to realize short circuit protection.

6

COMP

Compensation pin. This pin is the output of the transconductance error amplifier and the input to

the current comparator. It is used to compensate the control loop. Connect a series RC network

from this pin to GND. In some cases, an additional capacitor from this pin to GND pin is required.

7

EN

Control input pin. Forcing this pin above 1.5V enables the IC. Forcing this pin below 0.4V shuts

down the IC. When the IC is in shutdown mode, all functions are disabled to decrease the supply

current below 1μA.

8

SS

Soft-start control input pin. SS controls the soft start period. Connect a capacitor from SS to GND

to set the soft-start period. A 0.1μF capacitor sets the soft-start period to 9ms. To disable the soft-

start feature, leave SS unconnected.