12V or Adjustable, High-Efficiency,

6

_______________________________________________________________________________________

2ms/div

A: SHDN, 5V/div

A

B

0V

0V

ENTERING/EXITING SHUTDOWN

5V

______________________________________________________________Pin Description

____________________________Typical Operating Characteristics (continued)

PIN

NAME

FUNCTION

1

EXT

Gate Drive for External N-Channel Power Transistor

2

V+

3

FB

4

SHDN

5

REF

6

AGND

Analog Ground

7

GND

High-Current Ground Return for the Output Driver

8

CS

Power-Supply Input. Also acts as a voltage-sense point when in bootstrapped mode.

Feedback Input for Adjustable-Output Operation. Connect to ground for fixed-output operation.

Use a resistor divider network to adjust the output voltage. See

Setting the Output Voltage section.

below V+ (due to the DC path from V+ to the output) and the supply current drops to 5

µA

maximum. Connect to ground for normal operation.

1.5V Reference Output that can source 100

µA for external loads. Bypass to GND with 0.1µF.

The reference is disabled in shutdown.

Positive Input to the Current-Sense Amplifier. Connect the current-sense resistor between CS

and GND.