AS1337 datasheet(9/14 Pages) AMSCO

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AS1337

Datasheet - D e t a i l e d D e s c r i p t i o n

Shutdown Battery Feedthrough (AS1337A)

In shutdown the battery input of the AS1337A is connected to the output through the inductor and the small internal

synchronous rectifier P-FET. This allows the input battery to provide backup power for devices such as an idle micro-

controller, memory, or real-time-clock, without the usual diode forward drop. In this way a separate backup battery is

not needed.

Future Version (on request): Shutdown Battery Disconnect (AS1337B)

The AS1337B is designed to allow true output disconnect by opening both P-channel MOSFET rectifiers. This means

that VOUT is discharged and connected to GND.

POK Function

The POK output indicates if the output voltage is within 88% (typ.) of the nominal voltage level. As long as the output

voltage is within regulation the open-drain POK output is high impedance. The POK output can be tied to VIN or to

VOUT or to any external voltage up to VIN or VOUT via a pull-up resistance (see Figure 1 on page 1). If the output volt-

age drops below 88% (typ.) of the nominal voltage the POK pin is pulled to GND.

Note: It is important to consider that in shutdown mode the POK output is pulled to VIN in order to save current.

AS1337 Datasheet(PDF) 9 Page - ams AG