AS1337 datasheet(10/16 Pages) AMSCO

10 / 16 page

www.austriamicrosystems.com/DC-DC_Step-Up/AS1337

Revision 1.05

9 - 15

AS1337

Datasheet - Detailed Descr i pti on

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 microcontroller, memory, or real-time-clock, without the usual

diode forward drop. In this way a separate backup battery is not needed.

Shutdown Battery Disconnect (AS1337B)

The AS1337B is designed to allow true output disconnect by opening both P-channel MOSFET rectifiers. During Shutdown VOUT is discharged

via the internal NMOS transistor 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 voltage 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 датащи(PDF) 10 Page - ams AG