LTC6907 datasheet(15/24 Pages) AD

15 / 24 page

LTC6991

Rev. D

For more information www.analog.com

APPLICATIONS INFORMATION

LTC6991 as “Wake-Up Timer”

The output latch reset function provided by the RST pin

allows the LTC6991 to enable a larger system at regular

intervals. The on-time can be controlled by the system.

This allows the system to shut itself down immediately

after performing its tasks, reducing power consumption.

Figure 12 shows an example using “black boxes” for a

switching regulator and the system being duty-cycled.

In some cases, an RC filter may be necessary at the RST

LTC6991

THE SYSTEM CAN EXTEND tON AS LONG AS NEEDED (UP TO 50% OF tOUT)

V+

DIV

SET

OUT

GND

RST

RFILT

100k

RSET

665k

681k

tON

6991 F12

RSUPPLY

4.99k

1N4733A

5.1V

3V TO 20V

CFILT

0.1µF

tOUT

3570 SECONDS

SWITCHING

REGULATOR

VIN

VOUT

VREG

DONE/RST

LTC6991 OUT

SHDN

SYSTEM

V+

DONE

tOUT

Figure 12. Powering Up a System Once an Hour

input to filter start-up glitches from the system as it is

powered on.

If the LTC6991 is enabling a switching regulator that can

operate on supplies greater than 5.5V, it will be neces-

sary to limit the supply voltage provided to the LTC6991.

If the LTC6991 output is not heavily loaded, and if a large

RSET resistor is used, the supply current will not be much

larger than 100µA, so a simple regulator circuit can be

constructed using a Zener diode.

LTC6907 Datasheet(PDF) 15 Page - Analog Devices

LTC6907 Datasheet(HTML) 15 Page - Analog Devices

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24

Datasheet Download

Link URL