ADP3367

–8–

REV. 0

processor. Monitoring the supply, the ADM705 will generate a

reset if the supply voltage falls below 4.65 V. Early warning of

an impending power fail is generated by a power fail comparator

on the ADM705. A resistive divider network samples the pre-

regulator input voltage so that failing power is detected while

the regulator is still operating normally. An interrupt is gener-

ated so that a power-down sequence can be completed before

power is completely lost. The low dropout voltage on the

ADP3367 maximizes the available time to carry out the power-

down sequence. The resistor divider network R1 and R2 should

be selected so that the voltage on PFI is 1.25 V at the desired

warning voltage.

IN

OUT

GND

SET SHDN

ADP3367

10µF

+

+5V

ADM705

RESET

PFO

GND

PFI

UNREGULATED

DC

R1

R2

µP

RESET

INTERRUPT

Figure 15.

µP Regulator with Supply Monitoring and Early

Power-Fail Warning

OUTLINE DIMENSIONS

Dimensions shown in inches and (mm).

8-Lead Narrow-Body SOIC

(SO-8)

0.0098 (0.25)

0.0075 (0.19)

0.0500 (1.27)

0.0160 (0.41)

8

°

0

°

0.0196 (0.50)

0.0099 (0.25)

x 45

°

PIN 1

0.1574 (4.00)

0.1497 (3.80)

0.2440 (6.20)

0.2284 (5.80)

4

5

1

8

0.0192 (0.49)

0.0138 (0.35)

0.0500

(1.27)

BSC

0.0688 (1.75)

0.0532 (1.35)

0.0098 (0.25)

0.0040 (0.10)

0.1968 (5.00)

0.1890 (4.80)