AS1925, AS1926

Ultra-Low Vo ltage Microprocessor Supervisory

Circuit with Manual Reset

Dat a Sh eet

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Revision 1.00

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1 General Description

The AS1925/AS1926 microprocessor supervisory cir-

cuits were designed to assert a single reset if the moni-

tored supply voltage drops below its reset threshold or if

the manual reset is activated. The reset remains

above the reset threshold and the manual reset is deas-

serted.

Their small size, excellent circuit reliability, and low sup-

ply current (3.5µA) make the AS1925/AS1926 a very

low cost solution by eliminating external components

and adjustments when used with low-voltage (+0.9 to

+1.5V) systems.

The devices are available as the standard products

listed in Table 1.

The active-low open-drain reset output requires a pullup

resistor that can be connected to a voltage from 0 to

The devices are available in a 5-pin SOT23 package.

Figure 1. Block Diagram and Pinout

2 Key Features

!

Factory-Trimmed Reset Thresholds for Monitoring

Supplies from 0.9 to 1.5V

!

Low Power Consumption: 3.5µA

!

Reset Threshold Accuracy Over Temperature:

±2.5%

!

Four Timeout Periods: 1.5ms, 30ms, 210ms, and

1.68s

!

Three Reset Output Types:

- Active-Low Push/Pull

- Active-High Push/Pull

- Active Low Open-Drain

!

Low)

!

Manual Reset Input

!

!

5-pin SOT23 Package

3 Applications

The device is ideal for portable and battery-powered

systems, embedded controllers, intelligent instruments,

automotive systems, telecommunications equipment,

networking equipment, computer workstations and serv-

ers, critical CPU monitoring applications, and any low-

voltage application.

Table 1. Standard Products

Model

Output Type

AS1925

Active-Low Push/Pull,

Active-High Push/Pull

AS1926

Active-High Push/Pull,

Active-Low Open-Drain

GND

2

+

–

+

–

Reset

Output

AS1925/

AS1926

Reset Timeout

Period

Manual Reset

Detect

MRN

Pullup

AS1925/

AS1926

2

GND

3

RESET

1

RESETN

4 MRN

5

1

RESETN

4

MRN

3

RESET