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AS1901, AS1902, AS1903

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

8 Detailed Description

Interfacing to Microprocessors with Bi-Directional Reset Pins

The device has an open drain RESETN output, which enables easy interfacing to microprocessors (µP) with bi-direc-

tional reset pins, such as the Motorola 68HC11. The RESETN pin of the microcontroller (µC) can be connected directly

to the µP supervisor's RESETN output with a single pull-up resistor (see Figure 1 on page 1).

resets.

In the graph Maximum Transient Duration vs. Reset Threshold Overdrive (page 6), the conditions are shown, for which

when a reset signal is generated. As the amplitude of the transient increases, the maximum allowable pulse width

decreases.

Options

Table 4. Coding of Factory-trimmed Reset Active Time-Out Period

Device

Suffix

Min

Typ

Max

AS190x_xx

A

3

5

8

AS190x_xx

B

12

20

32

AS190x_xx

C

60

100

160

AS190x_xx

D

300

500

800

Table 5. Output Variants

Device

Output Functionality

AS1901xxx

Active Low (RESETN)

AS1902xxx

Active High (RESET)

AS1903xxx

Open Drain (RESETN)

Table 6. Coding of Factory-Trimmed Reset Threshold Voltages

Device

Suffix

Min

Typ

Max

Min

Max

AS190xx__

22

2.167

2.2

2.233

2.145

2.255

AS190xx__

23

2.285

2.32

2.355

2.262

2.378

AS190xx__

24

2.364

2.4

2.436

2.340

2.460

AS190xx__

25

2.463

2.5

2.538

2.438

2.563

AS190xx__

26

2.591

2.63

2.669

2.564

2.696

AS190xx__

27

2.660

2.7

2.741

2.633

2.768

AS190xx__

28

2.758

2.8

2.842

2.730

2.870

AS190xx__

29

2.886

2.93

2.974

2.857

3.003

AS190xx__

30

2.955

3.0

3.045

2.925

3.075

AS190xx__

31

3.034

3.08

3.126

3.003

3.157