HA16103FPJ View Datasheet(PDF) - Renesas Electronics

Part Name

Description

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HA16103FPJ

Watchdog Timer

Renesas Electronics 

HA16103FPJ/FPK

Watchdog Timer Function

The system contains a bandpass filter for pulse width detection, which outputs a reset pulse when input pulses are not at

the preselected frequency (at either a higher or lower frequency).

The RC characteristic of the bandpass filter may be set with external components Rf and Cf. Equation 3 specifies how

to determine the minimum pulse width (tmin) for runaway detection of the bandpass filter, and figure 4 shows the

characteristic of the filter.

HA16103

Rf Cf

tmin = Cf x Rf x 0.11 (s) ⋅ ⋅ ⋅ ⋅ Equation 3

Rf : Ω

2.0 m

1.8 m

1.6 m

1.4 m

(Ta = 25°C)

P—Run pulse duty ratio 50% (fixed)

VCC = 12 V

CR = 0.1 µF

RR = 180 k Ω

1.2 m

1.0 m

0.8 m

0.6 m

Cf = 0.022 µF

0.4 m

0.2 m

Cf = 0.01 µF

Cf = 0.0047 µF

100 k

200 k

Resistance Rf (Ω)

500 k

Figure 4 Characteristic of Power-On Reset Circuit

Rev.3.00 Jun 15, 2005 page 6 of 18

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