C1 U1

V

Input

CC

GND

Reset

240 ms

RESET (LM809)

RESET (LM810)

V

CC

V

threshold (5 V, 3.3 V, or 3 V)

CC

11

LM809, LM810

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SNVS052E – SEPTEMBER 1999 – REVISED APRIL 2016

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8.2.3 Application Curve

Figure 11. Reset Active Timeout

9 Power Supply Recommendations

The input of the LM809 is designed to handle up to the supply voltage absolute maximum rating of 6.5 V. If the

input supply is susceptible to any large transients above the maximum rating, then extra precautions should be

taken. An input capacitor is recommended to avoid false reset output triggers due to noise.

10 Layout

10.1 Layout Guidelines

Place the input capacitor as close as possible to the IC.

10.2 Layout Example

Figure 12. Layout Example