12.13.3. Pin Description
12.14. LM809
12.14.1. General Description
The LM809/810 microprocessor supervisory circuits can be used to monitor the power supplies in
microprocessor and digital systems. They provide a reset to the microprocessor during power-up, power-
down and brown-out conditions. The function of the LM809/810 is to monitor the VCC supply voltage and
assert a reset signal whenever this voltage declines below the factory-programmed reset threshold. The
reset signal remains asserted for 240ms after VCC rises above the threshold. The LM809 has an active-low
RESET output, while the LM810 has an active-high RESET output. Seven standard reset voltage options are
available, suitable for monitoring 5V, 3.3V, and 3V supply voltages. With a low supply current of only 15?A,
the LM809/810 are ideal for use in portable equipment.
12.14.2. Features
? Precise monitoring of 3V, 3.3V, and 5V supply voltages
? Superior upgrade to MAX809/810
? Fully specified overtemperature
? 140ms min. Power-On Reset pulse width, 240ms typical
Active-low RESET Output(LM809)
Active-high RESET Output(LM810)
? Guaranteed RESET Output valid for VCC?1V
? Low Supply Current, 15?A typ
? Power supply transient immunity
12.14.3. Pinning
19
Plasma TV Service Manual 04/08/2005 |
ACEC
