HA16117F Series
CMOS Watchdog Timer
REJ03F0142-0300
(Previous: ADE-204-018B)
Rev.3.00
Jun 15, 2005
Description
The HA16117F Series of ICs make a micro-processor (MPU) system fail-safe by monitoring its power supply to detect
voltage drops, and monitoring a P-RUN (program running) pulse to detect system crashes. Also referred to as
watchdog timers, these devices are essential in systems that aim for high levels of crash protection. Fabricated by a
CMOS process, they consume little power and are ideally suited for battery-operated systems.
These ICs are available in versions for industrial and communications equipment and automotive applications, as well
as for consumer products.
Functions
• ower-on reset
Sends a RES signal to the MPU for a fixed time at power-on
• Watchdog timer (WDT)
Monitors a P-RUN signal from the MPU and sends the MPU a RES signal if P-RUN departs from a set frequency
range
• Auto-reset
Outputs RES signals to the MPU at clocked intervals while P-RUN remains abnormal
• Supply voltage supervision
Outputs a low RES signal if the supply voltage (same as the MPU's VCC) falls below a low threshold level (VTL).
The threshold differs for different ICs in the series, allowing designers to choose an IC matching system
requirements (see ordering information)
Features
• Low power consumption
: Operating (ACC pin low) = 0.5 mW (Typ)
: Standby (ACC pin high) = 0.2 mW (Typ)
• Watchdog timer on/off control by ACC input signal
• Independent auto-reset high and low times (tRH and tRL)
• Watchdog monitoring by frequency filtering (independent of duty cycle)
• High-precision low voltage detection (±2%)
• Space- and weight-saving 8-pin SOP package
Ordering Information
The HA16117F Series includes three ICs with different low threshold levels (VTL).
HA16117FPA/FPAJ
HA16117FPB/FPBJ
HA16117FPC/FPCJ
Type No.
4.4 V Typ
4.2 V Typ
4.0 V Typ
Low Threshold Voltage (VTL)
Rev.3.00 Jun 15, 2005 page 1 of 30