ha16117fpc Renesas Electronics Corporation., ha16117fpc Datasheet - Page 3

• Manufacturer Part Number: ha16117fpc
• Description: Cmos Watchdog Timer
• Manufacturer: Renesas Electronics Corporation.

Block Diagram
The HA16117F consists of a low voltage detector, power-on and auto-reset circuit, and watchdog timer.
Low Voltage Detector
Uses a reference voltage source ( 1.25 V) and high-precision comparator to detect drops in the supply
voltage.
Power-On and Auto-Reset Circuit
Generates the RES waveform, using a multivibrator consisting of a current source I
external capacitor C
Note: The power-on reset circuit operates in both operating and standby modes.
Mode
Operating
Standby
0.1
5 V
R
510 k
R
750 k
1
2
PULSE from I/O port
4
6
8
2
P-RUN
GND
GND
C
Tadj
ACC Voltage
Low
High
1/2 frequency
R
R
, a current source I
divider
Power-on and auto-reset circuit
Watchdog timer
V
CC
1
duty 50%
(SW1 and SW2 are active high)
1
I
2.52 (117FA)
2.36 (117FB)
2.20 (117FC)
W.D in
2
adjustment
Function
Low voltage detection and WDT
Low voltage detection
(*I
1
< I
2
W.D out
duty (%)
that discharges C
Watchdog filter (f-duty converter)
2
)
1.25 V
n
Low voltage detector
SW2
W.D in frequency (Hz)
Normal range
f
L
/2
+
3
COMP.
I
2
C
0.01
R
F
, and a comparator.
f
I
H
1
/2
SW1
W.D out
duty n%
+
COMP.
HA16117F Series
7
ACC
RES
Operating: "Low"
Standby: "High"
5
1
that charges the
to Micro-
computer
3