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Part: HA1835P
Category:
Description: Watchdog Timer
Company: Hitachi Semiconductor (acquired by Renesas)
Datasheet: Download HA1835P datasheet File size : 283 kB
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Datasheet text preview:
HA1835P/HA1848P
Watchdog Timer
Description
The HA1835P and HA1848P is a monolithic voltage regulator control designed for microcomputer systems. In addition to the voltage regulator, it include watchdog timer function and power-on reset function. These ICs can perform many function in various microcomputer systems with few external parts.
Features
· Regulated power supply control function Wide area of operational voltage; V CC = 6 V to 30 V Available external PNP-type transistor, suited to any system power supply Built-in overcurrent limiter for external PNP-type transistor Output voltage can be adjusted exactry in the range from 4 V to 6 V · Watchdog timer Internal bandpass filter control circuit (pulse width detect type) and reset signal oscillator Fail-safe utility Bandpass filter characteristics can be set by external resister (Rf) and capacitance (Cf) · Automatic reset Automatic power-on reset Pulse generator characteristics can be set by external resistor (RR) and capacitance (CR) Alternative between RES and RES output
HA1835P/HA1848P
Pin Arrangement
RR CR P-RUN Rf Cf Vout GND 1 2 3 4 5 6 7 14 13 12 11 10 9 8 RES RES CS VCC VCONT Comp * Vadj
(Top View) Note: HA1848P: 9 pin is non connection.
Pin Functions
Pin No. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 Symbol RR CR P-RUN Rf Cf Vout GND Vadj Comp VCONT VCC CS RES * RES * Functions Reset pulse width depends on resistance connected to RR Recommended range: 100 k to 1 M Reset pulse width depends on capacitance connected to CR Clock pulse input terminal for watchdog timer Frequency band width of filter circuit depends on resistance connected to Rf Recommended range: 100 k to 500 k Frequency band width of filter circuit depends on capacitance connected to Cf Connect to external PNP transistor's collector: This pin supplies 5 V regulated voltage for internal circuit Ground Output voltage fine tuning terminal Phase compensation terminal: Connect less than 100 pF capacitor between V CC and Comp. HA1848P is non connection External PNP transistor's base control terminal Supply voltage terminal: Operating supply voltage range is 6 V to 30 V Connect current sense resistor, which protects the external PNP transistor, between V CC and CS Reset pulse output terminal for low level reset type microcomputer Reset pulse output terminal for high level reset type microcomputer
Note: RES and RES are open-collector output terminals, so connect a pull-up resistor of about 5 k.
2
HA1835P/HA1848P
Block Diagram
VCC C1 11 VCC Current Limiter Reference Voltage 12 CS 10 VCONT 6 Vout HA1835P RCS Q Vout
5 k
Error Amp
9 Comp * 8 Vadj 2 k 14 RES
P-RUN 3
Fail Detector (Band Pass Filter)
Power on Reset Detector Reset Signal Oscillator
13 RES
7
4 Rf 300 k
5 Cf 0.01 µF
1 RR 560 k
2 CR 0.1 µF
GND Note: HA1848P: 9 pin is non connection.
3
Others parts begin by ha
HA-1 HA-2 HA-3 HA-4 HA-5 HA-6 HA-7 HA-8 HA-9 HA-10
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