Download HA1835P Datasheet PDF
Hitachi Semiconductor
HA1835P
HA1835P is Watchdog Timer manufactured by Hitachi Semiconductor.
Description The HA1835P and HA1848P is a monolithic voltage regulator control designed for microputer 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 microputer 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 p - 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 p VCONT VCC CS RES - RES - Functions Reset pulse width depends on resistance connected to RR Remended range: 100 k Ω to 1 M Ω 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 Remended range: 100 k Ω to 500 k Ω 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 pensation terminal: Connect less than 100 p F capacitor between V CC and p. HA1848P is non connection External PNP transistor's...