DS1231-50N Maxim Integrated Products, DS1231-50N Datasheet
DS1231-50N
Specifications of DS1231-50N
Related parts for DS1231-50N
DS1231-50N Summary of contents
Page 1
... Replaces power-up reset circuitry No external capacitors required Optional 16-pin SOIC surface mount package DESCRIPTION The DS1231 Power Monitor Chip uses a precise tem- perature-compensated reference circuit which provides an orderly shutdown and an automatic restart of a pro- cessor-based system. A signal warning of an impending power failure is generated well before regulated DC voltages go out of specification by monitoring high volt- age inputs to the power supply regulators ...
Page 2
... The DS1231 Power Monitor detects out-of-tolerance power supply conditions and warns a processor-based system of impending power failure. The main elements of the DS1231 are illustrated in Figure 1. As shown, the DS1231 actually has two comparators, one for monitor- ing the input (Pin 1) and one for monitoring V (Pin 8) ...
Page 3
... POWER MONITOR BLOCK DIAGRAM Figure NMI MODE SELECTION GND TOLERANCE TOL BIAS 3 T.C. REFERENCE POWER-UP RESET Figure 2 DS1231 IN V MODE NMI TOL RST GND RST (-5% V THRESHOLD) CC MODE NMI DIGITAL DIGITAL SAMPLER DELAY MICROPROCESSOR + RST 8051 P DS1231 RST 6 RST 5 022698 3/9 ...
Page 4
... THEN 8 X 2.3 10K NOTE: RST requires a pull–up resister. 022698 4/9 –20 –35 V 2.3 2.15 TP 2.5 2.5 TP NOTE: HYSTERESIS TOLERANCE IS +60 mV Figure 4 CC DS1231 IN V +5V CC MODE NMI TOL RST TO P GND RST THRESHOLD SENSE V MAX X 5.0 X 2.3 VTP R1 = 25K – ...
Page 5
... A of collector current required by pin 1 and still have enough resistance to keep the maximum current through the opto-isolator’s LED within data sheet limits. Figure 7 illustrates how the DS1231 can be interfaced to the AC power line when the mode pin is grounded. DS1231 -10% V ...
Page 6
... NOTE: RST requires a pull–up resister. AC VOLTAGE MONITOR WITH OPTO-ISOLATION Figure 7 AC LINE INPUT NOTE: RST requires a pull–up resister. 022698 6/9 -5% V THRESHOLD CC DS1231 + MODE NMI TOL RST TO P GND RST CTR 33K DS1231 -5% V THRESHOLD CC + MODE NMI TO P TOL RST GND RST ...
Page 7
... C for 10 seconds ( MIN TYP MAX UNITS 4.5 5.0 5 4.5 to 5.5V) CC MIN TYP MAX UNITS 0 –0.5V V –0. -10 +10 A 1.0 2.0 mA 2.0 3.0 mA 0.5 2 0.1 A See Figure 3 4.50 4.62 4.74 V 4.25 4.37 4.49 V MIN TYP MAX UNITS DS1231/S NOTES 1 1 NOTES NOTES 022698 7/9 ...
Page 8
... DS1231/S AC ELECTRICAL CHARACTERISTICS PARAMETER SYMBOL V to NMI Delay t TP IPD V Slew Rate 4.75-4.25V Detect to RST and RST t CC RPD V Detect to NMI t CC IPU V Detect to RST and RST t CC RPU V Slew Rate 4.25-4.75V NOTES: 1. All voltages referenced to ground +5.0 volts with outputs open. ...
Page 9
... TIMING DIAGRAM: POWER-DOWN V TP INPUT PIN 1 MODE=V CC INPUT PIN 1 MODE=GND IPD NMI 4.75V RST RST CCTP 4.25V t RPD RST SLEWS WITH DS1231/S 022698 9/9 ...