DS1833 5v econoreset DS1833 022698 1/5 features ? automatically restarts microprocessor after power failure ? maintains activehigh reset for 350 ms after v cc re- turns to an intolerance condition ? accurate 5%, 10% or 15% microprocessor 5v power supply monitoring ? reduces need for discrete components ? precision temperaturecompensated voltage refer- ence and voltage sensor ? lowcost to92 package or surface mount sot223 package ? internal 5k pullup resistor ? operating temperature of 40 c to +85 c pin assignment dallas 12 3 1 23 DS1833 to92 package see mech. drawings section 1 23 4 sot223 package see mech. drawings section pin description pin 1 ground pin 2 reset pin 3 v cc pin 4 ground (sot223 only) description the DS1833 econoreset uses a precision temperature compensated reference and comparator circuit to moni- tor the status of the power supply (v cc ). when an out oftolerance condition is detected, an internal power fail signal is generated which forces reset to the active (high) state. when v cc returns to an intolerance con- dition, the reset signal is kept in the active state for ap- proximately 350 ms to allow the power supply and pro- cessor to stabilize.
DS1833 022698 2/5 operation power monitor the DS1833 provides the functions of detecting outof tolerance power supply conditions and warning a pro- cessorbased system of impending power failure. when v cc is detected as outoftolerance, as defined by the tolerance of the part selected, the rst signal is asserted. on powerup, rst is kept active for approxi- mately 350 ms after the power supply has reached the selected tolerance. this allows the power supply and microprocessor to stabilize before rst is released. block diagram figure 1 vcc tolerance and bias t.c. reference 350 ms delay ground rst v cc application example figure 2 DS1833 v cc microprocessor rst reset
DS1833 022698 3/5 power up figure 3 t r v cc rst 4.75v 4.00v v cctp t rpu v ol power down figure 4 t f v cc v cctp t rpd v oh rst rst slews with v cc 4.75v 4.00v
DS1833 022698 4/5 absolute maximum ratings* voltage on v cc pin relative to ground 0.5v to +7.0v voltage on i/o relative to ground 0.5v to v cc +0.5v operating temperature 40 c to +85 c storage temperature 55 c to +125 c soldering temperature 260 c for 10 seconds * this is a stress rating only and functional operation of the device at these or any other conditions above those indicated in the operation sections of this specification is not implied. exposure to absolute maximum rating conditions for extended periods of time may affect reliability. recommended dc operating conditions (40 c to +85 c) parameter symbol min typ max units notes supply voltage v cc 1.2 5.0 5.5 v 1 dc electrical characteristics (40 c to +85 c; v dd = 5v + 10%) parameter symbol min typ max units notes low level @ rst v ol 0.4 v 1 output current @ 0.4v i ol +8 ma operating current i cc 1.5 2 ma v cc trip point 5% v cctp1 4.5 4.625 4.74 v 1 v cc trip point 10% v cctp2 4.25 4.375 4.49 v 1 v cc trip point 15% v cctp3 4.0 4.125 4.24 v 1 output capacitance c out 10 pf internal pullup resistor r p 3.75 5 6.25 k w ac electrical characteristics (40 c to +85 c; v cc = 5v + 10%) parameter symbol min typ max units notes reset active time t rst 250 350 450 ms v cc detect to rst t rpd 100 ns v cc slew rate (4.75v 4.00v) t f 300 m s v cc slew rate (4.00v 4.75v) t r 0 ns v cc detect to rst t rpu 250 350 450 ms note: 1. all voltages are referenced to ground.
DS1833 022698 5/5 econoreset selection guide vcc trip point pushbutton detect min typ max min typ max 5v ds123315 4.0 4.125 4.24 2.4 3.3 5v ds123310 4.25 4.375 4.49 2.4 3.3 5v ds12335 4.5 4.625 4.75 2.4 3.3 5v ds1233d15 4.0 4.125 4.24 n/a n/a 5v ds1233d10 4.25 4.375 4.49 n/a n/a ds1233d5 4.5 4.625 4.75 n/a n/a DS183315 4.0 4.125 4.24 n/a n/a DS183310 4.25 4.375 4.49 n/a n/a DS18335 4.5 4.625 4.75 n/a n/a 33v ds1233a15 2.64 2.72 2.80 1.8 3.0 3.3v ds1233a10 2.8 2.88 2.97 1.8 3.0
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