ver: 0.4 apr 10, 2012 tel: 886-3-5788833 http://www.gmt.com.tw 1 G656/g657 global mixed-mode technology microprocessor reset ic features ? precision monitoring voltage of +2.2v and +3.7v ? fully specified over temperature ? available in three output configurations push-pull reset output (G656l) push-pull reset output (G656h) open-drain reset output (g657l) ? reset deassert time smaller than 100 s when v cc higher than monitor voltages (cd pin float- ing) ? externally programmable time delay generator ? 27 a supply current at v cc =3.3v ? guaranteed reset valid to v cc = 0.8v ? tsot-23-5 packages ? 2% threshold accuracy applications ? computers ? controllers ? intelligent instruments ? critical p and c power monitoring ? portable / battery-powered equipment ? automotive general description the G656/g657 are microprocessor ( p) supervisory circuits used to monitor the power supplies in p and digital systems. they provide excellent circuit reliability and low cost. these circuits perform a single function: they assert a reset signal whenever the v cc supply voltage declines below a preset threshold, with hysteresis keeping it asserted for time delay determined by externally pro- grammable time delay generator after v cc has risen above the reset threshold. the g657l has an open-drain output stage, while the G656 have push-pull outputs. the g657l ? s open-drain reset output requires a pull-up resistor that can be connected to a voltage higher than v cc . the G656l has an active-low reset output, while the G656h has an active-high reset output. the outputs are guaranteed to be in the correct logic state for v cc down to 0.8v. the G656/g657 are available in 5-pin tsot-23-5 package. pin configuration typical application circuit tsot-23-5 reset (reset) vcc 5 1 2 nc 4 3 gnd cd ()is for G656h *g657 only reset input gnd p vcc reset (reset) gnd G656/g657 vcc cd v cc c d r pull-up * G656/g657 icc may increased at high t a , therefore, can not connect resistors to vcc to prevent icc abnormal behavior at high t a . tsot-23-5 reset (reset) vcc 5 1 2 nc 4 3 gnd cd ()is for G656h *g657 only reset input gnd p vcc reset (reset) gnd G656/g657 vcc cd v cc c d r pull-up * G656/g657 icc may increased at high t a , therefore, can not connect resistors to vcc to prevent icc abnormal behavior at high t a .
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