STM6502 has two combined Smart Reset inputs (SR0andSR1) with delayed Smart Reset setup time (tSRC) programmed by an external capacitor on the SRC pin.STM6503 is similar to STM6502, has two combined delayed Smart Reset inputs (SR0,SR1) and three user-selectable delayed Smart Reset setup time (tSRC) options of 2 s, 6 s and 10 s through a three-state TSR input pin: when connected to ground, tSRC= 2 s; when left open, tSRC= 6 s; when connected to VCC, tSRC= 10 s (all the times are minimum).STM6504 has two independent Smart Reset inputs.SR0provides the delayed Smart Reset setup time (tSRC) function with three user-selectable tSRCoptions through a three-state TSR input pin: when connected to ground, tSRC= 2 s; when left open, tSRC= 6 s; when connected to VCC, tSRC= 10 s (all the times are minimum). SRE provides instant reset. SRE is edge-triggered with a special debounce time (tDEBOUNCE= 240 ms min.) at the falling edge after a valid reset period.STM6505 has two combined delayed Smart Reset inputs (SR0,SR1) and provides an adjustable reset delay setup time via an external capacitor connected to the SRC pin. TheRSToutput depends also on the VCCmonitoring threshold. STM6505 also provides independent low battery detect (BLD) output controlled by the secondary external input voltage VBAT. VBATis monitored for low voltage and provides an indication on the battery low detect output pin (BLD). VBATthreshold is 1.25 V, fixed, and an external resistor divider is to be used to set the actual battery voltage threshold. VBATthreshold hysteresis is 8 mV typ. (16 mV max.). VBDual Smart Reset push-button inputs with extended reset setup delayAdjustable Smart Reset setup delay (tSRC): by external capacitor or three-state logic (product options): tSRC= 2, 6, 10 s (min.)Power-on resetSingleRSToutput, active-low, open-drainFactory-programmable thresholds to monitor VCCin the range of 1.575 to 4.625 V typ.Operating voltage 1.0 V (active-low output valid) to 5.5 VLow supply currentOperating temperature:industrial grade –40 °C to +85 °CTDFN8 package: 2 mm x 2 mm x 0.75 mmRoHS compliant