The LTC?2935 ultra-low power voltage monitor provides
system initialization, power-fail warning and reset gen-
eration functions. Low quiescent current (500nA typical)
makes the LTC2935 an ideal choice for battery-operated
applications.
Three binary threshold-select inputs con??? gure one of eight
integrated reset thresholds, available from 3.3V to 2.25V
in 150mV increments. Early warning of an impending
low voltage condition is provided at the power-fail output
(PFO), whose threshold is 150mV above the con? gured
reset threshold. Supervisory circuits monitor VCC and
pull RST low when VCC drops below the con?? gured reset
threshold. When VCC is rising from an under-threshold
condition, an internal reset timer is started after exceed-
ing the reset threshold by 5%. A 200ms reset timeout
delays the return of the RST output to a high state. A
pushbutton switch connected to the MR input is typically
used to force a manual reset. Outputs RST and PFO are
available with open-drain (LTC2935-1) or active pull-up
(LTC2935-2) circuits. Operating temperature range is from
–40oC to 85oC.