LTC2934 Datasheet, PDF (1/12 Pages) Linear Technology – Ultra-Low Power Adjustable Supervisor with Power-Fail Output

FEATURES
n _{500nA Quiescent Current}
n _{±1.5% (Max) Accuracy over Temperature}
n _{Operates Down to 1.6V Supply}
n _{Adjustable Reset Threshold}
n _{Adjustable Power-Fail Threshold}
n _{Early Warning Power-Fail Output}
n _{Selectable 15ms or 200ms Reset Timeout}
n _{Manual Reset Input}
n _{Compact 8-Lead, 2mm × 2mm DFN and TSOT-23}
(ThinSOT™) Packages
APPLICATIONS
n _{Portable Equipment}
n _{Battery-Powered Equipment}
n _{Security Systems}
n _{Point-of-Sale Devices}
n _{Wireless Systems}
, LT, LTC, LTM are registered trademarks of Linear Technology Corporation. ThinSOT is
a trademark of Linear Technology Corporation. All other trademarks are the property of
their respective owners.
LTC2934
Ultra-Low Power
Adjustable Supervisor with
Power-Fail Output
DESCRIPTION
The LTC^®2934 ultra-low power voltage monitor provides
system initialization, power-fail warning and reset gen-
eration functions. Low quiescent current (500nA typical)
makes the LTC2934 an ideal choice for battery-operated
applications.
Precision power-fail and reset voltages can be configured
independently. Early warning of an impending low volt-
age condition is provided at the power-fail output (PFO)
when the PFI input falls below 0.4V. Supervisory circuits
monitor the ADJ input and pull RST low when ADJ falls
below 0.4V. When ADJ is rising from an under-threshold
condition, an internal reset timer is started after exceeding
the ADJ threshold by 5%. The 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 (LTC2934-1) or active pull-up circuits
(LTC2934-2). Operating temperature range is from –40ºC
to 85ºC.
TYPICAL APPLICATION
Configurable Low Power Voltage Supervisor
V_IN
750k
0.1μF
11.8k
237k
V_CC
ADJ
PFO
LTC2934-2
PFI
MR
RST
RT GND
POWER FAIL FALLING THRESHOLD = 1.686V
RESET FALLING THRESHOLD = 1.606V
BATTERY
POWERED
SYSTEM
LOGIC
2934 TA01a
Selectable Reset Timeout Period
V_CC
RST, RT = GND
15ms
RST, RT = V_CC
200ms
2934 TA01b
2934f
1