LTC2956_15 Datasheet, PDF (1/26 Pages) Linear Technology – Wake-Up Timer with Pushbutton Control

Features
n _{1.5V to 36V Supply Input Range}
n _{Adjustable Wake-Up Period: 250ms to 39 Days}
n _{Adjustable Maximum Awake Time}
n _{0.8µA Quiescent Current}
n _{0.3µA Shutdown Current}
n _{Pushbutton Input with Debouncing}
n _{Low Leakage EN Output Allows DC/DC Converter}
Control (LTC2956-1)
n _{High Voltage EN Output Drives External P-Channel}
MOSFET (LTC2956-2)
n _{±25kV ESD HBM on PB Input}
n _{12-Lead 3mm × 3mm QFN and MSOP Packages}
Applications
n _{Heartbeat Timers}
n _{Periodic Wake-Up Control}
n _{Portable and Battery-Powered Equipment}
n _{Intervalometers}
n _{Data Acquisition}
LTC2956
Wake-Up Timer with
Pushbutton Control
Description
The LTC^®2956 is a micropower, wide input voltage range,
configurable wake-up timer with pushbutton control. It
periodically wakes up and turns on a connected system
to perform tasks like monitoring temperature or capturing
images. After completing the task, the LTC2956 turns the
system off to conserve power.
The wake-up timer period can be adjusted from 250ms to
39 days using configuration resistors. The system awake
time can be controlled by the input pulse at the SLEEP
pin or adjusted by the capacitor at the ONMAX pin. The
LTC2956 operates over a wide supply input range from
1.5V to 36V. The low 800nA quiescent current suits bat-
tery powered applications.
The pushbutton input allows the user to shutdown, turn
on or reset the wake-up timer. With the timer in shutdown,
the quiescent current drops to 300nA. The LTC2956 also
provides three status outputs to indicate mode transitions
and pushbutton events. Two versions are available for
applications requiring either positive or negative enable
polarities.
L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks and
PowerPath and ThinSOT are trademarks of Linear Technology Corporation. All other trademarks
are the property of their respective owners.
Typical Application
+ ^VBAT
LT3060
V_IN
V_OUT
1µF
SHDN
10k
1.5nF
V_IN
EN
ONMAX LTC2956-1 ^PBOUT
ONALERT
PB
GND
LONG RANGE
OFFALERT
SLEEP
PERIOD
10k
TURNED ON
TURNING OFF
100k
100k
280k
9.76k
t_LONG = 1s, t_ONMAX = 20ms, t_PERIOD = 250ms
V_MAIN
10k
PB
SLEEP
µP
EN
2956 TA01a
SHORT PRESS STARTS
CYCLING TIMER
LONG PRESS STOPS
CYCLING TIMER
µP SHUTS OFF
POWER
TIMER PERIODICALLY
ENABLES POWER
t_AWAKE
t_SLEEP
t_PERIOD
2956 TA01b
2956f
For more information www.linear.com/LTC2956
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