LTC2954 Linear Technology, LTC2954 Datasheet - Page 6

• Manufacturer Part Number: LTC2954
• Description: Push Button On/Off Controller
• Manufacturer: Linear Technology

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PI FU CTIO S
LTC2954
6
V
 P  B (Pin 2/Pin 3): Push Button Input. Connecting  P  B to
ground through a momentary switch provides On/Off
control via the EN/  E  N and  I  N  T outputs. An internal 100k
pull-up resistor connects to an internal 1.9V bias voltage.
The rugged  P  B input withstands ±10kV ESD HBM and
can be pulled up to 26.4V externally without consuming
extra current.
ONT (Pin 3/Pin 2): Turn On Time Input. Placing an external
capacitor to ground determines the additional time (6.4
seconds/µF) the  P  B pin must be held low before the enable
output is asserted. Floating this pin results in a default turn
on debounce time of 32ms.
GND (Pin 4/Pin 1): Device Ground.
 I  N  T (Pin 5/Pin 8): Open Drain Interrupt Output. After a push
button turn off event is detected (t
interrupts the system (µP) by asserting the  I  N  T pin low.
The µP would perform power down and housekeeping
tasks and then assert the  K  I  L  L pin low, thus releasing the
enable output. The  I  N  T pulse width is a minimum of 32ms
and stays low as long as  P  B is asserted. If  P  B is asserted
for longer than t
are immediately released.
EN (LTC2954-1, Pin 6/Pin 7): Open Drain Enable Output.
This pin is intended to enable system power. EN is asserted
high after a valid  P  B turn on event (t
IN
U
(Pin 1/Pin 4): Power Supply Input: 2.7V to 26.4V.
U
PD,Min
U
+ t
PDT
(TSOT-23/DFN)
, the  I  N  T and EN/  E  N outputs
DB,OFF
DB,ON
), the LTC2954
+ t
ONT
). EN is
released low if: a)  K  I  L  L is not driven high (by μP) within
512ms of the initial valid  P  B power turn-on event, b)  K  I  L  L
is driven low during normal operation, c)  P  B is pressed
and held low (t
operating range for this low leakage pin is 0V to 26.4V.
  E  N (LTC2954-2, Pin 6/Pin 7): Open Drain Enable Bar
Output. This pin is intended to enable system power.  E  N is
asserted low after a valid  P  B turn-on event (t
 E  N releases high if: a)  K  I  L  L is not driven high (by μP) within
512ms of the initial valid  P  B power turn-on event, b)  K  I  L  L
is driven low during normal operation, c)  P  B is pressed
and held low (t
The operating range of this pin is 0V to 26.4V.
PDT (Pin 7/Pin 6): Power Down Time Input. A capacitor
to ground determines the additional time (6.4 seconds/µF)
that the push button must be held low before immediately
releasing the EN/  E  N and  I  N  T outputs. Floating this pin
results in a push button power down time of 64ms.
 K  I  L  L (Pin 8/Pin 5): Kill Input. Forcing  K  I  L  L low releases the
enable output. During system turn on, this pin is blanked
by a 512ms internal timer (t
system to pull  K  I  L  L high. This pin has an accurate 0.6V
threshold and can be used as a voltage monitor input.
Exposed Pad (Pin 9 DFN Only): Exposed Pad may be left
open or connected to device ground.
PD, Min
PD, Min
+ t
+ t
PDT
PDT
) during normal operation. The
 K  I  L  L , ON BLANK
) during normal operation.
) to allow the
DB, ON
+ t
ONT
2954f
).