LTC2952 Datasheet, PDF (1/28 Pages) Linear Technology – Push Button PowerPathTM Controller with Supervisor

FEATURES
■ _{Push-Button On/Off Control}
■ _{Automatic Low Loss Switchover Between DC}
Sources
■ _{Wide Operating Voltage Range: 2.7V to 28V}
■ _{Low 25µA Shutdown Current}
■ _{Guaranteed Threshold Accuracy: ±1.5% of}
Monitored Voltage Over Temperature
■ _{Adjustable Push-Button On/Off Timers}
■ _{Simple Interface Allows Graceful µP Shutdown}
■ _{Extendable House Keeping Wait Time Prior to}
Shutdown
■ _{200ms Reset Delay and 1.6s Watchdog Time Out}
■ _{±8kV HBM ESD on} ⎯_P⎯_{B Input}
■ _{20 pin TSSOP and QFN (4mm × 4mm) Packages}
APPLICATIONS
■ _{Desktop and Notebook Computers}
■ _{Portable Instrumentations}
■ _{Cell Phones, PDA and Handheld Computers}
■ _{Servers and Computer Peripherals}
■ _{Battery Backup Systems}
LTC2952
Push Button PowerPath^TM
Controller with Supervisor
DESCRIPTION
The LTC^®2952 is a power management device that features
three main functions: push-button on/off control of system
power, ideal diode power paths and system monitoring.
The LTC2952’s push-button input, which provides on/off
control of system power, has independently adjustable
ON and OFF debounce times. A simple microprocessor
interface involving an interrupt signal allows for proper
system housekeeping prior to power down.
The ideal diode power paths provide automatic low loss
switchover between two DC sources by regulating two
external P-channel MOSFETs to have a small 20mV for-
ward drop.
High reliability systems may utilize the LTC2952’s monitor-
ing features to ensure system integrity. These features in-
clude: power-fail, voltage monitoring and µP watchdog.
The LTC2952 operates over a wide operating voltage range
to accommodate a large variety of input power supplies. The
part’s combination of low 20mV external MOSFET regula-
tion and very low standby current matches battery powered
and power conscious application requirements.
, LT, LTC and LTM are registered trademarks of Linear Technology Corporation.
All other trademarks are the property of their respective owners.
TYPICAL APPLICATION
Push-Button Controller with Automatic Switchover Between Adapter and Battery
ADAPTER
3V TO 25V
Si6993DQ
12V BATTERY
Si6993DQ
G1
VS
G2
PFI
V_IN
V_OUT
LT1767-2.5
SHDN
511k
100k
V1
EN
V2
VM
LTC2952 ^RST
M1
G1STAT
M2
PFO
INT
PB
KILL
WDE
ONT GND OFFT
*22nF
*68nF
*OPTIONAL
365k
100k
2.5V
1k 10k
1k
1k
D2
D3
D1
µP
2952 TA01
Ideal Diode vs Schottky Diode
Forward Voltage Drop
1
CONSTANT
R_ON
IDEAL
DIODE
CONSTANT
VOLTAGE
SCHOTTKY
DIODE
0
0.02
FORWARD VOLTAGE (V)
0.50
2952 TA01b
2952f
1