LTC2952_15 Datasheet, PDF (1/30 Pages) Linear Technology – Pushbutton PowerPath Controller with Supervisor

FEATURES
n _{Pushbutton On/Off Control}
n _{Automatic Low Loss Switchover Between DC}
Sources
n _{Wide Operating Voltage Range: 2.7V to 28V}
n _{Low 25μA Shutdown Current}
n _{Guaranteed Threshold Accuracy: ±1.5% of}
Monitored Voltage Over Temperature
n _{Adjustable Pushbutton On/Off Timers}
n _{Simple Interface Allows Graceful μP Shutdown}
n _{Extendable Housekeeping Wait Time Prior to}
Shutdown
n _{200ms Reset Delay and 1.6s Watchdog Timeout}
n _{±8kV HBM ESD on PB Input}
n _{20-pin TSSOP and QFN (4mm × 4mm) Packages}
APPLICATIONS
n _{Desktop and Notebook Computers}
n _{Portable Instrumentations}
n _{Cell Phones, PDA and Handheld Computers}
n _{Servers and Computer Peripherals}
n _{Battery Backup Systems}
LTC2952
Pushbutton PowerPath
Controller with Supervisor
DESCRIPTION
The LTC^®2952 is a power management device that features
three main functions: pushbutton on/off control of system
power, ideal diode PowerPath™ controllers and system
monitoring. The LTC2952’s pushbutton input, which pro-
vides on/off control of system power, has independently
adjustable ON and OFF debounce times. A simple micro-
processor interface involving an interrupt signal allows
for proper system housekeeping prior to power-down.
The ideal diode PowerPath controllers provide automatic
low loss switchover between two DC sources by regulating
two external P-channel MOSFETs to have a small 20mV
forward 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.
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
Pushbutton 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 ^**
LTC2952
V2
VM
RST
M1
G1STAT
M2
PFO
INT
PB
KILL
365k
100k
2.5V
1k
1k
1k
D2
D3
D1
ONT GND OFFT WDE
*22nF
*68nF
*OPTIONAL
**SHDN INTERNALLY PULLED UP BY THE LT1767-2.5
10k
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
2952fb
1