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LTC2950-1/LTC2950-2
Push Button On/Off
Controller
FEATURES
Adjustable Push Button On/Off Timers
Low Supply Current: 6μA
Wide Operating Voltage Range: 2.7V to 26V
EN Output (LTC2950-1) Allows DC/DC Converter
Control
EN Output (LTC2950-2) Allows Circuit Breaker
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Simple Interface Allows Graceful μP Shut Down
High Input Voltage PB Pin with Internal Pull Up
Resistor
±10kV ESD HBM on PB Input
Accurate 0.6V Threshold on KILL Comparator Input
8-Pin 3mm × 2mm DFN and ThinSOTTM Packages
APPLICATIONS
Portable Instrumentation Meters
Blade Servers
Portable Customer Service PDA
Desktop and Notebook Computers
DESCRIPTION
The LTC®2950 is a micropower, wide input voltage range,
push button ON/OFF controller. The part contains a push
button input with independently programmable ON and OFF
debounce times that control the toggling of an open drain
enable output. The part also contains a simple micropro-
cessor interface to allow for proper system housekeeping
prior to power down. Under system fault conditions, an
internal KILL timer ensures proper power down.
The LTC2950 operates over a wide 2.7V to 26V input
voltage range to accommodate a wide variety of input
power supplies. Very low quiescent current (6μA typical)
makes the LTC2950 ideally suited for battery powered
applications. Two versions of the part are available to ac-
commodate either positive or negative enable polarities.
The parts are available in either 8-lead 3mm × 2mm DFN
or ThinSOT packages.
L, LT, LTC and 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.
TYPICAL APPLICATION
VIN
3V – 26V
VIN VOUT
DC/DC
BUCK
SHDN
VIN EN
LTC2950-1 INT
PB
GND ONT
KILL
OFFT
CONT*
0.033μF
COFFT*
0.033μF
R1
10k
INT
μP/μC
KILL
2950 TA01
*OPTIONAL
Turn On Debounce
EN
2V/DIV
PB
10ms/DIV
2950 TA01b
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LTC2950-1/LTC2950-2
ABSOLUTE MAXIMUM RATINGS (Note 1)
Supply Voltage (VIN) ..................................– 0.3V to 33V
Input Voltages
PB............................................................– 6V to 33V
ONT ......................................................– 0.3V to 2.7V
OFFT......................................................– 0.3V to 2.7V
KILL .........................................................– 0.3V to 7V
Output Voltages
INT.........................................................– 0.3V to 10V
EN/EN ....................................................– 0.3V to 10V
Operating Temperature Range
LTC2950-C1 .............................................. 0°C to 70°C
LTC2950-C2 .............................................. 0°C to 70°C
LTC2950-I1 .......................................... – 40°C to 85°C
LTC2950-I2 .......................................... – 40°C to 85°C
Storage Temperature Range
DFN Package..................................... – 65°C to 125°C
TSOT-23............................................ – 65°C to 150°C
Lead Temperature (Soldering, 10 sec) .................. 300°C
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PIN CONFIGURATION
TOP VIEW
GND 1
8 INT
ONT 2
7 EN/EN
9
PB 3
6 OFFT
VIN 4
5 KILL
DDB8 PACKAGE
8-LEAD (3mm s 2mm) PLASTIC DFN
TJMAX = 125°C, θJA = 165°C/W
EXPOSED PAD (PIN 9) UNCONNECTED
TOP VIEW
VIN 1
PB 2
ONT 3
GND 4
8 KILL
7 OFFT
6 EN/EN
5 INT
TS8 PACKAGE
8-LEAD PLASTIC TSOT-23
TJMAX = 125°C, θJA = 140°C/W
ORDER INFORMATION
Lead Free Finish
TAPE AND REEL (MINI) TAPE AND REEL
PART MARKING* PACKAGE DESCRIPTION
LTC2950CDDB-1#TRMPBF
LTC2950CDDB-2#TRMPBF
LTC295ICDDB-1#TRMPBF
LTC295ICDDB-2#TRMPBF
LTC2950CTS8-1#TRMPBF
LTC2950CTS8-2#TRMPBF
LTC2950ITS8-1#TRMPBF
LTC2950CDDB-1#TRPBF
LTC2950CDDB-2#TRPBF
LTC295ICDDB-1#TRPBF
LTC295ICDDB-2#TRPBF
LTC2950CTS8-1#TRPBF
LTC2950CTS8-2#TRPBF
LTC2950ITS8-1#TRPBF
LBKP
LBNG
LBKP
LBNG
LTBKN
LTBNF
LTBKN
8-Lead Plastic DFN
8-Lead Plastic DFN
8-Lead Plastic DFN
8-Lead Plastic DFN
8-Lead Plastic TSOT-23
8-Lead Plastic TSOT-23
8-Lead Plastic TSOT-23
LTC2950ITS8-2#TRMPBF LTC2950ITS8-2#TRPBF LTBNF
8-Lead Plastic TSOT-23
TRM = 500 pieces. *Temperature grades are identified by a label on the shipping container.
Consult LTC Marketing for parts specified with wider operating temperature ranges.
Consult LTC Marketing for information on lead based finish parts.
For more information on lead free part marking, go to: http://www.linear.com/leadfree/
For more information on tape and reel specifications, go to: http://www.linear.com/tapeandreel/
TEMPERATURE RANGE
0°C to 70°C
0°C to 70°C
–40°C to 85°C
–40°C to 85°C
0°C to 70°C
0°C to 70°C
–40°C to 85°C
–40°C to 85°C
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LTC2950-1/LTC2950-2
ELECTRICAL CHARACTERISTICS The denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at TA = 25C. VIN = 2.7V to 26.4V, unless otherwise noted. (Note 2)
SYMBOL
PARAMETER
CONDITIONS
MIN TYP MAX UNITS
VIN Supply Voltage Range
IIN VIN Supply Current
VUVL VIN Undervoltage Lockout
VUVL(HYST)
VIN Undervoltage Lockout
Hysteresis
Push Button Pin (PB)
VPB(MIN, MAX)
IPB
PB Voltage Range
PB Input Current
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VPB(VTH)
VPB(VOC)
PB Input Threshold
PB Open Circuit Voltage
Debounce Timing Pins (ONT, OFFT)
Steady State Operation
System Power On, VIN = 2.7V to 24V
VIN Falling
Single-Ended
2.5V < VPB < 26.4V
VPB = 1V
VPB = 0.6V
PB Falling
IPB = –1μA
2.7
2.2
50
26.4
6 12
2.3 2.4
300 600
V
μA
V
mV
–1
–1
–3
0.6
1
26.4
±1
–6 –12
–9 –15
0.8 1
1.6 2
V
μA
μA
μA
V
V
IONT, OFFT(PU) ONT/OFFT Pull Up Current
VONT, OFFT = 0V
IONT, OFFT(PD)
tDB, On
ONT/OFFT Pull Down Current
Internal Turn On Debounce Time
VONT, OFFT = 1.3V
ONT Pin Float, PB Falling Enable Asserted
tONT
tDB, Off
Additional Adjustable Turn On Time CONT = 1500pF
Internal Turn Off Debounce Time OFFT Pin Float, PB Falling INT Falling
tOFFT Additional Adjustable Turn Off Time COFFT = 1500pF
μP Handshake Pins (INT, KILL)
IINT(LKG)
VINT(VOL)
VKILL(TH)
VKILL(HYST)
IKILL(LKG)
tKILL(PW)
tKILL(PD)
tKILL, On Blank
tKILL, Off Delay
tEN/EN, Lock Out
IEN/EN(LKG)
VEN/EN(VOL)
INT Leakage Current
INT Output Voltage Low
KILL Input Threshold Voltage
KILL Input Threshold Hysteresis
KILL Leakage Current
KILL Minimum Pulse Width
KILL Propagation Delay
KILL Turn On Blanking (Note 3)
KILL Turn Off Delay (Note 4)
EN/EN Lock Out Time (Note 5)
EN/EN Leakage Current
EN/EN Voltage Output Low
VINT = 3V
IINT = 3mA
KILL Falling
VKILL = 0.6V
KILL Falling Enable Released
KILL = Low, Enable Asserted Enable Released
KILL = High, INT Asserted Enable Released
Enable Released Enable Asserted
VEN/EN = 1V, Sink Current Off
IEN/EN = 3mA
–2.4
2.4
26
9
26
9
0.57
10
30
400
800
200
–3
3
32
11.5
32
11.5
0.11
0.6
30
512
1024
256
0.11
–3.6
3.6
41
13.5
41
13.5
±1
0.4
0.63
50
±0.1
30
650
1300
325
±0.1
0.4
μA
μA
ms
ms
ms
ms
μA
V
V
mV
μA
μs
μs
ms
ms
ms
μA
V
Note 1: Stresses beyond those listed under Absolute Maximum Ratings
may cause permanent damage to the device. Exposure to any Absolute
Maximum Rating condition for extended periods may affect device
reliability and lifetime.
Note 2: All currents into pins are positive; all voltages are referenced to
GND unless otherwise noted.
Note 3: The KILL turn on blanking timer period is the waiting period
immediately after the enable output is asserted. This blanking time allows
sufficient time for the DC/DC converter and the μP to perform power up tasks.
The KILL and PB inputs are ignored during this period. If KILL remains low
at the end of this time period, the enable output is released, thus turning off
system power. This time delay does not include tDB, ON or tONT.
Note 4: The KILL turn off delay is the maximum delay from the initiation
of a shutdown sequence (INT falling), to the release of the enable output.
If the KILL input switches low at any time during this period, enable is
released, thus turning off system power. This time is internally fixed at
1024ms. This time delay does not include tDB, OFF or tOFFT.
Note 5: The enable lock out time is designed to allow an application to
properly power down such that the next power up sequence starts from a
consistent powered down configuration. PB is ignored during this lock out
time. This time delay does not include tDB, ON or tONT.
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LTC2950-1/LTC2950-2
TYPICAL PERFORMANCE CHARACTERISTICS
Supply Current vs Temperature
10
VIN = 26.4V
8
6 VIN = 3.3V
VIN = 2.7V
4
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0
–50 –25
0
25 50
TEMPERATURE (°C)
75 100
2950 G01
Turn On Debounce Time (tDB, ON
+ tONT) vs ONT External Capacitor
10000
TA = 25°C
VIN = 3.3V
1000
100
Supply Current vs Supply Voltage
10
TA = 25°C
8
6
4
2
0
0 5 10 15 20 25 30
VIN (V)
2950 G02
ONT Pull-Down Current
vs Temperature
–3.4
–3.2
VIN = 26.4V
–3.0
VIN = 2.7V
–2.8
Internal Default Turn On
Debounce Time (tDB, ON) vs VIN
50
TA = 25°C
40
30
20
10
0
0 5 10 15 20 25 30
VIN (V)
2950 G03
Internal Default Turn Off
Debounce Time (tDB, OFF) vs VIN
50
TA = 25°C
40
30
20
10
10
1 10 100 1000
ONT EXTERNAL CAPACITOR (nF)
2950 G04
Turn Off Debounce Time (tDB, OFF
+ tOFFT) vs OFFT External Capacitor
10000
TA = 25°C
VIN = 3.3V
1000
100
–2.6
–50 –25 0
25 50
TEMPERATURE (°C)
OFFT Pull-Down Current
vs Temperature
–3.4
75 100
2950 G05
–3.2
VIN = 26.4V
–3.0
VIN = 2.7V
–2.8
0
0 5 10 15 20 25 30
VIN (V)
2950 G06
PB Current vs PB Voltage
–250
–200
TA = 25°C
VIN = 3.3V
–150
–100
–50
10
1 10 100 1000
OFFT EXTERNAL CAPACITOR (nF)
2950 G07
–2.6
–50 –25 0
25 50
TEMPERATURE (°C)
75 100
2950 G08
4
0
–10 –5
0 5 10 15 20 25 30
PB VOLTAGE (V)
2950 G09
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LTC2950-1/LTC2950-2
TYPICAL PERFORMANCE CHARACTERISTICS
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PB Voltage vs External PB
Resistance to Ground
300
VIN = 3.3V
250
200 TA = 100°C
150 TA = 25°C
100 TA = –45°C
50
0
0 5 10 15 20
EXTERNAL PB RESISTANCE TO GROUND (kΩ)
2950 G10
EN/EN VOL vs Current Load
500
TA = 25°C
VIN = 3.3V
400
300
200
100
0
0 2 4 6 8 10
EN/EN CURRENT LOAD (mA)
2950 G11
EN (LTC2950-1) Voltage vs VIN
1.0
TA = 25°C
100k PULL-UP FROM EN TO VIN
0.8
0.6
0.4
0.2
0
01 2 3 4
VIN (V)
2950 G12
EN (LTC2950-2) Voltage vs VIN
4
TA = 25°C
100k PULL-UP FROM EN TO VIN
3
2
1
0
01 2 3 4
VIN (V)
2950 G13
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