LTC2950-1/LTC2950-2
Push Button On/Off
Controller
FEATURES
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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.
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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
Control
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 ThinSOT
TM
Packages
APPLICATIONS
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■
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Portable Instrumentation Meters
Blade Servers
Portable Customer Service PDA
Desktop and Notebook Computers
TYPICAL APPLICATION
V
IN
3V – 26V
Turn On Debounce
V
IN
V
OUT
DC/DC
BUCK
SHDN
EN
R1
10k
INT
μP/μC
KILL
2950 TA01
V
IN
LTC2950-1
PB
GND
ONT
C
ONT
*
0.033μF
EN
INT
KILL
OFFT
C
OFFT
*
0.033μF
2V/DIV
PB
10ms/DIV
*OPTIONAL
2950 TA01b
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1
LTC2950-1/LTC2950-2
ABSOLUTE MAXIMUM RATINGS
(Note 1)
Supply Voltage (V
IN
) ..................................– 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
PIN CONFIGURATION
TOP VIEW
GND 1
ONT 2
PB 3
V
IN
4
9
8
7
6
5
INT
EN/EN
OFFT
KILL
V
IN
1
PB 2
ONT 3
GND 4
TOP VIEW
8 KILL
7 OFFT
6 EN/EN
5 INT
DDB8 PACKAGE
8-LEAD (3mm 2mm) PLASTIC DFN
T
JMAX
= 125°C,
θ
JA
= 165°C/W
EXPOSED PAD (PIN 9) UNCONNECTED
TS8 PACKAGE
8-LEAD PLASTIC TSOT-23
T
JMAX
= 125°C,
θ
JA
= 140°C/W
ORDER INFORMATION
Lead Free Finish
TAPE AND REEL (MINI)
TAPE AND REEL
PART MARKING*
PACKAGE DESCRIPTION
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
LTC2950CDDB-1#TRMPBF LTC2950CDDB-1#TRPBF LBKP
8-Lead Plastic DFN
LTC2950CDDB-2#TRMPBF LTC2950CDDB-2#TRPBF LBNG
8-Lead Plastic DFN
LTC295ICDDB-1#TRMPBF LTC295ICDDB-1#TRPBF
LBKP
8-Lead Plastic DFN
LTC295ICDDB-2#TRMPBF LTC295ICDDB-2#TRPBF
LBNG
8-Lead Plastic DFN
LTC2950CTS8-1#TRMPBF LTC2950CTS8-1#TRPBF
LTBKN
8-Lead Plastic TSOT-23
LTC2950CTS8-2#TRMPBF LTC2950CTS8-2#TRPBF
LTBNF
8-Lead Plastic TSOT-23
LTC2950ITS8-1#TRMPBF
LTC2950ITS8-1#TRPBF
LTBKN
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/
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LTC2950-1/LTC2950-2
ELECTRICAL CHARACTERISTICS
SYMBOL
V
IN
I
IN
V
UVL
V
UVL(HYST)
PARAMETER
Supply Voltage Range
V
IN
Supply Current
V
IN
Undervoltage Lockout
The
●
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25C. V
IN
= 2.7V to 26.4V, unless otherwise noted. (Note 2)
CONDITIONS
Steady State Operation
System Power On, V
IN
= 2.7V to 24V
V
IN
Falling
●
●
●
MIN
2.7
TYP
6
MAX
26.4
12
2.4
600
UNITS
V
μA
V
mV
2.2
50
2.3
300
V
IN
Undervoltage Lockout
Hysteresis
Push Button Pin (PB)
V
PB(MIN,
MAX)
I
PB
PB
Voltage Range
PB
Input Current
Single-Ended
2.5V < V
PB
< 26.4V
V
PB
= 1V
V
PB
= 0.6V
PB
Falling
I
PB
= –1μA
V
ONT, OFFT
= 0V
V
ONT, OFFT
= 1.3V
ONT Pin Float,
PB
Falling
→
Enable Asserted
OFFT Pin Float,
PB
Falling
→
INT
Falling
●
●
●
●
●
●
●
●
●
●
●
–1
–1
–3
0.6
1
–2.4
2.4
26
9
26
9
–6
–9
0.8
1.6
–3
3
32
11.5
32
11.5
26.4
±1
–12
–15
1
2
–3.6
3.6
41
13.5
41
13.5
±1
0.11
0.4
0.63
50
±0.1
V
μA
μA
μA
V
V
μA
μA
ms
ms
ms
ms
μA
V
V
mV
μA
μs
μs
ms
ms
ms
μA
V
V
PB(VTH)
V
PB(VOC)
I
ONT, OFFT(PU)
I
ONT, OFFT(PD)
t
DB, On
t
ONT
t
DB, Off
t
OFFT
I
INT(LKG)
V
INT(VOL)
V
KILL(TH)
V
KILL(HYST)
I
KILL(LKG)
t
KILL(PW)
t
KILL(PD)
t
KILL,
On Blank
t
KILL,
Off Delay
t
EN/EN, Lock Out
I
EN/EN(LKG)
V
EN/EN(VOL)
PB
Input Threshold
PB
Open Circuit Voltage
ONT/OFFT Pull Up Current
ONT/OFFT Pull Down Current
Internal Turn On Debounce Time
Internal Turn Off Debounce Time
Debounce Timing Pins (ONT, OFFT)
Additional Adjustable Turn On Time C
ONT
= 1500pF
Additional Adjustable Turn Off Time C
OFFT
= 1500pF
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
KILL
Falling
→
Enable Released
KILL
= Low, Enable Asserted
→
Enable Released
KILL
= High,
INT
Asserted
→
Enable Released
Enable Released
→
Enable Asserted
V
EN/
EN
= 1V, Sink Current Off
I
EN/
EN
= 3mA
V
KILL
= 0.6V
V
INT
= 3V
I
INT
= 3mA
KILL
Falling
μP Handshake Pins (INT,
KILL)
●
●
●
0.57
10
0.6
30
●
●
●
●
●
●
●
30
30
400
800
200
512
1024
256
0.11
650
1300
325
±0.1
0.4
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 t
DB, ON
or t
ONT
.
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 t
DB, OFF
or t
OFFT
.
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 t
DB, ON
or t
ONT
.
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LTC2950-1/LTC2950-2
TYPICAL PERFORMANCE CHARACTERISTICS
Supply Current vs Temperature
10
V
IN
= 26.4V
8
V
IN
= 3.3V
V
IN
= 2.7V
4
I
VIN
(μA)
8
10
Supply Current vs Supply Voltage
T
A
= 25°C
50
Internal Default Turn On
Debounce Time (t
DB, ON
) vs V
IN
T
A
= 25°C
40
t
DB, ON
(ms)
I
VIN
(μA)
6
6
30
4
20
2
2
10
0
–50
–25
0
25
50
TEMPERATURE (°C)
75
100
2950 G01
0
0
5
10
15
V
IN
(V)
20
25
30
2950 G02
0
0
5
10
15
V
IN
(V)
20
25
30
2950 G03
Turn On Debounce Time (t
DB, ON
+ t
ONT
) vs ONT External Capacitor
10000
ONT PULL-DOWN CURRENT (μA)
T
A
= 25°C
V
IN
= 3.3V
–3.4
ONT Pull-Down Current
vs Temperature
50
Internal Default Turn Off
Debounce Time (t
DB, OFF
) vs V
IN
T
A
= 25°C
40
–3.2
V
IN
= 26.4V
–3.0
V
IN
= 2.7V
–2.8
t
DB, OFF
(ms)
75
100
2950 G05
t
DB, ON
+ t
ONT
(ms)
1000
30
20
100
10
10
1
100
10
ONT EXTERNAL CAPACITOR (nF)
1000
2950 G04
–2.6
–50
–25
0
25
50
TEMPERATURE (°C)
0
0
5
10
15
V
IN
(V)
20
25
30
2950 G06
Turn Off Debounce Time (t
DB, OFF
+ t
OFFT
) vs OFFT External Capacitor
10000
OFFT PULL-DOWN CURRENT (μA)
T
A
= 25°C
V
IN
= 3.3V
t
DB, OFF
+ t
OFFT
(ms)
–3.4
OFFT Pull-Down Current
vs Temperature
–250
PB
Current vs
PB
Voltage
T
A
= 25°C
V
IN
= 3.3V
–3.2
V
IN
= 26.4V
–3.0
V
IN
= 2.7V
–2.8
PB CURRENT (μA)
75
100
2950 G08
–200
1000
–150
–100
100
–50
10
1
100
10
OFFT EXTERNAL CAPACITOR (nF)
1000
2950 G07
–2.6
–50
–25
0
25
50
TEMPERATURE (°C)
0
–10
–5
0
5
10 15
PB VOLTAGE (V)
20
25
30
2950 G09
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LTC2950-1/LTC2950-2
TYPICAL PERFORMANCE CHARACTERISTICS
PB
Voltage vs External
PB
Resistance to Ground
300
V
IN
= 3.3V
250
200
150
100
50
0
0
5
10
15
20
EXTERNAL PB RESISTANCE TO GROUND (kΩ)
2950 G10
EN/EN V
OL
vs Current Load
500
T
A
= 25°C
V
IN
= 3.3V
400
EN/EN VOLTAGE (mV)
PB VOLTAGE (mV)
T
A
= 100°C
T
A
= 25°C
T
A
= –45°C
300
200
100
0
0
2
6
8
4
EN/EN CURRENT LOAD (mA)
10
2950 G11
EN (LTC2950-1) Voltage vs V
IN
1.0
T
A
= 25°C
100k PULL-UP FROM EN TO V
IN
4
EN
(LTC2950-2) Voltage vs V
IN
T
A
= 25°C
100k PULL-UP FROM EN TO V
IN
3
0.8
EN (V)
EN (V)
0
2
V
IN
(V)
2950 G12
0.6
2
0.4
1
0.2
0
1
3
4
0
0
1
2
V
IN
(V)
3
4
2950 G13
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