LTC2950-1/LTC2950-2
Pushbutton On/Off
Controller
FeaTures
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DescripTion
The LTC
®
2950 is a micropower, wide input voltage range,
pushbutton ON/OFF controller. The part contains a pushbut-
ton 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 26.4V 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, LTM, Linear Technology and the Linear logo are registered trademarks and
ThinSOT and PowerPath are trademarks of Linear Technology Corporation. All other trademarks
are the property of their respective owners.
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Adjustable Pushbutton On/Off Timers
Low Supply Current: 6µA
Wide Operating Voltage Range: 2.7V to 26.4V
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™ Packages
applicaTions
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Portable Instrumentation Meters
Blade Servers
Portable Customer Service PDA
Desktop and Notebook Computers
Typical applicaTion
V
IN
2.7V TO 26.4V
Turn On Debounce
V
IN
V
OUT
DC/DC
BUCK
SHDN**
EN
R1
10k
INT
KILL
2950 TA01
2950 TA01b
V
IN
LTC2950-1
PB
GND
ONT
C
ONT
*
0.033µF
EN
INT
KILL
OFFT
C
OFFT
*
0.033µF
2V/DIV
PB
µP/µC
10ms/DIV
*OPTIONAL
**SHDN INTERNALLY PULLED UP BY DC/DC
295012fd
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
LTC2950C-1 ............................................. 0°C to 70°C
LTC2950C-2 ............................................. 0°C to 70°C
LTC2950I-1 ..........................................–40°C to 85°C
LTC2950I-2 ..........................................–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
INT
7 EN/EN
6 OFFT
5
KILL
TOP VIEW
V
IN
1
PB
2
ONT 3
GND 4
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) PCB GND CONNECTION OPTIONAL
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)
LTC2950CDDB-1#TRMPBF
LTC2950CDDB-2#TRMPBF
LTC2950IDDB-1#TRMPBF
LTC2950IDDB-2#TRMPBF
LTC2950CTS8-1#TRMPBF
LTC2950CTS8-2#TRMPBF
LTC2950ITS8-1#TRMPBF
TAPE AND REEL
LTC2950CDDB-1#TRPBF
LTC2950CDDB-2#TRPBF
LTC2950IDDB-1#TRPBF
LTC2950IDDB-2#TRPBF
LTC2950CTS8-1#TRPBF
LTC2950CTS8-2#TRPBF
LTC2950ITS8-1#TRPBF
PART MARKING*
LBKP
LBNG
LBKP
LBNG
LTBKN
LTBNF
LTBKN
PACKAGE DESCRIPTION
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
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
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/
295012fd
2
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
V
IN
Undervoltage Lockout
Hysteresis
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
Enable Released
→
Enable Asserted
V
EN/
EN
= 1V, Sink Current Off
I
EN/
EN
= 3mA
V
ONT, OFFT
= 0V
V
ONT, OFFT
= 1.3V
ONT Pin Float,
PB
Falling
→
Enable Asserted
OFFT Pin Float,
PB
Falling
→
INT
Falling
l
l
l
l
l
l
l
l
The
l
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. 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
l
l
l
MIN
2.7
TYP
6
MAX
26.4
12
2.4
600
UNITS
V
µA
V
mV
2.2
50
2.3
300
Pushbutton, Enable (PB, EN/EN)
V
PB(MIN,
MAX)
I
PB
V
PB(VTH)
V
PB(VOC)
t
EN/EN, Lock Out
I
EN/EN(LKG)
V
EN/EN(VOL)
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
–1
–1
–3
0.6
1
200
–6
–9
0.8
1.6
256
0.11
–2.4
2.4
26
9
26
9
–3
3
32
11.5
32
11.5
26.4
±1
–12
–15
1
2
325
±0.1
0.4
–3.6
3.6
41
13.5
41
13.5
±1
0.11
0.57
10
V
KILL
= 0.6V
l
V
µA
µA
µA
V
V
ms
µA
V
µA
µA
ms
ms
ms
ms
µA
V
V
mV
µA
µs
µs
ms
ms
PB
Input Threshold
PB
Open Circuit Voltage
EN/EN Lock Out Time (Note 5)
EN/EN Leakage Current
EN/EN Voltage Output Low
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)
l
l
l
l
l
l
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)
KILL
Falling
→
Enable Released
KILL
= Low, Enable Asserted
→
Enable Released
KILL
= High,
INT
Asserted
→
Enable Released
V
INT
= 3V
I
INT
= 3mA
KILL
Falling
µP Handshake Pins (INT,
KILL)
l
l
l
0.4
0.63
50
±0.1
0.6
30
30
30
400
800
512
1024
650
1300
l
l
l
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
.
295012fd
3
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
t
DB, ON
(ms)
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
I
VIN
(µA)
6
6
30
4
20
2
2
10
0
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
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
T
A
= 25°C
V
IN
= 3.3V
–3.4
ONT PULL-DOWN CURRENT (µA)
ONT Pull-Down Current
vs Temperature
50
Internal Default Turn Off
Debounce Time (t
DB, OFF
) vs V
IN
T
A
= 25°C
–3.2
t
DB, OFF
(ms)
75
100
2950 G05
40
V
IN
= 26.4V
t
DB, ON
+ t
ONT
(ms)
1000
30
–3.0
V
IN
= 2.7V
–2.8
100
20
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
T
A
= 25°C
V
IN
= 3.3V
–3.4
OFFT PULL-DOWN CURRENT (µA)
OFFT Pull-Down Current
vs Temperature
–250
PB
Current vs
PB
Voltage
T
A
= 25°C
V
IN
= 3.3V
t
DB, OFF
+ t
OFFT
(ms)
–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
295012fd
4
LTC2950-1/LTC2950-2
Typical perForMance characTerisTics
PB
Voltage vs External
PB
Resistance to Ground
300
250
PB VOLTAGE (mV)
200
150
100
50
0
EN/EN VOLTAGE (mV)
V
IN
= 3.3V
500
EN/EN V
OL
vs Current Load
T
A
= 25°C
V
IN
= 3.3V
400
T
A
= 100°C
T
A
= 25°C
T
A
= –45°C
300
200
100
0
5
10
15
20
EXTERNAL PB RESISTANCE TO GROUND (k )
2950 G10
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
0.8
3
EN (V)
EN (V)
0
2
V
IN
(V)
2950 G12
0.6
2
0.4
0.2
1
0
1
3
4
0
0
1
2
V
IN
(V)
3
4
2950 G13
295012fd
5
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