manages system power via a push button interface. An
enable output toggles system power while an interrupt
output provides debounced push button status. The inter-
rupt output can be used in menu driven applications to
request a system power down.
The LTC2953 also features input and output power sup-
ply monitors. An uncommitted power fail comparator
provides real time input monitor information, while a
de-glitched under voltage lockout comparator gracefully
initiates a system power down. The under voltage lockout
comparator prevents the system from powering from a
low power supply.
The adjustable supply monitor input is compared against
an accurate internal 0.5V reference. The reset output
remains low until the supply monitor input has been in
compliance for 200ms.
The LTC2953 operates over a wide 2.7V to 27V input
voltage range and draws only 14μA of current. Two ver-
sions of the part accommodate either positive or negative
enable polarities.
, LT, LTC and LTM are registered trademarks of Linear Technology Corporation.
All other trademarks are the property of their respective owners.
Wide Operating Voltage Range: 2.7V to 27V
Push Button Control of System Power
Low Supply Current: 14μA
Power Fail Comparator Generates Warning
UVLO Comparator Gracefully Latches Power Off
Adjustable Supply Monitor with 200ms Reset
Adjustable Power Down Timer
Low Leakage EN Output (LTC2953-1) Allows DC/DC
Converter Control
High Voltage
⎯
E
⎯
N Output (LTC2953-2) Allows Circuit
Breaker Control
Simple Interface Allows Orderly System Power Up
and Power Down
±1.5% Threshold Tolerances
±10kV ESD HBM on
⎯
P
⎯
B Input
12-Pin 3mm
×
3mm DFN
APPLICATIONS
■
■
■
■
■
Push Button Power Path Control
Battery Power Supervisor
Portable Instrumentation, PDA
Blade Servers
Desktop and Notebook Computers
TYPICAL APPLICATION
V
IN
V
OUT
DC/DC
SHDN
100k
100k
100k
100k
RST
PFO
INT
KILL
PDT
1μF
t
PDT
= 6.4 SECONDS
2953f
2953 TA01
Push Button On/Off Control with Interrupt
3.3V
TURN ON PULSE
PB
SHORT
INTERRUPT PULSE
LONG
TURN OFF PULSE
+
8.4V
2150k
UVLO
V
IN
EN
100k
23.2k
PFI
196k
LTC2953-1
VM
499k
EN
TURNS ON
STAYS ON
TURNS OFF
PB
ON/OFF
GND
RST
GPIO
INT SYSTEM
LOGIC
KILL
INT
INTERRUPT
INTERRUPT
2954 TD01b
1
LTC2953
ABSOLUTE MAXIMUM RATINGS
(Note 1)
PIN CONFIGURATION
TOP VIEW
GND
V
M
KILL
PDT
PB
V
IN
1
2
3
4
5
6
13
12 INT
11 EN/EN
10 RST
9 PFO
8 PFI
7 UVLO
Supply Voltage (V
IN
) .................................. –0.3V to 33V
Input Voltages
⎯
P
⎯
B,
⎯
P
⎯
F
⎯
I, UVLO........................................... –6V to 33V
VM ......................................................... –0.3V to 20V
⎯
K
⎯
I
⎯
L
⎯
L ....................................................... –0.3V to 10V
PDT....................................................... –0.3V to 2.7V
Output Voltages
EN/
⎯
E
⎯
N,
⎯
P
⎯
F
⎯
O ............................................ –0.3V to 50V
⎯
R
⎯
S
⎯
T,
⎯
I
⎯
N
⎯
T ................................................ –0.3V to 10V
Operating Temperature Range
LTC2953C ................................................ 0°C to 70°C
LTC2953I ............................................. –40°C to 85°C
Storage Temperature Range................... –65°C to 125°C
DD PACKAGE
12-LEAD (3mm
´
3mm) PLASTIC DFN
T
JMAX
= 125°C,
θ
JA
= 43°C/W
EXPOSED PAD (PIN 13) PCB GROUND CONNECTION OPTIONAL
ORDER INFORMATION
LEAD FREE FINISH
LTC2953CDD-1#PBF
LTC2953CDD-2#PBF
LTC2953IDD-1#PBF
LTC2953IDD-2#PBF
TAPE AND REEL
LTC2953CDD-1#TRPBF
LTC2953CDD-2#TRPBF
LTC2953IDD-1#TRPBF
LTC2953IDD-2#TRPBF
PART MARKING*
LCWT
LCQT
LCWT
LCQT
PACKAGE DESCRIPTION
12-Lead (3mm
×
3mm) Plastic DFN
12-Lead (3mm
×
3mm) Plastic DFN
12-Lead (3mm
×
3mm) Plastic DFN
12-Lead (3mm
×
3mm) Plastic DFN
TEMPERATURE RANGE
0°C to 70°C
0°C to 70°C
–40°C to 85°C
–40°C to 85°C
Consult LTC Marketing for parts specified with wider operating temperature ranges. *The temperature grade is identified by a label on the shipping container.
Consult LTC Marketing for information on non-standard 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/
ELECTRICAL CHARACTERISTICS
SYMBOL
Supply Pin (V
IN
)
V
IN
I
IN
V
UVL
V
PB(MIN, MAX)
I
PB
Supply Voltage Range
V
IN
Supply Current
V
IN
Undervoltage Lockout
⎯
P
⎯
B Operating Voltage Range
⎯
P
⎯
B Input Current
PARAMETER
The
●
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V
IN
= 2.7V to 27V, unless otherwise noted (Note 2).
CONDITIONS
Steady State Operation
V
IN
= 2.7V to 27V
V
IN
Falling
Single-Ended
2.5V < V
PB
< 27V
V
PB
= 1V
V
PB
= 0.6V
⎯
P
⎯
B Falling
I
PB
= –1μA
●
●
●
MIN
2.7
TYP
MAX
27
UNITS
V
μA
V
V
μA
μA
μA
V
V
14
2.2
–1
–1
–3
0.6
1
–6
–9
0.8
1.6
2.3
26
2.5
27
±1
–12
–15
1
2
Push Button, Enable (
⎯
P
⎯
B, EN/
⎯
E
⎯
N)
●
●
●
●
●
●
V
PB(VTH)
V
PB(VOC)
⎯
P
⎯
B Input Threshold
⎯
P
⎯
B Open Circuit Voltage
2953f
2
LTC2953
ELECTRICAL CHARACTERISTICS
SYMBOL
I
EN(LKG)
V
EN(VOL)
t
EN, Lock Out
t
DB, ON
I
PDT(PU)
I
PDT(PD)
t
DB, OFF
t
PD, Min
t
PDT
t
INT
,
Min
t
INT, Max
V
KILL(TH)
V
KILL(HYST)
t
KILL(PW)
t
KILL(PD)
t
KILL, ON BLANK
I
KILL(LKG)
I
INT(LKG)
V
INT(VOL)
V
PFI(TH)
V
UVLO(TH)
VM
(TH)
ΔV
TH
V
PFI(HYST)
V
UVLO(HYST)
V
PFO(VOL)
V
RST(VOL)
PARAMETER
EN/
⎯
E
⎯
N Leakage Current
EN/
⎯
E
⎯
N Voltage Output Low
EN/
⎯
E
⎯
N Lock Out Time (Note 3)
Turn On Debounce Time
PDT Pull Up Current
PDT Pull Down Current
Turn Off Interrupt Debounce Time
Internal
⎯
P
⎯
B Power Down Delay
Time (Note 4)
Additional Adjustable
⎯
P
⎯
B Power
Down Delay Time
Minimum
⎯
I
⎯
N
⎯
T Pulse Width
Maximum
⎯
I
⎯
N
⎯
T Pulse Width
⎯
K
⎯
I
⎯
L
⎯
L Input Threshold Voltage
⎯
K
⎯
I
⎯
L
⎯
L Input Threshold Hysteresis
⎯
K
⎯
I
⎯
L
⎯
L Minimum Pulse Width
⎯
K
⎯
I
⎯
L
⎯
L Propagation Delay
⎯
K
⎯
I
⎯
L
⎯
L Turn On Blanking (Note 5)
⎯
K
⎯
I
⎯
L
⎯
L Leakage Current
⎯
I
⎯
N
⎯
T Leakage Current
⎯
I
⎯
N
⎯
T Output Voltage Low
⎯
P
⎯
F
⎯
I Input Threshold Voltage
UVLO Input Threshold Voltage
Adjustable Reset Threshold
⎯
P
⎯
F
⎯
I-UVLO Threshold Mismatch
⎯
P
⎯
F
⎯
I Input Hysteresis
UVLO Input Hysteresis
⎯
P
⎯
F
⎯
O Output Voltage Low
⎯
R
⎯
S
⎯
T Output Voltage Low
I
PFO
= 500μA
I = 3mA
⎯
K
⎯
I
⎯
L
⎯
L Falling
→
Enable Released
⎯
K
⎯
I
⎯
L
⎯
L = Low, Enable Asserted
→
Enable Released
V
KILL
= 0.6V
V
INT
= 3V
I
INT
= 3mA
Falling
Falling
Falling/Rising
The
●
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V
IN
= 2.7V to 27V, unless otherwise noted (Note 2).
CONDITIONS
V
EN/
⎯
E
⎯
N
= 1V, Sink Current Off
V
EN/
⎯
E
⎯
N
= 40V, Sink Current Off
I
EN/
⎯
E
⎯
N
= 500μA
Enable Released
→
Enable Asserted
⎯
P
⎯
B Falling
→
Enable Asserted
V
PDT
= 0V
V
PDT
= 1.3V
⎯
P
⎯
B, UVLO Falling
→ ⎯
I
⎯
N
⎯
T Falling
⎯
P
⎯
B, UVLO Falling
→
Enable Released
PDT Open
C
PDT
= 1500pF
⎯
I
⎯
N
⎯
T Asserted
→ ⎯
I
⎯
N
⎯
T Released
C
PDT
= 1500pF,
⎯
I
⎯
N
⎯
T Asserted
→ ⎯
I
⎯
N
⎯
T Released
⎯
K
⎯
I
⎯
L
⎯
L Falling
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
MIN
TYP
MAX
±0.1
±1
UNITS
μA
μA
V
ms
ms
μA
μA
ms
ms
ms
ms
ms
V
mV
μs
μs
ms
μA
μA
V
mV
mV
mV
mV
mV
mV
V
V
0.11
52
26
–2.4
2.4
26
52
9
26
35
0.57
10
30
64
32
–3
3
32
64
11.5
32
43.5
0.6
30
0.4
82
41
–3.6
3.6
41
82
13.5
41
54.5
0.63
50
30
On/Off Timing Pins (
⎯
P
⎯
B, UVLO, PDT,
⎯
I
⎯
N
⎯
T)
μP Handshake Pins (
⎯
K
⎯
I
⎯
L
⎯
L,
⎯
I
⎯
N
⎯
T)
400
512
650
±0.1
±0.1
0.11
492
492
492
–5
2
30
500
500
500
0
4
50
0.11
0.11
0.4
508
508
508
5
10
70
0.4
0.4
Power Fail and Voltage Monitor Pins (
⎯
P
⎯
F
⎯
I,
⎯
P
⎯
F
⎯
O, UVLO, VM,
⎯
R
⎯
S
⎯
T)
●
●
●
●
●
●
●
●
2953f
3
LTC2953
ELECTRICAL CHARACTERISTICS
SYMBOL
I
PFI(LKG)
I
PFO(LKG)
I
UVLO(LKG)
I
VM(LKG)
I
RST(LKG)
t
PFI
t
RST
t
uv
PARAMETER
⎯
P
⎯
F
⎯
I Leakage Current
⎯
P
⎯
FO Leakage Current
UVLO Leakage Current
VM Input Leakage Current
⎯
R
⎯
S
⎯
T Output Leakage Current
⎯
P
⎯
F
⎯
I Delay to
⎯
P
⎯
F
⎯
O
Reset Timeout Period
VM Under Voltage Detect to
⎯
R
⎯
S
⎯
T
VM Less Than VM
(TH)
By More Than 1%
The
●
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V
IN
= 2.7V to 27V, unless otherwise noted (Note 2).
CONDITIONS
V
PFI
= 0.5V
V
PFI
= 27V
V
PFO
= 1V
V
PFO
= 40V
V
UVLO
= 0.5V
V
UVLO
= 27V
VM = 0.5V
V
RST
= 3V
●
●
●
●
●
●
●
MIN
TYP
2
2
2
2
MAX
±10
±1
±10
±1
±10
±1
±10
±0.1
200
260
UNITS
nA
μA
nA
μA
nA
μA
nA
μA
μs
ms
μs
40
140
100
200
250
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 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.
⎯
P
⎯
B is ignored during this lock out
time. This time delay does not include t
DB, ON
.
Note 4:
To manually force a release of the EN/
⎯
E
⎯
N pin, either
⎯
P
⎯
B or UVLO
must be held low for at least t
PD, Min
(internal default power down timer) +
t
PDT
(adjustable by placing external capacitor at PDT pin).
Note 5:
The
⎯
K
⎯
I
⎯
L
⎯
L turn on blanking timer period (t
KILL, ON BLANK
) is the
waiting period immediately after enable output is asserted. This blanking
time allows sufficient time for the DC/DC converter and the μP to perform
power up tasks. The
⎯
K
⎯
I
⎯
L
⎯
L,
⎯
P
⎯
B and UVLO inputs are ignored during this
period. If
⎯
K
⎯
I
⎯
L
⎯
L remains low at the end of this blanking period, the enable
output is released, thus turning off system power.
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