LTC2952
Push Button PowerPath
TM
Controller with Supervisor
FEATURES
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DESCRIPTION
The LTC
®
2952 is a power management device that features
three main functions: push-button on/off control of system
power, ideal diode power paths and system monitoring.
The LTC2952’s push-button input, which provides on/off
control of system power, has independently adjustable
ON and OFF debounce times. A simple microprocessor
interface involving an interrupt signal allows for proper
system housekeeping prior to power down.
The ideal diode power paths provide automatic low loss
switchover between two DC sources by regulating two
external P-channel MOSFETs to have a small 20mV for-
ward 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.
, LT, LTC and LTM are registered trademarks of Linear Technology Corporation.
All other trademarks are the property of their respective owners.
Push-Button On/Off Control
Automatic Low Loss Switchover Between DC
Sources
Wide Operating Voltage Range: 2.7V to 28V
Low 25µA Shutdown Current
Guaranteed Threshold Accuracy: ±1.5% of
Monitored Voltage Over Temperature
Adjustable Push-Button On/Off Timers
Simple Interface Allows Graceful µP Shutdown
Extendable House Keeping Wait Time Prior to
Shutdown
200ms Reset Delay and 1.6s Watchdog Time Out
±8kV HBM ESD on
⎯
P
⎯
B Input
20 pin TSSOP and QFN (4mm
×
4mm) Packages
APPLICATIONS
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Desktop and Notebook Computers
Portable Instrumentations
Cell Phones, PDA and Handheld Computers
Servers and Computer Peripherals
Battery Backup Systems
TYPICAL APPLICATION
Push-Button Controller with Automatic Switchover Between Adapter and Battery
ADAPTER
3V TO 25V
V
IN
Si6993DQ
V
OUT
1k
365k
511k
G1
G2
V1
V2
VS
PFI
EN
VM
D1
M1
M2
PB
ONT
*22nF
GND
RST
LTC2952
G1STAT
PFO
INT
KILL
WDE
OFFT
*68nF
*OPTIONAL
2952 TA01
Ideal Diode vs Schottky Diode
Forward Voltage Drop
1
CONSTANT
R
ON
CURRENT (A)
2.5V
LT1767-2.5
SHDN
Si6993DQ
100k
D2
100k
D3
1k
1k
10k
12V BATTERY
IDEAL
DIODE
CONSTANT
VOLTAGE
SCHOTTKY
DIODE
0
µP
0.02
FORWARD VOLTAGE (V)
0.50
2952 TA01b
2952f
1
LTC2952
ABSOLUTE MAXIMUM RATINGS
(Notes 1, 2)
Supply Voltages
V1, V2, VS ............................................. –0.3V to 30V
Input Voltages
⎯
P
⎯
B .................................... –6V to MAX (V1, V2, VS) V
ONT, OFFT ................................................ –0.3V to 3V
M1, M2, PFI, VM, WDE,
⎯
K
⎯
I
⎯
L
⎯
L................... –0.3V to 7V
Output Voltages
G1, G2, EN .................... –0.3V to MAX (V1, V2, VS) V
G1STAT,
⎯
P
⎯
F
⎯
O,
⎯
R
⎯
S
⎯
T,
⎯
I
⎯
N
⎯
T ............................ –0.3V to 7V
Input Currents
⎯
P
⎯
B ...................................................... –1mA to 100μA
Operating Temperature Range
LTC2952C ................................................ 0°C to 70°C
LTC2952I ............................................. –40°C to 85°C
Storage Temperature Range................... –65°C to 150°C
Lead Temperature (Soldering, 10 sec) .................. 300°C
PACKAGE/ORDER INFORMATION
TOP VIEW
G1STAT
TOP VIEW
KILL
M1
M2
M2
M1
KILL
VM
PFI
WDE
PB
RST
PFO
1
2
3
4
5
6
7
8
9
20 G1STAT
19 G1
18 V1
17 VS
16 V2
15 G2
14 EN
13 INT
12 GND
11 OFFT
6
PFO
7
ONT
8
OFFT
9 10
GND
INT
VM 1
PFI 2
WDE 3
PB 4
RST 5
21
15 V1
14 VS
13 V2
12 G2
11 EN
G1
20 19 18 17 16
ONT 10
F PACKAGE
20-LEAD PLASTIC TSSOP
T
JMAX
= 125°C,
θ
JA
= 90°C/W
UF PACKAGE
20-LEAD (4mm
×
4mm) PLASTIC QFN
T
JMAX
= 125°C,
θ
JA
= 37°C/W
EXPOSED PAD (PIN 21), PCB GND CONNECTION OPTIONAL
ORDER PART NUMBER
LTC2952CF
LTC2952IF
F20 PART MARKING
LTC2952CF
LTC2952IF
ORDER PART NUMBER
LTC2952CUF
LTC2952IUF
UF20 PART MARKING
2952
2952
Order Options
Tape and Reel: Add #TR
Lead Free: Add #PBF Lead Free Tape and Reel: Add #TRPBF
Lead Free Part Marking:
http://www.linear.com/leadfree/
Consult LTC Marketing for parts specified with wider operating temperature ranges.
2952f
2
LTC2952
ELECTRICAL CHARACTERISTICS
SYMBOL
V
MAX
I
IN_OFF
PARAMETER
Operating Supply Voltage
Quiescent Supply Current Both Ideal
Diodes Switched Off
(M1 = Open, M2 = 0V)
The
●
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V1 = V2 = VS = 2.7V to 28V unless otherwise noted. (Notes 2, 3)
CONDITIONS
V1, V2 or VS
V1 = 2.7V to 28V, V2 = 0V, VS = Open or
V2 = 2.7V to 28V, V1 = 0V, VS = Open.
Measured Current at V1 or V2.
V1 = 2.7V to 28V, V2 = 3.5V, VS = Open.
Measured Current at V1.
V1 = 2.7V to 28V, V2 = 3.5V, VS = Open.
Measured Current at V2.
●
●
MIN
2.7
TYP
24
MAX
28
60
UNITS
V
µA
●
●
●
5
23
65
15
50
170
µA
µA
µA
I
IN_ON
Quiescent Supply Current Both Ideal
Diodes Switched On
(M1 = 0V, M2 = 0V)
V2 Preferential Threshold Voltage
(M1 = Open, M2 = 0V) (Note 4)
V1, V2 and VS Inter Pin Leakage to
the Highest Supply
Ideal Diode Power Path Forward
Regulation Voltage
Ideal Diode Power Path Fast Reverse
Turn-Off Threshold Voltage
Gate Turn-Off Current
Gate Turn-On Current
V1 = VS = 2.7V to 28V, V2 = 0V or
V2 = VS = 2.7V to 28V, V1 = 0V. Measured
Combined Current at V1 and VS or V2 and VS.
V1 = 28V, VS = Open.
V1 = 28V, V2 = VS = 0V; V1 = VS = 0V,
V2 = 28V; V1 = V2 = 0V, VS = 28V
(V1 or V2) – VS, 2.7V ≤ (V1 or V2) ≤ 28V
(V1 or V2) – VS, 2.7V ≤ (V1 or V2) ≤ 28V
ΔI
G
≤ –100μA/mV
G1 = G2 = V
MAX
– 1.5V
V1 = V2 = 2.7V to 28V,
VS = (V1 or V2) – 40mV,
G1 = G2 = V
MAX
–1.5V.
V1 = V2 = 2.7V to 28V,
VS = (V1 or V2) + 0.1V,
G1 = G2 = V
MAX
–1.5V.
V1 = V2 = 5V to 28V,
VS = (V1 or V2) – 0.1V,
G1 = G2 = V
MAX
– 1.5V.
I
GX
= 2µA, V
X
= 8V to 28V, VS = V
X
– 0.1V
Measure V
X
– V
GX
I
GX
= –2µA, V
X
= 2.7V to 28V, VS = V
X
+ 0.1V
Measure V
MAX
– V
GX
V
G(OFF)
to V
GS
≤ –3V, C
GATE
= 1nF (Note 5),
V1 = V2 = 12V
V
G(ON)
to V
GS
≥ –1.5V, C
GATE
= 1nF (Note 6),
V1 = V2 = 12V
I
⎯
P
⎯
B
= –1µA
V
⎯
P
⎯
B(VOC)
< V
⎯
P
⎯
B
≤ 28V
0V ≤ V
⎯
P
⎯
B
< V
⎯
P
⎯
B(VOC)
⎯
P
⎯
B Falling From High to Low
V2
PREF_TH
I
LEAK
●
3.3
3.8
±3
V
µA
Ideal Diode Function
V
FR
V
RTO
I
G(SRC)
I
G(SNK)
●
●
●
●
10
–20
–2
2
20
–35
–5
5
35
–64
–10
10
mV
mV
µA
µA
I
G(FASTSRC)
Gate Fast Turn-Off Source Current
●
–0.5
–2.5
–10
mA
I
G(FASTSNK)
Gate Fast Turn-On Sink Current
●
0.3
0.7
2
mA
V
G(ON)
V
G(OFF)
t
G(ON)
t
G(OFF)
Gate Clamp Voltage
Gate Off Voltage
Gate Turn-On Time
Gate Turn-Off Time
●
●
6
7
0.2
8
0.4
10
10
V
V
µs
µs
0.1
0.1
2.5
2.5
Push-Button Pin (
⎯
P
⎯
B)
⎯
P
⎯
B Open Circuit Voltage
V
⎯
P
⎯
B(VOC)
⎯ ⎯
PB Input Current
I
⎯
P
⎯
B
V
TH_
⎯
P
⎯
B
V
HYS_
⎯
P
⎯
B
⎯
P
⎯
B Input Threshold Voltage
⎯
P
⎯
B Input Hysteresis
●
●
●
●
●
1
–1
0.65
10
4
–10
0.77
25
6
±1
–25
0.8
150
V
µA
µA
V
mV
2952f
3
LTC2952
ELECTRICAL CHARACTERISTICS
SYMBOL
I
ONT,OFFT
t
DB,ON/OFF
PARAMETER
Debounce Time Pins (ONT, OFFT)
ONT/OFFT Pull-Up/Pull-Down Current V
ONT,
V
OFFT
= 0V (Pull-Up), V
ONT,
V
OFFT
= 1.5V
When Timer is Active
(Pull-Down)
Internal Default On-Time/Off-Time
t
DB,ON
: C
ONT
= Open, Measured Time Between
⎯
P
⎯
B Low
→
EN High, t
DB,OFF
: Measured Time
Between
⎯
P
⎯
B Low
→
INT High
●
●
The
●
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V1 = V2 = VS = 2.7V TO 28V unless otherwise noted. (Notes 2, 3)
CONDITIONS
MIN
±1.6
18
TYP
±2.0
26
MAX
±2.4
34
UNITS
µA
ms
t
ONT,OFFT
Additional Adjustable Turn-On/Turn-
C
ONT
= 1500pF, C
OFFT
= 1500pF
Off Time (Note 7)
⎯ ⎯⎯
Accurate Comparator Input Pins (VM, PFI, M1, M2, KIL
⎯
L)
V
TH_VM
V
TH
V
HYS
I
IN_LKG
I
M1_SRC
V
M1(VOC)
I
M1_LKG
V
WDE(H,TH)
V
WDE(L,TH)
I
WDE(IN,HL)
I
WDE(IN,HZ)
I
OUT_LKG
V
OL
I
EN(LKG)
V
EN(VOL)
VM Input Reset Threshold
⎯ ⎯⎯ ⎯
PFI, M1, M2, KILL Input Threshold
Voltage
⎯ ⎯⎯ ⎯
PFI, M1, M2, KILL Input Hysteresis
VM, PFI, M2,
⎯
K
⎯
I
⎯
L
⎯
L Input Current
M1 Input Pull-Up Current
M1 Voltage Open Circuit
M1 Input Leak Current
Input High Threshold Voltage
Input Low Threshold Voltage
High Low Input Current (Note 8)
V
WDE
= 0.7V, 1.1V
V
PIN
= 5V
I
PIN
= 1mA
V
EN
= 28V, EN Sink Current Off
I
EN
= 3mA
V1 = 1.2V and/or V2 = 1.2V, I
EN
= 100µA
Voltage Monitor/Watchdog Timing
t
RST
t
WDE
t
WDE(PW MIN)
t
VM(UV)
t
PFI
Reset Time-Out Period
Watch-Dog Time-Out Period
Minimum Period Between
Consecutive Edges
VM Undervoltage Detect to
⎯
R
⎯
S
⎯
T
⎯ ⎯ ⎯
PFI Delay to PFO
VM Less Than V
TH_VM
by more than 1%
PFI More or Less Than V
PFI_TH
by more than
1%
M1 = 6V
Both Falling and Rising
Falling
●
10
15
20
ms
●
●
●
0.492
0.492
5
–1.5
1
0.500
0.500
15
–3
4
0.508
0.508
25
±0.1
–5
6
±0.1
1.5
V
V
mV
µA
µA
V
µA
V
V
µA
µA
V = 0.5V
M1 = 1V
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
Watch-Dog/Extend Pin (WDE)
0.3
±25
±10
±1
0.4
±1
0.4
0.05
140
1.1
200
1.6
5
150
150
0.3
260
2.1
10
High Z Input Current
Open Drain Output Pins (G1STAT,
⎯
I
⎯
N
⎯
T,
⎯
R
⎯
S
⎯
T,
⎯
P
⎯
F
⎯
O)
Leakage Current
Voltage Output Low
EN Leakage Current
EN Voltage Output Low
µA
V
µA
V
V
ms
s
µs
µs
µs
High Voltage Open Drain Output Pin (EN)
2952f
4
LTC2952
ELECTRICAL CHARACTERISTICS
SYMBOL
PARAMETER
µP Handshake Timing
⎯⎯
IN
⎯
T Minimum Pulse Width
t
⎯
IN
⎯
T(MIN)
t
⎯
K
⎯
I
⎯
L
⎯
L(PW)
t
⎯
K
⎯
I
⎯
L
⎯
L,ON BLANK
t
⎯
K
⎯
I
⎯
L
⎯
L, OFF WAIT
t
EN, LOCKOUT
⎯
K
⎯
I
⎯
L
⎯
L Minimum Pulse Width
⎯
K
⎯
I
⎯
L
⎯
L ON Blanking (Note 9)
⎯
K
⎯
I
⎯
L
⎯
L Wait Time (Note 10)
Enable Lockout Time (Note 11)
The
●
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V1 = V2 = VS = 2.7V to 28V unless otherwise noted. (Notes 2, 3)
CONDITIONS
Minimum Measured Time
⎯
P
⎯
B Rising to
⎯
I
⎯
N
⎯
T Rising
Full Swing Pulse From 5V to 0V
⎯
K
⎯
I
⎯
L
⎯
L = 0V, Measured Time Between EN Rising
→
EN Falling
⎯
KILL = 1V, C
OFFT = OPEN
, Measured Time
⎯⎯ ⎯
Between
⎯
I
⎯
N
⎯
T Falling
→
EN Falling
Measured Time Between EN Falling
→
EN
Rising
●
●
●
●
●
MIN
10
TYP
50
150
MAX
250
500
530
530
530
UNITS
µs
µs
ms
ms
ms
270
270
270
400
400
400
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:
The greatest of V1, V2 or VS is the internal supply voltage (V
MAX
).
Note 3:
All currents into pins are positive; all voltages are referenced to
GND unless otherwise noted.
Note 4:
V2
PREF_TH
is the minimum voltage level at which V2 becomes the
preferential source of quiescent current when both of the ideal diodes are
off.
Note 5:
VS is stepped from (V1 or V2) + 0.2V to (V1 or V2) – 0.2V to
trigger the event. The gate voltages are initially V
G(OFF)
.
Note 6:
VS is stepped from V
X
– 0.2V to V
X
+ 0.2V to trigger the event.
Gate voltages are initially clamped at V
G(ON)
.
Note 7:
The Adjustable Turn-On and Turn-Off timer period is the adjustable
debounce period following the Internal Default-On and Default-Off timer
period respectively.
Note 8:
The input current to the three-state WDE pin are the pull-up
and the pull-down current when the pin is either set to 3.3V or GND
respectively. In the Open state, the maximum pull-up or pull-down leakage
current permissible is 10µA.
Note 9:
The Turn-On
⎯
K
⎯
I
⎯
L
⎯
L Blanking Time is the waiting period immediately
following the EN pin switching high; at the end of this period the input
to the
⎯
K
⎯
I
⎯
L
⎯
L needs to be high to indicate that the system has powered up
properly, otherwise the EN pin is immediately switched low.
Note 10:
The
⎯
K
⎯
I
⎯
L
⎯
L Wait Time during the power down process is the wait
period immediately following a valid turn-off command until the EN pin
switches low.
Note 11:
The Enable Lockout Time is the minimum wait time between the
last falling edge and the next rising edge on the EN pin.
2952f
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