LTC1644
1
1644f
The LTC
1644 is a Hot Swap
TM
controller that allows a board
to be safely inserted and removed from a CompactPCI bus
slot. External N-channel transistors control the 3.3V/5V
supplies, while on-chip switches control the
12V and 12V supplies. The 3.3V and 5V supplies can be
ramped up at a programmable rate. Electronic circuit break-
ers protect all four supplies against overcurrent faults. The
PWRGD output indicates when all of the supply voltages are
within tolerance. The OFF/ON pin is used to cycle the board
power or reset the circuit breaker. The PRECHARGE output
can be used to bias the bus I/O pins during card insertion
and extraction. PCI_RST# is combined on-chip with
HEALTHY# in order to generate LOCAL_PCI_RST#.
s
Hot Board Insertion into CompactPCI Bus
, LTC and LT are registered trademarks of Linear Technology Corporation.
s
Allows Safe Board Insertion and Removal from a
Live, CompactPCI
TM
Bus
s
Controls 12V, 3.3V, 5V and 12V Supplies
s
Adjustable Foldback Current Limit with Circuit
Breaker
s
Dual-Level Circuit Breakers Protect 5V and 3.3V
Supplies from Overcurrent and Short-Circuit Faults
s
LOCAL_PCI_RST# Logic On-Chip
s
PRECHARGE Output Biases I/O Pins During Card
Insertion and Extraction
s
Adjustable Supply Voltage Power-Up Rate
CompactPCI Bus
Hot Swap Controller
Hot Swap is a trademark of Linear Technology Corporation.
CompactPCI is a trademark of the PCI Industrial Computer Manufacturers Group.
Figure 1
DESCRIPTIO
U
FEATURES
APPLICATIO S
U
TYPICAL APPLICATIO
U
Z2
C5
0.01
F
C1
0.047
F
C4
0.01
F
GND
12V
IN
V
EEIN
OFF/ON
FAULT
PWRGD
RESETIN
3V
IN
3V
IN
*
5V
IN
*
3V
SENSE
17
3V
OUT
18
5V
IN
LTC1644
20-PIN SSOP
13
PRECHARGE
12
DRIVE
11
5V
OUT
3
5V
SENSE
14
16
GATE
15
1
2
5
6
7
9
12V
OUT
V
EEOUT
TIMER
RESETOUT
20
19
4
10
R18
2k
R19
1k
R20 1.2k
EARLY V(I/O)
R3
10
5V
IN
Z1
C6
0.01
F
C7
0.01
F
Z1, Z2: SMAJ12CA Z3, Z4: 1PMT5.0AT3 *5V
IN
AND 3V
IN
MAY BE USED AS SOURCES OF EARLY POWER
R4
10
R17
2k
5V
OUT
5V AT 5.7A
3V
OUT
3.3V AT 8A
12V
OUT
12V AT 500mA
V
EEOUT
12V AT 100mA
I/O DATA LINE 1
I/O DATA LINE 128
I/O #1
1644 F01
Q3
MMBT2222A
1V
10%
8
R11
51k
R10
18
5%
3V
IN
3V
OUT
R13 10
I/O #128
R14 10
R12
51k
R6
2k
R5
1k
R8 1k
R7
12
C3 4.7nF
R9
24
R1
0.005
Q1
IRF7413
Q2
IRF7413
R2
0.007
C2
0.1
F
C
LOAD(5VOUT)
C
LOAD(3VOUT)
C
LOAD(VEEOUT)
C
LOAD(12VOUT)
RESET#
PCI
BRIDGE
CHIP
PCB EDGE
BACKPLANE
CONNECTOR
R15
1
R16
1
BACKPLANE
CONNECTOR
5V
LONG 5V
3.3V
LONG 3.3V
12V
12V
BD_SEL#
HEALTHY#
PCI_RST#
GROUND
I/O PIN 1
I/O PIN 128
Z3
R21 1.74
R22 2.74
Z4
C8
0.1
F
PER 10
POWER
PINS
C9
0.1
F
PER 10
POWER
PINS
+
+
+
+
LTC1644
2
1644f
Supply Voltages
12V
IN
................................................................ 13.2V
V
EEIN
.................................................................. 14V
Input Voltages (Pins 5, 9) ....................... 0.3V to 13.5V
Output Voltages (Pins 6, 7, 10) .............. 0.3V to 13.5V
Analog Voltages and Currents
Pins 3, 11 to 14, 16 to 18 ................... 0.3V to 13.5V
Pins 4, 15 ............................. 0.3V to (12V
IN
+ 0.3V)
V
EEOUT
................................................... 14V to 0.3V
12V
OUT
............................................... 0.3V to 13.2V
Operating Temperature Range
LTC1644C ............................................... 0
C to 70
C
LTC1644I ............................................ 40
C to 85
C
Storage Temperature Range ................. 65
C to 150
C
Lead Temperature (Soldering, 10 sec).................. 300
C
ORDER PART
NUMBER
T
JMAX
= 140
C,
JA
= 135
C/W
Consult LTC Marketing for parts specified with wider operating temperature ranges.
LTC1644CGN
LTC1644IGN
ABSOLUTE AXI U
RATI GS
W
W
W
U
PACKAGE/ORDER I FOR ATIO
U
U
W
(Note 1)
ELECTRICAL CHARACTERISTICS
The
q
denotes the specifications which apply over the full operating temperature range, otherwise specifications are at T
A
= 25
C.
V
12VIN
= 12V, V
EEIN
= 12V, V
3VIN
= 3.3V, V
5VIN
= 5V unless otherwise noted.
SYMBOL
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
I
DD
V
12VIN
Supply Current
OFF/ON = 0V
q
3
8
mA
V
LKO
Undervoltage Lockout
12V
IN
, Ramping Down
q
6.00
8.30
10.80
V
3V
IN
, 5V
IN
, Ramping Down
q
2.25
2.48
2.75
V
V
FB
Foldback Current Limit Voltage
V
FB
= (V
5VIN
V
5VSENSE
), V
5VOUT
= 0V, TIMER = 0V
q
8
12
15
mV
V
FB
= (V
5VIN
V
5VSENSE
), V
5VOUT
= 3V, TIMER = 0V
q
40
51
70
mV
V
FB
= (V
3VIN
V
3VSENSE
), V
3VOUT
= 0V, TIMER = 0V
q
8
12
15
mV
V
FB
= (V
3VIN
V
3VSENSE
), V
3VOUT
= 2V, TIMER = 0V
q
40
51
70
mV
V
CB
Circuit Breaker Trip Voltage
V
CB
= (V
5VIN
V
5VSENSE
), TIMER = FLOAT
q
40
55
70
mV
V
CB
= (V
3VIN
V
3VSENSE
), TIMER = FLOAT
q
40
55
70
mV
t
OC
Overcurrent Fault Response Time
(V
5VIN
V
5VSENSE
) = 100mV, TIMER = FLOAT
q
30
45
60
s
(V
3VIN
V
3VSENSE
) = 100mV, TIMER = FLOAT
q
30
45
60
s
t
SC
Short-Circuit Response Time
(V
5VIN
V
5VSENSE
) = 200mV, TIMER = FLOAT
q
0.1
1.0
s
(V
3VIN
V
3VSENSE
) = 200mV, TIMER = FLOAT
q
0.1
1.0
s
I
CP
GATE Pin Output Current
OFF/ON = 0V, V
GATE
= 0V, TIMER = 0V
q
20
65
100
A
V
GATE
= 5V, OFF/ON = 4V
100
225
300
A
OFF/ON = 0V, V
GATE
= 2V, TIMER = FLOAT, FAULT = 0V
q
3
10
20
mA
V
GATE
External Gate Voltage
V
GATE
= (V
12VIN
V
GATE
), I
GATE
= 1
A
q
50
200
mV
V
DROP
Internal Switch Voltage Drop
V
DROP
= (V
12VIN
V
12VOUT
), I = 500mA
q
200
600
mV
V
DROP
= (V
EEOUT
V
EEIN
), I
EE
= 100mA
q
110
250
mV
I
CL
Current Foldback
12V
IN
= 12V, 12V
OUT
= 0V, TIMER = 0V
q
50
360
600
mA
12V
IN
= 12V, 12V
OUT
= 10V, TIMER = 0V
q
525
840
1500
mA
V
EEIN
= 12V, V
EEOUT
= 0V, TIMER = 0V
q
20
100
300
mA
V
EEIN
= 12V, V
EEOUT
= 10V, TIMER = 0V
q
200
320
650
mA
T
TS
Thermal Shutdown Temperature
130
C
1
2
3
4
5
6
7
8
9
10
TOP VIEW
GN PACKAGE
20-LEAD PLASTIC SSOP
20
19
18
17
16
15
14
13
12
11
12V
IN
V
EEIN
5V
OUT
TIMER
OFF/ON
FAULT
PWRGD
GND
RESETIN
RESETOUT
12V
OUT
V
EEOUT
3V
OUT
3V
IN
3V
SENSE
GATE
5V
SENSE
5V
IN
PRECHARGE
DRIVE
LTC1644
3
1644f
V
TH
Power Good Threshold Voltage
12V
OUT
q
10.8
11.1
11.4
V
V
EEOUT
q
10.4
10.5
11.1
V
3V
OUT
q
2.8
2.9
3.0
V
5V
OUT
q
4.50
4.62
4.75
V
V
3VONLY
3V Only Window Voltage
V
3VONLY
=
V
5VIN
V
3VIN
, V
5VOUT
= V
3VOUT
= 3V
q
50
107
200
mV
V
NOVEEIN
No V
EEIN
Threshold Voltage
V
EEIN
q
4
4.6
6.3
V
V
IL
Input Low Voltage
OFF/ON, RESETIN, FAULT
q
0.8
V
V
IH
Input High Voltage
OFF/ON, RESETIN, FAULT
q
2
V
I
IN
OFF/ON, RESETIN Input Current
OFF/ON, RESETIN = 0V
q
0.08
10
A
OFF/ON, RESETIN = 12V
IN
q
0.08
10
A
RESETOUT, FAULT Output Current
RESETOUT, FAULT = 5V, OFF/ON = 0V, RESETIN = 3.3V
q
0.08
10
A
PWRGD Output Current
PWRGD = 5V, OFF/ON = 4V
q
0.08
10
A
5V
SENSE
Input Current
5V
SENSE
= 5V, 5V
OUT
= 0V
q
55
100
A
3V
SENSE
Input Current
3V
SENSE
= 3.3V, 3V
OUT
= 0V
q
55
100
A
5V
IN
Input Current
5V
IN
= 5V, TIMER = 0V
q
1
1.5
mA
3V
IN
Input Current
3V
IN
= 3.3V, TIMER = FLOAT
q
490
625
A
3V
IN
= 3.3V, TIMER = 0V
q
380
550
A
5V
OUT
Input Current
5V
OUT
= 5V, OFF/ON = 0V, TIMER = 0V
q
102
400
A
3V
OUT
Input Current
3V
OUT
= 3.3V, OFF/ON = 0V, TIMER = 0V
q
161
500
A
I
TIMER
TIMER Pin Current
OFF/ON = 0V, V
TIMER
= 0V
q
15
21
27
A
V
TIMER
= 5V, OFF/ON = 4V
q
30
45
70
mA
V
TIMER
TIMER Threshold Voltages
(V
12VIN
V
TIMER
), FAULT = 0V
q
0.5
1
1.3
V
R
DIS
5V
OUT
Discharge Impedance
OFF/ON = 4V
q
45
100
3V
OUT
Discharge Impedance
OFF/ON = 4V
q
60
100
12V
OUT
Discharge Impedance
OFF/ON = 4V
q
430
1000
V
EEOUT
Discharge Impedance
OFF/ON = 4V
q
625
1000
V
OL
Output Low Voltage
PWRGD, RESETOUT, FAULT, I = 3mA
q
0.4
V
V
PXG
PRECHARGE Reference Voltage
V
5VIN
= 5V
q
0.95
1.00
1.05
V
V
5VIN
= V
3VIN
= 3.3V
q
0.95
1.00
1.05
V
ELECTRICAL CHARACTERISTICS
The
q
denotes the specifications which apply over the full operating temperature range, otherwise specifications are at T
A
= 25
C.
V
12VIN
= 12V, V
EEIN
= 12V, V
3VIN
= 3.3V, V
5VIN
= 5V unless otherwise noted.
SYMBOL
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
Note 1: Absolute Maximum Ratings are those values beyond which the life
of a device may be impaired.
Note 2: All currents into device pins are positive; all currents out of device
pins are negative. All voltages are referenced to ground unless otherwise
specified.
LTC1644
4
1644f
TYPICAL PERFOR A CE CHARACTERISTICS
U
W
3.3V and 5V Current Foldback
Profile
12V Output Current
12V Output Current
OUTPUT VOLTAGE (V)
0
1
2
3
4
5
OUTPUT CURRENT (A)
1644 G01
11
10
9
8
7
6
5
4
3
2
1
0
3V
OUT
5V
OUT
T
A
= 25
C
R
SENSE
= 0.005
OUTPUT VOLTAGE (V)
0
2
4
6
8
10
12
OUTPUT CURRENT (A)
1644 G02
1.0
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
T
A
= 25
C
12V
IN
= 12V
OUTPUT VOLTAGE (V)
0
2
4
6
8
10
12
OUTPUT CURRENT (A)
1644 G03
0.40
0.35
0.30
0.25
0.20
0.15
0.10
0.05
0
T
A
= 25
C
V
EEIN
= 12V
12V
IN
Supply Current
vs Temperature
12V
IN
Undervoltage Lockout
vs Temperature
5V
IN
UVLO Threshold Voltage
vs Temperature
TEMPERATURE (
C)
50
3.2
3.1
3.0
2.9
2.8
25
75
1644 G04
25
0
50
100
12V
IN
SUPPLLY CURRENT (mA)
TEMPERATURE (
C)
50
8.20
12V
IN
UNDERVOLTAGE LOCKOUT (V)
8.40
25
0
25
50
1644 G05
75
8.45
8.50
8.25
8.30
8.35
100
RAMPING
UP
RAMPING
DOWN
TEMPERATURE (
C)
50
5V
IN
UVLO THRESHOLD VOLTAGE (V)
2.49
2.50
2.51
25
75
1644 G06
2.48
2.47
2.46
25
0
50
2.52
2.53
2.54
2.55
100
RAMPING
UP
RAMPING
DOWN
3V
IN
UVLO Threshold Voltage
vs Temperature
5V Foldback Current Limit Voltage
vs Temperature
3V Foldback Current Limit Voltage
vs Temperature
TEMPERATURE (
C)
50
2.47
3V
IN
UVLO THRESHOLD VOLTAGE (V)
2.48
2.50
2.51
2.52
50
2.56
1644 G07
2.49
0
25
75
25
100
2.53
2.54
2.55
RAMPING
UP
RAMPING
DOWN
TEMPERATURE (
C)
50
0
5V FOLDBACK CURRENT LIMIT VOLTAGE (mV)
10
20
30
40
60
25
0
25
50
1644 G08
75
100
50
TIMER = 0V
5V
OUT
= 3V
5V
OUT
= 0V
TEMPERATURE (
C)
50
0
3V FOLDBACK CURRENT LIMIT VOLTAGE (mV)
10
20
30
40
60
25
0
25
50
1644 G09
75
100
50
TIMER = 0V
3V
OUT
= 2V
3V
OUT
= 0V
LTC1644
5
1644f
TYPICAL PERFOR A CE CHARACTERISTICS
U
W
5V/3.3V Circuit Breaker Trip
Voltage vs Temperature
5V/3.3V Circuit Breaker Overcurrent
Fault Response Time
vs Temperature
5V/3.3V Circuit Breaker Short-
Circuit Response Time
vs Temperature
GATE Pin Current vs Temperature
(V
GATE
= 2V, FAULT = 0V)
GATE Pin Current vs Temperature
(V
GATE
= 5V, OFF/ON = 4V)
GATE Pin Voltage vs Temperature
12V Internal Switch Voltage Drop
vs Temperature
V
EE
Internal Switch Voltage Drop
vs Temperature
TEMPERATURE (
C)
50
48.0
47.5
47.0
46.5
46.0
45.5
45.0
44.5
25
75
1644 G11
25
0
50
100
5V/3.3V CIRCUIT BREAKER OVERCURRENT
FAULT RESPONSE TIME (
s)
TEMPERATURE (
C)
50
0.100
5V/3.3V CIRCUIT BREAKER SHORT-CIRCUIT
RESPONSE TIME (
s)
0.105
0.110
0.115
0.120
0.125
25
0
25
50
1644 G12
75
100
GATE Pin Current vs Temperature
(V
GATE
= 0V, OFF/ON = 0V)
TEMPERATURE (
C)
50
GATE PIN CURRENT (mA)
6
8
10
25
75
1644 G13
4
2
0
25
0
50
12
14
16
100
V
GATE
= 2V
FAULT = 0V
TEMPERATURE (
C)
50
300
250
200
150
100
50
0
25
75
1644 G14
25
0
50
100
GATE PIN CURRENT (
A)
V
GATE
= 5V
OFF/ON = 4V
TEMPERATURE (
C)
50
85
GATE PIN CURRENT (A)
80
70
65
60
50
40
1644 G15
75
0
25
75
25
100
55
50
45
V
GATE
= 5V
OFF/ON = 4V
TEMPERATURE (
C)
50
11.97
11.96
11.95
11.94
11.93
11.92
25
75
1644 G16
25
0
50
100
GATE PIN VOLTAGE (V)
I
GATE
= 1
A
TEMPERATURE (
C)
50
0.35
0.30
0.25
0.20
0.15
0.10
0.05
0
25
75
1644 G17
25
0
50
100
V
CC
INTERNAL SWITCH VOLTAGE DROP (V)
I = 500mA
TEMPERATURE (
C)
50
0
V
EE
INTERNAL SWITCH VOLTAGE DROP (V) 0.02
0.06
0.08
0.10
50
0.18
1644 G18
0.04
0
25
75
25
100
0.12
0.14
0.16
I
EE
= 100mA
TEMPERATURE (
C)
50
56.2
56.0
55.8
55.6
55.4
55.2
55.0
54.8
25
75
1644 G10
25
0
50
100
5V/3.3V CIRCUIT BREAKER TRIP VOLTAGE (mV)
TIMER PIN FLOATING
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