LTC1642A
Hot Swap Controller
FEATURES
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DESCRIPTIO
Adjustable Undervoltage and Overvoltage
Protection
Foldback Current Limit
Adjustable Current Limit Time-Out
V
CC
: 2.97V to 16.5V Normal Operation, Protected
Against Surges to 33V
Single Channel NFET Driver
Latch Off or Automatic Retry on Current Fault
Driver for SCR Crowbar on Overvoltage
Adjustable Reset Timer
Reference Output with Uncommitted Comparator
16-Pin SSOP Package
The LTC
®
1642A is a 16-pin Hot Swap
TM
controller that
allows a board to be safely inserted and removed from a
live backplane. Using an external N-Channel pass transis-
tor, the board supply voltage can be ramped up at an
adjustable rate. A high side switch driver controls the
N-Channel gate for supply voltages ranging from 2.97V
to 16.5V.
The SENSE pin allows foldback limiting of the load current,
with circuit breaker action after an adjustable delay time.
The delay allows the part to power-up in current limit. The
CRWBR output can be used to trigger an SCR for crowbar
protection of the load if the input supply exceeds an
adjustable threshold. The RESET output can generate a
system reset with adjustable delay when the supply volt-
age falls below an adjustable threshold. The ON pin cycles
the board power. The LTC1642A is available in the 16-pin
SSOP package.
, LTC and LT are registered trademarks of Linear Technology Corporation. All other
trademarks are the property of their respective owners. Hot Swap is a trademark of Linear
Technology Corporation.
APPLICATIO S
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Hot Board Insertion
Electronic Circuit Breaker
InfiniBand
TM
Systems
TYPICAL APPLICATIO
BACKPLANE
12V
PLUG-IN CARD
0.010Ω
5%
FDS6630A
(SHORT PIN)
110k
1%
1N4705
18V
100Ω
5%
330Ω
5%
0.047µF
107k
1%
V
CC
SENSE
GATE
RESET
FB
CRWBR
COMP
–
COMP
+
UV = 10.8V
2.87k
1%
OV = 13.2V
11.3k
1%
ON
FAULT
OV
GND BRK TMR
LTC1642A
2N2222
13k
1%
COMPOUT
RST TMR
REF
0.33µF
GND
0.33µF
0.1µF
0.01µF
1642a TA01
U
+
12V
AT 2.5A
C
LOAD
POWER-GOOD = 11.4V
MCR
12DC
1642af
U
U
1
LTC1642A
ABSOLUTE
(Note 1)
AXI U RATI GS
PACKAGE/ORDER I FOR ATIO
TOP VIEW
CRWBR 1
BRK TMR 2
RST TMR 3
ON 4
RESET 5
FAULT 6
FB 7
GND 8
16 V
CC
15 SENSE
14 GATE
13 REF
12 COMP
–
11 COMP
+
10 COMPOUT
9
OV
Supply Voltage (V
CC
) .................................– 0.3V to 33V
SENSE Pin ................................... – 0.3V to (V
CC
+ 0.3V)
ON, FB, OV, COMP
+
, COMP
–
RESET, FAULT, COMPOUT .....................– 0.3V to 18.5V
Operating Temperature Range
LTC1642AC ............................................. 0°C to 70°C
LTC1642AI ......................................... – 40°C to 85°C
Storage Temperature Range ................. – 65°C to 150°C
Lead Temperature (Soldering, 10 sec).................. 300°C
ORDER PART
NUMBER
LTC1642ACGN
LTC1642AIGN
GN PART
MARKING
1642A
1642AI
GN PACKAGE
16-LEAD PLASTIC SSOP
T
JMAX
= 150°C,
θ
JA
= 130°C/W
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.
DC ELECTRICAL CHARACTERISTICS
The
●
denotes the specifications which apply over the full operating temperature range, otherwise specifications are at T
A
= 25°C.
V
CC
= 5V unless otherwise specified.
SYMBOL
V
CC
I
CC
V
LKHI
V
LKLO
V
LKHYST
V
FB
∆V
FB
V
FBHST
I
FB(IN)
V
OV
∆V
OV
V
OVHYST
I
OV(IN)
V
RST
∆V
RST
I
RST
V
BRK
∆V
BRK
I
BRK
V
CR
∆V
CR
I
CR
PARAMETER
Operating Voltage Range
V
CC
Supply Current
V
CC
Undervoltage Lockout
V
CC
Undervoltage Lockout
V
CC
Undervoltage Lockout Hysteresis
FB Pin Voltage Threshold
FB Pin Threshold Supply Variation
FB Pin Voltage Threshold Hysteresis
FB Pin Input Current
OV Pin Voltage Threshold
OV Pin Threshold Supply Variation
OV Pin Voltage Theshold Hysteresis
OV Pin Input Current
RST TMR Pin Voltage Threshold
RST TMR Pin Threshold Supply Variation
RST TMR Pin Current
BRK TMR Pin Voltage Threshold
BRK TMR Pin Threshold Supply Variation
BRK TMR Pin Current
CRWBR Pin Voltage Theshold
CRWBR Pin Threshold Supply Variation
CRWBR Pin Current
CONDITIONS
●
MIN
2.97
2.55
2.35
1.208
TYP
1.25
2.73
2.50
230
1.220
5
3
0
1.220
5
3
0
1.220
5
– 2.0
10
1.220
5
– 20
10
410
4
– 45
–1500
2.3
ON = V
CC
V
CC
Rising
V
CC
Falling
FB Falling
FB Falling, 2.97V
≤
V
CC
≤
16.5V
V
OV
= 5V
OV Rising
OV Rising, 2.97V
≤
V
CC
≤
16.5V
V
FB
= 5V
RST TMR Rising
RST TMR Rising, 2.97V
≤
V
CC
≤
16.5V
Timer On
Timer Off, V
RSTTMR
= 1.5V
BRK TMR Rising
BRK TMR Rising, 2.97V
≤
V
CC
≤
16.5V
Timer On
Timer Off, V
BRKTMR
= 1.5V
CRWBR Rising
2.97V
≤
V
CC
≤
16.5V
CRWBR On, V
CRWBR
= 0V
CRWBR On, V
CRWBR
= 2.1V
CRWBR Off, V
CRWBR
= 1.5V
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
MAX
16.5
3.0
2.95
2.95
1.232
15
±1
1.232
15
±1
1.250
15
– 2.5
1.250
15
– 30
425
15
– 60
1.208
1.200
– 1.5
1.200
– 15
375
– 30
–1000
UNITS
V
mA
V
V
mV
V
mV
mV
µA
V
mV
mV
µA
V
mV
µA
mA
V
mV
µA
mA
mV
mV
µA
µA
mA
1642af
2
U
W
U
U
W W
W
LTC1642A
DC ELECTRICAL CHARACTERISTICS
The
●
denotes the specifications which apply over the full operating temperature range, otherwise specifications are at T
A
= 25°C.
V
CC
= 5V unless otherwise specified.
SYMBOL
V
CB
PARAMETER
Circuit Breaker Trip Voltage
CONDITIONS
V
CB
= (V
CC
– V
SENSE
), V
FB
= GND
V
CB
= (V
CC
– V
SENSE
), V
FB
= 1V
2.97V
≤
V
CC
≤
16.5V,
V
CB
= (V
CC
– V
SENSE
), V
FB
= GND
V
CB
= (V
CC
– V
SENSE
), V
FB
= 1V
I
SENSE
I
GATE
∆V
GATE
SENSE Pin Input Bias Current
GATE Pin Output Current
External N-Channel Gate Drive
V
CC
= V
SENSE
= 16.5V
Charge Pump On, V
GATE
= GND
Charge Pump Off, V
GATE
= 5V
V
GATE
– V
CC,
V
CC
= 2.97V
V
GATE
– V
CC,
V
CC
= 5V
V
GATE
– V
CC,
V
CC
= 15V (0°C to 70°C)
V
GATE
– V
CC,
V
CC
= 15V (–40°C to 85°C)
ON Rising
ON Falling
V
ON
= 5V
●
●
●
●
●
●
●
●
●
●
●
●
MIN
15
45
12
42
– 20
4.5
10
6.5
6
1.30
1.20
TYP
25
52.5
25
52.5
– 25
10
5.9
11.5
8.5
8.5
1.34
1.22
110
0
MAX
36
60
39
63
0.5
– 30
8.0
14
18
18
1.38
1.26
±1
0.4
2
UNITS
mV
mV
mV
mV
µA
µA
mA
V
V
V
V
V
V
mV
µA
V
V
µA
V
mV
mV
mA
mV
mV
V
ONHI
V
ONLO
V
ONHYST
I
ON(IN)
V
OL
I
PU
V
REF
∆V
LNR
∆V
LDR
I
RSC
V
COS
V
CHYST
ON Pin Threshold
ON Pin Threshold
ON Pin Hysteresis
ON Pin Input Current
Output Low Voltage
Logic Output Pull-Up Current
Reference Output Voltage
Reference Supply Variation
Reference Load Regulation
Reference Short-Circuit Current
Comparator Offset Voltage
Comparator Hysteresis
RESET, FAULT, COMPOUT I
OL
= 1.54mA
●
RESET, FAULT I
O
= 5mA
RESET, FAULT = GND
No Load
2.97V
≤
V
CC
≤
16.5V, No Load
I
O
= 0mA to –1mA, Sourcing Only
V
REF
= 0V
V
CM
= V
REF
V
CM
= V
REF
●
●
●
●
– 15
1.208
1.220
5
2.5
4.5
±10
3
1.232
15
7.5
Note 1:
Absolute Maximum Ratings are those values beyond which the life
of a device may be impaired.
TYPICAL PERFOR A CE CHARACTERISTICS
∆V
GATE
vs Temperature
16
14
12
∆V
GATE
(V)
10
V
CC
= 15V
8
6
V
CC
= 3V
4
3
2
0
–50
0
V
CC
= 5V
∆V
GATE
(V)
V
CC
= 12V
12
15
T
A
= 25°C
9
I
GATE
(µA)
–25
0
25
50
75
TEMPERATURE (°C)
U W
100
125
1642a G03
∆V
GATE
vs V
CC
30
29
28
27
26
25
24
23
22
21
3
6
9
V
CC
(V)
12
15
1642a G26
I
GATE
vs Temperature
V
CC
= 3V
V
CC
= 5V
V
CC
= 12V
V
CC
= 15V
6
V
GATE
= 0V
–25
0
25
50
75
TEMPERATURE (°C)
100
125
20
–50
1642a G04
1642af
3
LTC1642A
TYPICAL PERFOR A CE CHARACTERISTICS
I
GATE
Pull-Up Current vs V
CC
25
CRWBR–TMR THRESHOLD VOLTAGE (mV)
20
I
GATE
(µA)
I
GATE
(A)
15
10
5
V
GATE
= 0V
T
A
= 25°C
3
6
9
V
CC
(V)
12
15
1642a G23
0
CRWBR Driver Current vs V
CC
2.0
T
A
= 25°C
CRWBR DRIVER CURRENT (mA)
CRWBR DRIVER CURRENT (mA)
1.6
FB THRESHOLD VOLTAGE (V)
1.2
0.8
0.4
0
3
6
9
V
CC
(V)
12
FB Threshold Voltage vs V
CC
1.232
T
A
= 25°C
FB THRESHOLD VOLTAGE (V)
1.226
FB RISING
OV THRESHOLD VOLTAGE (V)
1.224
1.222
1.220
OV RISING
1.224
1.220
1.216
1.212
1.208
3
6
OV THRESHOLD VOLTAGE (V)
1.228
FB FALLING
9
V
CC
(V)
12
4
U W
15
1642a G35
GATE Pull-Down Current (Current
Limit Active)
128
T
A
= 25°C
112
96
80
64
48
32
16
0
0
4
8
12
V
GATE
(V)
1642a G36
CRWBR-TMR Threshold Voltage
vs Temperature
405
404
403
402
401
400
399
398
397
396
395
–50
–25
0
25
50
75
TEMPERATURE (°C)
100
125
V
CC
= 5V
V
CC
= 12V
V
CC
= 5V
V
CC
= 3.3V
16
20
24
1642a G05
CRWBR Driver Current vs
Temperature
1.45
V
CC
= 5V
1.44
1.43
1.42
1.41
1.40
1.39
1.38
–50
1.224
1.226
FB Threshold Voltage vs
Temperature
V
CC
= 5V
FB RISING
1.222
1.220
FB FALLING
1.218
1.216
1.214
–50
–25
0
25
50
75
TEMPERATURE (°C)
100
125
–25
0
25
50
75
TEMPERATURE (°C)
100
125
1642a G13
1642a G06
OV Threshold Voltage vs
Temperature
1.232
V
CC
= 5V
OV Threshold Voltage vs V
CC
T
A
= 25°C
1.228
1.224
1.220
1.216
1.212
1.208
3
6
9
V
CC
(V)
12
15
1642a G28
OV RISING
OV FALLING
OV FALLING
1.218
1.216
1.214
–50
15
1642a G27
–25
0
25
50
75
TEMPERATURE (°C)
100
125
1642a G07
1642af
LTC1642A
TYPICAL PERFOR A CE CHARACTERISTICS
FAULT and RESET Pull-Up Current
(I
OH
) vs V
CC
160
140
PULL-UP CURRENT (µA)
120
100
80
60
40
20
0
3
6
9
V
CC
(V)
12
15
1642a G14
VOLTAGE (mV)
T
A
= –55°C
T
A
= 25°C
V
CC
= 3V
300
200
100
0
–50
V
CC
= 5V
V
CC
= 12V
V
CC
= 15V
VOLTAGE (V)
T
A
= 125°C
Current Limit Threshold Voltage
(Full Foldback) vs Temperature
CURRENT LIMIT THRESHOLD VOLTAGE (mV)
FB = 0V
27.0
26.5
V
CC
= 12V
26.0
V
CC
= 5V
25.5
V
CC
= 3V
25.0
24.5
–50
V
CC
= 15V
CURRENT LIMIT THRESHOLD VOLTAGE (mV)
27.5
ON PIN THRESHOLD VOLTAGE (V)
–25
0
25
50
75
TEMPERATURE (°C)
V
REF
vs V
CC
1.232
T
A
= 25°C
1.228
1.224
1.220
1.216
1.212
1.208
0
3
6
9
V
CC
(V)
12
15
1642a G24
10
V
ON
= 5V
∆V
REF
(mV)
V
REF
(V)
I
CC
(mA)
U W
100
FAULT and RESET V
OL
vs
Temperature
600
I
OL
= 1.54mA
500
400
FAULT and RESET V
OL
vs
Temperature
3.5
I
OL
= 5mA
3.0
2.5
2.0
1.5
1.0
0.5
0
–50
V
CC
= 3V
V
CC
= 5V
V
CC
= 12V
V
CC
= 15V
–25
0
25
50
75
TEMPERATURE (°C)
100
125
–25
0
25
50
75
TEMPERATURE (°C)
100
125
1642a G16
1642a G17
Current Limit Threshold Voltage
(Nominal) vs Temperature
57.0
FB = 1V
56.5
56.0
55.5
55.0
54.5
54.0
53.5
–50
V
CC
= 3V
–25
0
25
50
75
TEMPERATURE (°C)
100
125
V
CC
= 15V
V
CC
= 12V
V
CC
= 5V
1.36
1.40
ON Pin Threshold Voltage vs
Temperature
V
CC
= 12V
ON RISING
1.32
1.28
1.24
ON FALLING
1.20
–50
–25
0
25
50
75
TEMPERATURE (°C)
100
125
125
1642a G20
1642a G21
1642a G22
I
CC
vs V
CC
20
T
A
= 25°C
Reference O/P Impedance
0
–2
–4
–6
–8
–10
–12
–14
–16
–18
–20
–22
– 42
T
A
= 25°C
V
CC
= 5V
V
CC
= 3.3V
V
CC
= 12V,
15V
V
ON
= 0V
0
25
V
CC
(V)
50
1642a G25
0
2.5
5
7.5 10 12.5 15 17.5 20
I
REF
(mA)
1642a G37
1642af
5
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