LTC1642
Hot Swap Controller
FEATURES
■
■
■
■
■
■
■
■
■
■
DESCRIPTIO
Adjustable Undervoltage and Overvoltage
Protection
Foldback Current Limit
Adjustable Current Limit Time-Out
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
®
1642 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 above 2.97V.
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
voltage falls below an adjustable threshold. The ON
pin cycles the board power. The LTC1642 is available in
the 16-pin SSOP package.
, LTC and LT are registered trademarks of Linear Technology Corporation. Hot Swap is
a trademark of Linear Technology Corporation. All other trademarks are the property of
their respective owners.
APPLICATIO S
■
■
■
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
LTC1642
2N2222
13k
1%
COMPOUT
RST TMR
REF
0.33µF
GND
0.33µF
0.1µF
0.01µF
1642 TA01
U
+
12V
AT 2.5A
C
LOAD
POWER-GOOD = 11.4V
MCR
12DC
1642fb
U
U
1
LTC1642
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
LTC1642C ............................................... 0°C to 70°C
LTC1642I ............................................ – 40°C to 85°C
Storage Temperature Range ................. – 65°C to 150°C
Lead Temperature (Soldering, 10 sec).................. 300°C
The LTC1642A is Recommended for Applications
Where V
CC
is Higher Than 12V.
GN PACKAGE
16-LEAD PLASTIC SSOP
T
JMAX
= 150°C,
θ
JA
= 130°C/W
ORDER PART NUMBER
LTC1642CGN
LTC1642IGN
GN PART MARKING
1642
1642I
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
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 Threshold 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 Threshold
CRWBR Pin Threshold Supply Variation
CONDITIONS
●
MIN
2.97
2.55
2.35
1.208
TYP
1.25
2.73
2.50
230
1.220
5
3
0
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
UNITS
V
mA
V
V
mV
V
mV
mV
µA
V
mV
mV
µA
V
mV
µA
mA
V
mV
µA
mA
mV
mV
1642fb
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
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
1.208
1.220
5
3
0
1.200
– 1.5
1.200
– 15
375
1.220
5
– 2.0
10
1.220
5
– 20
10
410
4
2
U
W
U
U
W W
W
LTC1642
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
I
CR
PARAMETER
CRWBR Pin Current
CONDITIONS
CRWBR On, V
CRWBR
= 0V
CRWBR On, V
CRWBR
= 2.1V
CRWBR Off, V
CRWBR
= 1.5V
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
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
ON Rising
ON Falling
V
ON
= 5V
●
●
●
●
●
●
●
●
●
●
●
●
●
MIN
– 30
–1000
15
45
12
42
– 20
4.5
10
4.5
1.30
1.20
TYP
– 45
–1500
2.3
25
52.5
25
52.5
– 25
10
5.9
11.5
8.5
1.34
1.22
110
0
MAX
– 60
UNITS
µA
µA
mA
mV
mV
mV
mV
µA
µA
mA
V
V
V
V
V
mV
µA
V
V
µA
V
mV
mV
mA
mV
mV
V
CB
Circuit Breaker Trip Voltage
36
60
39
63
0.5
– 30
8.0
14
18
1.38
1.26
±1
0.4
2
I
SENSE
I
GATE
∆V
GATE
SENSE Pin Input Bias Current
GATE Pin Output Current
External N-Channel Gate Drive
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
3
1.232
15
7.5
±10
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
1642 G03
∆V
GATE
vs V
CC
30
29
28
27
26
25
24
23
22
21
3
6
9
V
CC
(V)
12
15
1642 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
1642 G04
1642fb
3
LTC1642
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
1642 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
1642 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)
1642 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
1642 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
1642 G13
1642 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
1642 G28
OV RISING
OV FALLING
OV FALLING
1.218
1.216
1.214
–50
15
1642 G27
–25
0
25
50
75
TEMPERATURE (°C)
100
125
1642 G07
1642fb
LTC1642
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
T
A
= –55°C
VOLTAGE (mV)
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
9
V
CC
(V)
12
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
1642 G24
10
V
ON
= 5V
∆V
REF
(mV)
V
REF
(V)
I
CC
(mA)
U W
15
1642 G14
FAULT and RESET V
OL
vs
Temperature
600
I
OL
= 1.54mA
500
400
3.0
2.5
2.0
1.5
1.0
0.5
3.5
FAULT and RESET V
OL
vs
Temperature
I
OL
= 5mA
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
0
–50
1642 G16
1642 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
100
125
1642 G20
1642 G21
1642 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
1642 G25
0
2.5
5
7.5 10 12.5 15 17.5 20
I
REF
(mA)
1642 G37
1642fb
5
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