LT4220
Dual Supply
Hot Swap Controller
FEATURES
s
s
s
s
s
DESCRIPTIO
s
s
s
s
Hot Swap
TM
Controller for Positive
and Negative Supplies
Supply Tracking Mode
±2.7V
to
±16.5V
Operation
Analog Current Limit with Foldback
Allows Safe Board Insertion and Removal
from a Live Backplane
Open-Collector Power Good Comparators
Automatic Retry or Latchoff After a Current Fault
Dual Undervoltage Lockout Comparator Inputs
Current Fault Indication
The LT
®
4220 16-pin dual voltage Hot Swap controller
allows a board to be safely inserted and removed from a
live backplane. The device operates with any combination
of 2.7V to 16.5V and –2.7V to –16.5V supplies. Using two
external N-channel pass transistors, the board supply
voltages can be ramped up at an adjustable rate. A select-
able tracking mode allows dual supply tracking control for
ramping the positive and negative supplies together.
The LT4220 features foldback current limit and latches off
both gates if either supply remains in current limit longer
than an adjustable time period. The IC can be configured
for automatic restart after a delay set by the same timer.
A power good signal indicates when the output voltages
monitored by the two FB comparators are within tolerance,
and the gate drive signals are at their full on voltage.
The LT4220 is available in a 16-lead narrow SSOP
package.
, LTC and LT are registered trademarks of Linear Technology Corporation.
Hot Swap is a trademark of Linear Technology Corporation.
APPLICATIO S
s
s
s
s
s
Live Board Insertion
RAID Systems
–5.2V ECL Supplies
Industrial Controls
Split Supply Systems
TYPICAL APPLICATIO
12V
V
CC
V
IN
+
R13
10Ω
C4
100nF
±12V
10A Hot Swap Controller
R
S
+
0.005Ω
Q1
SUB85N03-04
12V
V
OUT
+
C1
10nF
Z1*
R5
10Ω
7
16
V
CC
15
SENSE
+
R6
1k
+
CL1
CONNECTOR 2
CONNECTOR 1
R1
36.5k
R2
4.99k
R15
20k
TRACK
12
ON
+
C7
10nF
C6
1µF
11 FAULT
8
TIMER
LT4220
9
GND
14
GATE
+
10
PWRGD
13
R16, 20k
FB
+
R10
4.99k
R12
4.99k
R9
36.5k
D1
IN4001
R4
4.99k
R3
36.5k
C8
10nF
FB
–
6
ON
–
V
EE
1
C5
1µF
Z2*
R14
10Ω
R
S
0.005Ω
–
5
SENSEK SENSE
2
3
–
GATE
–
R11
36.5k
C2
4 R8 10nF
1k
R7
10Ω
D2
IN4001
C3
100nF
+
CL2
–12V
V
OUT
–
4220 TA01
–12V
V
EE
V
IN
–
* 1SMA13AT3 TRANSIENT
VOLTAGE SUPPRESSOR
Q2
SUB85N03-04
U
12V
V
IN
+
12V
V
OUT
+
–12V
V
IN
–
–12V
V
OUT
–
TIME (10ms/DIV)
4220f
U
U
1
LT4220
ABSOLUTE
MAXIMUM
RATINGS
(Notes 1, 2)
PACKAGE/ORDER INFORMATION
TOP VIEW
V
EE
SENSEK
SENSE
–
GATE
–
FB
–
ON
–
TRACK
TIMER
1
2
3
4
5
6
7
8
16 V
CC
15 SENSE
+
14 GATE
+
13 FB
+
12 ON
+
11 FAULT
10 PWRGD
9
GND
V
CC
to GND ............................................................. 22V
V
EE
to GND ........................................................... –22V
TRACK, TIMER .............................. – 0.3V to V
CC
+ 0.3V
ON
+
, FB
+
................................. V
EE
– 0.3V to V
CC
+ 0.3V
ON
–
, FB
–
.................................. V
EE
– 0.3V to V
CC
+ 0.3V
GATE
+
................................................ –0.3V to V
CC
+ 8V
GATE
–
.............................. –16.5V with V
EE
= –22V to 0V
SENSE
+
............................................. –0.3V to V
CC
+ 5V
SENSE
–
, SENSEK ....................... V
EE
– 0.3V to V
EE
+ 3V
PWRGD, FAULT ................................. –0.3V to V
CC
+ 5V
Operating Temperature Range
LT4220C ........................................... 0°C
≤
T
A
≤
70°C
LT4220I ....................................... –40°C
≤
T
A
≤
85°C
Storage Temperature Range ................. – 65°C to 150°C
Lead Temperature (Soldering, 10 sec).................. 300°C
ORDER PART
NUMBER
LT4220CGN
LT4220IGN
GN PART MARKING
4220
4220I
GN PACKAGE
16-LEAD PLASTIC SSOP
T
JMAX
= 125°C,
θ
JA
= 130°C/W
Consult LTC Marketing for parts specified with wider operating temperature ranges.
DC ELECTRICAL CHARACTERISTICS
SYMBOL
V
CC
I
CC
V
EE
I
EE
V
PLKO
V
MLKO
V
ON+H
V
ON+HYS
∆V
ON + H
∆V
ON – H
V
ON – HYS
V
ON – H
I
ON+
I
ON –
V
FB + H
V
FB + HYS
V
FB – H
V
FB – HYS
PARAMETER
V
CC
Operating Range
V
CC
Supply Current
V
EE
Operating Range
V
EE
Supply Current
V
CC
Undervoltage Lockout
V
EE
Undervoltage Lockout
ON
+
ON Threshold
ON
+
Hysteresis
ON
+
ON Threshold Line Regulation
ON
–
ON Threshold Line Regulation
ON
–
Hysteresis
ON
–
ON Voltage Threshold
ON
+
Input Current
ON
–
Input Current
FB
+
PWRGD Voltage Threshold
FB
+
Hysteresis
FB
–
PWRGD Voltage Threshold
FB
–
Hysteresis
ON
–
Falling
V
ON+
= 2V
V
ON–
= GND
FB
+
Rising
Gate = 5V
FB
–
Falling
Gate = 3V
ON
+
Rising
CONDITIONS
The
q
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V
CC
= 5V, V
EE
= –5V, unless otherwise noted.
MIN
q
q
q
TYP
2.7
MAX
16.5
4
–16.5
–2.4
2.55
–2.5
1.26
70
0.15
1
70
–1.26
±1
±1
1.26
70
–1.26
70
UNITS
V
mA
V
mA
V
V
V
mV
mV/V
mV/V
mV
V
µA
µA
V
mV
V
mV
2.7
–2.7
–1.6
2.35
–2.4
1.22
25
2.45
–2.45
1.24
50
0.02
0.05
25
–1.22
50
–1.24
0.01
0.01
1.22
25
–1.22
25
1.24
50
–1.24
50
q
q
q
q
V
CC
= 2.7V, V
EE
= –2.7V to V
CC
= 16.5V, V
EE
= –16.5V
V
CC
= 2.7V, V
EE
= –2.7V to V
CC
= 16.5V, V
EE
= –16.5V
q
q
q
q
q
q
q
q
q
q
2
U
W
U
U
W W
W
4220f
LT4220
DC ELECTRICAL CHARACTERISTICS
The
q
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V
CC
= 5V, V
EE
= –5V, unless otherwise noted.
SYMBOL PARAMETER
I
INFB+
I
INFB–
∆V
FB+H
∆
VFB–H
V
SENSE+
V
SENSE–
I
GATEUP+
I
GATEUP –
I
GATEDN+
I
GATEDN –
∆V
GATE+
∆V
GATE–
V
TIMERH
V
TIMERL
I
TIMERUP
I
TIMERDN
I
TIMER(R)
V
OL
I
OH
V
FOL
I
FPH
V
TRKTHR
I
TRK
V
TRKFB+
V
TRKFB–
FB
+
Input Current
FB
–
Input Current
FB
+
PWRGD Threshold Line Regulation
FB
–
PWRGD Threshold Line Regulation
SENSE
+
Trip Voltage (V
CC
– V
SENSE+
)
CONDITIONS
FB
+
= 3V
FB
–
= –3V
q
q
MIN
TYP
0.09
0.08
0.015
0.05
MAX
±1
±1
0.15
0.5
22
60
–22
–61
–17
–14
60
130
6
8
6
9
1.26
0.6
–85
4.5
7
0.3
0.5
UNITS
µA
µA
mV/V
mV/V
mV
mV
mV
mV
µA
µA
mA
mA
V
V
V
V
V
V
µA
µA
%
V
V
µA
V
V
µA
V
µA
mV
mV
V
CC
= 2.7V, V
EE
= –2.7V to V
CC
= 16.5V, V
EE
= –16.5V
q
V
CC
= 2.7V, V
EE
= –2.7V to V
CC
= 16.5V, V
EE
= –16.5V
q
V
FB+
= 0V, GATE
+
– 0.5V
V
FB+
= 1V, GATE
+
– 0.5V
q
q
q
q
q
q
q
q
q
q
6
36
–10
–43
–9
–6
20
30
3.5
5
3.5
7.5
1.22
0.4
–40
2
15
48
–15
–52
–13
–10
40
70
4
6.5
5.2
8.5
1.24
0.5
–65
3.3
5
SENSE
–
Trip Voltage (V
SENSEK
– V
SENSE–
) V
FB –
= 0V, GATE
–
– 0.5V
V
FB –
= –1V, GATE
–
– 0.5V
GATE
+
Pull-Up Current
GATE
–
Pull-Up Current
GATE
+
Pull-Down Current
GATE
–
Pull-Down Current
External N-Channel GATE
+
Drive
External N-Channel GATE
–
Drive
TIMER High Threshold, Sets FAULT
TIMER Low Threshold, Allows Restart
TIMER Pull-Up Current
TIMER Pull-Down Current
TIMER Current Ratio
PWRGD Output Low Voltage
PWRGD Leakage Current
FAULT Output Low Voltage
FAULT Leakage Current
TRACK Input Threshold
TRACK Input Current
TRACK Mode FB
+
Threshold
TRACK Mode FB
–
Threshold
TRACK = 16.5V
I
GATE+
= 0µA, TRACK = V
CC
(Note 3)
I
GATE–
= 0µA, TRACK = V
CC
(Note 3)
TIMER = 0V
TIMER = 1V
I
TIMERDN
/I
TIMERUP
I
O
= 2mA
I
O
= 5mA
V
PWRGD
= 16.5V
I
O
= 2mA
I
O
= 5mA
V
FAULT
= 16.5V
Charge Pump On, V
GATE+
= 7V
V
GATE
– = –3V
Any Fault Condition, V
GATE+
= 1V
Any Fault Condition, V
GATE–
= V
EE
+ 4V
V
GATE+
– V
CC
, V
CC
= 2.7V, V
EE
= –2.7V
V
CC
= 5V to 16.5V, V
EE
= –5V to –16.5V
V
GATE–
– V
EE
, V
CC
= 2.7V, V
EE
= –2.7V
V
CC
= 5V to 16.5V, V
EE
= –5V to –16.5V
q
q
q
q
q
q
q
q
q
q
0.1
2
0.3
0.5
0.06
0.3
0.8
0.05
40
40
2
1.1
2
70
80
4220f
3
LT4220
AC ELECTRICAL CHARACTERISTICS
SYMBOL
t
PHLON+
t
PLHON+
t
PHLFB +
t
PLHFB +
t
PHLON–
t
PLHON–
t
PHLFB –
t
PLHFB –
t
SENSE+
t
SENSE–
PARAMETER
ON
+
Low to GATE
+
Low
ON
+
High to GATE
+
High
FB
+
Low to PWRGD Low
FB
+
High to PWRGD High
ON
–
Low to GATE
–
Low
ON
–
High to GATE
–
High
FB
–
Low to PWRGD Low
FB
–
High to PWRGD High
SENSE
+
to GATE
+
Low
SENSE
–
to GATE
–
Low
CONDITIONS
The
q
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V
CC
= 5V, V
EE
= –5V, unless otherwise noted.
MIN
q
q
q
q
q
q
q
q
q
q
TYP
0.8
1.5
0.8
1.25
1
2.1
1
1.25
4
4
MAX
1.2
3
1.2
3
1.5
3.5
1.5
2
6
6
UNITS
µs
µs
µs
µs
µs
µs
µs
µs
µs
µs
5k Pull-Up to GATE
+
, 1nF Load Capacitor
5k Pull-Up to GATE
+
, 1nF Load Capacitor
5k Pull-Up to PWRGD
5k Pull-Up to PWRGD
5k Pull-Up to GATE
–
, 1nF Load Capacitor
5k Pull-Up to GATE
–
, 1nF Load Capacitor
5k Pull-Up to PWRGD
5k Pull-Up to PWRGD
1nF On GATE
+
, 100mV Step, 5k Pull-Up
1nF On GATE
–
, 100mV Step, 5k Pull-Up
0.6
0.6
0.5
0.6
0.6
1
0.6
0.8
1
1
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 referenced to ground (GND) unless
specified.
Note 3:
The absolute voltage difference between FB
+
and FB
–
required to
force either the GATE
+
or GATE
–
current to 0µA.
TYPICAL PERFOR A CE CHARACTERISTICS
Supply Current vs Supply Voltage
4
T
A
= 25°C
I
CC
SUPPLY CURRENT (mA)
V
CC
-SENSE
+
VOLTAGE (mV)
3
40
SENSEK-SENSE
–
VOLTAGE (mV)
2
I
EE
1
0
0
5
15
SUPPLY VOLTAGE (V)
10
4
U W
4220 G01
Positive Circuit Breaker Sense
Voltage vs FB
+
Voltage
50
V
CC
= 5V
V
EE
= –5V
ON
+
= 2V
ON
–
= –2V
T
A
= 25°C
60
50
40
30
20
10
Negative Circuit Breaker Sense
Voltage vs FB
–
Voltage
V
CC
= 5V
V
EE
= –5V
ON
+
= 2V
ON
–
= –2V
T
A
= 25°C
30
20
10
20
0
–1.5
–1.0
–0.5
0
0.5
FB
+
VOLTAGE (V)
1.0
1.5
4220 G02
0
–1.5
–1.0
–0.5
0
0.5
FB
–
VOLTAGE (V)
1.0
1.5
4220 G03
4220f
LT4220
TYPICAL PERFOR A CE CHARACTERISTICS
GATE
+
8
GATE
+
DRIVE (V
GATE
+
– V
CC
) (V)
Drive vs V
CC
10
GATE
–
DRIVE (V
GATE
–
– V
EE
) (V)
T
A
= 25°C
7
V
CC
= 5V
GATE
+
PULL-UP CURRENT (µA)
V
EE
= –5V
6
V
EE
= –2.7V
5
4
0
3
6
9
V
CC
(V)
12
GATE
+
Pull-Down Current vs
GATE
+
Voltage
60
GATE
+
PULL-DOWN CURRENT (mA)
GATE
–
PULL-UP CURRENT (µA)
GATE
–
PULL-DOWN CURRENT (mA)
50
40
30
20
10
0
0
2
4
6
+
8
10
GATE VOLTAGE (V)
4220 G07
PWRGD and FAULT V
OL
vs
Sink Current
900
800
700
600
V
OL
(mV)
TIMER PULL-UP CURRENT (µA)
HYSTERESIS VOLTAGE (mV)
V
CC
= 5V
V
EE
= –5V
T
A
= 25°C
500
400
FAULT
PWRGD
300
200
100
0
0
2
6
8
SINK CURRENT (mA)
4
10
4220 G10
U W
15
4220 G04
GATE
–
Drive vs V
EE
T
A
= 25°C
16
14
12
10
8
6
4
2
0
0
3
6
9
V
EE
(V)
12
15
18
4220 G05
GATE
+
Pull-Up Current vs
GATE
+
Voltage
9
8
7
V
CC
= 2.7V
6
5
4
V
CC
= 5V
V
EE
= –5V
V
SENSE
+
= V
CC
V
SENSE
–
= V
EE
T
A
= 25°C
0
1
2
3
4
5
6
7
4220 G06
18
GATE
+
VOLTAGE (V
GATE+
– V
CC
) (V)
GATE
–
Pull-Up Current vs
GATE
–
Voltage
12
10
8
6
4
2
0
70
60
50
40
30
20
10
0
GATE
–
Pull-Down Current vs
GATE
–
Voltage
V
CC
= 5V
V
EE
= –5V
ON
–
= 0V
FB
–
= –2V
T
A
= 25°C
V
CC
= 5V
V
EE
= –5V
ON
+
= 0V
FB
+
= 2V
T
A
= 25°C
12
14
V
CC
= 5V
V
EE
= –5V
SENSE
+
= V
CC
SENSE
–
= V
EE
T
A
= 25°C
0
2
–
4
6
–
8
10
4220 G08
0
GATE VOLTAGE (V
GATE
– V
EE
) (V)
3
5
6
2
4
7
1
–
–
– V ) (V)
GATE VOLTAGE (V
GATE
EE
8
4220 G09
TIMER Pull-Up Current vs V
CC
75
T
A
= 25°C
45.0
44.5
70
44.0
43.5
43.0
42.5
42.0
41.5
50
0
3
6
9
V
CC
(V)
4220 G11
ON
+
, ON
–
and FB
+
, FB
–
Hysteresis vs Temperature
65
60
55
12
15
18
41.0
–40
–20
40
20
60
0
TEMPERATURE (°C)
80
4220 G12
4220f
5
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