4218 is a Hot Swap™ controller that allows a board
to be safely inserted and removed from a live backplane.
An internal high side switch driver controls the gate of an
external N-channel MOSFET for supply voltages from 2.9V
to 26.5V. A dedicated 12V version (LTC4218-12) contains
preset 12V specific thresholds, while the standard LTC4218
allows adjustable thresholds.
The LTC4218 provides an accurate (5%) current limit with
current foldback limiting. The current limit threshold can
be adjusted dynamically using an external pin. Additional
features include a current monitor output that amplifies
the sense voltage for ground referenced current sensing.
Overvoltage, undervoltage and powergood monitoring
are also provided.
, LT, LTC and LTM 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.
■
Wide Operating Voltage Range: 2.9V to 26.5V
Adjustable, 5% Accurate (15mV) Current Limit
Current Monitor Output
Adjustable Current Limit Timer Before Fault
Powergood and Fault Outputs
Adjustable Inrush Current Control
2% Accurate Undervoltage and Overvoltage
Protection
Available in 16-Lead SSOP and 16-Pin 5mm
×
3mm
DFN Packages
APPLICATIONS
■
■
■
■
RAID Systems
ATCA, AMC, μTCA Systems
Server I/O Cards
Industrial
TYPICAL APPLICATION
12V, 6A Card Resident Application
2mΩ
12V
Si7108DN
V
OUT
12V
6A
330μF
V
IN
10V/DIV
I
IN
1A/DIV
V
OUT
10V/DIV
Power-Up Waveform
+
10Ω
SENSE
–
SENSE
V
DD
UV
AUTO
RETRY
LTC4218DHC-12
FLT
TIMER
0.1μF
0.1μF
INTV
CC
GND
I
MON
20k
PG
10k
+
GATE SOURCE
12V
1k
0.01μF
PG
10V/DIV
4218 TA01b
25ms/DIV
ADC
4218 TA01a
4218fb
1
LTC4218
ABSOLUTE MAXIMUM RATINGS
(Notes 1, 2)
Supply Voltage (V
DD
) ................................. –0.3V to 35V
Input Voltages
FB, OV, UV ............................................. –0.3V to 12V
TIMER................................................... –0.3V to 3.5V
SENSE
–
............................ V
DD
– 10V or –0.3V to V
DD
SENSE
+
............................ V
DD
– 10V or –0.3V to V
DD
SOURCE........................................ – 5V to V
DD
+ 0.3V
Output Voltages
I
SET
, I
MON
................................................. –0.3V to 3V
PG,
FLT
.................................................. –0.3V to 35V
INTV
CC
.................................................. –0.3V to 3.5V
GATE (Note 3) ........................................ –0.3V to 35V
Operating Temperature Range
LTC4218C ................................................ 0°C to 70°C
LTC4218I .............................................–40°C to 85°C
Storage Temperature Range
DHC Package .....................................–65°C to 125°C
GN Package .......................................–65°C to 150°C
Lead Temperature (Soldering, 10 sec)
GN Package Only .............................................. 300°C
PIN CONFIGURATION
TOP VIEW
NC
V
DD
UV
OV
TIMER
INTV
CC
GND
SOURCE
1
2
3
4
5
6
7
8
17
16 SENSE
+
15 SENSE
–
14 I
SET
13 I
MON
12 FB
11 FLT
10 PG
9
GATE
NC
V
DD
UV
OV
TIMER
INTV
CC
GND
SOURCE
1
2
3
4
5
6
7
8
TOP VIEW
16 SENSE
+
15 SENSE
–
14 I
SET
13 I
MON
12 FB
11 FLT
10 PG
9
GATE
DHC PACKAGE
16-LEAD (5mm
×
3mm) PLASTIC DFN
T
JMAX
= 125°C,
θ
JA
= 43°C/W
EXPOSED PAD (PIN 17) IS SUBSTRATE GND
GN PACKAGE
16-LEAD PLASTIC SSOP
T
JMAX
= 150°C,
θ
JA
= 135°C/W
ORDER INFORMATION
LEAD FREE FINISH
LTC4218CDHC-12#PBF
LTC4218IDHC-12#PBF
LTC4218CGN#PBF
LTC4218IGN#PBF
TAPE AND REEL
LTC4218CDHC-12#TRPBF
LTC4218IDHC-12#TRPBF
LTC4218CGN#TRPBF
LTC4218IGN#TRPBF
PART MARKING*
421812
421812
4218
4218
PACKAGE DESCRIPTION
16-Lead (5mm
×
3mm) Plastic DFN
16-Lead (5mm
×
3mm) Plastic DFN
16-Lead Plastic SSOP
16-Lead Plastic SSOP
TEMPERATURE RANGE
0°C to 70°C
–40°C to 85°C
0°C to 70°C
–40°C to 85°C
Consult LTC Marketing for parts specified with wider operating temperature ranges. *The temperature grade is identified by a label on the shipping container.
Consult LTC Marketing for information on non-standard lead based finish parts.
For more information on lead free part marking, go to:
http://www.linear.com/leadfree/
For more information on tape and reel specifications, go to:
http://www.linear.com/tapeandreel/
4218fb
2
LTC4218
ELECTRICAL CHARACTERISTICS
SYMBOL
DC Characteristics
V
DD
I
DD
V
DD(UVL)
V
DD(UVTH)
ΔV
DD(UVHYST)
V
DD(OVTH)
ΔV
DD(OVHYST)
V
SOURCE(PGTH)
ΔV
SNS(TH)
Input Supply Range
Input Supply Current
Input Supply Undervoltage Lockout
Input Supply Undervoltage Threshold
Input Supply Undervoltage Hysteresis
Input Supply Overvoltage Threshold
Input Supply Overvoltage Hysteresis
SOURCE Powergood Threshold
Current Limit Sense Voltage Threshold
(V
SENSE+
– V
SENSE–
)
SENSE
–
Pin Input Current
SENSE
+
Pin Input Current
External N-Channel Gate Drive
(V
GATE
– V
SOURCE
)
Gate High Threshold (V
GATE
– V
SOURCE
)
External N-Channel Gate Pull-Up Current
External N-Channel Gate Fast Pull-Down
Current
External N-Channel Gate Pull-Down Current
Gate Drive On, V
GATE
= V
SOURCE
= 12V
Fast Turn Off, V
GATE
= 18V,
V
SOURCE
=12V
Gate Drive Off, V
GATE
= 18V,
V
SOURCE
=12V
V
IN
= 1.2V, LTC4218 Only
LTC4218-12 Only
V
IN
Rising
FET On
V
DD
Rising
LTC4218-12 Only V
DD
Rising
LTC4218-12 Only
LTC4218-12 Only V
DD
Rising
LTC4218-12 Only
LTC4218-12 Only V
SOURCE
Rising
LTC4218-12 Only
V
FB
= 1.23V
V
FB
= 0V
V
FB
= 1.23V, R
SET
= 20kΩ
V
SENSE–
= 12V
V
SENSE+
= 12V
V
DD
= 2.9V to 26.5V (Note 3)
I
GATE
= 0, –1μA
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
The
●
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V
DD
= 12V unless otherwise noted.
PARAMETER
CONDITIONS
MIN
2.9
1.6
2.65
9.6
520
14.7
183
10.2
127
14.25
2.8
6.7
2.73
9.88
640
15.05
244
10.5
170
15
3.75
7.5
4
5.5
5
3.5
–19
100
200
6.15
4.2
–24
170
250
TYP
MAX
26.5
5
2.85
10.2
760
15.4
305
10.8
213
15.75
4.7
8.325
±10
±20
6.5
4.8
–29
220
340
UNITS
V
mA
V
V
mV
V
mV
V
mV
mV
mV
mV
μA
μA
V
V
μA
mA
μA
ΔV
SOURCE(PGHYST)
SOURCE Powergood Hysteresis
I
SENSE–(IN)
I
SENSE+(IN)
ΔV
GATE
ΔV
GATE-HIGH(TH)
I
GATE(UP)
I
GATE(FST)
I
GATE(DN)
Inputs
I
(IN)
R
(IN)
V
(TH)
ΔV
OV(HYST)
ΔV
UV(HYST)
V
UV(RTH)
ΔV
FB(HYST)
R
ISET
I
SOURCE
OV, UV, FB Pin Input Current
OV, UV, FB Pin Input Resistance
OV, UV, FB Pin Threshold Voltage
OV Pin Hysteresis
UV Pin Hysteresis
UV Pin Reset Threshold Voltage
FB Pin Power Good Hysteresis
I
SET
Pin Output Resistor
SOURCE Pin Input Current
●
●
●
●
●
0
13
1.21
10
50
0.55
10
19.5
50
1
18
1.235
20
80
0.62
20
20
70
2
0
0.4
0
1.2
0.1
–80
1.4
1.235
0.21
–100
2
±1
23
1.26
30
110
0.7
30
20.5
90
4
±1
0.8
±10
1.28
0.3
–120
2.6
μA
kΩ
V
mV
mV
V
mV
kΩ
μA
μA
μA
V
μA
V
V
μA
μA
4218fb
V
UV
Falling
●
●
●
V
SOURCE
= V
GATE
= 12V, LTC4218-12 Only
●
●
V
SOURCE
= V
GATE
= 12V, LTC4218 Only
●
V
SOURCE
= V
GATE
= 0V
I
OUT
= 2mA
V
OUT
= 30V
V
TIMER
Rising
V
TIMER
Falling
V
TIMER
= 0V
V
TIMER
= 1.2V
●
●
●
●
●
●
Outputs
V
(OL)
I
(OH)
V
TIMER(H)
V
TIMER(L)
I
TIMER(UP)
I
TIMER(DN)
PG,
FLT
Pin Output Low Voltage
PG,
FLT
Pin Input Leakage Current
TIMER Pin High Threshold
TIMER Pin Low Threshold
TIMER Pin Pull Up Current
TIMER Pin Pull-Down Current
3
LTC4218
ELECTRICAL CHARACTERISTICS
SYMBOL
I
TIMER(RATIO)
I
MON(FS)
I
MON(OFF)
G
IMON
AC Characteristics
t
PHL(GATE)
t
PHL(SENSE)
Input High (OV), Input Low (UV) to GATE
Low Propagation Delay
V
SENSE+
– V
SENSE–
High to GATE Low
Propagation Delay
Turn-On Delay
V
GATE
< 16.5V Falling
V
FB
= 0, Step (V
SENSE+
– V
SENSE–
) to
60mV, C
GATE
= 1.5nF, V
GATE
< 16.5V
Falling
Step V
UV
to 2V, V
GATE
> 13V
●
●
The
●
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V
DD
= 12V unless otherwise noted.
PARAMETER
TIMER Pin Current Ratio I
TIMER(DN)
/
I
TIMER(UP)
I
MON
Fullscale Output Current
I
MON
Pin Offset Current
I
MON
Pin Gain
V
SENSE+
– V
SENSE–
= 15mV
V
SENSE+
– V
SENSE–
= 1mV
V
SENSE+
– V
SENSE–
= 15mV and 1mV
CONDITIONS
●
●
●
●
MIN
1.6
94
6.47
TYP
2
100
±0
6.67
3
0.2
MAX
2.7
106
±6
6.87
5
1
UNITS
%
μA
μA
μA/mV
μs
μs
t
D(ON)
●
50
100
150
ms
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:
All currents into pins are positive, all voltages are referenced to
GND unless otherwise specified.
Note 3:
An internal clamp limits the GATE pin to a maximum of 6.5V above
the SOURCE pin. Driving either GATE or SOURCE pin to voltages beyond
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