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 power good monitoring
are also provided.
L,
LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear
Technology Corporation. All other trademarks are the property of their respective owners.
n
Wide Operating Voltage Range: 2.9V to 26.5V
Adjustable, 5% Accurate 15mV Current Limit
Current Monitor Output
Adjustable Current Limit Timer Before Fault
Power Good 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
n
n
n
n
RAID Systems
ATCA, AMC, µTCA Systems
Server I/O Cards
Industrial
typical application
12V, 6A Card Resident Application
12V
*
10
SENSE
–
SENSE
V
DD
AUTO
RETRY
OV
UV
FLT
TIMER
0.1µF
1µF
INTV
CC
GND
LTC4218DHC-12
PG
I
SET
I
MON
20k
2V = 7.5A
4218 TA01a
Power-Up Waveform
V
OUT
12V
6A
330µF
V
IN
10V/DIV
I
IN
1A/DIV
V
OUT
10V/DIV
PG
10V/DIV
4218 TA01b
2m
Si7108DN
+
CONTACT BOUNCE
GATE SOURCE
1k
0.01µF
10k
+
25ms/DIV
ADC
*TVS: DIODES INC SMAJ17A
4218fh
For more information
www.linear.com/LTC4218
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 Ambient Temperature Range
LTC4218C ................................................ 0°C to 70°C
LTC4218I .............................................–40°C to 85°C
Storage Temperature Range .................. –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
(http://www.linear.com/product/LTC4218#orderinfo)
PART MARKING*
421812
421812
4218
4218I
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
LTC4218CDHC-12#TRPBF
LTC4218IDHC-12#TRPBF
LTC4218CGN#TRPBF
LTC4218IGN#TRPBF
Consult LTC Marketing for parts specified with wider operating temperature ranges. *The temperature grade is identified by a label on the shipping container.
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/.
Some packages are available in 500 unit reels through
designated sales channels with #TRMPBF suffix.
4218fh
2
For more information
www.linear.com/LTC4218
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)
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
Outputs
V
INTVCC
V
OL
I
OH
V
TIMER(H)
V
TIMER(L)
I
TIMER(UP)
I
TIMER(DN)
INTV
CC
Output Voltage
PG,
FLT
Output Low Voltage
PG,
FLT
Input Leakage Current
TIMER High Threshold
TIMER Low Threshold
TIMER Pull Up Current
TIMER Pull-Down Current
I
SINK
= 0mA, –10mA
I
SINK
= 2mA
V = 30V
V
TIMER
Rising
V
TIMER
Falling
V
TIMER
= 0V
V
TIMER
= 1.2V
l
l
l
l
l
l
The
l
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
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 Power Good Threshold
Current Limit Sense Voltage Threshold
(V
SENSE+
– V
SENSE–
)
SENSE
–
Input Current
SENSE
+
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
PIN
= 1.2V, LTC4218 Only
LTC4218-12 Only
V
PIN
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
CONDITIONS
l
l
l
l
l
l
l
l
l
l
l
l
l
l
l
l
l
l
l
MIN
2.9
TYP
MAX
26.5
UNITS
V
mA
V
V
mV
V
mV
V
mV
mV
mV
mV
µA
µA
V
V
µA
mA
µA
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
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
400
ΔV
SOURCE(PGHYST)
SOURCE Power Good Hysteresis
OV, UV, FB Input Current
OV, UV, FB Input Resistance
OV, UV, FB Threshold Voltage
OV Hysteresis
UV Hysteresis
UV Reset Threshold Voltage
FB Power Good Hysteresis
I
SET
Internal Resistor
SOURCE Input Current
l
l
l
l
l
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
3.1
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
µA
kΩ
V
mV
mV
V
mV
kΩ
µA
µA
µA
V
V
UV
Falling
l
l
l
V
SOURCE
= V
GATE
= 12V, LTC4218-12 Only
V
SOURCE
= V
GATE
= 12V, LTC4218 Only
V
SOURCE
= V
GATE
= 0V
l
l
l
0.8
±10
1.28
0.3
–120
2.6
V
µA
V
V
µA
µA
4218fh
For more information
www.linear.com/LTC4218
3
LTC4218
electrical characteristics
SYMBOL
I
TIMER(RATIO)
I
MON(FS)
I
MON(OFF)
G
IMON
BW
IMON
AC Characteristics
t
PHL(GATE)
t
PHL(SENSE)
t
D(ON)
t
D(FAULT)
Input High (OV), Input Low (UV) to GATE
Low Propagation Delay
V
SENSE+
– V
SENSE–
High to GATE Low
Propagation Delay
Turn-On Delay
UV Low to Clear Fault Latch 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
l
l
The
l
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 Current Ratio I
TIMER(DN)
/I
TIMER(UP)
I
MON
Full-Scale Output Current
I
MON
Offset Current
I
MON
Gain
I
MON
Bandwidth
V
SENSE+
– V
SENSE–
= 15mV
V
SENSE+
– V
SENSE–
= 1mV
V
SENSE+
– V
SENSE–
= 15mV and 1mV
CONDITIONS
l
l
l
l
MIN
1.6
94
6.47
TYP
2
100
±0
6.67
250
3
0.2
MAX
2.7
106
±6
6.87
UNITS
%
µA
µA
µA/mV
kHz
5
1
µs
µs
l
50
100
1
150
ms
µs
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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