applications that allows a board to be safely inserted and
removed from a live backplane. The part integrates a Hot
Swap controller, power MOSFET and current sense resis-
tor in a single package for small form factor applications.
The LTC4232-1 provides separate inrush current control
and a 10% accurate 5A current limit with foldback cur-
rent limiting. The current limit threshold can be adjusted
dynamically using an external pin. Additional features
include a current monitor output that amplifies the sense
resistor voltage for ground referenced current sensing
and a MOSFET temperature monitor output. Thermal limit,
overvoltage, undervoltage and power good monitoring
are also provided.
The PCI Express compliant LTC4232-1 allows faster turn-on
than the LTC4232 by providing a shorter (16ms) debounce
delay and external control of the GATE ramp rate.
L,
LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear
Technology Corporation. Hot Swap and PowerPath are trademarks of Linear Technology
Corporation. All other trademarks are the property of their respective owners.
n
Reduced 16ms Turn-On Delay
Small Footprint
33mΩ MOSFET with R
SENSE
Wide Operating Voltage Range: 2.9V to 15V
Adjustable, 10% Accurate Current Limit
Current and Temperature Monitor Outputs
Overtemperature Protection
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 5mm
×
3mm DFN Package
APPLICATIONS
n
n
n
n
RAID Systems
Server I/O Cards
PCI Express Systems
Industrial
TYPICAL APPLICATION
12V, 5A Card Resident Application with Auto-Retry
Power-Up Waveforms
12V
*
107k
V
DD
UV
FLT
5.23k
10k
LTC4232DHC-1
OV
PG
GATE
OUT
150k
FB
20k
10k
3.3nF
100k
4.7nF
TIMER
0.1µF
1µF
*DIODES INC. SMAJ22A
INTV
CC
GND
I
SET
I
MON
20k
ADC
42321 TA01a
+
V
OUT
12V
5A
150µF
V
IN
10V/DIV
I
IN
1A/DIV
V
OUT
10V/DIV
CONTACT BOUNCE
PG
10V/DIV
4ms/DIV
42321 TA01b
42321f
For more information
www.linear.com/LTC4232-1
1
LTC4232-1
ABSOLUTE MAXIMUM RATINGS
(Notes 1, 2)
PIN CONFIGURATION
TOP VIEW
V
DD
UV
OV
TIMER
INTV
CC
GND
OUT
OUT
1
2
3
4
5
6
7
8
17
SENSE
16 V
DD
15 I
SET
14 I
MON
13 FB
12
FLT
11 PG
10 GATE
9
OUT
Supply Voltage (V
DD
) ................................. –0.3V to 28V
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
Output Voltages
I
SET
, I
MON
................................................. –0.3V to 3V
PG,
FLT
.................................................. –0.3V to 35V
OUT ............................................ –0.3V to V
DD
+ 0.3V
INTV
CC
.................................................. –0.3V to 3.5V
GATE (Note 3) ........................................ –0.3V to 33V
Operating Temperature Range
LTC4232C-1 ............................................. 0°C to 70°C
LTC4232I-1 ..........................................–40°C to 85°C
Junction Temperature (Notes 4, 5)........................ 125°C
Storage Temperature Range .................. –65°C to 150°C
DHC PACKAGE
16-LEAD (5mm
×
3mm) PLASTIC DFN
T
JMAX
= 125°C,
θ
JA
= 43°C/W
EXPOSED PAD (PIN 17) IS SENSE,
θ
JA
= 43°C/W SOLDERED, OTHERWISE
θ
JA
= 140°C/W
ORDER INFORMATION
LEAD FREE FINISH
LTC4232CDHC-1#PBF
LTC4232IDHC-1#PBF
TAPE AND REEL
LTC4232CDHC-1#TRPBF
LTC4232IDHC-1#TRPBF
PART MARKING*
42321
42321
PACKAGE DESCRIPTION
16-Lead (5mm
×
3mm) Plastic DFN
16-Lead (5mm
×
3mm) Plastic DFN
TEMPERATURE RANGE
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.
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/
ELECTRICAL CHARACTERISTICS
SYMBOL
V
DD
I
DD
V
DD(UVL)
I
OUT
R
ON
I
LIM(TH)
PARAMETER
Input Supply Range
Input Supply Current
Input Supply Undervoltage Lockout
OUT Pin Leakage Current
MOSFET + Sense Resistor On-Resistance
Current Limit Threshold
DC Characteristics
The
l
denotes those specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V
DD
= 12V unless otherwise noted.
CONDITIONS
l
MIN
2.9
TYP
MAX
15
UNITS
V
mA
V
µA
µA
mΩ
A
A
A
MOSFET On, No Load
V
DD
Rising
V
OUT
= V
GATE
= 0V, V
DD
= 15V
V
OUT
= V
GATE
= 12V
V = 1.23V, I
SET
Open
V
FB
= 0V, I
SET
Open
V
FB
= 1.23V, R
SET
= 20kΩ
l
l
l
l
l
l
l
l
1.6
2.63
1
15
5.0
1.2
2.6
2.73
0
2
33
5.6
1.5
2.9
3
2.85
±150
4
50
6.1
1.8
3.3
42321f
2
For more information
www.linear.com/LTC4232-1
LTC4232-1
ELECTRICAL CHARACTERISTICS
SYMBOL
Inputs
I
IN
V
TH
ΔV
OV(HYST)
ΔV
UV(HYST)
V
UV(RTH)
ΔV
FB(HYST)
R
ISET
Outputs
V
INTVCC
V
OL
I
OH
V
TIMER(H)
V
TIMER(L)
I
TIMER(UP)
I
TIMER(DN)
I
TIMER(RATIO)
A
IMON
I
OFF(IMON)
I
GATE(UP)
I
GATE(DN)
I
GATE(FST)
t
PHL(GATE)
t
PHL(ILIM)
t
D(ON)
t
D(CB)
INTV
CC
Output Voltage
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
TIMER Pin Current Ratio I
TIMER(DN)
/I
TIMER(UP)
I
MON
Pin Current Gain
I
MON
Pin Offset Current
Gate Pull-Up Current
Gate Pull-Down Current
Gate Fast Pull-Down Current
Input High (OV), Input Low (UV) to Gate Low
Propagation Delay
Short-Circuit to Gate Low
Turn-On Delay
Circuit Breaker Filter Delay Time (Internal)
I
OUT
= 2.5A
I
OUT
= 150mA
Gate Drive On, V
GATE
= V
OUT
= 12V
Gate Drive Off, V
GATE
= 18V, V
OUT
= 12V
Fast Turn Off, V
GATE
= 18V, V
OUT
= 12V
V
GATE
< 16.5V Falling
V
FB
= 0, Step I
SENSE
to 6A,
V
GATE
< 15V Falling
Step V
UV
to 2V, V
GATE
> 13V
V
FB
= 0V, Step I
SENSE
to 3A
l
l
l
l
l
The
l
denotes those specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V
DD
= 12V unless otherwise noted.
PARAMETER
OV, UV, FB Pin Input Current
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 Internal Resistor
V
DD
= 5V, 15V, I
LOAD
= 0mA, –10mA
I = 2mA
V = 30V
V
TIMER
Rising
V
TIMER
Falling
V
TIMER
= 0V
V
TIMER
= 1.2V
V
UV
Falling
CONDITIONS
V = 1.2V
V
PIN
Rising
l
l
l
l
l
l
l
MIN
TYP
0
MAX
±1
1.26
30
110
0.7
30
21
3.3
0.8
±10
1.28
0.3
–120
2.6
2.7
21.5
±4.5
–29
340
UNITS
µA
V
mV
mV
V
mV
kΩ
V
V
µA
V
V
µA
µA
%
µA/A
µA
µA
µA
mA
1.21
10
50
0.55
10
19
2.8
1.235
20
80
0.62
20
20
3.1
0.4
0
l
l
l
l
l
l
l
l
l
l
l
l
1.2
0.1
–80
1.4
1.6
18.5
–18
180
1.235
0.21
–100
2
2
20
0
–24
250
140
8
1
AC Characteristics
10
5
24
2.7
24
µs
µs
ms
ms
ms
8
1.3
8
16
2
16
t
D(AUTO-RETRY)
Auto-Retry Turn-On Delay (Internal)
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 OUT. Driving this pin to voltages beyond the clamp may damage the
device.
Note 4:
This IC includes overtemperature protection that is intended
to protect the device during momentary overload conditions. Junction
temperature will exceed 125°C when overtemperature protection is active.
Continuous operation above the specified maximum operating junction
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