LT4250H Datasheet PDF - Linear Technology

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LT4250H
Linear Technology

Part Number LT4250H
Description Negative 48V Hot Swap Controller
Page 12 Pages


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LT4250L/LT4250H
Negative 48V
Hot Swap Controller
FEATURES
s Allows Safe Board Insertion and Removal
from a Live – 48V Backplane
s Circuit Breaker Immunity to Voltage Steps and
Current Spikes
www.DataShseetP4Uro.cgormammable Inrush and
Short-Circuit Current Limits
s Pin Compatible with LT1640L/LT1640H
s Operates from –20V to – 80V
s Programmable Overvoltage Protection
s Programmable Undervoltage Lockout
s Power Good Control Output
s Bell-Core Compatible ON/OFF Threshold
U
APPLICATIO S
s Central Office Switching
s – 48V Distributed Power Systems
s Negative Power Supply Control
DESCRIPTIO
The LT®4250L/LT4250H are 8-pin, negative 48V Hot SwapTM
controllers that allow a board to be safely inserted and
removed from a live backplane. Inrush current is limited to
a programmable value by controlling the gate voltage of an
external N-channel pass transistor. The pass transistor is
turned off if the input voltage is less than the program-
mable undervoltage threshold or greater than the over-
voltage threshold. A programmable current limit protects
the system against shorts. After a 500µs timeout the
current limit activates the electronic circuit breaker. The
PWRGD (LT4250L) or PWRGD (LT4250H) signal can be
used to directly enable a power module. The LT4250L is
designed for modules with a low enable input and the
LT4250H for modules with a high enable input.
The LT4250L/LT4250H are available in 8-pin PDIP and SO
packages.
, LTC and LT are registered trademarks of Linear Technology Corporation.
Hot Swap is a trademark of Linear Technology Corporation.
TYPICAL APPLICATIO
–48V RTN
(SHORT PIN)
–48V RTN
R4
549k
1%
UV =
38.5V
UV
RELEASE
AT 43V
OV =
71V
R5
6.49k
1%
R6
10k
1%
3
UV
2
OV
VEE
4
SENSE
5
*
–48V
INPUT 1
0.1µF
10V
R1
0.02
5%
–48V
INPUT 2
* DIODES INC. SMAT70A
THESE COMPONENTS ARE APPLICATION
SPECIFIC AND MUST BE SELECTED BASED
UPON OPERATING CONDITIONS AND DESIRED
PERFORMANCE. SEE APPLICATIONS
INFORMATION.
8
VDD
LT4250L
1
PWRGD
GATE
DRAIN
6
R3
1k, 5%
7
C1
470nF
25V
R2
10
5%
C2
15nF
100V
VEE AND
DRAIN
20V/DIV
ID (Q1)
5A/DIV
Q1
IRF530
C3 +
0.1µF
100V
C4
100µF
100V
2
1
ON/OFF
VIN+
VOUT+
SENSE +
9
8
7
TRIM
SENSE 6
4 VIN–
VOUT– 5
+
5V
C5
100µF
16V
LUCENT
JW050A1-E
4250 TA01
Voltage Step On Input Supply
500µs/DIV
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LT4250L/LT4250H
ABSOLUTE MAXIMUM RATINGS (Note 1), All Voltages Referred to VEE
Supply Voltage (VDD – VEE) .................... – 0.3V to 100V
PWRGD, PWRGD Pins ........................... – 0.3V to 100V
SENSE, GATE Pins .................................... – 0.3V to 20V
UV, OV Pins .............................................. – 0.3V to 60V
DRAIN Pin .................................................. –2V to 100V
Maximum Junction Temperature ......................... 125°C
Operating Temperature Range
LT4250LC/LT4250HC ............................. 0°C to 70°C
LT4250LI/LT4250HI .......................... – 40°C to 85°C
Storage Temperature Range ................ – 65°C to 150°C
Lead Temperature (Soldering, 10 sec)................. 300°C
PACKAGE/ORDER I FOR ATIO
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ORDER PART
TOP VIEW
NUMBER
PWRGD 1
OV 2
UV 3
VEE 4
8 VDD
7 DRAIN
6 GATE
5 SENSE
LT4250LCN8
LT4250LCS8
LT4250LIN8
LT4250LIS8
N8 PACKAGE
8-LEAD PDIP
S8 PACKAGE
8-LEAD PLASTIC SO
TJMAX = 125°C, θJA = 120°C/W (N8)
TJMAX = 125°C, θJA = 150°C/W (S8)
S8 PART MARKING
4250L
4250LI
TOP VIEW
PWRGD 1
OV 2
UV 3
VEE 4
8 VDD
7 DRAIN
6 GATE
5 SENSE
N8 PACKAGE
8-LEAD PDIP
S8 PACKAGE
8-LEAD PLASTIC SO
TJMAX = 125°C, θJA = 120°C/W (N8)
TJMAX = 125°C, θJA = 150°C/W (S8)
Consult LTC Marketing for parts specified with wider operating temperature ranges.
ORDER PART
NUMBER
LT4250HCN8
LT4250HCS8
LT4250HIN8
LT4250HIS8
S8 PART MARKING
4250H
4250HI
ELECTRICAL CHARACTERISTICS The q denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at TA = 25°C. (Note 2), VDD = 48V, VEE = 0V unless otherwise noted.
SYMBOL
DC
VDD
IDD
VUVL
VCL
IPU
IPD
ISENSE
VGATE
VUVH
VUVL
VUVHY
IINUV
VOVH
VOVL
PARAMETER
Supply Voltage Operating Range
Supply Current
Undervoltage Lockout
Current Limit Trip Voltage
GATE Pin Pull-Up Current
GATE Pin Pull-Down Current
SENSE Pin Current
External Gate Drive
UV Pin High Threshold Voltage
UV Pin Low Threshold Voltage
UV Pin Hysteresis
UV Pin Input Current
OV Pin High Threshold Voltage
OV Pin Low Threshold Voltage
CONDITIONS
UV = 3V, OV = VEE, SENSE = VEE
VCL = (VSENSE – VEE)
Gate Drive On, VGATE = VEE
Gate Drive OFF
VSENSE = 50mV
(VGATE – VEE), 20V VDD 80V
UV Increasing
UV Decreasing
VUV = VEE
OV Increasing
OV Decreasing
MIN TYP MAX
q 20
80
q 1.6 5
q 15.4
q 40 50 60
q – 30 – 45 – 60
24 50 70
– 20
q 10 13.5 18
q 1.240 1.255 1.270
q 1.105 1.125 1.145
130
q – 0.02 – 0.5
q 1.235 1.255 1.275
q 1.210 1.235 1.255
UNITS
V
mA
V
mV
µA
mA
µA
V
V
V
mV
µA
V
V
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LT4250L/LT4250H
ELECTRICAL CHARACTERISTICS The q denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at TA = 25°C. (Note 2), VDD = 48V, VEE = 0V unless otherwise noted.
SYMBOL PARAMETER
CONDITIONS
MIN TYP MAX
VOVHY
IINOV
VDL
VGH
IDRAIN
VOL
OV Pin Hysteresis
OV Pin Input Current
DRAIN Low Threshold
GATE High Threshold
Drain Input Bias Current
PWRGD Output Low Voltage
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PWRGD Output Low Voltage
(PWRGD – DRAIN)
IOH Output Leakage
AC
20
VOV = VEE
q – 0 .03 – 0.5
VDRAIN – VEE, DRAIN Decreasing
1.1 1.6 2.3
VGATE – VGATE Decreasing
1.3
VDRAIN = 48V
q 10
80 500
PWRGD (LT4250L), (VDRAIN – VEE) < VDL
IOUT = 1mA
IOUT = 5mA
q
q
0.48 0.8
1.2 3.0
PWRGD (LT4250H), VDRAIN = 5V
IOUT = 1mA
q 0.75 1.0
PWRGD (LT4250L), VDRAIN = 48V, VPWRGD = 80V q
PWRGD (LT4250H), VDRAIN = 0V, VPWRGD = 80V q
0.05 10
0.05 10
tPHLOV
tPHLUV
tPLHOV
tPLHUV
tPHLSENSE
tPHLCB
tPHLDL
OV High to GATE Low
UV Low to GATE Low
OV Low to GATE High
UV High to GATE High
SENSE High to Gate Low
Current Limit to GATE Low
DRAIN Low to PWRGD Low
DRAIN Low to (PWRGD – DRAIN) High
Figures 1a, 2
Figures 1a, 3
Figures 1a, 2
Figures 1a, 3
Figures 1a, 4a
Figures 1b, 4b
(LT4250L) Figures 1a, 5a
(LT4250H) Figures 1a, 5a
1.7
1.5
5.5
6.5
13
500
1
1
tPHLGH
GATE High to PWRGD Low
(LT4250L) Figures 1a, 5b
GATE High to (PWRGD – DRAIN) High (LT4250H) Figures 1a, 5b
1.5
1.5
UNITS
mV
µA
V
V
µA
V
V
V
µA
µA
µs
µs
µs
µs
µs
µs
µs
µs
µs
µs
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 are referenced to VEE unless otherwise
specified.
TYPICAL PERFOR A CE CHARACTERISTICS
Supply Current vs Supply Voltage
1.8
TA = 25°C
1.7
1.6
1.5
1.4
1.3
1.2
1.1
0
0 20 40 60 80 100
SUPPLY VOLTAGE (V)
1640 G01
Supply Current vs Temperature
1.6
VDD = 48V
1.5
1.4
1.3
1.2
1.1
1.0
– 50 – 25
0
25 50
TEMPERATURE (°C)
75 100
1640 G02
Gate Voltage vs Supply Voltage
15
TA = 25°C
14
13
12
11
10
9
8
7
6
0 20 40 60 80 100
SUPPLY VOLTAGE (V)
1640 G03
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LT4250L/LT4250H
TYPICAL PERFOR A CE CHARACTERISTICS
Gate Voltage vs Temperature
15.0
VDD = 48V
14.5
14.0
13.5
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13.0
12.5
12.0
– 50 – 25 0 25 50
TEMPERATURE (°C)
75 100
1640 G04
Gate Pull-Down Current
vs Temperature
55
VGATE = 2V
52
49
46
43
40
– 50 – 25 0
25 50 75
TEMPERATURE (°C)
100
1640 G07
Current Limit Trip Voltage
vs Temperature
55
54
53
52
51
50
49
48
– 50 – 25
0 25 50
TEMPERATURE (°C)
75 100
1640 G05
PWRGD Output Low Voltage
vs Temperature (LT4250L)
0.5
IOUT = 1mA
0.4
0.3
0.2
0.1
0
– 50 – 25
0 25 50
TEMPERATURE (°C)
75 100
1640 G08
Gate Pull-Up Current
vs Temperature
48
47 VGATE = 0V
46
45
44
43
42
41
40
– 50
– 25 0 25 50
TEMPERATURE (°C)
75 100
1640 G06
PWRGD Output Impedance
vs Temperature (LT4250H)
8
VDRAIN – VEE > 2.4V
7
6
5
4
3
2
– 50 – 25 0 25 50
TEMPERATURE (°C)
75 100
1640 G09
PIN FUNCTIONS
PWRGD/PWRGD (Pin 1): Power Good Output Pin. This pin
will latch a power good indication when VDRAIN is within VDL
of VEE and VGATE is within VGH of VGATE. This pin can be
connected directly to the enable pin of a power module.
When the DRAIN pin of the LT4250L is above VEE by more
than VDL or VGATE is more than VGH from VGATE, the
PWRGD pin will be high impedance, allowing the pull-up
current of the module’s enable pin to pull the pin high and
turn the module off. When VDRAIN drops below VDL and
VGATE rises above VGH, the PWRGD pin sinks current to
VEE, pulling the enable pin low and turning on the module.
4
This condition is latched until the GATE pin is turned off via
the UV, OV, UVLO or the electronic circuit breaker.
When the DRAIN pin of the LT4250H is above VEE by more
than VDL or VGATE is more than VGH from VGATE, the
PWRGD pin will sink current to the DRAIN pin which pulls
the module’s enable pin low, forcing it off. When VDRAIN
drops below VDL and VGATE rises above VGH, the PWRGD
sink current is turned off, allowing the module’s pull-up
current to pull the enable pin high and turn on the module.
This condition is latched until the GATE pin is turned off via
the UV, OV, UVLO or the electronic circuit breaker.
4250lhf



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