19-3494; Rev 1; 8/11
-48V Hot-Swap Controllers
with External R
SENSE
General Description
The MAX5949A/MAX5949B are hot-swap controllers that
allow a circuit card to be safely hot plugged into a live
backplane. The MAX5949A/MAX5949B operate from
-20V to -80V and are well-suited for -48V power systems.
These devices are pin and function compatible with the
LT4250 and pin compatible with the LT1640.
The MAX5949A/MAX5949B provide a controlled turn-on
to circuit cards preventing glitches on the power-supply
rail and damage to board connectors and components.
The MAX5949A/MAX5949B provide undervoltage, over-
voltage, and overcurrent protection. These devices
ensure the input voltage is stable and within tolerance
before applying power to the load.
Both the MAX5949A and MAX5949B protect a system
against overcurrent and short-circuit conditions by turn-
ing off the external MOSFET in the event of a fault con-
dition. The MAX5949A/MAX5949B also provide
protection against input voltage steps. During an input
voltage step, the MAX5949A/MAX5949B limit the cur-
rent drawn by the load to a safe level without turning off
power to the load.
Both devices feature an open-drain power-good status
output (PWRGD for the MAX5949A or PWRGD for the
MAX5949B) that can be used to enable downstream
converters.
The MAX5949A/MAX5949B are available in an 8-pin SO
package. Both devices are specified for the extended
-40°C to +85°C temperature range.
Features
o
Allow Safe Board Insertion and Removal
from a Live -48V Backplane
o
Pin and Function Compatible with LT4250L
(MAX5949A)
o
Pin Compatible with LT1640L (MAX5949A)
o
Pin and Function Compatible with LT4250H
(MAX5949B)
o
Pin Compatible with LT1640H (MAX5949B)
o
Circuit-Breaker Immunity to Input Voltage Steps
and Current Spikes
o
Withstand -100V Input Transients with No
External Components
o
Programmable Inrush and Short-Circuit Current
Limits
o
Operate from -20V to -80V
o
Programmable Overvoltage Protection
o
Programmable Undervoltage Lockout
o
Power Up into a Shorted Load
o
Power-Good Control Output
MAX5949A/MAX5949B
Ordering Information
PART
MAX5949AESA+
MAX5949BESA+
TEMP RANGE
-40°C to +85°C
-40°C to +85°C
PIN-PACKAGE
8 SO
8 SO
Applications
Telecom Line Cards
Network Switches/Routers
Central-Office Line Cards
Server Line Cards
Base-Station Line Cards
Central-Office Switching
-48V Distributed Power Systems
Negative Power-Supply Controls
+Denotes
a lead(Pb)-free/RoHS-compliant package.
Pin Configuration
TOP VIEW
+
1
2
3
8
7
V
DD
DRAIN
GATE
SENSE
PWRGD
(PWRGD)
OV
UV
MAX5949A
MAX5949B
6
5
Typical Operating Circuit and Selector Guide appear at end
of data sheet.
V
EE
4
SO
( ) FOR MAX5949B.
________________________________________________________________
Maxim Integrated Products
1
For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,
or visit Maxim’s website at www.maxim-ic.com.
-48V Hot-Swap Controllers
with External R
SENSE
MAX5949A/MAX5949B
ABSOLUTE MAXIMUM RATINGS
(All voltages are referenced to V
EE
, unless otherwise noted.)
Supply Voltage (V
DD
- V
EE
) .................................-0.3V to +100V
PWRGD,
PWRGD
.................................................-0.3V to +100V
DRAIN (Note 1)........................................................-2V to +100V
PWRGD to DRAIN .............................................… -0.3V to +95V
PWRGD to V
DD
........................................................-95V to +85V
SENSE (Internally Clamped) .................................-0.3V to +1.0V
GATE (Internally Clamped) ....................................-0.3V to +18V
UV and OV..............................................................-0.3V to +60V
Current Through SENSE ...................................................±40mA
Current into GATE...........................................................±300mA
Current into DRAIN .........................................-100mA to +20mA
Current into Any Other Pin................................................±20mA
Continuous Power Dissipation (T
A
= +70°C)
8-Pin SO (derate 5.9mW/°C above +70°C)..................471mW
Operating Temperature Range ...........................-40°C to +85°C
Junction Temperature .....................................................+150°C
Storage Temperature Range .............................-65°C to +150°C
Lead Temperature (soldering, 10s) .................................+300°C
Soldering Temperature (reflow) .......................................+260°C
Note 1:
Test condition per Figure 1. DRAIN current must be limited to the specified 100mA maximum.
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional
operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to
absolute maximum rating conditions for extended periods may affect device reliability.
ELECTRICAL CHARACTERISTICS
(V
EE
= 0V, V
DD
= 48V, T
A
= -40°C to +85°C. Typical values are at T
A
= +25°C, unless otherwise noted.) (Notes 2, 5)
PARAMETER
POWER SUPPLIES
Operating Input Voltage Range
Supply Current
GATE Pin Pullup Current
GATE Pin Pulldown Current
External Gate Drive
GATE to VEE Clamp Voltage
CIRCUIT BREAKER
Current-Limit Trip Voltage
SENSE Input Bias Current
UNDERVOLTAGE LOCKOUT
Internal Undervoltage-Lockout
Voltage High
Internal Undervoltage-Lockout
Voltage Low
UV PIN
UV High Threshold
UV Low Threshold
UV Hysteresis
UV Input Bias Current
OV PIN
OV High Threshold
OV Low Threshold
OV Hysteresis
OV Input Bias Current
V
OVH
V
OVL
V
OVHY
I
INOV
V
OV
= V
EE
OV voltage increasing
OV voltage decreasing
1.235
1.210
1.255
1.235
20
0
-0.5
1.275
1.255
V
V
mV
µA
V
UVH
V
UVL
V
UVHY
I
INUV
V
UV
= V
EE
UV voltage increasing
UV voltage decreasing
1.240
1.105
1.255
1.125
130
0
-0.5
1.270
1.145
V
V
mV
µA
V
UVLOH
V
UVLOL
V
DD
increasing
V
DD
decreasing
13.8
11.8
15.4
13.4
17.0
15.0
V
V
V
CL
I
SENSE
V
CL
= V
SENSE
- V
EE
V
SENSE
= 50mV
40
0
50
-0.2
60
-2
mV
µA
V
DD
I
DD
I
PU
I
PD
∆V
GATE
V
GSCLMP
(Note 3)
Gate drive on, V
GATE
= V
EE
Gate drive off, V
GATE
= 2V, T
A
= +25°C
V
GATE
- V
EE
, 20V
≤
V
DD
≤
80V
V
GATE
- V
EE
, I
GS
= 30mA
-30
24
10
15
20
0.7
-45
50
13.5
16.4
80
2
-60
70
18
18
V
mA
µA
mA
V
V
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
GATE DRIVE AND CLAMPING CIRCUITS
2
_______________________________________________________________________________________
-48V Hot-Swap Controllers
with External R
SENSE
ELECTRICAL CHARACTERISTICS (continued)
(V
EE
= 0V, V
DD
= 48V, T
A
= -40°C to +85°C. Typical values are at T
A
= +25°C, unless otherwise noted.) (Notes 2, 5)
PARAMETER
DRAIN Input Bias Current
DRAIN Threshold for Power-Good
GATE High Threshold
PWRGD,
PWRGD
Output
Leakage
PWRGD
Output Low Voltage
PWRGD Output Low Voltage
AC PARAMETERS
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
GATE High to
PWRGD
Low
GATE High to (PWRGD - DRAIN)
High
TURN-OFF
Latch-Off Period
t
OFF
(Note 4)
51
64
78
ms
t
PHLOV
t
PHLUV
t
PLHOV
t
PLHVL
t
PHLSENSE
t
PHLCB
t
PHLDL
MAX5949B, Figures 2a, 6a
MAX5949A, Figures 2a, 6b
t
PHLGH
MAX5949B, Figures 2a, 6b
2.5
3.4
1.6
µs
Figures 2a, 3
Figures 2a, 4
Figures 2a, 3
Figures 2a, 4
Figures 2a, 5a
Figures 2b, 5b
MAX5949A, Figures 2a, 6a
350
0.5
0.4
4
5.5
1
500
1.8
µs
3
650
µs
µs
µs
µs
µs
µs
SYMBOL
I
DRAIN
V
DL
V
GH
I
OH
V
OL
V
OL
V
DRAIN
= 48V
V
DRAIN
- V
EE
threshold for power-good
condition, DRAIN decreasing
∆V
GATE
- V
GATE
threshold for power-good
condition,
∆V
GATE
- V
GATE
decreasing
PWRGD
(MAX5949A) = 80V, V
DRAIN
= 48V,
PWRGD (MAX5949B) = 80V, V
DRAIN
= 0V
V
PWRGD
- V
EE
; V
DRAIN
- V
EE
< V
DL
,
I
SINK
= 5mA (MAX5949A)
V
PWRGD
- V
DRAIN
; V
DRAIN
= 5V,
I
SINK
= 1mA (MAX5949B)
0.11
0.11
CONDITIONS
MIN
10
1.1
1.0
TYP
80
1.4
1.4
MAX
250
2.0
2.0
10
0.4
0.4
UNITS
µA
V
V
µA
V
V
PWRGD OUTPUT SIGNAL REFERENCED TO DRAIN
MAX5949A/MAX5949B
Note 2:
Note 3:
Note 4:
Note 5:
All currents into device pins are positive; all currents out of device pins are negative. All voltages are referenced to V
EE
,
unless otherwise specified.
Current into V
DD
with UV = 3V, OV = DRAIN = PWRGD = SENSE = V
EE
, GATE = open.
Minimum duration of GATE pulldown following a circuit-breaker fault. The circuit breaker can be reset during this time by
toggling UV low, but the GATE pulldown does not release until t
OFF
has elapsed.
Limits are 100% tested at T
A
= +25°C and +85°C. Limits at -40°C are guaranteed by design.
_______________________________________________________________________________________
3
-48V Hot-Swap Controllers
with External R
SENSE
MAX5949A/MAX5949B
Typical Operating Characteristics
(V
DD
= 48V, V
EE
= 0V, T
A
= +25°C, unless otherwise noted.)
SUPPLY CURRENT vs. SUPPLY VOLTAGE
MAX5949 toc01
GATE VOLTAGE vs. SUPPLY VOLTAGE
T
A
= +85°C
14
GATE VOLTAGE (V)
13
T
A
= -45°C
12
11
10
T
A
= +25°C
MAX5949 toc02
CURRENT-LIMIT TRIP VOLTAGE
vs. TEMPERATURE
MAX5949 toc03
900
800
SUPPLY CURRENT (µA)
700
600
500
400
300
200
100
0
0
20
40
60
80
T
A
= -40°C
T
A
= +85°C
T
A
= +25°C
15
53
52
TRIP VOLTAGE (mV)
51
50
49
48
47
46
9
8
100
0
20
40
60
80
100
SUPPLY VOLTAGE (V)
SUPPLY VOLTAGE (V)
-40
-15
10
35
60
85
TEMPERATURE (°C)
GATE PULLUP CURRENT
vs. TEMPERATURE
MAX5949 toc04
GATE PULLDOWN CURRENT
vs. TEMPERATURE
65
GATE PULLDOWN CURRENT (mA)
60
55
50
45
40
35
30
25
V
GATE
= 2V
MAX5949 toc05
45.0
44.8
GATE PULLUP CURRENT (µA)
44.6
44.4
44.2
44.0
43.8
43.6
43.4
43.2
43.0
V
GATE
= 0V
70
-40
-15
10
35
60
85
-40
-15
10
35
60
85
TEMPERATURE (°C)
TEMPERATURE (°C)
PWRGD OUTPUT LOW VOLTAGE
vs. TEMPERATURE (MAX5949A)
MAX5920 toc06
PWRGD OUTPUT IMPEDANCE
vs. TEMPERATURE (MAX5949B)
MAX5949 toc07
50
PWRGD OUTPUT LOW VOLTAGE (mV)
45
40
35
30
25
20
15
10
5
0
I
OUT
= 1mA
10,000
OUTPUT IMPEDANCE (GΩ)
-40
85
1000
100
10
1
-15
10
35
60
-50
-25
0
25
50
75
100
TEMPERATURE (°C)
TEMPERATURE (°C)
4
_______________________________________________________________________________________
-48V Hot-Swap Controllers
with External R
SENSE
Test Circuits
R
5kΩ
PWRGD/PWRGD
OV
V
OV
V
DD
DRAIN
V
S
48V
MAX5949A/MAX5949B
V+
5V
V
DD
UV
PWRGD/PWRGD
OV
V
EE
MAX5949_
SENSE
GATE
DRAIN
100mA MAX
TEST VOLTAGE
V
UV
MAX5949A
MAX5949B
UV
GATE
V
DRAIN
V
EE
2V
SENSE
V
SENSE
Figure 1. -2V DRAIN Voltage Test Circuit
Figure 2a. Test Circuit 1
PWRGD/PWRGD
OV
V
DD
DRAIN
V
S
48V
10kΩ
V
S
20V
UV
V
UV
V
EE
MAX5949A
MAX5949B
10Ω
GATE
0.1µF
N
IRF530
SENSE
10Ω
Figure 2b. Test Circuit 2
_______________________________________________________________________________________
5
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