19-2946; Rev 1; 2/06
-48V Hot-Swap Controllers with External
R
SENSE
and High Gate Pulldown Current
General Description
The MAX5921/MAX5939 hot-swap controllers allow a cir-
cuit card to be safely hot plugged into a live backplane.
The MAX5921/MAX5939 operate from -20V to -80V and
are well suited for -48V power systems. These devices
are pin compatible with both the LT1640 and LT4250 and
provide improved features over these devices.
The MAX5921/MAX5939 provide a controlled turn-on to
circuit cards preventing damage to board connectors,
board components, and preventing glitches on the
power-supply rail. The MAX5921/MAX5939 provide
undervoltage, overvoltage, and overcurrent protection.
These devices ensure that the input voltage is stable
and within tolerance before applying power to the load.
Both the MAX5921 and MAX5939 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 MAX5921/MAX5939 protect against input
voltage steps by limiting the load current to a safe level
without turning off power to the load.
The device features an open-drain power-good status
output,
PWRGD
or PWRGD for enabling downstream
converters (see
Selector Guide).
A built-in thermal shut-
down feature is also included to protect the external
MOSFET in case of overheating. The MAX5939 features
a latched fault output. The MAX5921 contains built-in
autoretry circuitry after a fault condition.
The MAX5921/MAX5939 are available in an 8-pin SO
package and operate in the extended -40°C to +85°C
temperature range.
Features
♦
Allows Safe Board Insertion and Removal
from a Live -48V Backplane
♦
Pin-Compatible with LT1640 and LT4250
♦
Circuit Breaker Immunity to Input Voltage Steps
and Current Spikes
♦
450mA GATE Pulldown Current During Short-
Circuit Condition
♦
Exponential GATE Pulldown Current
♦
Withstands -100V Input Transients with No
External Components
♦
Programmable Inrush and Short-Circuit Current
Limits
♦
Operates from -20V to -80V
♦
Programmable Overvoltage Protection
♦
Programmable Undervoltage Lockout
with Built-In Glitch Filter
♦
Overcurrent Fault Integrator
♦
Powers Up into a Shorted Load
♦
Power-Good Control Output
♦
Thermal Shutdown Protects External MOSFET
MAX5921/MAX5939
Ordering Information
PART
MAX5921AESA
MAX5921BESA
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
Ordering Information continued at end of data sheet.
Pin Configuration
TOP VIEW
PWRGD
(PWRGD)
1
2
3
8
7
V
DD
DRAIN
GATE
SENSE
Typical Operating Circuit and Selector Guide appear at end
of data sheet.
OV
UV
MAX5921
MAX5939
6
5
V
EE
4
SO
() FOR MAX5921B/F AND MAX5939B/F.
________________________________________________________________
Maxim Integrated Products
1
For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at
1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.
-48V Hot-Swap Controllers with External
R
SENSE
and High Gate Pulldown Current
MAX5921/MAX5939
ABSOLUTE MAXIMUM RATINGS
All Voltages Are Referenced to VEE, Unless Otherwise Noted
Supply Voltage (VDD - VEE )................................-0.3V to +100V
DRAIN, PWRGD,
PWRGD
....................................-0.3V to +100V
PWRGD to DRAIN .............................................… -0.3V to +95V
PWRGD to VDD .......................................................-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 into SENSE...........................................................+40mA
Current into GATE...........................................................+300mA
Current into Any Other Pin................................................+20mA
Continuous Power Dissipation (TA = +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
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, unless otherwise noted. Typical values are at T
A
= +25°C, unless otherwise noted.) (Notes 1, 4)
PARAMETER
POWER SUPPLIES
Operating Input Voltage Range
Supply Current
V
DD
I
DD
Current into V
DD
with UV = 3V, OV, DRAIN,
SENSE = V
EE
, GATE = floating
GATE drive on, V
GATE
= V
EE
V
SENSE
- V
EE
= 100mV, V
GATE
= 2V (Note 2)
V
GATE
- V
EE
, steady state, 20V
≤
V
DD
≤
80V
V
GATE
- V
EE
, I
GS
= 30mA
V
CL
= V
SENSE
- V
EE
V
SENSE
= 50mV
-30
24
10
15
40
-1
20
0.7
80
2
V
mA
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
GATE DRIVER AND CLAMPING CIRCUITS
Gate Pullup Current
Gate Pulldown Current
External Gate Drive
GATE to V
EE
Clamp Voltage
CIRCUIT BREAKER
Current-Limit Trip Voltage
SENSE Input Current
UNDERVOLTAGE LOCKOUT
Supply Internal Undervoltage
Lockout Voltage High
Supply Internal Undervoltage
Lockout Voltage Low
UV INPUT
UV High Threshold
UV Low Threshold
UV Hysteresis
UV Input Current
OV INPUT
OV High Threshold
OV Low Threshold
OV Voltage Reference Hysteresis
OV Input Current
V
OVH
V
OVL
V
OVHY
I
INOV
OV = V
EE
-0.5
OV voltage rising
OV voltage decreasing
1.235
1.189
1.255
1.205
50
0
1.275
1.221
V
V
mV
µA
V
UVH
V
UVL
V
UVHY
I
INUV
UV = V
EE
-0.5
UV voltage increasing
UV voltage decreasing
1.240
1.105
1.255
1.125
130
0
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
50
-0.2
60
0
mV
µA
I
PU
I
PD
∆V
GATE
V
GSCLMP
-45
50
13.5
16.4
-60
70
18
18
µA
mA
V
V
2
_______________________________________________________________________________________
-48V Hot-Swap Controllers with External
R
SENSE
and High Gate Pulldown Current
ELECTRICAL CHARACTERISTICS (continued)
(V
EE
= 0V, V
DD
= 48V, T
A
= -40°C to +85°C, unless otherwise noted. Typical values are at T
A
= +25°C, unless otherwise noted.) (Notes 1, 4)
PARAMETER
DRAIN Input Current
DRAIN Threshold for PWRGD
GATE High Threshold
PWRGD,
PWRGD
Output
Leakage
PWRGD
Low Voltage
(V
PWRGD
- V
EE
)
PWRGD Low Voltage
(V
PWRGD
- V
DRAIN
)
OVERTEMPERATURE PROTECTION
Overtemperature Threshold
Overtemperature Hysteresis
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
t
PHLOV
t
PHLUV
t
PLHOV
t
PLHUV
t
PHLSENSE
Figures 1a, 2
Figures 1a, 3
Figures 1a, 2
Figures 1a, 3
Figures 1a, 4a
Time from continuous
A, B versions
current limit to GATE
shutdown (see
Overcurrent
Fault Integrator
section),
E, F versions
Figures 1b, 4b
Figures 1a, 5a; A and E versions
t
PHLDL
Figures 1a, 5a; B and F versions
Figures 1a, 5b; A and E versions
t
PHLGH
Figures 1a, 5b; B and F versions
8.2
8.2
8.2
ms
0.35
1.4
0.5
0.4
3.3
8.4
1
0.5
2.0
8.2
ms
0.65
ms
2.6
µs
µs
µs
ms
µs
T
OT(TH)
T
HYS
Junction temperature, temperature rising
See
Thermal Shutdown
section
135
20
°C
°C
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
, decreasing
V
PWRGD
= 80V, V
DRAIN
= 48V
V
PWRGD
= 80V, V
DRAIN
= 0V
V
DRAIN
- V
EE
< V
DL
, I
SINK
= 5mA
(A, E versions)
V
DRAIN
= 5V, I
SINK
= 5mA (B, F versions)
0.11
0.11
CONDITIONS
MIN
10
1.1
1.0
TYP
80
1.7
1.6
MAX
250
2.0
2.0
10
10
0.4
0.4
UNITS
µA
V
V
µA
V
V
PWRGD OUTPUT SIGNAL (REFERENCED TO DRAIN)
MAX5921/MAX5939
Current Limit to GATE Low
t
PHLCL
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 3)
A, B, E, F versions
128 x
t
PHLCL
ms
Note 1:
Note 2:
Note 3:
Note 4:
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.
Gate pulldown current after the current limit to GATE low (t
PHLCL
) time has elapsed.
Minimum duration of GATE pulldown following a circuit breaker fault. The MAX5921_ automatically restarts after a circuit
breaker fault. The MAX5939_ is latched off and can be reset by toggling UV low. The GATE pulldown does not release until
t
OFF
has elapsed.
The min/max limits are 100% production tested at +25°C and +85°C and guaranteed by design at -40°C.
_______________________________________________________________________________________
3
-48V Hot-Swap Controllers with External
R
SENSE
and High Gate Pulldown Current
MAX5921/MAX5939
Typical Operating Characteristics
(V
DD
= +48V, V
EE
= 0V, T
A
= +25°C, unless otherwise noted.)
SUPPLY CURRENT
vs. SUPPLY VOLTAGE
MAX5921TOC01
GATE VOLTAGE
vs. SUPPLY VOLTAGE
MAX5921TOC02
CURRENT-LIMIT TRIP VOLTAGE
vs. TEMPERATURE
58
56
TRIP VOLTAGE (mV)
54
52
50
48
46
44
42
40
MAX5921TOC03
900
800
SUPPLY CURRENT (µA)
700
600
500
400
300
200
100
0
0
20
40
60
80
T
A
= -40°C
T
A
= +25°C
T
A
= +85°C
15
14
13
GATE VOLTAGE (V)
12
11
10
9
8
7
T
A
= +25°C
60
100
0
20
40
60
80
100
-40
-15
10
35
60
85
SUPPLY VOLTAGE (V)
SUPPLY VOLTAGE (V)
TEMPERATURE (°C)
GATE PULLUP CURRENT
vs. TEMPERATURE
MAX5921TOC04
GATE PULLDOWN CURRENT
vs. TEMPERATURE AFTER A FAULT
MAX5921TOC05
GATE PULLDOWN CURRENT
vs. OVERDRIVE DURING A CURRENT FAULT
V
GATE
= 2V
MAX5921TOC06
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
-40
V
GATE
= 0V
70
65
GATE PULLDOWN CURRENT (mA)
60
55
50
45
40
35
30
25
V
GATE
= 2V
90
GATE PULLDOWN CURRENT (mA)
75
60
45
30
15
0
-15
10
35
60
85
-40
-15
10
35
60
85
0
20
40
60
80
100
TEMPERATURE (°C)
TEMPERATURE (°C)
OVERDRIVE (mV)
GATE PULLDOWN CURRENT
vs. OVERDRIVE DURING A SHORT CIRCUIT
MAX5921TOC07
PWRGD OUTPUT LOW VOLTAGE
vs. TEMPERATURE (MAX5921A)
MAX5921TOC08
PWRGD OUTPUT LEAKAGE CURRENT
vs. TEMPERATURE (MAX5921B)
PWRGD OUTPUT LEAKAGE CURRENT (nA)
V
DRAIN
- V
EE
> 2.4V
MAX5921TOC09
500
GATE PULLDOWN CURRENT (mV)
V
GATE
= 2V
180
PWRGD OUTPUT LOW VOLTAGE (mV)
160
140
120
100
80
60
40
20
I
OUT
= 5mA
100
400
10
300
1
200
0.1
100
0.01
0
600
750
900
OVERDRIVE (mV)
1050
1200
0
-40
-15
10
35
60
85
TEMPERATURE (°C)
0.001
-40
-15
10
35
60
85
TEMPERATURE (°C)
4
_______________________________________________________________________________________
-48V Hot-Swap Controllers with External
R
SENSE
and High Gate Pulldown Current
MAX5921/MAX5939
R
5kΩ
PWRGD/PWRGD
OV
V
OV
V
DD
+
DRAIN
V
S
V
DRAIN
+48V
-
V+
5V
MAX5921
MAX5939
UV
V
EE
V
UV
GATE
SENSE
V
SENSE
Figure 1a. Test Circuit 1
+
PWRGD/PWRGD
OV
V
DD
+
DRAIN
V
S
+48V
-
10kΩ
V
S
+20V
-
MAX5921
MAX5939
GATE
UV
V
EE
SENSE
0.1µF
10Ω
IRF530
V
UV
Figure 1b. Test Circuit 2
_______________________________________________________________________________________
5
京公网安备 11010802033920号
Copyright © 2005-2026 EEWORLD.com.cn, Inc. All rights reserved
电子工程世界
