19-2850; Rev 0; 4/03
+60V Simple Swapper Hot-Swap Switch
General Description
The MAX5923 is a fully integrated Simple Swapper™
hot-swap switch for positive supply rails. The device
allows the safe insertion and removal of circuit cards
into live backplanes or ports without causing glitches
on the power-supply rail. The device also monitors vari-
ous circuit parameters and disconnects the load if a
fault condition occurs, alerting the host with a logic-
level
FAULT
output. The MAX5923 operates over the
+16V to +60V input voltage range.
During startup, an integrated 0.45Ω power MOSFET
regulates the current and voltage between the back-
plane power source and the load. After startup, the
MOSFET is fully enhanced to reduce its on-resistance.
To ensure robust operation, the MAX5923 contains
built-in safety features that monitor fault conditions and
prevent damage to the internal MOSFET.
The MAX5923 monitors three parameters for fault condi-
tions: zero current, overcurrent, and thermal overload.
The output overcurrent limit counts the time the MAX5923
spends in an overcurrent condition and shuts down the
pass transistor if the current limit is exceeded for the over-
current time limit. The zero-current detection counts the
time the output current is below the zero-current threshold
and shuts down the pass transistor if the counter reaches
the zero-current time limit. The thermal monitoring feature
shuts down the pass transistor if the die temperature
reaches the overtemperature limit. A fault logic output
indicates when an overtemperature or an overcurrent
condition has occurred and a zero-current logic output
indicates if there is a zero-current condition.
An undervoltage detection circuitry keeps the pass tran-
sistor off until the input voltage is above the undervoltage
lockout (UVLO) threshold, which is internally set or can be
set externally with a resistive divider. A power-OK (POK)
output is provided to signal when the output voltage has
reached to within 0.75V of the input voltage. An Enable
input allows the host system to disconnect the system
from the load and/or reset a fault condition by toggling
Enable.
The MAX5923 is available in a 20-pin TSSOP package
and operates in the extended -40°C to +85°C tempera-
ture range.
o
0.45Ω Integrated Power Switch
o
Programmable Output Current Up to 800mA
o
Over/Undercurrent-Limit Detection
o
Input Logic Signals Compatible with 1.8V to 5V
CMOS Logic
o
Separate Analog and Digital Grounds with Up to
±4V Offset
o
Power-OK Status Output
o
Overcurrent Protection with Status Outputs
o
Built-In Thermal Shutdown
o
Internal Switch Protection Circuitry
o
Current-Limit Foldback with Timeout and Duty-
Cycle Control
o
Latch or Autorestart Fault Management
Features
o
Wide Operating Input Range: +16V to +60V
MAX5923
Ordering Information
PART
MAX5923EUP
TEMP RANGE
-40°C to +85°C
PIN-PACKAGE
20 TSSOP
Typical Operating Circuit
+16V TO +60V
IN
R
SENSE
DRAIN
VDIG
R
PU
OUT
D1
+1.65V TO +5.5V
MAX5923
UVLO
LATCH
R
PU
ON
OFF
EN
ZC_EN
R
PU
ZC
FAULT
POK
AGND_S
DGND
Applications
Network Routers/Switches
Current Limiter
Servers
Industrial Equipment
ALL SIGNAL AND DIGITAL INPUTS/OUTPUTS ARE REFERENCED TO DGND.
DGND CAN BE
±4V
FROM AGND_S.
Simple Swapper is a trademark of Maxim Integrated Products, Inc.
Pin Configuration appears at end of data sheet.
1
________________________________________________________________
Maxim Integrated Products
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.
+60V Simple Swapper Hot-Swap Switch
MAX5923
ABSOLUTE MAXIMUM RATINGS
All Voltages with Respect to AGND_S, Unless Otherwise Noted
IN ............................................................................-0.3V to +76V
UVLO ........................................................................-0.3V to +6V
VDIG to DGND .........................................................-0.3V to +6V
OUT .......................................................-0.3V to (V
DRAIN
+ 0.3V)
DRAIN ..........................................................-0.3V to (V
IN
+ 0.3V)
EN, ZC_EN,
ZC, FAULT,
POK
and LATCH to DGND ...............................................-0.3V to +6V
DGND ..........................................................................-5V to +5V
Maximum Current into DRAIN...............................................0.8A
Maximum Current into POK,
ZC, FAULT
(sinking)..............20mA
Continuous Power Dissipation (T
A
= +70°C)
20-Pin TSSOP (derate 11.1mW/°C above +70°C) .......879mW
Operating Temperature Range ...........................-40°C to +85°C
Junction Temperature ......................................................+150°C
Storage Temperature Range .............................-65°C to +160°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
IN
= 48V, VDIG = 3.3V, AGND_S = AGND = DGND = 0V, R
SENSE
= 0.5Ω ±1%, UVLO = open, EN = VDIG, T
A
= -40°C to +85°C, unless
otherwise noted. Typical values are at T
A
= +25°C.)
PARAMETER
Analog Input Voltage Range
Analog Input Supply Current
Digital Input Voltage Range
Digital Input Supply Current
DGND-to-AGND Operating
Voltage Range
Current-Limit Response Time
OUT Current-Limit Foldback
Voltage
Current-Limit Sense Voltage
(V
IN
- V
DRS
) (Note 3)
Current-Limit Sense Foldback
Voltage (V
IN
- V
DRS
)
Overcurrent Timeout
D
MOS
On-Resistance
Power-Off OUT Sink Current
Maximum Output Voltage Slew
Rate
Maximum Output Current Slew
Rate
Power-OK Threshold (V
IN
- V
OUT
)
POK Output Low Voltage
POK Output Leakage Current
V
THPOK
V
FBSTOP
OUT shorted to AGND (Note 1)
(Note 2)
Maximum voltage across R
SENSE
at V
OUT
>
V
FBSTOP
0°C to +85°C
V
ILIM_fb
t
OC
R
DSON
V
OUT
= 0V
0°C to +85°C
OUT shorted to AGND (Note 4)
I
OUT
= 100mA
T
A
= +25°C
T
A
= +85°C
198
203
64
50
50
SYMBOL
V
IN
I
IN
V
DIG
I
DIG
V
DIG
= 5V
-4
1
18
212
212
70
60
60
0.45
0.75
15
100
35
650
750
10
0.4
0.05
1
850
225
221
76
75
70
mV
ms
Ω
µA
V/ms
A/ms
mV
%
V
µA
V
IN
= 72V, measured at AGND after OUT
has stopped slewing
1.65
0.05
CONDITIONS
MIN
16
1
TYP
MAX
60
1.6
5.5
0.1
+4
UNITS
V
mA
V
mA
V
µs
V
V
ILIM
mV
EN = DGND, V
OUT
= 48V
dV
OUT
/dt, V
OUT
rising, no load
dI
OUT
/dt, V
OUT
rising, C
LOAD
= 100µF
V
OUT
rising, POK from low to high
Hysteresis
V
POK
= 3.3V
V
POK_LOW
I
POK
= 3mA
2
_______________________________________________________________________________________
+60V Simple Swapper Hot-Swap Switch
ELECTRICAL CHARACTERISTICS (continued)
(V
IN
= 48V, VDIG = 3.3V, AGND_S = AGND = DGND = 0V, R
SENSE
= 0.5Ω ±1%, UVLO = open, EN = VDIG, T
A
= -40°C to +85°C, unless
otherwise noted. Typical values are at T
A
= +25°C.)
PARAMETER
POK Output Delay (Note 5)
Zero-Current Detection Threshold
Voltage (V
IN
- V
DRS
)
ZC
Output Low Voltage
ZC
Output Leakage Current
Zero-Current Detection Delay
Zero-Current Deglitch Time
Thermal Shutdown
Shutdown Autorestart Time
UNDERVOLTAGE LOCKOUT
Default V
IN
UVLO
UVLO Comparator Threshold
UVLO Input Resistance
LOGIC SIGNALS
EN, LATCH, and ZC_EN Input
High Voltage
EN, LATCH, and ZC_EN Input
Low Voltage
EN, LATCH, and ZC_EN Input
Current
EN Low Pulse Width
FAULT
Output Low Voltage
FAULT
Output Leakage Current
V
OL
I
SINK
= 3mA
V
FAULT
= 3.3V
0.05
V
IH
1.65V < V
DIG
< 5.5V
1.65V < V
DIG
< 2.0V
2.0V < V
DIG
< 5.5V
-1
3
0.4
1
0.7
×
V
DIG
0.3V
×
V
DIG
0.8
+1
µA
µs
V
µA
V
UVLO
TH
V
REF
UVLO floating, V
IN
rising
Hysteresis
Referenced to AGND
Hysteresis
50
1.31
26
28
2.5
1.33
110
1.36
30
V
V
mV
kΩ
t
RESTART
t
ZCDEL
t
ZC_DEG
SYMBOL
t
POK_LOW
CONDITIONS
POK from high to low, V
OUT
falling
MIN
1
74
2.7
I
ZC
= 3mA
V
ZC
= 3.3V
ZC
from high to low, I
OUT
falling (Note 6)
I
OUT
rising
Temperature rising
Hysteresis
LATCH = low (Note 7)
1.6
300
0.05
350
10
150
30
1.92
2.24
TYP
1.4
88
3.75
MAX
1.8
102
4.8
0.4
1
400
UNITS
ms
mV
V
µA
ms
ms
°C
s
MAX5923
t
POK_HIGH
POK from low to high, V
OUT
rising
V
ZCTH
V
ZC_LOW
V
IL
V
This is the time from an output overcurrent or short-circuit condition until the output goes into regulated current limit.
OUT voltage above which the output current limit is at its full value.
See the
Overcurrent Protection
section.
This is the time the part stays in current-limit mode during overload condition. After t
OC
elapses (or when the junction tem-
perature hits +150°C) the part shuts down.
Note 5:
See
Typical Operating Characteristics.
Note 6:
This is the delay from I
OUT
falling below the zero-current threshold until
ZC
goes low. A
ZC
condition shuts down and latches
off the IC.
Note 7:
See the
Fault Management
section.
Note 1:
Note 2:
Note 3:
Note 4:
_______________________________________________________________________________________
3
+60V Simple Swapper Hot-Swap Switch
MAX5923
Typical Operating Characteristics
(V
IN
= 48V, VDIG, EN, LATCH, CLASS, ZC_EN = 3.3V, DCA, AGND_S = AGND = DGND = 0V, R
SENSE
= 0.5Ω, UVLO floating,
T
A
= +25°C, unless otherwise noted.)
V
IN
SUPPLY CURRENT
vs. INPUT VOLTAGE
MAX5923 toc01
V
IN
SUPPLY CURRENT
vs. TEMPERATURE
MAX5923 toc02
DIGITAL SUPPLY CURRENT
vs. TEMPERATURE
11.9
11.8
11.7
I
DIG
(µA)
11.6
11.5
11.4
MAX5923 toc03
1.00
0.95
SUPPLY CURRENT (mA)
0.90
0.85
T
A
= +25°C
0.80
T
A
= -40°C
0.75
0.70
32
36
40
44
48
52
56
MEASURED AT
AGND
1.00
0.95
SUPPLY CURRENT (mA)
0.90
0.85
0.80
V
IN
= 32V
0.75
0.70
V
IN
= 48V
MEASURED AT
AGND
V
IN
= 60V
12.0
T
A
= +85°C
11.3
11.2
11.1
11.0
60
-40
-25
-10
5
20
35
50
65
80
-40
-25
-10
5
20
35
50
65
80
INPUT VOLTAGE (V)
TEMPERATURE (°C)
TEMPERATURE (°C)
V
IN
UNDERVOLTAGE LOCKOUT
vs. TEMPERATURE
MAX5923 toc04
MOSFET R
DS-ON
vs. TEMPERATURE
MAX5923 toc05
SENSE TRIP VOLTAGE vs. TEMPERATURE
214
SENSE TRIP VOLTAGE (V)
213
212
211
210
209
208
207
206
V
IN
= 32V
V
IN
= 48V
V
IN
= 60V
MAX5923 toc06
40
39
DEFAULT V
IN
UVLO (V)
38
V
IN
RISING
0.60
0.55
ON-RESISTANCE (Ω)
0.50
0.45
0.40
0.35
0.30
I
OUT
= 100mA
215
37
36
35
34
33
32
-40 -25 -10
5
20
35
50
65
80
TEMPERATURE (°C)
V
IN
FALLING
205
-40 -25 -10
5
20
35
50
65
80
-40 -25 -10
5
20
35
50
65
80
TEMPERATURE (°C)
TEMPERATURE (°C)
FOLDBACK CURRENT LIMIT (ILIM vs. V
OUT
)
MAX5923 toc07
ZERO-CURRENT DETECTION THRESHOLD
VOLTAGE vs. TEMPERATURE
MAX5923 toc08
ON-RESISTANCE vs. V
DRAIN
I
OUT
= 100mA
0.7
ON-RESISTANCE (Ω)
0.6
T
A
= +25°C
0.5
0.4
0.3
0.2
0.1
T
A
= -40°C
T
A
= +85°C
MAX5923 toc09
0.60
0.55
0.50
0.45
ILIM (A)
0.40
0.35
0.30
0.25
0.20
0.15
0.10
0.05
0
0
5
10 15
3.70
3.68
3.66
ON-RESISTANCE (Ω)
3.64
3.62
3.60
3.58
3.56
3.54
3.52
3.50
V
IN
= 32V
V
IN
= 48V
V
IN
= 60V
0.8
20 25 30 35 40 45 50
-40 -25 -10
5
20
35
50
65
80
28
33
38
43
48
53
58
63
68
73
OUTPUT VOLTAGE (V)
TEMPERATURE (°C)
INPUT VOLTAGE (V)
4
_______________________________________________________________________________________
+60V Simple Swapper Hot-Swap Switch
Typical Operating Characteristics (continued)
(V
IN
= 48V, VDIG, EN, LATCH, CLASS, ZC_EN = 3.3V, DCA, AGND_S = AGND = DGND = 0V, R
SENSE
= 0.5Ω, UVLO floating,
T
A
= +25°C, unless otherwise noted.)
OVERCURRENT TIMEOUT
(R
LOAD
FROM 240
Ω
TO 75
Ω
)
MAX5923 toc10
MAX5923
DIGITAL SUPPLY CURRENT vs. VDIG
30
28
26
24
22
20
18
16
14
12
10
8
6
4
2
0
0
1.0
2.0
3.0
VDIG (V)
4.0
5.0
MAX5923 toc11
20V/div
0V
5V/div
0V
200mA/div
0A
5V/div
0V
V
OUT
I
DIG
(µA)
POK
I
OUT
FAULT
20ms/div
6.0
SHORT-CIRCUIT RESPONSE TIME
MAX5923 toc12
POK LOW-TO-HIGH DELAY TIME
MAX5923 toc13
20V/div
0V
5V/div
0V
200mA/div
0A
5V/div
0V
20ms/div
V
OUT
POK
5V/div
POK
I
OUT
V
OUT
20V/div
FAULT
40ms/div
POK HIGH-TO-LOW DELAY TIME
MAX5923 toc14
ZC TO OUT DELAY
MAX5923 toc15
20V/div
20V/div
0V
V
OUT
0V
5V/div
0V
5V/div
0V
1.25mA/div
0A
V
OUT
POK
ZC
5V/div
0V
POK
I
OUT
1ms/div
400µs/div
_______________________________________________________________________________________
5
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