19-1514; Rev 0; 7/99
Fault-Protected, High-Voltage,
Signal-Line Protector
General Description
The MAX4505 is a single signal-line protector featuring a
fault-protected input and Rail-to-Rail
®
signal handling
capability. The input is protected from overvoltage faults
up to ±36V with power on or ±40V with power off. During
a fault condition, the input terminal becomes an open cir-
cuit and only nanoamperes of leakage current flow from
the source, while the switch output (AOUT) furnishes typ-
ically 19mA from the appropriate polarity supply to the
load. This ensures an unambiguous rail-to-rail output
when a fault begins and ends.
The MAX4505 protects both unipolar and bipolar analog
signals using either unipolar (+9V to +36V) or bipolar
(±8V to ±18V) power supplies. The device has no logic
control inputs; the protector is always on when the sup-
plies are on. On-resistance is 100Ω max, and on-leakage
is less than 0.5nA at T
A
= +25°C. The MAX4505 is avail-
able in 5-pin SOT23 and 8-pin µMAX packages.
Features
o
Overvoltage Protection
±40V with Power Off
±36V with Power On
o
Open Signal Paths with Power Off
o
Output Clamps to Either Rail with an Input
Overvoltage
o
100Ω max On-Resistance
o
10ns Overvoltage Turn-On Delay
o
No Latchup During Power Sequencing
o
Rail-to-Rail Signal Handling
o
500Ω Output Clamp Resistance During
Overvoltage
o
Tiny 5-Pin SOT23 Package
MAX4505
Applications
Process Control Systems
Hot-Insertion Boards/Systems
Data-Acquisition Systems
Redundant/Backup Systems
ATE Equipment
Sensitive Instruments
PART
MAX4505EUK-T
MAX4505EUA
Ordering Information
TEMP. RANGE
-40°C to +85°C
-40°C to +85°C
PIN-
PACKAGE
5 SOT23-5
8 µMAX
TOP
MARK
ADLW
—
Typical Operating Circuit
TOP VIEW
V-
V-
Pin Configurations
MAX4505
V-
V+
V+
V+
AIN
1
5
V-
V+
2
RAIL
SENSOR
AOUT
3
IN
AIN
AOUT
OUT
R
OUT
MAX4505
4
N.C.
SOT23-5
Pin Configurations continued at end of data sheet.
Rail-to-Rail is a registered trademark of Nippon Motorola, Ltd.
________________________________________________________________
Maxim Integrated Products
1
For free samples & the latest literature: http://www.maxim-ic.com, or phone 1-800-998-8800.
For small orders, phone 1-800-835-8769.
Fault-Protected, High-Voltage,
Signal-Line Protector
MAX4505
ABSOLUTE MAXIMUM RATINGS
(Voltages referenced to GND)
V+ ........................................................................-0.3V to +44.0V
V- .........................................................................-44.0V to +0.3V
V+ to V-................................................................-0.3V to +44.0V
AIN, AOUT (Notes 1, 2) .......................................................±44V
AIN Overvoltage with Power On ..........................................±36V
AIN Overvoltage with Power Off ..........................................±40V
Continuous Current into Any Terminal..............................±30mA
Peak Current into Any Terminal
(pulsed at 1ms, 10% duty cycle)...............................±70mA
Continuous Power Dissipation (T
A
= +70°C)
5-Pin SOT23-5 (derate 7.10mW/°C above +70°C) ...571mW
8-Pin µMAX (derate 4.10mW/°C above +70°C) ........330mW
Operating Temperature Ranges
MAX4505C_ _ ..................................................0°C to +70°C
MAX4505E_ _ ...............................................-40°C to +85°C
Storage Temperature Range .............................-55°C to +150°C
Lead Temperature (soldering, 10sec) .............................+300°C
Note 1:
The AOUT pin is not fault protected. Signals on AOUT exceeding V+ or V- are clamped by internal diodes. Limit forward
diode current to maximum current rating.
Note 2:
The AIN pin is fault protected. Signals on AIN exceeding -36V to +36V may damage the device. These limits apply with
power applied to V+ or V-, or ±40V with V+ = V- = 0.
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.
RECOMMENDED OPERATING GUIDELINES
V+ to GND ..............................................................-0.3V to +40V
V- to GND ...............................................................-32V to +0.3V
V+ to V- ..................................................................................40V
AIN .......................................................................................±40V
AOUT...............................................................................V+ to V-
AIN to AOUT.........................................................40V differential
Continuous Current into Any Terminal ..............................≤30mA
Peak Current into Any Terminal
(pulsed at 1ms, 10% duty cycle) ...............................≤70mA
ELECTRICAL CHARACTERISTICS—Dual Supplies
(V+ = +15V, V- = -15V, T
A
= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at T
A
= +25°C.) (Note 3)
PARAMETER
ANALOG SWITCH
Fault-Free Analog Signal Range
(Note 4)
Analog Signal-Path Resistance
Signal-Path Leakage Current
(Note 5)
Input Capacitance
FAULT PROTECTION
Fault-Protected Analog Signal
Range (Notes 4, 6)
Input Signal-Path Leakage
Current, Supplies On
Input Signal-Path Leakage
Current, Supplies Off
Output Clamp Current,
Supplies On
Output Clamp Resistance,
Supplies On
±Fault Output Turn-On
Delay Time
2
V
AIN
I
AIN(ON)
I
AIN(OFF)
I
AOUT
R
AOUT
Applies with power on
Applies with power off
V
AIN
= ±25V, V
AOUT
= open
V
AIN
= ±40V, V
AOUT
= open
V+ = 0, V- = 0
V
AIN
= 25V
V
AIN
= -25V
I
AOUT
= 1mA
V
AIN
= 25V
V
AIN
= -25V
E
E
+25°C
E
+25°C
E
+25°C
+25°C
+25°C
+25°C
+25°C
-36
-40
-20
-200
-20
-500
13
-26
19
-19
0.5
0.4
10
0.2
0.1
36
40
20
200
20
500
26
-13
1.0
1.0
V
nA
nA
mA
kΩ
ns
V
AIN
R
ON
I
AOUT(ON)
C
AIN
V
AIN
= ±15V
V
AIN
= ±10V, I
AOUT
= 1mA
V
AOUT
= ±10V, V
AIN
= ±10V
or floating
V
AIN
= 0, f = 1MHz
E
+25°C
E
+25°C
E
+25°C
-0.5
-20
20
V-
65
V+
100
125
0.5
20
V
Ω
nA
pF
SYMBOL
CONDITIONS
T
A
MIN
TYP
MAX
UNITS
R
L
= 10kΩ, V
AIN
= ±25V
_______________________________________________________________________________________
Fault-Protected, High-Voltage,
Signal-Line Protector
ELECTRICAL CHARACTERISTICS—Dual Supplies (continued)
(V+ = +15V, V- = -15V, T
A
= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at T
A
= +25°C.) (Note 3)
PARAMETER
±Fault Recovery Time
POWER SUPPLY
Power-Supply Range
V+, V-
I+
Power-Supply Current
I-
V
AIN
= 15V
V
AIN
= 15V
E
+25°C
E
+25°C
E
-150
-240
-45
±8
45
±18
150
240
µA
V
SYMBOL
CONDITIONS
R
L
= 10kΩ, V
AIN
= ±25V
T
A
+25°C
MIN
TYP
25
MAX
UNITS
µs
MAX4505
ELECTRICAL CHARACTERISTICS—Single Supply
(V+ = +12V, V- = 0, T
A
= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at T
A
= +25°C.) (Note 3)
PARAMETER
ANALOG SWITCH
Fault-Free Analog Signal Range
(Note 4)
Analog Signal-Path Resistance
Signal-Path Leakage Current
(Note 5)
FAULT PROTECTION
Fault-Protected Analog Signal
Range (Notes 4, 6)
Input Signal-Path Leakage
Current, Supply On (Note 7)
Input Signal-Path Leakage
Current, Supply Off (Note 7)
Output Clamp Current,
Supply On
Output Clamp Resistance,
Supply On
±Fault Output Turn-On
Delay Time
±Fault Recovery Time
POWER SUPPLY
Power-Supply Range
Power-Supply Current
Note 3:
Note 4:
Note 5:
Note 6:
Note 7:
Note 8:
V+, V-
I+
V
AIN
= 12V
E
+25°C
E
+9
5
+36
25
40
V
µA
V
AIN
I
AIN(ON)
I
AIN(OFF)
I
AOUT
R
AOUT
Applies with power on
Applies with power off
V
AIN
= ±25V, V
AOUT
= 0
V
AIN
= ±40V
V
AIN
= 25V
V
AIN
= ±25V
R
L
= 10kΩ, V
AIN
= 25V
R
L
= 10kΩ, V
AIN
= 25V
E
E
+25°C
E
+25°C
E
+25°C
+25°C
+25°C
+25°C
-36
-40
-20
-200
-20
-500
3
5.5
1.0
10
2.5
0.2
0.2
36
40
20
200
20
500
10
2.5
V
nA
nA
mA
kΩ
ns
µs
V
AIN
R
ON
I
AOUT(ON)
V
AIN
= 12V
V
AIN
= 10V, I
AOUT
= 1mA
V
AIN
= 10V or floating
E
+25°C
E
+25°C
E
-0.5
-20
0.05
0
125
V+
200
250
0.5
20
V
Ω
nA
SYMBOL
CONDITIONS
T
A
MIN
TYP
MAX
UNITS
The algebraic convention is used in this data sheet; the most negative value is shown in the minimum column.
See Fault-Free Analog Signal Range vs. Supply Voltage graph in the
Typical Operating Characteristics.
Leakage parameters are 100% tested at maximum rated hot temperature and guaranteed by correlation at T
A
= +25°C.
Guaranteed by design.
Guaranteed by testing with dual supplies.
SOT packaged parts are 100% tested at +25°C. Limits at the maximum rated temperature are guaranteed by design and
correlation limits at +25°C. Leakage tests are typical for SOT packaged parts.
_______________________________________________________________________________________
3
Fault-Protected, High-Voltage,
Signal-Line Protector
MAX4505
Typical Operating Characteristics
(T
A
= +25°C, unless otherwise noted.)
ON-RESISTANCE vs. OUTPUT VOLTAGE
(DUAL SUPPLIES)
MAX4505 toc01
ON-RESISTANCE vs. OUTPUT VOLTAGE
(SINGLE SUPPLY)
V- = 0
V+ = +9V
200
V+ = +12V
MAX4505 toc02
ON-RESISTANCE vs. OUTPUT VOLTAGE
AND TEMPERATURE (DUAL SUPPLIES)
MAX4505 toc03
140
120
100
R
ON
(Ω)
80
60
40
20
0
-20
-15
-10
-5
0
V
OUT_
(V)
5
10
15
V+ = +18V
V- = -18V
V+ = +10V
V- = -10V
V+ = +15V
V- = -15V
V+ = +8V
V- = -8V
250
120
100
80
R
ON
(Ω)
60
T
A
= +25°C
40
20
T
A
= -40°C
T
A
= +125°C
T
A
= +85°C
T
A
= +70°C
R
ON
(Ω)
150
V+ = +20V
V+ = +30V
50
V+ = +36V
100
T
A
= -55°C
V+ = +15V
V- = -15V
-15
-10
-5
0
V
OUT_
(V)
5
10
15
20
0
0
5
10
15
20
25
30
35
V
OUT_
(V)
0
ON-RESISTANCE vs. OUTPUT VOLTAGE
AND TEMPERATURE (SINGLE SUPPLY)
MAX4505 toc04
OUTPUT CLAMP RESISTANCE
(SUPPLIES ON) vs. TEMPERATURE
MAX4505 toc05
OUTPUT CLAMP CURRENT (SUPPLIES ON)
vs. TEMPERATURE
20
15
10
I
OUT
(mA)
5
0
-5
-10
-15
V- = -15V
V+ = +15V
MAX4505 toc06
250
V+ = +12V
V- = 0
T
A
= +125°C
T
A
= +85°C
0.7
0.6
0.5
R
OUT
(kΩ)
0.4
0.3
0.2
0.1
V
IN
= -25V
V+ = +15V
V- = -15V
V
IN
= ±2.5V
V
IN
= +25V
25
200
R
ON
(Ω)
150
T
A
= +70°C
100
T
A
= -40°C T
A
= +25°C
T
A
= -55°C
50
-20
-25
-40 -30 -20 -10 0 10 20 30 40 50 60 70 80
TEMPERATURE (°C)
-55 -40 -25 -10 5 20 35 50 65 80 95 110 125
TEMPERATURE (°C)
0
0
0
2
4
6
V
OUT_
(V)
8
10
12
OUTPUT TRANSFER CHARACTERISTICS
(DUAL SUPPLIES)
MAX4505 toc07
OUTPUT TRANSFER CHARACTERISTICS
(SINGLE SUPPLY)
35
OUTPUT CLAMP VOLTAGE (V)
30
25
20
15
10
5
0
0
5
V+ = +9V
INPUT VOLTAGE LINEARLY SWEPT
BETWEEN 0 AND 36V
10
15
20
25
30
35
40
INPUT VOLTAGE (V)
-15
-20
V+ = +15V
V+ = +12V
V+ = +25V
OUTPUT LOAD = 1MΩ
V- = 0
V+ = +36V
MAX4505 toc08
FAULT-FREE ANALOG SIGNAL RANGE
vs. SUPPLY VOLTAGE
15
OUTPUT VOLTAGE (V)
10
5
0
-5
-10
MAX4505 toc09
20
15
OUTPUT CLAMP VOLTAGE (V)
10
5
0
-5
-10
-15
-20
-30
-20
(V+ = +18V, V- = -18V)
(V+ = +15V, V- = -15V)
(V+ = +10V, V- = -10V)
(V+ = +8V, V- = -8V)
INPUT VOLTAGE
LINEARLY SWEPT
BETWEEN -30V
AND +30V
40
20
(V+ = +8V, V- = -8V)
(V+ = +10V, V- = -10V)
(V+ = +15V, V- = -15V)
(V+ = +18V, V- = -18V)
OUTPUT LOAD = 1MΩ
-10
0
10
20
30
INPUT VOLTAGE (V)
-20
-15
-10
-5
0
5
10
15
20
INPUT VOLTAGE (V)
4
_______________________________________________________________________________________
Fault-Protected, High-Voltage,
Signal-Line Protector
Typical Operating Characteristics (continued)
(T
A
= +25°C, unless otherwise noted.)
FAULT-FREE OUTPUT LEAKAGE CURRENT
(SUPPLIES ON)
MAX4505 toc10
MAX4505
INPUT FAULT LEAKAGE CURRENT
(SUPPLIES ON)
MAX4505 toc11
POWER SUPPLY CURRENT
vs. TEMPERATURE
60
SUPPLY CURRENT (µA)
40
20
0
-20
-40
-60
-80
I-
I+ SINGLE SUPPLY +12V
V+ = +15V
V- = -15V
MAX4505 toc12
100n
10n
LEAKAGE CURRENT (A)
1n
100p
10p
1p
0.1p
0.01p
-55
V
OUT
= ±10V
I
OUT
(V+ = +15V, V- = -15V)
1µ
100n
LEAKAGE CURRENT (A)
10n
1n
I
IN
AT +25V (V+ = +15V, V- = -15V)
80
I+
I
OUT
(V+ = +12V, V- = 0)
100p
10p
1p
0.1p
I
IN
AT +25V (V+ = +12V, V - = 0)
-30
-5
20
45
70
95
120 145
-55 -35 -15
5
25
45
65
85 105 125
-40 -30 -20 -10 0 10 20 30 40 50 60 70 80
TEMPERATURE (°C)
TEMPERATURE (°C)
TEMPERATURE (°C)
SUPPLY CURRENT vs. INPUT VOLTAGE
MAX4505 toc13
FREQUENCY RESPONSE
MAX4505 toc15
FAULT-FREE SIGNAL PERFORMANCE
MAX4505 toc16
60
I+
40
SUPPLY CURRENT (µA)
20
0
-20
-40
I-
-60
-15
-10
-5
0
5
10
10
0
-10
-20
BANDWIDTH (dB)
-30
-40
-50
-60
-70
-80
-90
-100
0.01
V+ = +15V
V- = -15V
0.1
1
10
100
+15V
IN_
10V/div
-15V
+15V
OUT_
0
10V/div
-15V
15
1000
5µs/div
FAULT-FREE RAIL-TO-RAIL SIGNAL HANDLING
WITH ±15V SUPPLIES
INPUT VOLTAGE (V)
FREQUENCY (MHz)
INPUT OVERVOLTAGE
vs. OUTPUT CLAMPING
MAX4505 toc17
FAULT RECOVERY
MAX4505 toc18
+25V
+16V
IN_
0
+15V
-25V
0
OUT_
0
OUT_
5V/div
0
V+ = +15V
V- = -15V
+15V
IN_
5V/div
0
-15V
5µs/div
±25V OVERVOLTAGE INPUT WITH THE OUTPUT
CLAMPED AT ±15V
5µs/div
_______________________________________________________________________________________
5
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