19-1514; Rev 0; 7/99
Fault-Protected, High-Voltage,
Signal-Line Protector
MAX405
General Description
Features
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 ±±36 ꢀith poꢀer on or ±406 ꢀith poꢀer off. ꢁuring
a fault condition, the input terminal becomes an open cir-
cuit and only nanoamperes of leakage current floꢀ from
the source, ꢀhile the sꢀitch output (AOUT) furnishes typ-
ically 19mA from the appropriate polarity supply to the
load. This ensures an unambiguous rail-to-rail output
ꢀhen a fault begins and ends.
♦ Overvoltage Protection
±40V with Power Off
±36V with Power On
♦ Open Signal Paths with Power Off
♦ Output Clamps to Either Rail with an Input
Overvoltage
♦ 100Ω max On-Resistance
♦ 10ns Overvoltage Turn-On Delay
♦ No Latchup During Power Sequencing
♦ Rail-to-Rail Signal Handling
The MAX4505 protects both unipolar and bipolar analog
signals using either unipolar (+96 to +±36) or bipolar
(±ꢂ6 to ±1ꢂ6) poꢀer supplies. The device has no logic
control inputs; the protector is alꢀays on ꢀhen the sup-
plies are on. On-resistance is 100Ω max, and on-leakage
is less than 0.5nA at T = +25°C. The MAX4505 is avail-
A
able in 5-pin SOT2± and ꢂ-pin µMAX packages.
♦ 500Ω Output Clamp Resistance During
Overvoltage
♦ Tiny 5-Pin SOT23 Package
Applications
Ordering Information
Process Control Systems
Hot-Insertion Boards/Systems
ꢁata-Acquisition Systems
Redundant/Backup Systems
ATE Equipment
PIN-
PACKAGE
TOP
MARK
PART
TEMP. RANGE
MAX4505EUK-T -40°C to +ꢂ5°C
5 SOT2±-5
ꢂ µMAX
AꢁLW
—
MAX4505EUA
-40°C to +ꢂ5°C
Sensitive Instruments
Typical Operating Circuit
Pin Configurations
TOP VIEW
V-
V+
V-
V+
MAX4505
V-
AIN
V+
1
2
3
5
4
V-
V+
MAX4505
RAIL
SENSOR
AOUT
N.C.
AOUT
OUT
IN
AIN
SOT23-5
R
OUT
Pin Configurations continued at end of data sheet.
Rail-to-Rail is a registered trademark of Nippon Motorola, Ltd.
________________________________________________________________ Maxim Integrated Products
1
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