19-0326; Rev 0; 12/94
Signal-Line Circuit Protectors
____________________________Features
o ±40V Overvoltage Protection
o Open Signal Paths with Power Off
100Ω Signal Paths with Power On
o 1nA Max Path Leakage at +25°C
o 44V Maximum Supply Voltage Rating
o Automatic Protection; No Programming or
Controls
______________Ordering Information
PART†
TEMP. RANGE
PIN-PACKAGE
MAX366CPA
0°C to +70°C
8 Plastic DIP
MAX366CSA
MAX366C/D
MAX366EPA
0°C to +70°C
0°C to +70°C
-40°C to +85°C
8 SO
Dice*
8 Plastic DIP
MAX366ESA
MAX366MJA
MAX367CPN
-40°C to +85°C
-55°C to +125°C
0°C to +70°C
8 SO
8 CERDIP**
18 Plastic DIP
MAX367CWN
MAX367C/D
MAX367EPN
0°C to +70°C
0°C to +70°C
-40°C to +85°C
18 Wide SO
Dice*
18 Plastic DIP
MAX367EWN
MAX367MJN
-40°C to +85°C
-55°C to +125°C
18 Wide SO
18 CERDIP**
________________________Applications
† MAX367 available after January 1, 1995.
Process Control Systems
Redundant/Backup Systems
Hot-Insertion Boards/Systems ATE Equipment
Data-Acquisition Systems
Sensitive Instruments
* Dice are tested at TA = +25°C only.
* Contact factory for availability.
Pin Configurations appear at end of data sheet.
___________________________________________________Typical Operating Circuit
ELECTRONICS
PROTECTOR
FAULT!
REMOTE SENSOR
MAX366
+28V
+10V REG.
V+
8
1
OUT1
7
2
IN2
OUT2
6
3
(SHORT)
IN1
IN3
OUT3
5
4
(OPEN)
+12V
SENSITIVE
AMPLIFIER
V-
FAULT!
________________________________________________________________ Maxim Integrated Products
Call toll free 1-800-998-8800 for free samples or literature.
1
MAX366/MAX367
_______________General Description
The MAX366 and MAX367 are multiple, two-terminal circuit
protectors. Placed in series with signal lines, each two-terminal device guards sensitive circuit components against
voltages near and beyond the normal supply voltages.
These devices are used at interfaces where sensitive circuits are connected to the external world and could
encounter damaging voltages (up to 35V beyond the supply rails) during power-up, power-down, or fault conditions.
The MAX366 contains three independent protectors and
the MAX367 contains eight. They can protect analog signals using either unipolar (4.5V to 36V) or bipolar (±2.25V
to ±18V) power supplies. Each protector is symmetrical.
Input and output terminals may be freely interchanged.
These devices are voltage-sensitive MOSFET transistor
arrays that are normally on when power is applied and
normally open circuit when power is off. With ±10V supplies, on-resistance is 100Ω max and leakage is less than
1nA at +25°C.
When signal voltages exceed or are within approximately
1.5V of either power-supply voltage (including when
power is off), the two-terminal resistance increases dramatically, limiting fault current as well as output voltage to
sensitive circuits. The protected side of the switch maintains the correct polarity and clamps approximately 1.5V
below the supply rail. There are no “glitches” or polarity
reversals going into or coming out of a fault condition.
