19-1902; Rev 1; 8/94
High-Voltage, Fault-Protected
Analog Multiplexers
____________________________Features
The MAX378 8-channel single-ended (1-of-8) multiplexer
and the MAX379 4-channel differential (2-of-8) multiplexer
use a series N-channel/P-channel/N-channel structure to
provide significant fault protection. If the power supplies to
the MAX378/MAX379 are inadvertently turned off while
input voltages are still applied, all channels in the muxes
are turned off, and only a few nanoamperes of leakage current will flow into the inputs. This protects not only the
MAX378/MAX379 and the circuitry they drive, but also the
sensors or signal sources that drive the muxes.
o
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o
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The series N-channel/P-channel/N-channel protection
structure has two significant advantages over the simple
current-limiting protection scheme of the industry’s firstgeneration fault-protected muxes. First, the Maxim protection scheme limits fault currents to nanoamp leakage
values rather than many milliamperes. This prevents damage to sensors or other sensitive signal sources. Second,
the MAX378/MAX379 fault-protected muxes can withstand
a continuous ±60V input, unlike the first generation, which
had a continuous ±35V input limitation imposed by power
dissipation considerations.
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All digital inputs have logic thresholds of 0.8V and 2.4V,
ensuring both TTL and CMOS compatibility without requiring pull-up resistors. Break-before-make operation is
guaranteed. Power dissipation is less than 2mW.
________________________Applications
Data Acquisition Systems
Industrial and Process Control Systems
Avionics Test Equipment
Signal Routing Between Systems
o
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Fault Input Voltage ±75V with Power Supplies Off
Fault Input Voltage ±60V with ±15V Power Supplies
All Switches Off with Power Supplies Off
On Channel Turns OFF if Overvoltage Occurs on
Input or Output
Only Nanoamperes of Input Current Under All
Fault Conditions
No Increase in Supply Currents Due to Fault
Conditions
Latchup-Proof Construction
Operates from ±4.5V to ±18V Supplies
All Digital Inputs are TTL and CMOS Compatible
Low-Power Monolithic CMOS Design
______________Ordering Information
TEMP. RANGE
PART
PIN-PACKAGE
0°C to +70°C
MAX378CPE
16 Plastic DIP
MAX378CWG
0°C to +70°C
24 Wide SO
MAX378CJE
0°C to +70°C
16 CERDIP
MAX378C/D
0°C to +70°C
Dice**
MAX378EPE
-40°C to +85°C
16 Plastic DIP
MAX378EWG
-40°C to +85°C
24 Wide SO
MAX378EJE
-40°C to +85°C
16 CERDIP
MAX378MJE
-55°C to +125°C
16 CERDIP
MAX378MLP
-55°C to +125°C
20 LCC*
Ordering Information continued at end of data sheet.
* Contact factory for availability.
**The substrate may be allowed to float or be tied to V+ (JI CMOS).
__________________________________________________________Pin Configurations
TOP VIEW
A0 1
16 A1
A0 1
16 A1
EN 2
15 A2
EN 2
15 GND
V- 3
14 GND
V- 3
IN1 4
MAX378
14 V+
MAX379
13 V+
IN1A 4
IN2 5
12 IN5
IN2A 5
12 IN2B
IN3 6
11 IN6
IN3A 6
11 IN3B
IN4 7
10 IN7
IN4A 7
10 IN4B
OUT 8
9
IN8
DIP
Pin Configurations continued at end of data sheet.
OUTA 8
13 IN1B
9
OUTB
DIP
________________________________________________________________ Maxim Integrated Products
Call toll free 1-800-998-8800 for free samples or literature.
1
MAX378/MAX379
_______________General Description