Differential Input/Output

Applies to Closed3610 HD26F I/O Extension Module - TTL-RS422 and 3612 HD26F I/O Extension Module - TTL-CMOS5V-RS422.

Differential Input/Output Simplified Schematic

The driver and the receiver complies with the ANSI/TIA/EIA-422B specification.

DC Characteristics

Parameter Conditions Min. Typ. Max. Units
Common mode voltage   -7   +7 V
Input impedance     120   Ohm
ESD protection Human Body Model (HBM) 15     kV
Contact discharge 8     kV
Air gap discharge 15     kV

Driver

Parameter Conditions Min. Typ. Max. Units
Low-level output current       30 mA
Low-level output voltage 20 mA   0.2 0.4 V
High-level output current       -30 mA
High-level output voltage -20 mA 2.4 3   V
Differential output voltage 0 mA 2   4 V

Receiver

Parameter Conditions Min. Typ. Max. Units
Differential amplitude   200     mV

AC characteristics

Driver

Parameter Min. Typ. Max. Units
Pulse width 50     ns
Pulse rate 0   10 MHz
10%-90% rise/fall time   TBD   µs

Receiver

Parameter Min. Typ. Max. Units
Pulse width 50     ns
Pulse rate 0   10 MHz
10%-90% rise/fall time   TBD   µs

Logical map

The state of the port is as follows:

Relative V+/V- voltageLogical State
V+ > V-HIGH
V+ < V-LOW

Compatible sources

Sources with the following drivers are compatible:

● RS-422 differential line drivers
● Complementary TTL drivers

Compatible loads

Loads with the following receivers are compatible:

● RS-422 differential line receivers