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TTL Input/Output

Specification of the TTL GPIO input/output ports

Simplified schematic

The receiver is LVTTL and 5 V TTL compliant. The driver is a 3.3 V TTL driver

DC characteristics

Parameter Conditions Min. Typ. Max. Units
Common mode input voltage   0   5 V
Low-level output current       64 mA
Low-level output voltage @ 16 mA 0.64     V
@ 32 mA 0.98     V
@ 64 mA 1.51     V
High-level output current       -32 mA
High-level output voltage @-8 mA 2.28     V
@-32 mA 1.52     V
ESD protection Human Body Model (HBM) 2     kV
Note: The I/O port includes a latch-up protection.

AC characteritics

Parameter Min. Typ. Max. Units
Pulse width 100     ns
Pulse rate 0   5 MHz
10%-90% rise/fall time     1 µs

Logical Map

The state of the port is reported as follows:

Input voltageLogical State
VIN > 2.0 VHIGH
VIN < 0.8 VLOW
Unconnected input portUndetermined

Compatible drivers and receivers

The following drivers are compatible:

  • Totem-pole LVTTL, TTL, 5 V CMOS drivers

The following receivers are compatible:

  • LVTTL, TTL, 3-Volt CMOS receivers