Page 116 - DCAP108_DIGITAL_CIRCUITS_AND_LOGIC_DESIGNS

Unit 7: Standard Integrated Circuits (ICs)

7.3.1 Test Parameters for TTL Devices Notes
Table 7.1: Test Parameter

Test Parameter Unit Typical Description

V
Logic High Input Voltage, Vih(Logic This is the minimum voltage that an
“1”) input of a TTL digital IC is guaranteed
to recognize as a Logic “1”.

Standard Spec: 2.0 V min.

Logic Low Input Voltage, Vil (Logic V This is the maximum voltage that an
“0”) input of a TTL digital IC is guaranteed
to recognize as a Logic “0”. Standard
Spec: 0.8 V max.

Logic High Output Voltage, Voh V This is the minimum voltage that an
(Logic “1”) output of a TTL digital IC is guaranteed
to deliver as a Logic “1”.

Standard Spec: 2.4 V min.
V
Logic Low Output Voltage, Vol This is the maximum voltage that an
(Logic “0”) output of a TTL digital IC is guaranteed
to deliver as a Logic “0”.
Standard Spec: 0.4 V max.

Logic High Input Current, Iih µA This is the minimum amount of current
needed by an input of a TTL digital IC
to stay at Logic “1”.
Example of an Actual Spec:
50 µA min. when Vcc=Max; Vin = 2.7V

Logic Low Input Current, Iil mA This is the maximum amount of current
that the input of a TTL digital IC can
sink to stay at Logic “0”.
Example of an Actual Spec:
-1.6 mA max. when Vcc=max;
Vin = 0.5V

Output Short Circuit Current, Ios mA This is the amount of current that a
short-circuited TTL digital output
exhibits or can handle.
Example of an Actual Spec:
-40 mA min., -65 mA typ., -100 mA
max. when Vcc=max; Vout = 0V
Supply Current, Icc mA This is the Vcc supply current exhibited
by a TTL IC.
Example of an Actual Spec:
30 mA min., 50 mA max. when
Vcc=max

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