HD74AC Datasheet, PDF (29/52 Pages) Hitachi Semiconductor – HD74AC Series Common Information

Definition of Specifications
4. Symbols and Terms Defined for HD74AC Series
Explanation of Symbols Used in Electrical Characteristics and Recommended Operating Conditions
Table 5 DC Characteristics
Symbol Term
V_IH
High level input voltage
V_IL
Low level input voltage
V_OL
Low level output voltage
V_OH
High level output voltage
V_t+
Forward input threshold
voltage
V_t-
Reverse input threshold
voltage
V_h
Hysteresis voltage
I _IN
Input leakage current
I _OZ
Off-state output current
(high-impedance)
I _CC
Quiescent Supply current
I _OLD
Minimum Dynamic Output
Current
I _OHD
I _CCT
Maximum I_CC /Input
Description
High level input voltage to ensure that a logic element operates
under some constraint
Low level input voltage to ensure that a logic element operates
under some constraint
Output voltage in effect when, under the input condition for
bringing the output low, the rated output current is allowed to flow
to the output terminal
Output voltage in effect when, under the input condition for
bringing the output high, the rated output current is allowed to flow
to the output terminal
Input voltage in effect when the operation of a logic element varies
as the input is allowed to go up form a voltage level lower than the
reverse input threshold voltage V_t-
Input voltage in effect when the operation of a logic element varies
as the input is allowed to drop up form a voltage level higher than
the forward input threshold voltage V_t+
Difference between forward input threshold voltage V_t+ and reverse
threshold voltage V_t-
Input current that flows in when the rated maximum input voltage
is applied to the input terminal
Current that flows to the 3-state output of an element under the
input condition for bringing the output to high-impedance state
Current that flows to the supply therminal (V_CC) under the rated
input condition
Output current that flows in when, under the condition for bringing
the output low,the output terminal is tied to the rated out voltage
V_OLD.
Output current that flows out when, under the condition for
bringing the output high, the output terminal is tied to the rated out
voltage V_OHD.
Current that flows to the supply terminal (V_CC) under the rated input
condition
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