Inputs

Data IO

Operation or Function

G

DIR

CAB

CBA

SAB

SBA

A1 Thru A8

B1 Thru B8

’ALS646 ’ALS647

’ALS648 ’ALS649

’AS646

’AS648

LL

X

X

X

L

Output

Input

Real-Time B Data to A Bus

Real-Time B Data to A Bus

L

L

X

X

X

H

Stored B Data to A Bus

Stored B Data to A Bus

LH

X

X

L

X

Input

Output

Real-Time A Data to B Bus

Real-Time A Data to B Bus

L

H

X

X

H

X

Stored A Data to B Bus

Stored A Data to B Bus

The data output functions ie data at the bus pins may be enabled or disabled by various signals at the G and DIR inputs Data input functions are always enabled

The data output functions ie data at the bus pins will be stored on every low-to-high transition on the clock inputs

Symbol

Parameter

Conditions

Typ

Guaranteed

Units

Limit

Maximum Operating

MHz

Frequency

Maximum Propagation

pF

ns

Delay A or B Input

to B or A Output

Maximum Propagation

pF

ns

Delay CBA or CAB

Input to A or B Output

Maximum Propagation

pF

ns

Delay SBA or SAB Input to A

or B Output with A or B high

Maximum Propagation

pF

ns

Delay SBA or SAB Input to A

or B Output with A or B low

Maximum Enable

ns

Time G or DIR Input to

pF

A or B Output

Maximum Disable

ns

Time G or DIR Input to

A or B Output

74HC

54HC

Symbol

Parameter

Conditions

Units

Typ

Guaranteed Limits

Maximum Operating

pF

V

MHz

Frequency

V

MHz

V

MHz

Maximum Propagation

pF

V

ns

Delay A or B Input

pF

V

ns

to B or A Output

pF

V

ns

pF

V

ns

pF

V

ns

pF

V

ns

Maximum Propagation

pF

V

ns

Delay CBA or CAB

pF

V

ns

Input to A or B Output

pF

V

ns

pF

V

ns

pF

V

ns

pF

V

ns

3