Philips Semiconductors

Product specification

74F657

Octal transceiver with 8-bit parity generator/checker

90 July 30

7

AC ELECTRICAL CHARACTERISTICS

LIMITS

SYMBOL

PARAMETER

TEST

UNIT

CONDITION

MIN

TYP

MAX

MIN

MAX

MIN

MAX

Propagation delay

An to Bn or Bn to An

Waveform 2

2.5

3.0

5.5

6.0

7.5

7.5

2.5

3.0

8.0

8.0

2.0

2.5

9.0

9.0

ns

Propagation delay

An to PARITY

Waveform 1, 2

7.0

7.0

10.0

10.0

14.0

15.0

7.0

7.0

16.0

16.0

5.5

6.5

16.5

19.0

ns

Propagation delay

ODD/EVEN to PARITY,

ERROR

Waveform 1, 2

4.5

4.5

7.5

8.0

11.0

11.5

4.5

4.5

12.0

12.5

3.5

4.0

13.0

15.5

ns

Propagation delay

Bn to ERROR

Waveform 1, 2

8.0

8.0

14.0

14.0

20.5

20.5

7.5

7.5

22.5

22.5

7.5

7.5

24.5

25.0

ns

Propagation delay

PARITY to ERROR

Waveform 1, 2

8.0

8.0

11.5

12.0

15.5

15.5

7.5

8.0

16.5

17.0

6.5

6.5

18.5

20.0

ns

to high or low level

Waveform 3, 4

3.0

4.0

5.5

7.0

8.0

9.5

3.0

4.0

9.0

11.0

2.0

4.0

9.0

13.0

ns

Output disable time

from high or low level

Waveform 3, 4

2.0

2.0

4.5

4.0

7.5

6.0

2.0

2.0

8.0

6.5

1.0

1.0

8.0

7.5

ns

Note to AC electrical characteristics

1. These delay times reflect the 3-state recovery time only and not the signal through the buffers or the parity check circuitry. To assure VALID

information at the ERROR pin, time must be allowed for the signal to propagate through the drivers (B to A), through the parity check circuitry

(same as A to PARITY), and to the ERROR output. VALID data at the ERROR pin > (B to A) + (A to PARITY).

AC WAVEFORMS

VM

VM

VM

VM

tPLH

tPHL

An, Bn,

ODD/EVEN,

PARITY

PARITY,

ERROR

SF00418

Waveform 1. Propagation delay for inverting outputs

PARITY,

ERROR

An, Bn,

ODD/EVEN,

PARITY

SF00420

Waveform 2. Propagation delay for non-Inverting outputs

OE

0V

An, Bn,

PARITY,

ERROR

SF00419

Waveform 3. 3-state output enable time to high level and output

disable time from high level

OE

3.5V

An, Bn,

PARITY,

ERROR

SF00421

Waveform 4. 3-state output enable time to low level and output

disable time from low level

Note to AC waveforms