SN74LS95N 参数 Datasheet PDF下载

SN54/74LS95B

DESCRIPTION OF TERMS

SETUP TIME(ts) —is defined as the minimum time required

for the correct logic level to be present at the logic input prior to

the clock transition from HIGH to LOW in order to be recog-

nized and transferred to the outputs.

HOLD TIME (th) — is defined as the minimum time following

the clock transition from HIGH to LOW that the logic level must

be maintained at the input in order to ensure continued recog-

nition. A negative HOLD TIME indicates that the correct logic

level may be released prior to the clock transition from HIGH to

LOW and still be recognized.

AC WAVEFORMS

The shaded areas indicate when the input is permitted to change for predictable output performance.

D

1.3 V

1.3 V

1.3 V

1.3 V

th(L)

ts(L)

ts(H)

th(H)

CP1 or CP2

1.3 V

1.3 V

tW

l/fmax

1.3 V

*The Data Input is

(DS for CP1) or (Pn for CP2).

tPHL

tPLH

Q

1.3 V

1.3 V

Figure 1

(H

L ONLY)

(L

H ONLY)

(L

H ONLY)

S

1.3 V

1.3 V

STABLE

ts(H)

ts(L)

th(L)

ts(L)

ts(H)

th(L OR H)

CP1

1.3 V

1.3 V

1.3 V

1.3 V

tW

ts(L)

ts(H)

th(H)

1.3 V

1.3 V

1.3 V

1.3 V

CP2

tW

Figure 2

FAST AND LS TTL DATA

5-174