74HC_HCT20

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© NXP B.V. 2012. All rights reserved.

Product data sheet

Rev. 3 — 3 September 2012

7 of 16

NXP Semiconductors

74HC20; 74HCT20

Dual 4-input NAND gate

11. Waveforms

Measurement points are given in Table 8.

VOL and VOH are typical voltage output levels that occur with the output load.

Fig 7.

Waveforms showing the input (nA, nB, nC, nD) to output (nY) propagation delays and the output

transition times

Q$Q%Q&

Q' LQSXW

Q< RXWSXW

90

9;

9,

W7+/

W7/+

92+

90

9<

92/

*1'

DDD

W3+/

W3/+

Table 8.

Measurement points

Type

Input

Output

VM

VM

VX

VY

74HC20

0.5VCC

0.5VCC

0.1VCC

0.9VCC

74HCT20

1.3 V

1.3 V

0.1VCC

0.9VCC

Test data is given in Table 9.

Definitions test circuit:

RT = termination resistance should be equal to output impedance Zo of the pulse generator.

CL = load capacitance including jig and probe capacitance.

Fig 8.

Test circuit for measuring switching times

001aah768

tW

tW

tr

tr

tf

VM

VI

negative

pulse

GND

VI

positive

pulse

GND

10 %

90 %

90 %

10 %

VM

VM

VM

tf

VCC

DUT

RT

VI

VO

CL

G