50%

Input

50%

VCC

0 V

50%

50%

VOH

VOL

tPLH

(1)

tPHL

(1)

VOH

VOL

tPHL

(1)

tPLH

(1)

Output

Output

50%

50%

VOH

VOL

Output

VCC

0 V

Input

tf

(1)

tr

(1)

90%

10%

90%

10%

tr

(1)

90%

10%

tf

(1)

90%

10%

CL

(1)

From Output

Under Test

Test

Point

6

SN74HCS21-Q1

SCLS761 – FEBRUARY 2020

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Product Folder Links: SN74HCS21-Q1

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Copyright © 2020, Texas Instruments Incorporated

7 Parameter Measurement Information

•

Phase relationships between waveforms were chosen arbitrarily. All input pulses are supplied by generators

having the following characteristics: PRR

≤ 1 MHz, ZO = 50 Ω, tt < 2.5 ns.

•

The outputs are measured one at a time, with one input transition per measurement.

CL= 50 pF and includes probe and jig capacitance.

Figure 5. Load Circuit

Figure 6. Voltage Waveforms

Transition Times

The maximum between tPLH and TPHL is used for tpd.

Figure 7. Voltage Waveforms

Propagation Delays