74HC_HCT299_3 © NXP B.V. 2008. All rights reserved.
Product data sheet Rev. 03 — 28 July 2008 16 of 24
NXP Semiconductors
74HC299; 74HCT299
8-bit universal shift register; 3-state
Measurement points are given in Table 8.
V
OL
and V
OH
are typical voltage output levels that occur with the output load.
Fig 10. 3-state enable and disable times for OEn inputs
t
PLZ
t
r
t
f
t
PHZ
outputs
disabled
outputs
enabled
outputs
enabled
I/On output
LOW to OFF
OFF to LOW
I/On output
HIGH to OFF
OFF to HIGH
OEn input
V
I
GND
V
M
V
M
10 %
10 %
90 %
90 %
V
M
t
PZL
t
PZH
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V
OH
V
OL
V
OH
V
OL
Table 8. Measurement points
Type Input Output
V
I
V
M
V
M
74HC299 V
CC
0.5V
CC
0.5V
CC
74HCT299 3 V 1.3 V 1.3 V
Test data is given in Table 9.
Definitions for test circuit:
DUT = Device Under Test.
R
T
= Termination resistance should be equal to output impedance Z
o
of the pulse generator.
C
L
= Load capacitance including jig and probe capacitance.
R
L
= Load resistance.
S1 = Test selection switch
Fig 11. Test circuit for measuring switching times
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DUT
V
CC
V
I
V
O
R
T
R
L
= 1 kΩ
C
L
50 pF
PULSE
GENERATOR
DUT
V
CC
S1
open
