![](/html/Hitachi/917365/page6.png)
HD74LVC244A
Test Circuit
VCC
VCC
Input
Pulse generator
Zout = 50 Ω
1G, 2G
1Y1 to 2Y4
1A1 to 2A4
Output
CL =
50 pF
500 Ω S1
450 Ω
50 Ω Scope
OPEN
*1 See under table
GND
Note:
1. CL includes probe and jig capacitance.
Symbol
tPLH / t PHL
tZH/ t HZ
tZL / t LZ
S1
Vcc=2.7V,
3.3±0.3V
Vcc=5.0±0.5V
OPEN OPEN
GND
GND
6V
2×Vcc
Waveforms – 1
Input A
Output Y
10 %
tr
90 %
Vref
tPLH
Vref
tf
90 %
Vref
10 %
tPHL
Vref
Notes:
1. tr = 2.5 ns, tf = 2.5 ns
2. Input waveform : PRR = 10 MHz, duty cycle 50%
VIH
GND
VOH
VOL
6