HD74HC640 Datasheet, PDF (8/11 Pages) Hitachi Semiconductor – Octal Bus Transceivers (with 3-state outputs)

HD74HC640, HD74HC643
HD74HC643
• Waveform – 1
t_r
t_f
90 %
90 %
V_CC
Input B
50 %
50 %
10 %
10 %
0V
t_PLH
t_PHL
Output A
50 %
10 %
90 %
90 %
V_OH
50 %
10 %
V_OL
t_TLH
t_THL
• Waveform – 2
t_f
t_r
90 %
90 %
V_CC
Input G
50 %
50 %
10 %
10 %
0V
t_ZL
t_LZ
V_OH
Waveform - A
50 %
10 %
t_ZH
t_HZ
V_OL
Waveform - B
50 %
90 %
V_OH
V_OL
Notes : 1. Input waveform : PRR ≤ 1 MHz, duty cycle 50%, t_r ≤ 6 ns, t_f ≤ 6 ns
2. Waveform - A is for an output with internal conditions such that the
output is low except when disabled by the output control.
3. Waveform - B is for an output with internal conditions such that the
output is high except when disabled by the output control.
4. The output are measured one at a time with one transition per measurement.
Rev.2.00 Mar 30, 2006 page 8 of 10