HD74HC240 Datasheet, PDF (5/8 Pages) Hitachi Semiconductor – Octal Buffers/Line Drivers/Line Receivers(with inverted 3-state outputs)

HD74HC240
Test Circuit
VCC
Input
Pulse Generator
Zout = 50 Ω
VCC
1G, 2G
Output
1Y1 to 2Y4
1A1 to 2A4
1 k Ω _S1
C_L =
50 pF
OPEN
GND
V_CC
Note : 1. C_L includes probe and jig capacitance.
TEST
t_PLH / t _PHL
t_ZH/ t _HZ
t_ZL / t _LZ
S1
OPEN
GND
V_CC
Waveforms
• Waveform – 1
t_f
t_r
90 %
90 %
V_CC
Input A
50 %
50 %
10 %
10 %
0V
t_PLH
t_PHL
Output Y
50 %
10 %
90 %
t_TLH
90 %
V_OH
50 %
10 %
V_OL
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
90 %
V_OH
50 %
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 Jan 31, 2006 page 5 of 7