HD74LS257 Datasheet, PDF (4/6 Pages) Hitachi Semiconductor – Quadruple 2-line-to-1-line Data Selectors/Multiplexers(with non inverted 3-state outputs)

HD74LS257
Testing Method
Test Circuit
4.5V
Input
P.G.
Zout = 50Ω
V_CC
OC
Output
S
Y
A
B
CL
RL
S1
5kΩ
S2
Notes: 1. C_L includes probe and jig capacitance.
2. All diodes are 1S2074(H).
Waveform
Output
Control
t_THL
90%
1.3V
10%
t_ZL
Waveform 1
S1 closed,
S2 open _1.3V
t_ZH
Waveform 2
1.3V
S1 open, S2 closed
t_TLH
3V
90%
3V
1.3V
10%
0V
0V
4.5V
V_OL
V_OH
0V
t_LZ
S1 and,
S2 closed
1.5V
V_OL
t_HZ
0.5V
V_OH
0.5V
S1 and, S2 closed
1.5V
Notes:
1. Input pulse; t_TLH ≤ 15 ns, t_THL ≤ 6 ns, PRR = 1 MHz, duty cycle = 50%
2. Waveform 1 is for an output with internal conditions such that the output is low except when
disabled by the output control.
3. Waveform 2 is for an output with internal conditions such that the output is high except when
disabled by the output control.
Rev.3.00, Jul.15.2005, page 4 of 5