74AHC_AHCT257_Q100 All information provided in this document is subject to legal disclaimers. © NXP B.V. 2013. All rights reserved.
Product data sheet Rev. 1 — 22 July 2013 9 of 17
NXP Semiconductors 74AHC257-Q100; 74AHCT257-Q100
Quad 2-input multiplexer; 3-state
[1] Typical values are measured at nominal supply voltage (V
CC
= 3.3 V and V
CC
= 5.0 V).
[2] t
pd
is the same as t
PLH
and t
PHL
.
[3] t
en
is the same as t
PZL
and t
PZH
.
[4] t
dis
is the same as t
PLZ
and t
PHZ
.
[5] C
PD
is used to determine the dynamic power dissipation (P
D
in W).
P
D
=C
PD
V
CC
2
f
i
N+(C
L
V
CC
2
f
o
) where:
f
i
= input frequency in MHz;
f
o
= output frequency in MHz;
C
L
= output load capacitance in pF;
V
CC
= supply voltage in V;
N = number of inputs switching;
(C
L
V
CC
2
f
o
) = sum of the outputs.
74AHCT257-Q100; V
CC
= 4.5 V to 5.5 V
t
pd
propagation
delay
nI0, nI1 to nY; see Figure 6
[2]
C
L
= 15 pF - 3.7 6.5 1.0 8.0 1.0 9.0 ns
C
L
= 50 pF - 4.9 8.5 1.0 10.0 1.0 11.0 ns
S to nY; see Figure 6
[2]
C
L
= 15 pF - 5.1 9.0 1.0 10.5 1.0 11.5 ns
C
L
= 50 pF - 6.4 10.5 1.0 12.5 1.0 13.5 ns
t
en
enable time OE to nY; see Figure 7
[3]
C
L
= 15 pF - 3.9 8.0 1.0 9.0 1.0 10.0 ns
C
L
= 50 pF - 5.1 10.0 1.0 11.0 1.0 12.0 ns
t
dis
disable time OE to nY; see Figure 7
[4]
C
L
= 15 pF - 4.5 7.5 1.0 8.0 1.0 8.5 ns
C
L
= 50 pF - 6.5 9.5 1.0 10.5 1.0 11.5 ns
C
PD
power
dissipation
capacitance
f
i
= 1 MHz; V
I
=GNDtoV
CC
[5]
4 outputs switching via
input S
-51- - - - -pF
1 output switching via
input I
-15- - - - -pF
Table 7. Dynamic characteristics …continued
Voltages are referenced to GND (ground = 0 V); for test circuit, see Figure 8.
Symbol Parameter Conditions 25 C 40 C to +85 C 40 C to +125 C Unit
Min Typ
[1]
Max Min Max Min Max