Datasheet
CY54FCT138T, CY74FCT138T
1-OF-8 DECODERS
SCCS013B – MAY 1994 – REVISED OCTOBER 2001
5
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
electrical characteristics over recommended operating free-air temperature range (unless
otherwise noted) (continued)
PARAMETER
TEST CONDITIONS
CY54FCT138T CY74FCT138T
UNIT
PARAMETER
TEST
CONDITIONS
MIN TYP
†
MAX MIN TYP
†
MAX
UNIT
#
V
CC
= 5.5 V,
Outputs open,
Switch E
1
E
2
or
One output
switching
at f
1
= 10 MHz
V
IN
≤ 0.2 V or
V
IN
≥ V
CC
– 0.2 V
0.7 1.4
I
C
#
Switch
E
1
,
E
2
,
or
E
3
1
at 50% duty
cycle
V
IN
= 3.4 V or GND 1 2.4
mA
I
C
#
V
CC
= 5.25 V,
Outputs open,
Switch E
1
E
2
or
One output
switching
at f
1
= 10 MHz
V
IN
≤ 0.2 V or
V
IN
≥ V
CC
– 0.2 V
0.7 1.4
||
mA
Switch
E
1
,
E
2
,
or
E
3
1
at 50% duty
cycle
V
IN
= 3.4 V or GND 1 2.4
||
C
i
5 10 5 10 pF
C
o
9 12 9 12 pF
†
Typical values are at V
CC
= 5 V, T
A
= 25°C.
#
I
C
= I
CC
+ ∆I
CC
× D
H
× N
T
+ I
CCD
(f
0
/2 + f
1
× N
1
)
Where:
I
C
= Total supply current
I
CC
= Power-supply current with CMOS input levels
∆I
CC
= Power-supply current for a TTL high input (V
IN
= 3.4 V)
D
H
= Duty cycle for TTL inputs high
N
T
= Number of TTL inputs at D
H
I
CCD
= Dynamic current caused by an input transition pair (HLH or LHL)
f
0
= Clock frequency for registered devices, otherwise zero
f
1
= Input signal frequency
N
1
= Number of inputs changing at f
1
All currents are in milliamperes and all frequencies are in megahertz.
||
Values for these conditions are examples of the I
CC
formula.
switching characteristics over operating free-air temperature range (see Figure 1)
PARAMETER
FROM TO
CY54FCT138T CY54FCT138CT
UNIT
PARAMETER
(INPUT) (OUTPUT)
MIN MAX MIN MAX
UNIT
t
PLH
A
O
1.5 12 1.5 6
ns
t
PHL
A
O
1.5 12 1.5 6
ns
t
PLH
E E
O
1.5 12.5 1.5 6.1
ns
t
PHL
E
1
or
E
2
O
1.5 12.5 1.5 6.1
ns
t
PLH
E
3
O
1.5 12.5 1.5 6.1
ns
t
PHL
E
3
O
1.5 12.5 1.5 6.1
ns
switching characteristics over operating free-air temperature range (see Figure 1)
PARAMETER
FROM TO
CY74FCT138T CY74FCT138AT CY74FCT138CT
UNIT
PARAMETER
(INPUT) (OUTPUT)
MIN MAX MIN MAX MIN MAX
UNIT
t
PLH
A
O
1.5 9 1.5 5.8 1.5 5
ns
t
PHL
A
O
1.5 9 1.5 5.8 1.5 5
ns
t
PLH
E E
O
1.5 9 1.5 5.9 1.5 5
ns
t
PHL
E
1
or
E
2
O
1.5 9 1.5 5.9 1.5 5
ns
t
PLH
E
3
O
1.5 9 1.5 5.9 1.5 5
ns
t
PHL
E
3
O
1.5 9 1.5 5.9 1.5 5
ns