1999 Sep 28
2
Philips Semiconductors
Product specification
Octal bus transceiver; 3-state
74AHC245; 74AHCT245
FEATURES
ESD protection:
HBM EIA/JESD22-A114-A
exceeds 2000 V
MM EIA/JESD22-A115-A
exceeds 200 V
CDM EIA/JESD22-C101
exceeds 1000 V
Balanced propagation delays
All inputs have a Schmitt-trigger
action
Inputs accepts voltages higher than
V
CC
For AHC only:
operates with CMOS input levels
For AHCT only:
operates with TTL input levels
Specified from
-
40 to +85 and +125
C.
DESCRIPTION
The 74AHC/AHCT245 is a
high-speed Si-gate CMOS device.
The 74AHC/AHCT245 is an octal
transceiver featuring non-inverting
3-state bus compatible outputs in
both send and receive directions.
The 74AHC245/74AHCT245 features
an Output Enable (OE) input for easy
cascading and a send/receive (DIR)
input for direction control.
OE controls the outputs so that the
buses are effectively isolated.
FUNCTION TABLE
See Note 1.
Note
1. H = HIGH voltage level;
L = LOW voltage level;
X = don't care;
Z = high-impedance OFF-state.
QUICK REFERENCE DATA
GND = 0 V; T
amb
= 25
C; t
r
= t
f
3.0 ns.
Notes
1. C
PD
is used to determine the dynamic power dissipation (P
D
in
W).
P
D
= C
PD
V
CC
2
f
i
+
(C
L
V
CC
2
f
o
) where:
f
i
= input frequency in MHz;
f
o
= output frequency in MHz;
(C
L
V
CC
2
f
o
) = sum of outputs;
C
L
= output load capacitance in pF;
V
CC
= supply voltage in Volts.
2. The condition is V
I
= GND to V
CC
.
INPUTS
INPUTS/OUTPUTS
OE
DIR
A
n
B
n
L
L
A = B
inputs
L
H
inputs
B = A
H
X
Z
Z
SYMBOL
PARAMETER
CONDITIONS
TYPICAL
UNIT
AHC
AHCT
t
PHL
/t
PLH
propagation delay
C
L
= 15 pF;
V
CC
= 5 V
3.5
5.0
ns
A
n
to B
n
, B
n
to A
n
C
I
input capacitance
V
I
= V
CC
or GND 3.5
3.5
pF
C
O
output
capacitance
4.0
4.0
pF
C
PD
power dissipation
capacitance
C
L
= 50 pF;
f = 1 MHz;
notes 1 and 2
12
15
pF
1999 Sep 28
5
Philips Semiconductors
Product specification
Octal bus transceiver; 3-state
74AHC245; 74AHCT245
RECOMMENDED OPERATING CONDITIONS
LIMITING VALUES
In accordance with the Absolute Maximum Rating System (IEC 134); voltages are referenced to GND (ground = 0 V).
Notes
1. The input and output voltage ratings may be exceeded if the input and output current ratings are observed.
2. For SO packages: above 70
C the value of P
D
derates linearly with 8 mW/K.
For TSSOP packages: above 60
C the value of P
D
derates linearly with 5.5 mW/K.
SYMBOL
PARAMETER
CONDITIONS
74AHC
74AHCT
UNIT
MIN.
TYP.
MAX.
MIN.
TYP.
MAX.
V
CC
DC supply voltage
2.0
5.0
5.5
4.5
5.0
5.5
V
V
I
input voltage
0
-
5.5
0
-
5.5
V
V
O
output voltage
0
-
V
CC
0
-
V
CC
V
T
amb
operating ambient temperature
range
see DC and AC
characteristics per
device
-
40
+25
+85
-
40
+25
+85
C
-
40
+25
+125
-
40
+25
+125
C
t
r
,t
f
(
t/
f) input rise and fall rates
V
CC
= 3.3 V
0.3 V
-
-
100
-
-
-
ns/V
V
CC
= 5 V
0.5 V
-
-
20
-
-
20
SYMBOL
PARAMETER
CONDITIONS
MIN.
MAX. UNIT
V
CC
DC supply voltage
-
0.5
+7.0
V
V
I
input voltage range
-
0.5
+7.0
V
I
IK
DC input diode current
V
I
<
-
0.5 V; note 1
-
-
20
mA
I
OK
DC output diode current
V
O
<
-
0.5 V or V
O
> V
CC
+ 0.5 V; note 1
-
20
mA
I
O
DC output source or sink current
-
0.5 V < V
O
< V
CC
+ 0.5 V
-
25
mA
I
CC
DC V
CC
or GND current
-
75
mA
T
stg
storage temperature range
-
65
+150
C
P
D
power dissipation per package
for temperature range:
-
40 to +125
C; note 2
-
500
mW