74HC245; 74HCT245
Octal buffer/line driver; 3-state
Product datasheet, Rev. 1.0
Aug 08, 2024
1.General Description
The 74HC245; 74HCT245 are 8-bit transceivers with 3-state outputs. The device features an
output enable ( OE ) and send/receive (DIR) for direction control. A HIGH on OE causes the
outputs to assume a high-impedance OFF-state. Inputs include clamp diodes. This enables the
use of current limiting resistors to interface inputs to voltages in excess of VCC.
2.Features and Benefits
Wide supply voltage range from 2.0 V to 6.0 V
High noise immunity
CMOS low power dissipation
Latch-up performance exceeds 250 mA
Octal bidirectional bus interface
Non-inverting 3-state outputs
Complies with JEDEC standards:
•
JESD8C (2.7 V to 3.6 V)
•
JESD7A (2.0 V to 6.0 V)
Input levels:
•
For 74HC245: CMOS level
•
For 74HCT245: TTL level
ESD protection:
•
HBM ANSI/ESDA/JEDEC JS-001 Class 3A exceeds 6000 V
•
CDM ANSI/ESDA/JEDEC JS-002 Class C3 exceeds 2000 V
Multiple package options
Rev. 1.0 – Aug 08, 2024
1
74HC245; 74HCT245
Octal buffer/line driver; 3-state
3.Ordering Information
Table 1. Ordering information
Package
Type number
Name
74HC245D
SOP-20L
74HC245PW
TSSOP-20L
Description
Quantity
plastic small outline package; 20 leads;
body width 7.5 mm
plastic thin shrink small outline package; 20 leads;
body width 4.4 mm
2000
2000
4.Function Diagram
Fig. 1. Logic symbol
Rev. 1.0 – Aug 08, 2024
Fig. 2. IEC logic symbol
2
74HC245; 74HCT245
Octal buffer/line driver; 3-state
5.Pinning Information
5.1. Pinning
Fig. 3. Top view pin configuration SOP and TSSOP
5.2. Pin description
Table 2. Pin description
Symbol
Pin
Description
DIR
1
Direction control
A0, A1, A2, A3, A4, A5, A6, A7
2, 3, 4, 5, 6, 7, 8, 9
Data input/output
GND
10
Ground (0 V)
B7, B6, B5, B4, B3, B2, B1, B0
11, 12, 13, 14, 15, 16, 17, 18
Data input/output
OE
19
Output enable input (active LOW)
VCC
20
Supply voltage
Rev. 1.0 – Aug 08, 2024
3
74HC245; 74HCT245
Octal buffer/line driver; 3-state
6.Functional Description
Table 3. Function table
H = HIGH voltage level; L = LOW voltage level; X = don’t care; Z = high-impedance OFF-state.
Input
Input/output
OE
DIR
An
Bn
L
L
A=B
input
L
H
input
B=A
H
X
Z
Z
7.Absolute Maximum Ratings
Stresses exceeding the absolute maximum ratings may damage the device. The device may not function
or be operable above the recommended operating conditions and stressing the parts to these levels is
not recommended. In addition, extended exposure to stresses above the recommended operating
conditions may affect device reliability. The absolute maximum ratings are stress ratings only.
Table 4. Absolute Maximum Ratings
In accordance with the Absolute Maximum Rating System (IEC 60134). Voltages are referenced to GND.
Symbol
Parameter
Conditions
VCC
supply voltage
IIK
input clamping current
VI < -0.5 V or VI > VCC + 0.5 V
IOK
output clamping current
VO < -0.5 V or VO > VCC + 0.5 V
IO
output current
VO = -0.5 V to (VCC + 0.5 V)
ICC
supply current
IGND
ground current
Ptot
total power dissipation
Tstg
storage temperature
Min
Max
Unit
-0.5
7.0
V
[1]
±20
mA
[1]
±20
mA
±25
mA
50
mA
-50
-65
mA
500
mW
150
°C
[1] The input and output voltage ratings may be exceeded if the input and output current ratings are observed.
Rev. 1.0 – Aug 08, 2024
4
74HC245; 74HCT245
Octal buffer/line driver; 3-state
8.Recommended Operating Conditions
The Recommended Operating Conditions table defines the conditions for actual device operation.
Recommended operating conditions are specified to ensure optimal performance to the datasheet
specifications. MDD does not recommend exceeding them or designing to Absolute Maximum Ratings.
Table 5. Recommended Operating Conditions
Symbol
Parameter
VCC
Conditions
74HC245
74HCT245
Unit
Min
Typ
Max
Min
Typ
Max
supply voltage
2.0
5.0
6.0
2.7
5.0
5.5
V
VI
input voltage
0
VCC
0
VCC
V
VO
output voltage
0
VCC
0
VCC
V
Tamb
ambient temperature
-40
125
-40
125
°C
Δt/ΔV
input transition rise and
fall rate
Rev. 1.0 – Aug 08, 2024
VCC = 2.0 V
VCC = 4.5 V
VCC = 6.0 V
625
1.67
139
83
ns/V
1.67
139
ns/V
ns/V
5
74HC245; 74HCT245
Octal buffer/line driver; 3-state
9.Static Characteristics
Table 6. Static characteristics
At recommended operating conditions. Voltages are referenced to GND (ground = 0 V). Typical values
measured at Tamb = 25°C (unless otherwise noted).
Symbol
Parameter
Conditions
-40 °C to +85 °C
Min
Typ
Max
-40 °C to +125 °C
Min
Max
Unit
74HC245
VIH
VIL
HIGH-level
input voltage
LOW-level
input voltage
VCC = 2.0 V
1.5
1.5
V
VCC = 4.5 V
3.15
3.15
V
VCC = 6.0 V
4.2
4.2
V
VCC = 2.0 V
0.5
0.5
V
VCC = 4.5 V
1.35
1.35
V
VCC = 6.0 V
1.8
1.8
V
VI = VIH or VIL
VOH
HIGH-level
output voltage
IO = -20 μA; VCC = 2.0 V
1.9
1.9
V
IO = -20 μA; VCC = 4.5 V
4.4
4.4
V
IO = -20 μA; VCC = 6.0 V
5.9
5.9
V
IO = -6.0 mA; VCC = 4.5 V
3.84
3.7
V
IO = -7.8 mA; VCC = 6.0 V
5.34
5.2
V
VI = VIH or VIL
VOL
II
IOZ
ICC
CI
CI/O
LOW-level
output voltage
input leakage
current
OFF-state
output current
supply current
input
capacitance
Input/output
capacitance
Rev. 1.0 – Aug 08, 2024
IO = 20 μA; VCC = 2.0 V
0.1
0.1
V
IO = 20 μA; VCC = 4.5 V
0.1
0.1
V
IO = 20 μA; VCC = 6.0 V
0.1
0.1
V
IO = 6.0 mA; VCC = 4.5 V
0.33
0.4
V
IO = 7.8 mA; VCC = 6.0 V
0.33
0.4
V
±1
±1
μA
±5
±10
μA
20
40
μA
VI = VCC or GND ;
VCC = 6.0 V
VI = VIH or VIL ; VCC = 6.0 V ;
VO = VCC or GND
VI = VCC or GND ; IO = 0 A ;
VCC = 6.0 V
4.0
pF
7.7
pF
6
74HC245; 74HCT245
Octal buffer/line driver; 3-state
Symbol
Parameter
Conditions
-40 °C to +85 °C
Min
Typ
Max
-40 °C to +125 °C
Min
Max
Unit
74HCT245
VIH
VIL
HIGH-level
input voltage
LOW-level
input voltage
VCC = 3 V
2.0
2.0
V
VCC = 4.5 V
2.0
2.0
V
VCC = 5.5 V
2.1
2.1
V
VCC = 3 V
0.8
0.8
V
VCC = 4.5 V
0.8
0.8
V
VCC = 5.5 V
0.8
0.8
V
VI = VIH or VIL;
VOH
HIGH-level
output
voltage
IO = -20 μA; VCC = 3 V
2.9
2.9
V
IO = -20 μA; VCC = 4.5 V
4.4
4.4
V
IO = -6.0 mA; VCC = 4.5 V
3.84
3.7
V
VI = VIH or VIL;
VOL
II
IOZ
ICC
ΔICC
CI
CI/O
LOW-level
output
voltage
input leakage
current
OFF-state
output
current
supply
current
additional
supply
current
input
capacitance
Input/output
capacitance
Rev. 1.0 – Aug 08, 2024
IO = 20 μA; VCC = 3 V
0.1
0.1
V
IO = 20 μA; VCC = 4.5 V
0.1
0.1
V
IO = 6.0 mA; VCC = 4.5 V
0.33
0.4
V
VI = VCC or GND ;
VCC = 5.5 V
±1
±1
μA
VI = VIH or VIL ; VCC = 5.5 V ;
VO = VCC or GND
±5
±10
μA
20
40
μA
400
490
μA
VI = VCC or GND; IO = 0 A; VCC =
5.5 V
per pin ; VI = VCC - 2.1 V; IO = 0
A; other inputs at VCC or GND;
VCC = 4.5 V to 5.5 V
4.0
pF
7.7
pF
7
74HC245; 74HCT245
Octal buffer/line driver; 3-state
10. Dynamic Characteristics
Table 7. Dynamic characteristics
Voltages are referenced to GND (ground = 0 V); for test circuit see Fig. 6. Typical values measured at Tamb
= 25°C (unless otherwise noted).
Symbol
Parameter
-40 °C to +85 °C
Conditions
Min
Typ
-40 °C to +125 °C
Max
Min
Max
Unit
74HC245
An to Bn or Bn to An;
see Fig. 4
tpd
propagation
delay
[1]
VCC = 2.0 V
35
40
ns
VCC = 4.5 V
20
25
ns
VCC = 6.0 V
15
20
ns
VCC = 2.0 V
35
40
ns
VCC = 4.5 V
20
25
ns
VCC = 6.0 V
15
20
ns
VCC = 2.0 V
35
40
ns
VCC = 4.5 V
20
25
ns
VCC = 6.0 V
15
20
ns
VCC = 2.0 V
9
11
ns
VCC = 4.5 V
6
8
ns
VCC = 6.0 V
4
5
ns
OE to An or Bn;
see Fig. 5
ten
enable time
[2]
OE to An or Bn;
see Fig. 5
tdis
disable time
[3]
see Fig. 4
tt
transition
time
CPD
power
dissipation
capacitance
Rev. 1.0 – Aug 08, 2024
per buffer;
VI
=
GND
[5]
[4]
to
VCC
18
pF
8
74HC245; 74HCT245
Octal buffer/line driver; 3-state
Symbol
-40 °C to +85 °C
Parameter
Conditions
tpd
propagation
delay
ten
enable time
tdis
disable time
An to Bn or Bn to An; VCC = 4.5V;
see Fig. 4
[1]
OE to An or Bn; VCC = 4.5V;
see Fig. 5
[2]
OE to An or Bn; VCC = 4.5V
see Fig. 5
[3]
VCC=4.5V;
see Fig. 4;
[4]
Min
Typ
-40 °C to +125 °C
Max
Min
Max
Unit
74HCT245
tt
CPD
transition
time
power
dissipation
capacitance
per buffer;
VI = GND to VCC – 1.5 V
[5]
18
20
25
ns
20
25
ns
20
25
ns
6
8
ns
pF
[1] tpd is the same as tPHL and tPLH.
[2] ten is the same as tPZH and tPZL.
[3] tdis is the same as tPLZ and tPHZ.
[4] tt is the same as tTHL and tTLH.
[5] CPD is used to determine the dynamic power dissipation (PD in μW).
PD = CPD × VCC2 × fi × N + Σ(CL × VCC2 × fo) where:
fi = input frequency in MHz;
fo = output frequency in MHz;
CL = output load capacitance in pF;
VCC = supply voltage in V;
N = number of inputs switching;
Σ(CL × VCC2 × fo) = sum of outputs.
Rev. 1.0 – Aug 08, 2024
9
74HC245; 74HCT245
Octal buffer/line driver; 3-state
10.1. Waveforms and test circuit
Measurement points are given in Table 8.
VOL and VOH are typical output voltage levels that occur with the output load.
Fig. 4. Input (An, Bn) to output (Bn, An) propagation delays and output transition times
Measurement points are given in Table 8.
VOL and VOH are typical output voltage levels that occur with the output load.
Fig. 5. 3-state enable and disable times
Table 8. Measurement points
Input
Output
VM
VM
VX
VY
74HC245
0.5VCC
0.5VCC
0.1VCC
0.9VCC
74HCT245
1.3 V
1.3 V
0.1VCC
0.9VCC
Type
Rev. 1.0 – Aug 08, 2024
10
74HC245; 74HCT245
Octal buffer/line driver; 3-state
Test data is given in Table 9.
Definitions for test circuit:
RL = Load resistance.
CL = Load capacitance including jig and probe capacitance.
RT = Termination resistance should be equal to the output impedance Zo of the pulse generator.
VEXT = External voltage for measuring switching times.
Fig. 6. Test circuit for measuring switching times
Table 9. Test data
Type
Input
Load
VEXT
VI
tr = tf
CL
RL
tPLH, tPHL
tPZH, tPHZ
tPZL, tPLZ
74HC245
VCC
≤ 2.5 ns
50 pF
500Ω
open
GND
2VCC
74HCT245
3V
≤ 2.5 ns
50 pF
500Ω
open
GND
2VCC
Rev. 1.0 – Aug 08, 2024
11
74HC245; 74HCT245
Octal buffer/line driver; 3-state
11. Package Outline
SOP-20L
Symbol
A
A1
A2
A3
B
B1
C
C1
C2
C3
Dimensions In Millimeters
Min.
Max.
12.600
12.900
0.381
0.431
1.240
1.300
0.450
0.460
7.400
7.600
10.206
10.406
2.150
2.300
0.938
1.038
0.938
1.2038
0.145
0.205
Rev. 1.0 – Aug 08, 2024
Symbol
C4
D
D1
D2
R1
R2
θ1
θ2
θ3
Dimensions In Millimeters
Min.
Max.
0.246
0.262
1.353
1.453
0.764
0.964
0.18TYP
0.30TYP
0.20TYP
12° TYP
12° TYP
0° ~ 8°
12
74HC245; 74HCT245
Octal buffer/line driver; 3-state
TSSOP-20L
Symbol
A
A1
A2
A3
b
b1
c
c1
D
E1
Dimensions In Millimeters
Min.
Max.
1.20
0.05
0.15
0.80
1.05
0.39
0.49
0.20
0.28
0.19
0.25
0.13
0.17
0.12
0.14
6.40
6.60
4.30
4.50
Rev. 1.0 – Aug 08, 2024
Symbol
E
e
L
L1
θ
Dimensions In Millimeters
Min.
Max.
6.20
6.60
0.65BSC
0.45
0.75
1.00REF
0°
8°
13
74HC245; 74HCT245
Octal buffer/line driver; 3-state
12. Abbreviations
Table 10. Abbreviations
Acronym
Description
CMOS
Complementary Metal-Oxide Semiconductor
DUT
Device Under Test
ESD
ElectroStatic Discharge
HBM
Human Body Model
CDM
Charged Device Model
13. Revision History
Table 11. Revision history
Document ID
Release Date
Data sheet status
74HC_HCT245 Rev. 1.0
Apr 18, 2025
Product datasheet
Rev. 1.0 – Aug 08, 2024
Change notice
Supersedes
14
