74HC244; 74HCT244
Octal buffer/line driver; 3-state
Product datasheet, Rev. 1.0
Aug 08, 2024
1.General Description
The 74HC244; 74HCT244 are 8-bit buffer/line drivers with 3-state outputs. The device can be
used as two 4-bit buffers or one 8-bit buffer. The device features two output enables (1OE and
2OE), each controlling four of the 3-state outputs. A HIGH on nOE causes the outputs to assume
a high-impedance OFF-state. Inputs include clamp diodes that enable 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 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 74HC244: CMOS level
•
For 74HCT244: 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
74HC244; 74HCT244
Octal buffer/line driver; 3-state
3.Ordering Information
Table 1. Ordering information
Type number
74HC244D
74HCT244D
74HC244PW
74HCT244PW
Rev. 1.0 – Aug 08, 2024
Package
Name
Description
Quantity
SOP-20L
plastic small outline package; 20 leads;
body width 7.5 mm
2000
TSSOP-20L
plastic thin shrink small outline package; 20 leads;
body width 4.4 mm
2000
2
74HC244; 74HCT244
Octal buffer/line driver; 3-state
4.Function Diagram
Fig. 1. Functional diagram
Fig. 2. Logic symbol
Rev. 1.0 – Aug 08, 2024
Fig. 3. IEC logic symbol
3
74HC244; 74HCT244
Octal buffer/line driver; 3-state
5.Pinning Information
5.1. Pinning
Fig. 4. Top view pin configuration SOP and TSSOP
5.2. Pin description
Table 2. Pin description
Symbol
Pin
Description
1OE, 2OE
1, 19
Output enable input(active LOW)
1A0, 1A1, 1A2, 1A3
2, 4, 6, 8
Data input
2Y0, 2Y1, 2Y2, 2Y3
3, 5, 7, 9
Bus output
GND
10
Ground (0V)
2A0, 2A1, 2A2, 2A3
17, 15, 13, 11
Data input
1Y0, 1Y1, 1Y2, 1Y3
18, 16, 14, 12
Bus output
VCC
20
Supply voltage
Rev. 1.0 – Aug 08, 2024
4
74HC244; 74HCT244
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
Output
nOE
nAn
nYn
L
L
L
L
H
H
H
X
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
5
74HC244; 74HCT244
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
74HC244
74HCT244
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
6
74HC244; 74HCT244
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
74HC244
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
LOW-level
output
voltage
input
leakage
current
OFF-state
output
current
supply
current
input
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
VI = VCC or GND ;
VCC = 6.0 V
±1
±1
μA
VI = VIH or VIL ; VCC = 6.0 V ;
VO = VCC or GND
±5
±10
μA
VI = VCC or GND ; IO = 0 A ;
VCC = 6.0 V
20
40
μA
Pin OE
4.0
pF
Pin nAn
7.7
pF
7
74HC244; 74HCT244
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
74HCT244
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
0.7
0.7
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
LOW-level
output
voltage
input
leakage
current
OFF-state
output
current
supply
current
additional
supply
current
input
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
Pin OE
4.0
pF
Pin nAn
7.7
pF
8
74HC244; 74HCT244
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. 7. 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
74HC244
nAn to nYn; see Fig. 5
tpd
propagation
delay
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
nOE to nYn; see Fig. 6
ten
enable time
nOE to nYn; see Fig. 6
tdis
disable time
see Fig. 5
tt
CPD
transition
time
power
dissipation
capacitance
Rev. 1.0 – Aug 08, 2024
[1]
Per buffer ;
VI
=
GND
[5]
[2]
[3]
[4]
to
VCC
18
pF
9
74HC244; 74HCT244
Octal buffer/line driver; 3-state
Symbol
Parameter
Conditions
tpd
propagation
delay
ten
enable time
tdis
disable time
nA to nY; VCC = 4.5 V;
see Fig. 5
nOE to nYn; VCC = 4.5 V;
see Fig. 6
nOE to nYn; VCC = 4.5 V;
see Fig. 6
-40 °C to +85 °C
Min
Typ
-40 °C to +125 °C
Max
Min
Max
Unit
74HCT244
tt
CPD
transition
time
power
dissipation
capacitance
[1]
[2]
[3]
VCC = 4.5 V; see Fig. 5
[4]
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
10
74HC244; 74HCT244
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. 5. The input nAn to output nYn propagation delays
Measurement points are given in Table 8.
VOL and VOH are typical output voltage levels that occur with the output load.
Fig. 6. 3-state enable and disable times
Table 8. Measurement points
Input
Output
VM
VM
VX
VY
74HC244
0.5VCC
0.5VCC
0.1VCC
0.9VCC
74HCT244
1.3 V
1.3 V
0.1VCC
0.9VCC
Type
Rev. 1.0 – Aug 08, 2024
11
74HC244; 74HCT244
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. 7. 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
74HC244
VCC
≤ 2.5 ns
50 pF
500Ω
open
GND
2VCC
74HCT244
3V
≤ 2.5 ns
50 pF
500Ω
open
GND
2VCC
Rev. 1.0 – Aug 08, 2024
12
74HC244; 74HCT244
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°
13
74HC244; 74HCT244
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°
14
74HC244; 74HCT244
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
TTL
Transistor-Transistor Logic
13. Revision History
Table 11. Revision history
Document ID
Release Date
Data sheet status
74HC_HCT244 Rev. 1.0
Nov 01, 2024
Product datasheet
Rev. 1.0 – Aug 08, 2024
Change notice
Supersedes
15