ST M74HCT245 User Manual
M74HCT245
OCTAL BUS TRANSCEIVER WITH 3 STATE OUTPUTS (NON INVERTED)
■HIGH SPEED:
tPD = 13ns (TYP.) at VCC = 4.5V
■LOW POWER DISSIPATION: ICC = 4μA(MAX.) at TA=25°C
■COMPATIBLE WITH TTL OUTPUTS : VIH = 2V (MIN.) VIL = 0.8V (MAX)
■SYMMETRICAL OUTPUT IMPEDANCE: |IOH| = IOL = 6mA (MIN)
■BALANCED PROPAGATION DELAYS: tPLH tPHL
■PIN AND FUNCTION COMPATIBLE WITH 74 SERIES 245
DESCRIPTION
The M74HCT245 is an advanced high-speed CMOS OCTAL BUS TRANSCEIVER (3-STATE) fabricated with silicon gate C2MOS technology.
This IC is intended for two-way asynchronous communication between data buses, and the direction of data transmission is determined by DIR input. The enable input G can be used to disable the device so that the buses are effectively isolated.
DIP |
SOP |
TSSOP |
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ORDER CODES |
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PACKAGE |
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TUBE |
T & R |
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DIP |
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M74HCT245B1R |
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SOP |
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M74HCT245M1R |
M74HCT245RM13TR |
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TSSOP |
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M74HCT245TTR |
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All inputs are equipped with protection circuits against static discharge and transient excess voltage.
All floating bus terminals during High Z State must be held HIGH or LOW.
PIN CONNECTION AND IEC LOGIC SYMBOLS
August 2001 |
1/9 |
M74HCT245
INPUT AND OUTPUT EQUIVALENT CIRCUIT |
PIN DESCRIPTION |
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PIN No |
SYMBOL |
NAME AND FUNCTION |
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1 |
DIR |
Directional Control |
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2, 3, 4, 5, 6, |
A1 to A8 |
Data Inputs/Outputs |
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7, 8, 9 |
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18, 17, 16, |
B1 to B8 |
Data Inputs/Outputs |
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15, 14, 13, |
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12, 11 |
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19 |
G |
Output Enable Input |
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10 |
GND |
Ground (0V) |
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20 |
VCC |
Positive Supply Voltage |
TRUTH TABLE
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INPUTS |
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FUNCTION |
OUTPUT |
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G |
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DIR |
A BUS |
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B BUS |
Yn |
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L |
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L |
OUTPUT |
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INPUT |
A = B |
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L |
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H |
INPUT |
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OUTPUT |
B = A |
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H |
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X |
Z |
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Z |
Z |
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X : Don’t Care |
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Z : High Impedance |
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ABSOLUTE MAXIMUM RATINGS |
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Symbol |
Parameter |
Value |
Unit |
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VCC |
Supply Voltage |
-0.5 to +7 |
V |
VI |
DC Input Voltage |
-0.5 to VCC + 0.5 |
V |
VO |
DC Output Voltage |
-0.5 to VCC + 0.5 |
V |
IIK |
DC Input Diode Current |
± 20 |
mA |
IOK |
DC Output Diode Current |
± 20 |
mA |
IO |
DC Output Current |
± 35 |
mA |
ICC or IGND |
DC VCC or Ground Current |
± 70 |
mA |
PD |
Power Dissipation |
500(*) |
mW |
Tstg |
Storage Temperature |
-65 to +150 |
°C |
TL |
Lead Temperature (10 sec) |
300 |
°C |
Absolute Maximum Ratings are those values beyond which damage to the device may occur. Functional operation under these conditions is not implied
(*) 500mW at 65 °C; derate to 300mW by 10mW/°C from 65°C to 85°C
RECOMMENDED OPERATING CONDITIONS
Symbol |
Parameter |
Value |
Unit |
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VCC |
Supply Voltage |
4.5 to 5.5 |
V |
VI |
Input Voltage |
0 to VCC |
V |
VO |
Output Voltage |
0 to VCC |
V |
Top |
Operating Temperature |
-55 to 125 |
°C |
tr, tf |
Input Rise and Fall Time (VCC = 4.5 to 5.5V) |
0 to 500 |
ns |
2/9
M74HCT245
DC SPECIFICATIONS
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Test Condition |
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Value |
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Symbol |
Parameter |
VCC |
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TA = 25°C |
-40 to 85°C |
-55 to 125°C |
Unit |
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(V) |
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Min. |
Typ. |
Max. |
Min. |
Max. |
Min. |
Max. |
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VIH |
High Level Input |
4.5 |
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2.0 |
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2.0 |
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2.0 |
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V |
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Voltage |
to |
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5.5 |
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VIL |
Low Level Input |
4.5 |
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0.8 |
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0.8 |
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0.8 |
V |
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Voltage |
to |
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5.5 |
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VOH |
High Level Output |
4.5 |
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IO=-20 μA |
4.4 |
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4.5 |
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4.4 |
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4.4 |
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V |
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Voltage |
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IO=-6.0 mA |
4.18 |
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4.31 |
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4.13 |
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4.10 |
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VOL |
Low Level Output |
4.5 |
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IO=20 μA |
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0.0 |
0.1 |
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0.1 |
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0.1 |
V |
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Voltage |
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IO=6.0 mA |
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0.17 |
0.26 |
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0.33 |
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0.40 |
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II |
Input Leakage |
5.5 |
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VI = VCC or GND |
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± 0.1 |
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± 1 |
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± 1 |
μA |
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Current |
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IOZ |
High Impedance |
5.5 |
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VI = VIH or VIL |
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± 0.5 |
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± 5 |
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± 10 |
μA |
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Output Leakage |
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VO = VCC or GND |
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Current |
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ICC |
Quiescent Supply |
5.5 |
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VI = VCC or GND |
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4 |
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40 |
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80 |
μA |
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Current |
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ICC |
Additional Worst |
5.5 |
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Per Input pin |
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2.0 |
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2.9 |
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3.0 |
mA |
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Case Supply |
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VI = 0.5V or |
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Current |
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VI = 2.4V |
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Other Inputs at |
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VCC or GND |
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IO = 0 |
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AC ELECTRICAL CHARACTERISTICS (CL = 50 pF, Input tr = tf = 6ns)
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Test Condition |
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Value |
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Symbol |
Parameter |
VCC |
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CL |
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TA = 25°C |
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-40 to 85°C |
-55 to 125°C |
Unit |
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(V) |
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(pF) |
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Min. |
Typ. |
Max. |
Min. |
Max. |
Min. |
Max. |
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tTLH tTHL |
Output Transition |
4.5 |
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50 |
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7 |
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12 |
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15 |
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18 |
ns |
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Time |
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tPLH tPHL |
Propagation Delay |
4.5 |
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50 |
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13 |
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22 |
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28 |
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33 |
ns |
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Time |
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150 |
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18 |
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30 |
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38 |
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45 |
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tPZL tPZH |
High Impedance |
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50 |
RL = 1 KΩ |
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19 |
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30 |
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38 |
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45 |
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Output Enable |
4.5 |
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150 |
RL = 1 KΩ |
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24 |
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38 |
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48 |
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57 |
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Time |
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tPLZ tPHZ |
High Impedance |
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RL = 1 KΩ |
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Output Disable |
4.5 |
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50 |
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17 |
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30 |
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38 |
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45 |
ns |
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Time |
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3/9
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