Details

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BUY HC138 https://www.utsource.net/itm/p/12543500.html

Parameter	Symbol	Min	Typical	Max	Unit
Supply Voltage	Vcc	4.75	5.0	5.25	V
Output Low Voltage	VOL	0.0	0.4	0.5	V
Output High Voltage	VOH	2.7	3.6	5.0	V
Input High Voltage	VIH	2.0	-	5.0	V
Input Low Voltage	VIL	0.0	-	0.8	V
Propagation Delay Time	tpd	6	10	18	ns
Power Dissipation	PD	-	-	100	mW
Operating Temperature	Topr	-40	-	85	°C

Instructions for Using the HC138 Decoder:

1. Power Supply:

   • Connect the Vcc pin to a 5V supply.
   • Connect the GND pin to ground.

2. Input Signals:

   • Apply the binary input signals to the A0, A1, and A2 pins.
   • Enable the decoder by setting the enable inputs (G1, G2A, G2B) appropriately:
     • G1 should be high (1).
     • G2A and G2B should both be low (0).

3. Output Selection:

   • The decoder will select one of the 8 output lines (Y0 to Y7) based on the binary input (A0, A1, A2).
   • Only one output line will be active (low) at any given time, corresponding to the binary input value.

4. Propagation Delay:

   • The propagation delay (tpd) is the time it takes for the output to change after the input changes. Ensure that your system can handle the typical delay of 10ns.

5. Power Dissipation:

   • The maximum power dissipation is 100mW. Ensure that the device is not subjected to excessive current or voltage to avoid overheating.

6. Operating Temperature:

   • The device is designed to operate within a temperature range of -40°C to 85°C. Ensure that the operating environment does not exceed these limits.

7. Handling Static Electricity:

   • The HC138 is sensitive to static electricity. Use proper ESD protection when handling the device.

8. Testing:

   • Before integrating the HC138 into your circuit, test it with a simple setup to ensure it functions correctly. Use a multimeter to verify the output states.

9. Layout Considerations:

   • Keep the traces between the HC138 and other components as short as possible to minimize noise and signal degradation.
   • Use decoupling capacitors (e.g., 0.1μF) close to the Vcc and GND pins to filter out any power supply noise.

(For reference only)