Details

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Parameter	Symbol	Conditions	Min	Typ	Max	Unit
Input Voltage	VIN	-	3.0	-	40.0	V
Output Voltage	VOUT	Adj.	1.25	-	37.0	V
Output Current	IOUT	-	0.0	1.5	-	A
Line Regulation	-	0 to 40V input range	-	0.01	-	%
Load Regulation	-	0 to 1.5A load current	-	0.1	-	%
Dropout Voltage	VDROPOUT	IOUT = 1.5A	-	3.0	-	V
Quiescent Current	IQ	-	-	5.0	10.0	mA
Temperature Range	TJ	-	-40	-	125	°C
Storage Temperature	TSTG	-	-65	-	150	°C
Thermal Resistance	θJA	TO-220 package	-	65.0	-	°C/W

Instructions for Using the LM317T:

1. Circuit Configuration:

   • Input Capacitor (CIN): Place a 0.1 μF ceramic capacitor close to the input pin to filter out noise.
   • Output Capacitor (COUT): Use a 1 μF tantalum or electrolytic capacitor between the output and adjust pins to improve transient response and stability.
   • Adjust Resistor (R1): Connect a 240 Ω resistor between the output and adjust pins.
   • Variable Resistor (R2): Connect a variable resistor between the adjust pin and ground to set the desired output voltage.

2. Output Voltage Calculation:

   • The output voltage ( V_ ) can be calculated using the formula: [ V_ = 1.25 left(1 + fracright) + I_ cdot R2 ]
   • For most applications, ( I_ ) is very small (about 50 μA) and can be neglected, simplifying the formula to: [ V_ approx 1.25 left(1 + fracright) ]

3. Thermal Considerations:

   • Ensure adequate heat sinking if the device will be operating at high power levels. The thermal resistance from junction to ambient (( theta_ )) is 65°C/W for the TO-220 package.
   • Calculate the power dissipation (( P_D )) using the formula: [ P_D = (V_ - V_) times I_ ]
   • The temperature rise (( Delta T )) can be estimated using: [ Delta T = P_D times theta_ ]

4. Protection:

   • The LM317T includes internal overtemperature and overcurrent protection circuits. However, it is still important to design the circuit to avoid excessive power dissipation and to ensure proper operation within the specified temperature range.

5. Mounting:

   • Mount the LM317T on a heatsink if necessary, ensuring good thermal contact. Use thermal grease or a thermal pad to enhance heat transfer.

6. Testing:

   • Before finalizing the design, test the circuit under various conditions to ensure stability and performance meet the requirements.

By following these guidelines, you can effectively use the LM317T in your power supply or voltage regulation applications.

(For reference only)