Details

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BUY LM3578 https://www.utsource.net/itm/p/12607749.html

Parameter	Symbol	Conditions	Min	Typ	Max	Unit
Input Voltage	VIN		8		40	V
Switching Frequency	fSW		50	100	200	kHz
Output Current Limit	IOLIM		0.6		1.5	A
Start-Up Current	ISU			70		渭A
Operating Supply Current	IOSC			3.5		mA
Shutdown Current	ISD			0.5		渭A
Reference Voltage	VREF		1.23		1.29	V
Feedback Input Current	IFB			25		nA
Thermal Shutdown Temperature	TSD			160		掳C
Maximum Junction Temperature	TJMAX				150	掳C

Instructions for LM3578

1. Power Supply Connection:

   • Connect the input voltage (VIN) between the VIN pin and ground.
   • Ensure the input voltage is within the specified range of 8V to 40V.

2. Frequency Setting:

   • The switching frequency can be set by an external resistor connected between the RT/CT pin and ground.
   • Choose the value of the resistor based on the desired switching frequency within the 50kHz to 200kHz range.

3. Output Configuration:

   • For buck or boost configurations, connect the appropriate inductor and capacitor values as per the application circuit diagram.
   • Use the feedback network to set the output voltage accurately.

4. Current Limiting:

   • The device has a built-in current limit feature that restricts the output current to prevent damage.
   • Adjust the sense resistor if necessary to set the current limit within 0.6A to 1.5A.

5. Thermal Considerations:

   • Ensure adequate heat sinking if operating near the maximum junction temperature (150掳C).
   • Monitor the thermal shutdown temperature (around 160掳C) to avoid unintended shutdowns.

6. Shutdown Functionality:

   • Utilize the shutdown pin to control the operation of the LM3578 externally.
   • When the shutdown pin is pulled low, the supply current drops to about 0.5渭A.

7. Stability and Compensation:

   • Add compensation components as recommended in the datasheet to ensure stable operation under varying load conditions.

For detailed design considerations and specific application circuits, refer to the full datasheet of the LM3578.

(For reference only)