LM2576: How to Adjust Output Voltage

Sadanori Kato

Part Number: LM2576

Hi,

Can the output voltage be adjusted by adding R3 resistor from 10ohm to 100ohm between VOUT and FEEDBACK pin such as the following schematic?
Could you please tell me how to adjust the output voltage?

Best regards,
Kato

over 5 years ago

0 Marshall_Beck over 5 years ago

TI__Mastermind 35210 points

Hello Kato,

Please see 8.2.3 Adjusted Output Voltage Version section of the datasheet.

Ensure appropriate device orderable is selected.

0 Sadanori Kato over 5 years ago in reply to Marshall_Beck

Guru 36540 points

Hi Marshall-san,

Thank you for your prompt reply.

Could you please tell me whether the fixed voltage versions can adjust the output voltage with an external resistor?
If the output voltage cannot be adjusted with an external resistor, please tell me that reason.

Best regards,
Kato

0 Marshall_Beck over 5 years ago in reply to Sadanori Kato

TI__Mastermind 35210 points

For fixed output voltage, external voltage divider can be used with FB=5V, though output voltage will need to be greater than 5V.

Internal compensation is defined for 5VOUT (for fixed version), thus loop response will change and BOM may need to be adapted.

0 Sadanori Kato over 5 years ago in reply to Marshall_Beck

Guru 36540 points

Hi Marshall-san,

Thank you for the information.

For 5V fixed output voltage, could you please tell me the recommended value range of resistor if adding R3 between VOUT and FEEDBACK pin?

Best regards,
Kato

0 Marshall_Beck over 5 years ago in reply to Sadanori Kato

TI__Mastermind 35210 points

You need voltage divider.The values of the voltage divider Following Figure 32 equations in the datasheet of LM2576 and substituing vref for 5V, corresponding resistor divider values can be obtained.

0 Sadanori Kato over 5 years ago in reply to Marshall_Beck

Guru 36540 points

Hi Marshall-san,

Thank you for your comment!

I understand.

Best regards,
Kato

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LM2576: How to Adjust Output Voltage