This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

BUF634: Requirement check about the BUF634

Part Number: BUF634
Other Parts Discussed in Thread: OPA569

Hi Team,

My customer plan to use a buffer to drive high current from a amplify.

Below is the basic requirement:

1.The output current better to range from 0~300mA. And 0~250mA is acceptable.

2. The resister load is about 3.5ohm to 5ohm.

3. The working temperature is the room temperature.

Please help to reply below questions:

1. Can the BUF634 meet the requirement as above. If not, do you have the recommendation?

2. The datasheet indicate the BUF634 can output 250mA current. So is the current fixed, or it's a maximum current? The current will be changed according to the voltage swing and the resister load?

3. Customer use the SOIC package, if the output current is 250mA, do they need to add the Heat Sink in the surface of the unit? Any PCB layout need to be considerate?

3. For the maximum 300mA current, any other part do you recommend?

Please look into the questions as above!

Lacey

Thanks a lot!

  • Hi Lacey,

    3.5R might be a little too low. The BUF634 is specified for a 100R load.

    The problem with the 3.5R load is that when driving a high current through it the output voltage swing will be very low which results in a large voltage drop across the output stage of BUF634. This will considerably heat up the BUF634. Also, with such a heavy load the distortion factor can rise.

    So, in any case I would use the BUF634 in TO220 package with a proper heat sink and power it with a decreased supply voltage.

    Kai

  • OPA569 is better choice. Run at minimum supply to reduce power dissipation. Check op amp for BW and Slew Rate depending on how fast customer wants to use in the end application. Link below will help on power dissipation and thermal design. We can review customer proposed schematic. Email me direct if you need more help.
    4. TI Precision Labs - Op Amps: Power and Temperature
    training.ti.com/ti-precision-labs-op-amps
  • Lacey

    We haven't heard back from you so we assume this answered your questions. If you need additional help just post another reply below.

    Thanks
    Dennis