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SN74AXCH8T245: 50mA drive current per channel.

Sveinn Jia
Expert 7220 points

Part Number: SN74AXCH8T245
Other Parts Discussed in Thread: SN74LXC8T245

Hi Team,

The customer is considering using SN74AXCH8T245 between an FPGA and the load, and would like to know whether the device can provide approximately 50mA drive current per channel.

From the datasheet, I found that:

  • The device Absolute Maximum Rating specifies ±50mA continuous output current (IO).
  • However, I could not find a recommended operating drive-current specification (such as IOH/IOL = ±24mA) like those provided for the LVC/LVCH families.
  • The datasheet mainly provides VOH/VOL versus IOH/IOL characteristics rather than a guaranteed output-drive specification.

Could you please help clarify:

  1. Can SN74AXCH8T245 be used as a 50mA output driver on a per-channel basis?
  2. Is the ±50mA rating only an Absolute Maximum Rating, or is continuous operation near this level supported?
  3. If the customer requires approximately 50mA drive capability, would TI recommend another device family (for example LVC/LVCH buffer families or a dedicated driver solution) instead of AXCH?

Thank you.

Best Regards,

 

  • 0
    TI__Mastermind 39080 points

    Hello Sveinn,

    As you noted, there is an absolute max limit on output current which is ±50mA. This limit is given per channel. However, you also need to look at the 'Continuous current through VCCA, VCCB, or GND' parameter. There it says you cannot exceed ±100mA through VCCA or VCCB. Meaning you can only use two channels to output 50mA before the part permanently is damaged. 

    Now the SN74LXC8T245 extends the continuous current through VCC to 200mA. You would be limited to four channels at 50mA. Other than LXC and LVC, we don't have another device that can output 50mA to all channels.

    Regards,

    Josh