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Can UCD9222+UCD7242 be operate at 5V?

Udayakumar Raju
Prodigy 130 points
Other Parts Discussed in Thread: UCD9222, UCD7242

 UCD9222+UCD7142 combo pack is used to supply core voltages of C6655. On our custom board, there is no 12V rail. We do only have 5V rail on board. So all required power rails are derived from 5V supply. 

It would be great help, if anyone throws some lights on below queries.

Do UCD9222+UCD7242 work at 5V?

Has any one done design with 5V and working without issues?

 any suggestion /recommendations are welcome.

Regards,

Udaya

 

  • 0
    TI__Genius 13700 points

    UCD92xx controllers run from 3.3V and have an internal regulator that can r'un from 5V and 12V but I might suggest either a small LDO (<100ma needed) to just power the controller or you could use a larger one if powering more devices across the board.  Keep the decoupling close to the pins on the same side of the PCB as the controller connected with direct traces that don't have change layers.  If using a larger LDO to power multiple items then I suggest putting a 1 to 2 ohm resistor between V33D and V33A with 4.7uF capacitors decoupling each pin to GND with the 3.3V source attacing to the 3V3D pin first.  The PowerPad under the UCD9222 should be tied directly to the DGND and AGND pins and the decoupling capacitors.

    The UCD7242 is designed for operation down to 4.75V using the internal VGG but can go down to 2.2 using an external VGG.  Running from 5V, you will get better efficiency tying VGG_DIS to VGG and tying the 5V to VGG even though the datasheet only recommends this below 4.75V.

    There have been numerous designs with 5V bias already in production.  The Fusion Digital Power Designer software will help you make component seletions for the power stage.