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UCD74106 Maximum output voltage capability?

John Galvin
Intellectual 475 points
Other Parts Discussed in Thread: PTD08A020W, UCD9246, UCD74106, UCD7230

I'm currently using the 2 x UCD9246 with a combination of PTD08A020W & UCD74106RGM for an FPGA board. I now have a new requirement which needs a 4.5V output. The PTD08A020W states the output voltage range but the UCD74106 does not. I know the range is dependent on the feedback resistors but what is the of Maximum output voltage capability of the UCD74106?

  • 0
    TI__Genius 13700 points

    The PTD08A020W module uses the UCD7230 mosfet driver.  The maximum output rail voltage that can be achieved by the UCD7230 driver is limited by the absolute maximum voltage ratings of the POS/NEG pins used by the DCR current sensing circuit which is 5.6V.  So a rail voltage of 5.0V can be driven by the UCD7230.

    The UCD74106 driver uses a completely different method for sensing the output current so it is not subject to this limitation and therefore could produce a rail voltage, in theory, up to its input voltage rail.

    Note:  If the POS/NEG inputs of the UCD7230 were left unused (grounded) , this driver could also be used, in theory, for an output rail voltage up to its input rail voltage.

    While it is possible to implement a 5.0V rail using the UCD7230 driver while using the DCR current sensing circuit, as in the PTD module, there can be other limiations applied to a design when developing a complete POL solution.  In the case of the PTD modules, they were specifically developed and optimized to operate over the 0.7 to 3.6V output voltage range and this specification, and possibly others, determines the limitation.  For the PTD application it is the module's specification which drives its absolute maximum output voltage rating rather than the absolute maximum rating of the driver setting the limitation on the module's output voltage.