FPGA Central

Hi, I need someone more experinced to confirm me if the TPS54610 I have
choosen for the 2.5V voltage supply of my Spartan3 will handle reverse
current (that arises from using 3.3V signals on 2.5V dedicated pins
like CCLK, TDI, TMS...). One the schematic of a Spartan3 evaluation
board I saw an LM3475MF for this supply and this also should work
without the need of a shunt Rpar resistor to avoid reverse current from
entering the regulator. Please advice me on the TSP54610.
Thanks, Marco

On 6 Mar 2006 08:27:19 -0800, "Marco" <marco@marylon[email protected]> wrote:

>Hi, I need someone more experinced to confirm me if the TPS54610 I have
>choosen for the 2.5V voltage supply of my Spartan3 will handle reverse
>current (that arises from using 3.3V signals on 2.5V dedicated pins
>like CCLK, TDI, TMS...). One the schematic of a Spartan3 evaluation
>board I saw an LM3475MF for this supply and this also should work
>without the need of a shunt Rpar resistor to avoid reverse current from
>entering the regulator. Please advice me on the TSP54610.
>Thanks, Marco

Commonly, switching regulators described as "synchronous" will both
source and sink current at their outputs.

The data sheet says (in reference to high output voltages):
"The TPS54610 is capable of sinking current continuously until the
output reaches the regulation set-point."

I've never used a switcher for VCCAUX though, only VCCINT.

Note that linear (i.e. series pass) regulators won't be damaged by
output voltages higher than the setpoint, however the output voltage
will not be controlled by the regulator.

Regards,
Allan

Thanks, so I could use the TPS54610 without the need for the shunt Rpar
resistor, right?
Marco

On 6 Mar 2006 23:37:26 -0800, "Marco" <[email protected]> wrote:

>Thanks, so I could use the TPS54610 without the need for the shunt Rpar
>resistor, right?

Yes.

Allan.