Power Supply design for THS4531 (Vs+ = 4V and Vs- = -1V)

How much current do you require for each rail?

Hi John,

JohnTucker said:

How much current do you require for each rail?

Each THS4531 consumption is 250uA and each ADC pin of TMS320F28377D will take very minor current compare to it. So i am thinking to design with 3x margin.

1. Total current required to drive 9 number of THS4531 = (250uA * 3) * 9 = 6.7 mA

2. Total current required to drive 18 number of THS4531 = (250uA * 3) * 18 = 13.5 mA (another requirement)

Please suggest solution for both option.

Thanks and Regards,

Maulik

 

You could use the TPS62080 to go from 5V to 4V or an LDO.

For the -1V rail, you could use the TPS62120 from 5V with this app note: www.ti.com/.../slva478b.pdf

Some customers use the TPS60400 charge pump (from the 4V rail) and then an LDO to get -1V. This would be less efficient.

Hi Chris,

I have source of +5V, +3V and +1.2V. There is no fix requirement of -1V, I can negotiate between any fix value from -400mV to -1.2V.

Can charge pump circuit convert +1.2V to -1.2V? Please suggest reliable part.

Regards,

Maulik Timbadiya

No, there is nothing that can work off of just 1.2Vin.

Is there any other solution if i extend -1.2V to -1.5V?

Vin = +1.2, +3.3, +5V

Vout = -400mV to -1.5V (Any Fix Potential)

Regards,

Maulik

Try looking at LM27762 for Vin = 5 V and Vout = 4V and -1.5 V

Thanks Mr. John Tucker,

Any alternate of LM27762 IC?

Same kind of IC available in SOIC package?

Thanks and Regards,

Maulik Timbadiya

I don't actually support that range of parts, so I do not know all the package variants. I post to this forum a lot, and just happened to know about that specific part that I though you might use.