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REF5050-EP: Regarding Voltage Regulator

Bhuvaneshwari K
Intellectual 370 points
Part Number: REF5050-EP
Other Parts Discussed in Thread: DAC80508, DAC63204, DAC80501

Tool/software:

Hi Team,

Could you please suggest a part number for vref generator for ADC with below spec.

1.Input voltage 1.8V to 5V 

2.Output voltage 1.8V to 5V 

3.current rating 6mA  to 10mA or above.

Also it should be margined using Voltage margining DAC.

  • 0
    TI__Genius 9230 points

    Hello,

    Here are some precision voltage references that could fit your requirements:

    REF35: Accuracy of ±0.05%, Options from 1.024V to 5V, input voltage range of Vout + Vdo to 6V, output current rating ±10mA

    REF20: Accuracy of ±0.05%, Options from 1.25V to 4.096V, input voltage range of Vout + Vdo to 5.5V, output current rating ±20mA

    REF50E: Accuracy of ±0.025%, Options from 2.5V to 5V, input voltage range of Vout + Vdo to 42V, output current rating ±10mA

    Here are a couple of questions:

    1. Which ADC are you using? I can also give you a more specific recommendation based off of the precision of your ADC. 

    2. In terms of margining using a DAC, these voltage references to not have a feedback pin like many LDOs or DC/DC converters. Will that be an issue? The parts above all have extremely tight, exceptional accuracy ratings. 

    3. What is the application of the voltage reference here? Is it just for an ADC reference, or is there something else as well that is leading to higher current rating needs?

    Thanks,

    Jackson

  • 0 in reply to Jackson Wightman
    Intellectual 370 points

    Hi, 
    Thanks for the reply, Jackson. 

    1. I am using 12-bit SAR ADC from customer. 
    2. Yes, I need to margin the output of the Vref Generator. Since I have VT corner testing with 15% Voltage margin of the ADC reference voltage. 
    3. The application of Vref generator here is to give reference voltage to ADC only. The current rating for the ADC Vref is 5mA. So, I need Vref generator with current rating more than 6 mA to 10mA. 

    Yes, I found all the precision voltage references you suggested have constant Voltage reference. Please suggest a solution to this requirement. 
    Also please suggest a Voltage margining DAC with 16 bit or more. 
    Does DAC80508 support Voltage margining through LDO or SW Regulator? 

    Thanks

  • 0 in reply to Bhuvaneshwari K
    TI__Genius 9230 points

    Hello,

    We do not currently have a voltage reference that is adjustable for a margining application. I have requested to connect with you as a friend on E2E so we can discuss this in more detail over private message and so I can provide our best recommendation. Once you accept the request, we can continue this conversation. 

    I have looped in the DAC experts to add comments on DAC selection. 

    Thanks,

    Jackson

  • 0 in reply to Jackson Wightman
    TI__Mastermind 42273 points

    Hello, 

    Any voltage or current output DAC can be used to margin an LDO or switching regulator as long as the margining scheme looks something like this.

     

    Voltage Margining and Scaling Circuit with a Voltage Output Smart DAC (Rev. A)

    Voltage Margining and Scaling Circuit With Current Output Smart DAC (Rev. A)

    We have DACs designed for margining like DAC63204 that have high impedance when powered off as to not margin the LSO/regulator when off. Those max out at 12-bits, so DAC80508 would also work if you need 16-bits and 8-channels, just without the hi-z feature I mentioned. If you only need one channel, then you could consider the DAC80501.

    Best,

    Katlynne