REF3025: Reverse current on output for REF30XX

Songzhen Guo

Part Number: REF3025
Other Parts Discussed in Thread: REF3033, , REF3125, REF3325, REF3225, REF3425, REF1933, REF1925

Hi Team,

REF3025 and REF3033 was used in customer's project.There is a problem when REF30XX is used for offset voltage.

Here is the schematic on customer site:

When Vin is less than 2.5V, REF3025 output a current, it's OK;

When Vin is bigger than 2.5V(Sometimes 5~7V), the current flow to REF3025. Is it OK for REF30525? How much current can REF3025 hold in this application?

Songzhen Guo

over 4 years ago

0 Marcoo Z over 4 years ago

TI__Mastermind 19370 points

Hi BR,

I can help you with this request. What are the sizes on R1 and R2?

The REF3025 cannot sink current and maintain proper regulation. I would recommended a REF3125 or REF3325 which are P2P which can sink current.

0 Songzhen Guo over 4 years ago in reply to Marcoo Z

TI__Intellectual 2770 points

Hi，

Thanks so much for your help.

R1,R2 is determined by the sink current of reference output voltage. REF3225 seems suit for customer.

REF1933AIDDCT also need evaluate for this application, Could you check it for us? Thanks.

Songzhen Guo

0 Marcoo Z over 4 years ago in reply to Songzhen Guo

TI__Mastermind 19370 points

Hi Songzhen,

I would highly recommend to use the REF3425 over the REF3225 as the REF3225 is NRND.

The REF1933 can also work for this application but it does have a 3.3V/1.65V rail instead of a 2.5V rail.

If you need REF19xx in 2.5V it will be the REF1925.

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REF3025: Reverse current on output for REF30XX