REF2041: hi-Z output when disabled

Kyson Tan

Part Number: REF2041

Tool/software:

Hi,

We are using REF2041 to provide the reference voltage to AD5686R-EP. Since AD5686R has internal Vref enabled by default, we keep REF2041 EN=LOW (disabled) until we turn off AD5686R's internal Vref. According to the REF2041 datasheet, REF2041 output should be hi-Z when EN=LOW. However, we noticed that REF2041 is sinking current when AD5686R's internal Vref is enabled, so REF2041 output doesn't appear to be hi-Z? Are we misinterpreting something?

Thanks,

Kyson

1 month ago

0 Henry Naguski 1 month ago

TI__Intellectual 1700 points

Hi Kyson,

How much current is REF2041 sinking? REF20xx is able to sink up to 20mA, so there should be no issue if the current is less than 20mA.

-Henry

0 Kyson Tan 1 month ago in reply to Henry Naguski

Prodigy 120 points

There is no easy way to measure the current on our actual design, so I have a separate setup instead. Vcc=5V was applied to REF2041 with EN=GND, then I connected an external power supply at 2.5V 20mA to Vref pin. The current was clamped and the voltage dropped below 2.5V, indicating that the current Vref pin trying to sink is more than 20mA.

0 Henry Naguski 1 month ago in reply to Kyson Tan

TI__Intellectual 1700 points

Kyson,

We will investigate if there are any discrepancies in the datasheet in regards to the output impedance when disabled. The device will not be damaged as long as the current is less than 20mA.

-Henry

Power management

Power management forum

REF2041: hi-Z output when disabled