# LTM8074 To find the average output voltage tolerance

Hi team,

We want to design a power supply with an accuracy of 5V ± 2%.

We are considering excluding transient voltage fluctuations such as load regulation and line regulation.

I think the LTM8074 is just right for us because the LTM8074 meets the input voltage and load current specifications.

Therefore, I would like to confirm whether the output voltage is within 5V ± 2%.

The data sheet has the following formula:

RFB = 192.73/ (VOUT – 0.774)

From this formula, VOUT can be calculated as follows.

VOUT = 192.73 / RFB + 0.774

The above 0.774 is the FB terminal voltage, and the tolerance seems to be ± 1.8%.

192.73 is the resistance on the top side of the FB in the module.

Does the resistance tolerance of 192.73kohm affect when determining the VOUT tolerance?

I think that if this built-in resistance varies, the FB voltage will also be affected.

In other words, I think that the FB voltage tolerance is listed including that.

It is believed that the tolerance calculation is affected only by the FB terminal voltage tolerance and RFB tolerance, not by the built-in resistance of 192.73kohms.

Is it correct?

If not, can you tell me how to calculate the tolerance?

Also, I want to know whether LTM8074 fits in 5V ± 2%.

Best regards,

T-yoshi

Parents
• Hi team,

Any update on this issue?

We don't have time to design, so we have to decide on a device right away.

Please advise if the DC output accuracy can achieve 5V ± 2%.

Best regards,

T-yoshi

• Hi Yoshi, the voltage at FB tolerance is for the internal reference voltage. The internal resistor has 1% tolerance, which needs to be considered with the RFB tolerance.