TLV772: Vin 3v ,Vout 0.8v

Hello there,

To calculate your resistor values, the formula is Vout = Vfb ( 1 + (R1/R2)). For this device, Vfb is 0.6V and you want Vout = 0.8V. Solving for R1, R1 is 0.333 x R2. 

It should also be noted that the resistors can not be to large as it could lead to some unexpected behaviors. To calculate this maximum, we use your output voltage divide by the max feedback current *100 as a good measure to ensure that the device operates as intended. For this device the max feedback current is 10nA.

Rtotal = (Vout/ Ifb*100) = (0.8 / 10nA * 100) = 80kΩ.

This means that the sum of R1 + R2 can go up to 80kΩ to ensure the device operates properly. 

To summarize:

To get your required output voltage, you have to meet these specs based on your application:

R1 = 0.333 x R2

R1 + R2 ≤ 80kΩ

Hope this helped,

Jorge