# TLVH431 biasing resistance and output voltage calculation ?

#### mishra87

Joined Jan 17, 2016
741
Hi All,

I want to give very precise voltage reference to MCU(STM32F4) Vref+ pin for my measurement.
So could any body explain calculation for me.
Vin = 5V
Vout = 3.3V

R_supply : ?
R_upper : ?
R_lower : ?
Vout : ?

Regards

#### mishra87

Joined Jan 17, 2016
741

#### crutschow

Joined Mar 14, 2008
24,968
I don't understand the IREF = 1mA in the table, as the data sheet only lists a maximum of 0.5μA.

But you obviously didn't use that value in your table calculations, since those values for R1 and R2 seem correct for the low (or zero) value of IREF.

How "very precise" do you need the voltage?

Last edited:

#### mishra87

Joined Jan 17, 2016
741
I don't understand the IREF = 1mA in the table, as the data sheet only lists a maximum of 0.5μA.

But you obviously didn't use that value in your table calculations, since those values for R1 and R2 seem correct for the low (or zero) value of IREF.

How "very precise" do you need the voltage?
0 5% accuracy . I want .

I gave someheadroon 0.5uA to 1mA.
I took some headroom for these calculation.

#### Dodgydave

Joined Jun 22, 2012
9,162
Hi All,

I want to give very precise voltage reference to MCU(STM32F4) Vref+ pin for my measurement.
So could any body explain calculation for me.
Vin = 5V
Vout = 3.3V

R_supply : ?
R_upper : ?
R_lower : ?
Vout : ?

Regards
Any resistors with a ratio of 0.32 for R1/R2 = 3.3V out