AN3395

Rcg resistance selection

Doc ID 018779 Rev 1

5/11

2.4

Selection of Rcg (example)

According to Equation 1, the maximum limit of Rcg is obtained, that is Rcg < 36 m

Ω.

Let's choose a 33 m

Ω resistor.

Power rating = 33 m

Therefore, a 1/8 W (125 mW) resistor is sufficient, however, it is possible to use a 20 m

Ω

resistor that will only dissipate 45 mW instead of 74 mW.

A 20 m

Ω resistor is optimal because 20 mΩ x 2.2 A = 44 mV, which is acceptable in

comparison with the full scale range of 80 mV.