Analog/RF IntgCkts

A RFIC designer's notes

dBm is the power ratio of measured power referenced to 1 milliwatt (mW) in decibels (dB).

$P_{o,mW} = \frac{V_{p}^2}{2R_L}/1mW$

(1) $\begin{eqnarray*} P_{o,dBm} &=& 10 ~ \log (P_{o,mW}) \\ &=& 20 ~ \log (V_p) - 10 ~ \log (2 R_L) + 30 \end{eqnarray*}$

A change in power ratio by a factor of 10 is a 10 dB change.
A change in power ratio by a factor of 2 is approximately a 3 dB change.

Voltage across 50 $\Omega$ load, at 10dBm –> 1V
For every 10x in voltage, power increases by 20dB.