When calculating PLL loop filter values, one need to know the phase detector gain in mA/Hz for a "charge pump phase detector". Very often the charge pump current is defined if you are using a synthesiser chip. My question is therefore: What is the relationship between phase detector gain in mA/Hz and charge pump current in mA? I often see in literature that they define the ratio between phase detector gain and charge pump current as a 1:1 ratio. But is this really correct?
Charge pump vs. phase detector gain for a PLL
Aug 17, 2006
2 Replies
That is not correct... it is mA/radian
Nope. Read the data sheet more carefully.
...Jim Thompson
| James E.Thompson, P.E. | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC\'s and Discrete Systems | manus |
| Phoenix, Arizona Voice:(480)460-2350 | |
| E-mail Address at Website Fax:(480)460-2142 | Brass Rat |
| http://www.analog-innovations.com | 1962 |
I love to cook with wine. Sometimes I even put it in the food.
Yes. the gain is current / phase delta
very often the data sheet will give you the full scale current output where full scale is +2pi radians (+360 degrees) and -2pi radians (-360 degrees).
Mark
Join the Discussion
Have something to add? Share your thoughts — no account required.
Didn't find your answer?
Ask the community — no account required