Data Sheet

ADMV8420

Rev. B | Page 11 of 14

APPLICATIONS INFORMATION

TYPICAL APPLICATION CIRCUIT

Figure 26 shows the typical application circuit for the ADMV8420.

The RFIN and RFOUT pins are dc-coupled and external voltage

must not be applied. It is recommended to install 100 pF series

capacitors (C1 and C2) on the RF traces to prevent any prestage

or poststage interaction with the filter.

shown with 100 pF as the typical value. However, the selection

of the C3 capacitor is determined based on the system design

criteria for phase noise and tuning speed. That is, there is a

baseband noise characteristic for a particular control voltage,

which can translate into additive phase noise within the filter.

Minimizing baseband noise on the control voltage can be done

by capacitive means at the expense of voltage rise time, which

impacts the tuning speed of the filter. Carefully consider the

control voltage baseband noise and rise time performance to

ensure that system performance metrics are met.

C2

100pF

C1

100pF

C3

100pF

RFOUT

RFIN

2

1

3

4

5

6

18

17

16

15

14

13

ADMV8420

PACKAGE

BASE

GND

Figure 26. Typical Application Circuit