Datasheet

LTC6406
18
6406fc
APPLICATIONS INFORMATION
driven differentially it will appear at each fi ltered output
as a single-ended capacitance of twice the value. To halve
the fi lter bandwidth, for example, two 3.9pF capacitors
could be added (one from each fi ltered output to ground).
Alternatively, one 1.8pF capacitor could be added between
the fi ltered outputs, which also halves the fi lter bandwidth.
Combinations of capacitors could be used as well; a three
capacitor solution of 1.2pF from each fi ltered output to
ground plus a 1.2pF capacitor between the fi ltered outputs
would also halve the fi lter bandwidth (Figure 8).
Figure 7. LTC6406 Filter Topology Modifi ed for 2x Filter
Bandwidth (Two External Resistors)
Figure 8. LTC6406 Filter Topology Modifi ed for 1/2x Filter
Bandwidth (Three External Capacitors)
–
+
7 8
14 13
12
V
–
9
V
–
V
–
V
–
6406 F07
LTC6406
FILTERED OUTPUT
(1.7GHz)
+OUTF
–OUTF
49.9Ω
49.9Ω
1.25pF
1.25pF
50Ω
50Ω
1.25pF
+OUT +OUTF
–OUT –OUTF
–
+
7 8
14 13
12
V
–
9
V
–
V
–
V
–
6406 F08
LTC6406
FILTERED OUTPUT
(425MHz)
1.25pF
1.25pF
50Ω
50Ω
1.25pF
1.2pF
1.2pF
1.2pF
+OUTF
–OUTF
+OUT +OUTF
–OUT –OUTF