ADL5801

Rev. 0 | Page 14 of 20

RFIP

T3

C8

C9

RFIP

ADL5801

GND

GND

RFIN

17

16

15

14

Figure 29. RF Interface

GND

LOIP

T2

C4

C5

LOIP

LOIN

GND

GND

ADL5801

GND

1

2

3

4

5

6

Figure 30. LO Interface

Table 4. Suggested Components for the RF and LO Interfaces

RF and LO

Frequency

T1, T3, T5

C8, C9

C4, C5

900 MHz

Mini-Circuits® TC1-1-13M+

5.6 pF

100 pF

1900 MHz

Mini-Circuits TC1-1-13M+

5.6 pF

100 pF

2500 MHz

Mini-Circuits TC1-1-43+

2 pF

8 pF

IF PORT

The IF port features an open-collector, differential output

interface. It is necessary to bias the open collector outputs using

one of the schemes presented in Figure 31 and Figure 32.

Figure 31 shows the use of center-tapped impedance transformers.

The turns ratio of the transformer should be selected to provide

the desired impedance transformation. In the case of a 50 Ω

load impedance, a 4:1 impedance ratio transformer should be

used to transform the 50 Ω load into a 200 Ω differential load at

the IF output pins.

Figure 32 shows a differential IF interface where pull-up choke

inductors are used to bias the open-collector outputs. The

shunting impedance of the choke inductors used to couple dc

current into the mixer core should be large enough at the IF

frequency of operation not to load down the output current

before it reaches the intended load. Additionally, the dc current

handling capability of the selected choke inductors must be at

least 45 mA.

The self-resonant frequency of the selected choke inductors

must be higher than the intended IF frequency. A variety of

suitable choke inductors is commercially available from

manufacturers such as Coilcraft® and Murata. An impedance

transforming network may be required to transform the final

load impedance to 200 Ω at the IF outputs.

NC

GND

C50

C13

L3

R3

R2

T1

T5

T8

VPOS

IFOP

GND

IFON IFOP

23

22

21

20

19

ADL5801

Figure 31. Biasing the IF Port Open-Collector Outputs

Using a Center-Tapped Impedance Transformer

NC

GND

C20

C19

C13

L3

L1

L2

R3

R2

T1

T5

T8

VPOS

VPOS

GND

IFON IFOP

23

22

21

20

19

ADL5801

IMPEDANCE

TRANSFORMING

NETWORK

Figure 32. Biasing the IF Port Open-Collector Outputs

Using Pull-Up Choke Inductors