LTC5556

24

Rev 0

For more information www.analog.com

Figure 17. 5.6GHz to 7.2GHz Input Matching with Wideband IF Output Match

5.6GHz to 7.2GHz RF Application with Wideband IF

The LTC5556’s RF inputs are optimized for operation up

to 6GHz, but may be used up to 8GHz with degraded

performance. Figure 17 shows an example where the RF

input is matched from 5.6GHz to 7.2GHz and the IF out-

put is matched for wideband operation up to 800MHz.

Figure 18. Measured Performance for 5.6GHz to 7.2GHz Downconverter with Wideband IF Output

5556 F17

½ LTC5556

LO

RF1

RF1

(50)

1.1pF

0.3pF

680nH

680nH

IF

12nH

12nH

10nF

IF1

(100 DIFF)

10nF

18nH

1nF

18nH

680nH

680nH

1nF

The measured performance is summarized in Figure 18,

where the RF input is swept from 6.1GHz to 6.9GHz, with

a fixed 6.03GHz LO, resulting in a wideband 70MHz to

870MHz IF output, centered at 470MHz.

3dB

6dB

9dB

12dB

15dB

0dB

0dB

15dB

IIP3

IF = 470MHz

LOW SIDE LO

RF FREQUENCY (GHz)

5.5 5.7 5.9 6.1 6.3 6.5 6.7 6.9 7.1 7.3

–9

–6

–3

0

3

6

9

12

15

18

21

24

5556 F18a

IIP3

NF

IF = 470MHz

LOW SIDE LO

FULL PWR

RED PWR

IF ATTENUATION (dB)

0

2

4

6

8

10

12

14

16

–9

–6

–3

0

3

6

9

12

15

18

21

3

6

9

12

15

18

21

24

27

30

33

5556 F18b

0dB

RF = 6.1GHz to 6.9GHz

LO = 6.03GHz

3dB

6dB

9dB

12dB

15dB

IF FREQUENCY (MHz)

70 170 270 370 470 570 670 770 870

–10

–8

–6

–4

–2

0

2

4

6

8

10

5556 F18c

Conv Gain and IIP3 vs RF Frequency

and IF Attenuation (3dB Steps)

6.5GHz Conv Gain, IIP3, and SSB NF

vs IF Attenuation (0.5dB Steps)

Conv Gain vs IF Frequency and

Attenutation, Swept RF/Fixed LO

APPLICATIONS INFORMATION