8

LT5500

5500f

LO

MIX_IN

LNA_OUT

LNA_IN

RF OUT

LNA_GND

GND

GS

EN

LT5500

MIX_GND

*REFER TO FIGURE 6 FOR POWER SUPPLY

PINS BYPASSING RECOMMENDATION

5500 F03

••

T1

IF

RF

C4

100pF

100pF

C17

L3

L5

4.7nH

L7

IF OUTPUT

RF INPUT

L4

100pF

100pF

L2

GAIN

SELECT

ENABLE

LO INPUT

MIXER RF

INPUT

C2

100pF

APPLICATION DEPENDENT

COMPONENT VALUES

RF INPUT

L4

L2

L3

C4

C17

L9

C23

L7

T1

1.8GHz

4.7nH

12nH

4.7nH

220pF

10pF

5.6nH

1.8pF

280MHz IF OUTPUT

2.5GHz

2.7nH

4.7nH

1.8nH

220pF

10pF

2.7nH

1.5pF

BIAS

C23

L9

15nH

TC8-1 MINI-CIRCUITS

*

Figure 3. Simplified Test Schematic for 1.8GHz and 2.5GHz Applications

An IF transformer can be used to create a single-ended

output. The additional discrete components necessary to

achieve a 50Ω match are tabulated in Figure 3. Alterna-

tively, the discrete solution shown in Figure 4 can be used

to perform differential to single-ended conversion. For

best LO and RF signal suppression at the IF output, a

transformer should be used. If it is desirable to reduce the

gain of the mixer, a resistor between the IF outputs can be

used.

LO Buffer

The LO inputs can be driven either differentially or single

ended. A single-ended configuration is shown along with

example component values in Figure 3. Optionally, the LO

can be driven differentially as shown in Figure 5.

C14

C12

L10

L11

100pF

5500 F04

13

12

50Ω

IF OUTPUT

LT5500

IF OUTPUT

L10, L11

C12

C14

280MHz

27nH

3.3pF

2.2pF

Figure 4. Alternative Mixer IF Output Matching

Figure 5. Optional Transformer-Based Differential LO Drive

L3

5500 F05

TX1

4:1

LO INPUT

L3

TX1

2.22GHz

3.3nH

TOKO-BF4

LO INPUT

19

18

LT5500