8

Application Circuit Description and Layout

Bill of Materials

Circuit

Symbol

Size

Description

Value

Manufacturer

Value

Manufacturer

C2

0402

0.1

mF

Murata

0.1

mF

Murata

C3

0603

2.2

mF

Murata

2.2

mF

Murata

C7

0402

10 pF

Murata

2.4 pF

Murata

C8

0402

2.4 pF

Murata

3.3 pF

Murata

L1

0402

2.2 nH

Murata

1.5 nH

Murata

C9

0402

NR

3.9 nH

Murata

Note: NR – not required in actual PCB design

Figure 25. Circuit diagram

Figure 26. Demoboard

For best performance, MGA-31489 is an input and output prematched driver amplifier. To bias MGA-31489, a +5V supply

(Vdd) is connected to the output pin through a RF choke, L1 (which isolates the inband signal from the DC supply).

The bypass capacitor helps to eliminate out of low band frequency signals from the power supply, C2 and C3. Blocking

capacitors are required for its input (C7) and output (C8), to isolate the supply voltage from preceeding and succeeding

circuits. C7 and L3 also play a part in input tuning to improve input return loss while L1 and C8 help in tuning output. The

recommended output tuning is for achieving best OIP3, while meeting typical specifications for other parameters.

14X

Input Matching Circuit

1.

Γ_mag = 0.117, G_ang = -137.3°

2.

Γ_mag = 0.081, G_ang = -33.3°

Output Matching Circuit

1.

Γ_mag = 0.291, G_ang = 58.0°

2.

Γ_mag = 0.325, G_ang = 100.9°

C11

C10

AVAGO

TECHNOLOGIES

IN

Jul 2009

REV 3.2

SOT-89

L3

C9

C7

OUT

C1

L1

L2

L4

C4

C6

C5

C8

C12

C3

C2

CTxx

14X

L1

RFout

C8

C7

RFin

Vdd

C3

C2

C9*

*Component indicated as C9 is to match with demoboard marking.