AN 074 Rev E

6 / 24

19-November-2002

Applications Note No. 074

Silicon Discretes

Figure 8. Schematic Diagram of Complete BGA430 + BGB540 LNB I.F. Amplifier

C1

22 pF

C3

22 pF

R2

18 ohms

R1

300 ohms

R3

300 ohms

C2

22 pF

IC1

MMIC

BGA430

B6HF

C4

1.5 pF

3 dB Pad

Purpose of Pad :

1) Gain Reduction (especially at lower end of band)

2) Provide good input termination for HPF

High Pass Filter

Butterworth

f

Purpose of HPF :

Adjust overall gain

slope of cascade

C5

22 pF

L2

4.7 nH

R5

43 ohms

C6

22 pF

+5.0 Volts

22.9 mA

17.0 mA

RF Input

950 - 2150 MHz

IC2

MMIC

BGB540

B6HFe

RF Output

(Total Current Draw = 39.9 mA)

Notes:

1) Using C4 as both a DC block and as a Highpass Filter element enables the elimination of one capacitor

2) Bias current of Stage 2 (BGB540 MMIC) can be increased or decreased to vary overall output compression point

3) Stage 1 (BGA430) requires careful attention to proper grounding !

J1

J2

J3

L1

3.0 nH

R4

2K

(R Bias)

R6

30 ohms

1.55 mA

15.45 mA

Black Rectangles = Microstriplines on PCB

(PCB Track or Trace)

Figure 9. Bill Of Material (BOM) for Complete BGA430 + BGB540 LNB I.F. Amplifier

REFERENCE

DESIGNATOR

VALUE

MANUFACTURER

CASE SIZE

FUNCTION

C1, C3, C5

22 pF

VARIOUS

0402

DC BLOCK

C2, C6

22 pF

VARIOUS

0402

RF BYPASS

C4

1.5 pF

VARIOUS

0402

DC BLOCK & HIGH PASS FILTER

FUNCTION

L1

3.0 nH

MURATA LQP15M

0402

HIGH PASS FILTER FUNCTION

L2

4.7 nH

MURATA LQP15M

0402

“RF CHOKE” / DC FEED FOR BGB540,

INFLUENCES BGB540 OUTPUT MATCH

R1, R3

300 OHMS

VARIOUS

0402

FOR 3 dB ATTENUATOR PAD

R2

18 OHMS

VARIOUS

0402

FOR 3 dB ATTENUATOR PAD

R4

2K

VARIOUS

0402

DEVICE CURRENT)

R5

43 OHMS

VARIOUS

0402

RF STABILITY AND OUTPUT MATCH FOR

IC2 (BGB540)

R6

30 OHMS

VARIOUS

0402

DROP 5V SUPPLY TO ~ 4.5V. MAY BE

OMITTED IF MAXIUM RATINGS OF IC2

ARE NOT EXCEEDED.

IC1

-

INFINEON TECHNOLOGIES

SOT363

BGA430 Si MMIC, B6HF PROCESS

IC2

-

INFINEON TECHNOLOGIES

SOT343

BGB540 ACTIVE BIASED TRANSISTOR

MMIC, B6HFe PROCESS

J1, J2

-

JOHNSON 142-0701-841

-

RF INPUT / OUTPUT CONNECTOR

J3

-

AMP 5 PIN HEADER

MTA-100 SERIES

P/N 640456-5 OR

641215-5 (GOLD PLATING)

-

DC CONNECTOR

PINS 1, 2, 4, 5 = GROUND