BBVA-A VMOS Input Broadband Amplifier

revision date: 5 NOV 1999

 

Mark Connelly, WA1ION Billerica, MA, USA

web: http://home.comcast.net/~markwa1ion/exaol1/weblink.htm

 

The BBVA-A broadband amplifier is a good choice for low-noise amplification in the 150 to 6500 kHz frequency range. A VMOS type FET, the Vishay-Siliconix VN10KM, is used as the gain device. The input impedance of the amplifier is about 300 to 600 ohms and its output works well into 50 or 75 ohm loads. For maximum power transfer to the amplifier's input from a 50 or 75 ohm source, a 1:4 step-up transformer, Mini-Circuits T4-6T-X65, is recommended. Gain is approximately 20 dB. Outputs of at least 1.5 Vrms (4.2 vpp or +16.5 dBm) into 50 ohms should be achievable before distortion becomes excessive. The supply should be regulated at +10 VDC if possible. Operation at higher voltages will not improve gain or intercept point greatly; further it will require the transistor to be heat-sinked to prevent thermal failure.

GIF drawing files may be downloaded and subsequently viewed and printed at correct scaling by using a program such as Microsoft Photo Editor or Adobe Photoshop.

Figure 1: Schematic (fits one page)

Figure 1: Schematic (high resolution)

Figure 2: Assembly (fits one page)

Figure 2: Assembly (high resolution)

BBVA-A VMOS Input Broadband Amplifier Card parts list

Item

Designator

Description/Value

Vendor

Vendor Stock #

QTY

1

-

perfboard:1.0"X1.4"

RS

276-1396 (cut)

1

2

C 1,2,3

capacitor, 0.1 uF

MOU

539-CK05104K

3

3

D 1

diode, 1N4003

MOU

592-1N4003A

1

4

H 1

screw, 4-40 X .25"

MOU

572-01880

1

5

H 1

spacer, 4-40 X .5"

MOU

534-1450C

1

6

H 1

solder lug, #4

MOU

534-7311

1

7

P 1-5

flea-clip,.042"hole

MOU

574-T42-1/100

5

8

Q 1

FET, VN10KM

RSC

900-5530

1

9

R 1

resistor, 47 ohm

CS

RA47

1

10

R 2

resistor,2.2 megohm

CS

RA2.2M

1

11

R 3

resistor,4.7 megohm

CS

RA4.7M

1

12

R 4

resistor, 680 ohm

CS

RA680

1

13

R 5

resistor, 4.7 ohm

CS

RA4.7

1

14

R 6

resistor, 10 ohm

CS

RA10

1

15

RFC 1

inductor, 1.8 mH

MOU

434-05-182J

1

Misc. items: hook-up wire, buss wire, solder "AS REQUIRED"

Vendor Codes

CS

Circuit Specialists = http://www.cir.com

MOU

Mouser Electronics = http://www.mouser.com

RS

Radio Shack (retail) = http://www.radioshack.com

RSC

RadioShack.com (on-line, ex-Tech America) = http://www.radioshack.com



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