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Page 4 of 8

Issue A

LANSDALE Semiconductor, Inc.

ML1490

Figure 11. Noise Figure versus

Source Resistance

Figure 12. Noise Figure versus

AGC Gain Reduction

Figure 13. Harmonic Distortion versus AGC Gain

Reduction for AM Carrier (For Test Circuit, See Figure 14)

Figure 14. 10.7 MHz Amplifier Gain

55 dB, BW

100 kHz

RS, SOURCE RESISTANCE (Ω)

0

2.0

4.0

6.0

8.0

10

12

14

16

18

20

100

200

400 600

1.0 k

2.0 k

4.0 k

10 k

f = 30 MHz

f = 60 MHz

f = 105 MHz

VCC = 12 Vdc

GR, GAIN REDUCTION (dB)

0

5

10

15

20

25

30

35

40

0

–10

–20

–30

–40

–50

–60

–70

–80

f = 30 MHz

Test circuit has tuned input

providing a source resistance

optimized for best noise figure.

BW = 1.0 MHz

GR, GAIN REDUCTION (dB)

0

5.0

10

15

20

25

30

35

40

0

10

20

3040

5060

7080

f = 10.7 MHz

Modulation: 90 % AM, fm = 1.0 kHz

Load at Pin 8 = 2.0 k

Ω

EO = peak–to–peak envelope of

modulated 10.7 MHz carrier at Pin 8

760 mVpp

240 mVpp

EO = 2400 mVpp

Toroid core (–124 pF)

L1 = 24 turns, #22 AWG wire

on a T12–44 micro metal

L2 = 20 turns, #22 AWG wire

on a T12–44 micro metal

Toroid core (–100 pF)

0.002

0.002

0.002

L1

+12 Vdc

RFC

L2

36 pF

1

2

3

4

5

6

7

8

50

Ω Load

82 pF

10.7 MHz

(50

Ω Source)

VAGC

5.6 k

50–150 pF

ML1490

Legacy Applications Information