BCW72LT1

3

Motorola Small–Signal Transistors, FETs and Diodes Device Data

NOISE FIGURE CONTOURS

(VCE = 5.0 Vdc, TA = 25°C)

Figure 5. Narrow Band, 100 Hz

IC, COLLECTOR CURRENT (µA)

500 k

Figure 6. Narrow Band, 1.0 kHz

IC, COLLECTOR CURRENT (µA)

10

2.0 dB

BANDWIDTH = 1.0 Hz

Figure 7. Wideband

IC, COLLECTOR CURRENT (µA)

10

10 Hz to 15.7 kHz

Noise Figure is defined as:

NF

+ 20 log10

en2 ) 4KTRS ) In

2RS2

4KTRS

1 2

= Noise Voltage of the Transistor referred to the input. (Figure 3)

= Noise Current of the Transistor referred to the input. (Figure 4)

= Boltzman’s Constant (1.38 x 10–23 j/

°K)

= Temperature of the Source Resistance (

°K)

= Source Resistance (Ohms)

en

In

K

T

RS

3.0 dB 4.0 dB

6.0 dB

10 dB

50

100

200

500

1 k

10 k

5 k

20 k

50 k

100 k

200 k

2 k

20

30

50 70 100

200 300

500 700

1 k

10

20

30

50 70 100

200 300

500 700

1 k

500 k

100

200

500

1 k

10 k

5 k

20 k

50 k

100 k

200 k

2 k

1 M

500 k

50

100

200

500

1 k

10 k

5 k

20 k

50 k

100 k

200 k

2 k

20

30

50

70

100

200 300

500 700

1 k

BANDWIDTH = 1.0 Hz

1.0 dB

2.0 dB

3.0 dB

5.0 dB

8.0 dB

1.0 dB

2.0 dB

3.0 dB

5.0 dB

8.0 dB