2N5087

http://onsemi.com

3

NOISE FIGURE CONTOURS

(VCE = –5.0 Vdc, TA = 25°C)

500k

100

200

500

1.0k

10k

5.0k

20k

50k

100k

200k

2.0k

1.0M

500k

100

200

500

1.0k

10k

5.0k

20k

50k

100k

200k

2.0k

1.0M

Figure 3. Narrow Band, 100 Hz

IC, COLLECTOR CURRENT (µA)

Figure 4. Narrow Band, 1.0 kHz

IC, COLLECTOR CURRENT (µA)

10

0.5 dB

BANDWIDTH = 1.0 Hz

Figure 5. 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

1.0 dB

2.0 dB

3.0 dB

20 30

50 70 100

200 300

500 700 1.0k

10

20 30

50 70 100

200 300

500 700 1.0k

500k

100

200

500

1.0k

10k

5.0k

20k

50k

100k

200k

2.0k

1.0M

20 30

50 70 100

200 300

500 700 1.0k

BANDWIDTH = 1.0 Hz

5.0 dB

0.5 dB

1.0 dB

2.0 dB

3.0 dB

5.0 dB

0.5 dB

1.0 dB

2.0 dB

3.0 dB

5.0 dB