ST-4 Datasheet, PDF (1/1 Pages) Micronetics, Inc. – MINI-NOISE DIODES 10 KHZ TO 3 GHZ

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http://www.micronetics.com/Noise_Diode_SMT/Surface_Mount_Microwave_ST4.pdf
ST-4 MINI-NOISE DIODES
10 KHZ TO 3 GHZ
DESCRIPTION
Micronetics' ST-4 Diode with
its small, surface mount SOT-
23 package are ideally suited
for medium and high volume
production circuits. Their
Gaussian wideband highly
stable noise characteristics
make them ideal for several
applications from built-in
Microwave receiver calibra-
tion, to A/D dithering.
MINI -NOISE DIODE SPECIFICATIONS
MODEL
NUMBER
ST-4
Band:
Band:
FREQUENCY
ENRdB BIAS
10 kHz – 3 GHz
4mA
10 kHz – 500 MHz 34 dB (min)
500 MHz – 3 GHz 29 dB (min)
TYP DC+ Bias
8.5
PIN OPTIONS
Option #1:
Pin 1 - Ground
Pin 2 - Bias/Noise Output
Pin 3 - N/C
(1) ENR is measured in a 50 ohm system.
(2) Spectral response varies with bias current. Differing levels of ENR
and in-band flatness can be realized by adjusting bias current.
Application Notes:
Microwave Receiver Calibration: There are two built-in tests commonly
performed with noise. One is a straightforward noise figure or noise tem-
perature test. The other is a spectral calibration, which uses the broad-
band flat frequency output of the noise to test frequency response. This
test typically requires a higher amplitude noise signal than the noise
temperature test and may require a gain stage to boost the signal.
A/D Converter Dithering Circuit: Sensitivity can be increased significantly
when summing low frequency noise (in the range of 10 KHz - 5 MHz
depending on the A/D converter) with the IF frequency prior to the input
of the A/D Converter. The noise signal amplitude needs to be boosted
significantly from the output of the noise diode. Designers usually take
two approaches, one at 50 ohm in which standard radio frequency gain
blocks are used and the noise is combined with the signal at 50 ohms.
The signal +noise is then converted to high impedance prior to being fed
into the A/D. The second uses op amps to boost the noise signal and the
noise is summed with the signal all at high impedance and fed directly
into the A/D.
Encryption: In this usage, the Gaussian output of the noise is used to
generate random numbers by sampling the voltage of the noise using an
A/D converter. Frequency requirements are usually a function of the sys-
tem parameters of the random numbers desired. As with the dithering cir-
cuit, the noise amplitude form the diode needs to be boosted with gain.
These circuits are typically high impedance.
See style code Z on our web-
site for additional outline
details.
http://www.micronetics.com
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WEB: WWW.MICRONETICS.COM