TSH350_07 STMICROELECTRONICS [STMicroelectronics], TSH350_07 Datasheet - Page 14

• Manufacturer Part Number: TSH350_07
• Description: 550MHz low noise current feedback amplifier
• Manufacturer: STMICROELECTRONICS [STMicroelectronics]

Noise measurements
5
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Noise measurements
The noise model is shown in
●
●
●
Figure 32. Noise model
The thermal noise of a resistance R is
where F is the specified bandwidth.
On a 1Hz bandwidth the thermal noise is reduced to:
where k is the Boltzmann's constant, equal to 1,374.10-23J/°K. T is the temperature (°K).
The output noise eNo is calculated using the Superposition Theorem. However, eNo is not
the simple sum of all noise sources, but rather the square root of the sum of the square of
each noise source, as shown in
Equation 1
eN is the input voltage noise of the amplifier
iNn is the negative input current noise of the amplifier
iNp is the positive input current noise of the amplifier
R3
R3
N3
N3
eNo
R1
R1
=
Figure
iN+
iN+
iN-
iN-
N1
N1
V1
N2
N2
Equation
2
+
V2
32:
eN
eN
2
+
4kTR
1:
V3
4kTR F
+
+
_
_
2
+
V4
R2
R2
2
+
V5
2
+
V6
output
output
2
HP3577
HP3577
Input noise:
Input noise:
8nV/ Hz
8nV/ Hz
TSH350