RHF310 STMICROELECTRONICS [STMicroelectronics], RHF310 Datasheet - Page 13

• Manufacturer Part Number: RHF310
• Description: Rad-hard 400 ?A high-speed operational amplifier
• Manufacturer: STMICROELECTRONICS [STMicroelectronics]

RHF310
4
Noise measurements
The noise model is shown in
●
●
●
Figure 24. Noise model
The thermal noise of a resistance R is:
where ΔF is the specified bandwidth, and k is the Boltzmann's constant, equal to
1,374.10-23J/°K. T is the temperature (°K).
On a 1 Hz bandwidth the thermal noise is reduced to:
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: input voltage noise of the amplifier.
iNn: negative input current noise of the amplifier.
iNp: positive input current noise of the amplifier.
eNo
=
R3
N3
V1
R1
2
+
Figure
iN
iN
V2
N1
Doc ID 15577 Rev 3
+
-
Equation
N2
2
+
V3
24.
eN
2
+
V4
1.
4kTRΔF
+
4kTR
_
2
+
V5
R2
2
+
V6
2
Output
HP3577
Input noise:
8 nV/√Hz
Noise measurements
AM00837
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