TSH300 STMicroelectronics, TSH300 Datasheet - Page 14

• Manufacturer Part Number: TSH300
• Description: Ultra low noise high-speed op-amp
• Manufacturer: STMicroelectronics

Specifications of TSH300

• Structure: VFA
• Input Noise: 0.65 nV/√Hz
• Slew Rate: 230 V/μs

Noise Measurements
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Noise Measurements
The noise model is shown in
Figure 45. 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: input voltage noise of the amplifier
iNn: negative input current noise of the amplifier
iNp: positive input current noise of the amplifier
eNo
2
=
eN
2
g
2
+
iNn
R3
R3
N3
N3
eNo
2
R1
R1
R2
=
2
Figure 45
V1
+
iN+
iN+
iN-
iN-
iNp
N1
N1
2
+
N2
N2
2
V2
2
R3
+
, where:
eN
eN
4kTR F
2
V3
4kTR
2
g
2
+
+
+
_
_
+
V4
2
R2
------- -
R1
+
V5
R2
R2
2
2
+
4kTR1 4kTR2 g
V6
2
+
(Equation 1)
output
output
+
HP3577
HP3577
Input noise:
Input noise:
8nV/ Hz
8nV/ Hz
2
4kTR3
(Equation 2)
TSH300