TS616 STMicroelectronics, TS616 Datasheet - Page 24

• Manufacturer Part Number: TS616
• Description: Multi video line driver (6 lines) and ADSL driver
• Manufacturer: STMicroelectronics

Specifications of TS616

• Low Noise: 2.5nV/√Hz
• High Output Current: 420mA
• High Slew Rate: 420V/µs
• -3db Bandwidth: 40MHz @ gain = 12dB on 25

Noise measurements
7.1
24/37
The output noise eNo is calculated using the Superposition Theorem. However eNo is not
the 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
Equation 2
The input noise of the instrumentation must be extracted from the measured noise value.
The real output noise value of the driver is:
Equation 3
The input noise is called the Equivalent Input Noise as it is not directly measured but is
evaluated from the measurement of the output divided by the closed loop gain (eNo/g).
After simplification of the fourth and the fifth term of
Equation 4
Measurement of eN
If we assume a short-circuit on the non-inverting input (R3=0),
Equation 5
In order to easily extract the value of eN, the resistance R2 will be chosen as low as
possible. On the other hand, the gain must be large enough:
●
●
●
R1=10
Equivalent input noise: 2.57 nV/ Hz
Input voltage noise: eN=2.5 nV/ Hz
=
eN
R2=910
2
No
No
g
2
2
No
+
=
=
iNn
+
=
eN
eNo
V1
Equation
R2
------- -
R1
2
2
eN
R3=0, Gain=92
2
+
=
R2
2
g
2
V2
2
2
+
4kTR1
g
2
+
Measured
iNn
2
+
iNp
1.
+
V3
iNn
2
2
2
+
+
R2
2
4kTR2
R3
V4
2
R2
2
2
2
+
–
+
iNp
2
V5
g
instrumentation
+
+
2
g
2
2
Equation 2
1
+
+
+
R3
4kTR2
V6
g
R2
------- -
R1
2
2
4kTR2
2
g
2
4kTR3
Equation 4
we obtain:
+
2
1
+
R2
------- -
R1
becomes:
2
4kT
TS616