TS616 STMicroelectronics, TS616 Datasheet - Page 32

• 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

Increasing the line level using active impedance matching
32/37
First let’s consider the unloaded system. We can assume that the currents through R1, R2
and R3 are respectively:
As Vo
The gain, for the loaded system is given by
Equation 6
The system shown in
as the internal impedance of the system. From this, the output voltage becomes:
Equation 7
where Ro is the synthesized impedance and Iout the output current.
On the other hand Vo can be expressed as:
Equation 8
By identification of both
Rs1 = Rs2 = Rs:
Equation 9
°
equals Vo without load, the gain in this case becomes:
Figure 70
Vo
Equation 7
GL
Vo
=
=
Vi 1
-----------------------------------------------
=
G
Vo withload
------------------------------------ -
is an ideal generator with a synthesized impedance acting
=
ViG
Ro
2Vi
-------- -
R1
+
1
Vo noload
------------------------------- -
and
2R2
---------- -
Vi
–
R1
=
R2
------- -
R3
–
--------------------------- and
---------------- -
1 R2
Vi Vo
Vi
Equation
Ro
+
Rs
–
–
R2
R2
------- -
R3
------- -
R3
Equation
=
Iout
–
1
-- -
2
=
Rs1Iout
----------------------
1
----------------------------------- -
1
1
----------------------------------- -
8, the synthesized impedance is, with
+
–
+
1
2R2
---------- -
R2
------- -
R3
R1
----------------------- -
1
2R2
---------- -
–
Vi
R1
6:
–
R2
------- -
R3
R3
+
R2
------- -
R3
+
Vo
+
R2
------- -
R3
R2
------- -
R3
TS616