TS616 查看數據表（PDF） - STMicroelectronics

零件编号

产品描述 (功能)

生产厂家

TS616

Dual wide band operational amplifier with high output current

STMicroelectronics 

TS616

Increasing the line level using active impedance matching

Figure 70. Equivalent schematic - Ro is the synthesized impedance

Ro

Iout

Vi.Gi

1/2RL

Let us write Vo°=kVo, where k is the matching factor varying between 1 and 2. If we assume

that the current through R3 is negligible, we can calculate the output resistance, Ro:

Ro = ------k---V----o----R-----L------

RL + 2Rs1

After choosing the k factor, Rs will be equal to 1/2RL(k-1).

For a good impedance matching we assume that:

Equation 10

Ro = 12-- RL

From Equation 9 and Equation 10, we derive:

Equation 11

R-----2-- = 1 – 2----R-----s-

R3

RL

By fixing an arbitrary value of R2, Equation 11 becomes:

R3 = -------R-----2--------

1 – 2----R-----s-

RL

Finally, the values of R2 and R3 allow us to extract R1 from Equation 6, so that:

Equation 12

with GL the required gain.

R1 = ------------------------2----R-----2-------------------------

2

⎛

⎝

1

–

RR-----23--⎠⎞

GL

–

1

–

R-----2--

R3

Table 6. Components calculation for impedance matching implementation

GL (gain for the loaded system)

GL is fixed for the application requirements

GL= Vo/Vi= 0.5(1+2R2/R1+R2/R3)/(1-R2/R3)

R1

2R2/[2(1-R2/R3)GL-1-R2/R3]

R2 (= R4)

Arbitrarily fixed

R3 (= R5)

R2/(1-Rs/0.5RL)

Rs

0.5RL(k-1)

Load viewed by each driver kRL/2

33/37

Share Link: