Test conditions

TSH80, TSH82

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DocID009413 Rev 10

4

Test conditions

4.1

Layout precautions

To make the best use of the TSH8x circuits at high frequencies, some precautions have to

be taken with regard to the power supplies.

•

In high-speed circuit applications, the implementation of a proper ground plane on both

sides of the PCB is mandatory to ensure low inductance and low resistance common

return.

•

Power supply bypass capacitors (4.7 µF and ceramic 100 pF) should be placed as

close as possible to the IC pins in order to improve high frequency bypassing and

reduce harmonic distortion. The power supply capacitors must be incorporated for both

the negative and positive pins.

•

All inputs and outputs must be properly terminated with output resistors. Thus, the

amplifier load is resistive only and the stability of the amplifier is improved.

All leads must be wide and must be as short as possible, especially for op-amp inputs

and outputs, in order to decrease parasitic capacitance and inductance.

•

Time constants result from parasitic capacitance. To reduce time constants in lower-

gain applications, use a low feedback resistance (under 1 k

Ω).

•

Choose the smallest component size possible (SMD).

•

On the output, the load capacitance must be negligible to maintain good stability. Place

ca serial resistance as close as possible to the output pin to minimize the effect of the

load capacitance.

Figure 32. CCIR330 video line