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DRIVING A CAPACITIVE LOAD

+

_

THS6062

360 Ω

Input

Output

360 Ω

20 Ω

OFFSET VOLTAGE

THS6062

SLOS228D – JANUARY 1999 – REVISED OCTOBER 2007

Driving capacitive loads with high performance amplifiers is not a problem as long as certain precautions are

taken. The first is to realize that the THS6062 has been internally compensated to maximize its bandwidth and

slew rate performance. When the amplifier is compensated in this manner, capacitive loading directly on the

output will decrease the device's phase margin leading to high frequency ringing or oscillations. Therefore, for

capacitive loads of greater than 10 pF, it is recommended that a resistor be placed in series with the output of

the amplifier, as shown in Figure 45. A minimum value of 20

Ω should work well for most applications. For

example, in 75-

Ω transmission systems, setting the series resistor value to 75 Ω both isolates any capacitance

loading and provides the proper line impedance matching at the source end.

Figure 45. Driving a Capacitive Load

the corresponding gains. The following schematic and formula are used to calculate the output offset voltage:

Figure 46. Output Offset Voltage Model

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