½CLC412

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Application Introduction

Offered in an 8-pin package for reduced space and cost,

the wideband CLC412 dual current-feedback op amp

provides closely matched DC & AC electrical performance

characteristics making the part an ideal choice for

wideband signal processing. Applications such as

broadcast-quality video systems, IQ amplifiers, filter

blocks, high-speed peak detectors, integrators and

transimpedance amplifiers will all find superior

performance in the CLC412 dual op amp.

Feedback Resistor Selection

The loop gain and frequency response for a current-

feedback operational amplifier is determined largely by

Ω, a

gain of +2V/V and operation with

±5V power supplies

recommended value will peak the frequency response

and extend the bandwidth while increasing its value will

below its recommended value will cause overshoot,

ringing and eventually oscillation.

shows the CLC412’s frequency and phase response as

Ω). This plot shows that one particular value of

specified gain setting, i.e. 634

Ω at a gain of +2V/V.

Current-feedback op amps, unlike voltage-feedback op

amps, have a direct relationship between their frequency

and phase response to the value of the feedback resistor,

loop frequency response.

When configuring the CLC412 for other inverting or non-

inverting gains, it is necessary to adjust the value of the

feedback resistor in order to optimize the device’s

frequency and phase response. The two plots below

provide the means of selecting the recommended

feedback-resistor value for both inverting and non-

approaching a non-zero minimum (dashed line) at high

gains, which is characteristic of current-feedback op

amps, while the linear portion of the two (solid) curves

≥50Ω). This limitation is due to the desire to keep

resistance. Therefore, the resulting small-signal

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½CLC412

Figure 1

Figure 2

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