Figure 3: Single Supply Circuit

Power Dissipation

The power dissipation of an amplifier can be described

in two conditions:

(No Load Condition)

(with Load Condition)

The following steps can be taken to determine the

power consumption of the CLC436:

1. Determine the quiescent power

2. Determine the RMS power at the output stage

3. Determine the total RMS power

The maximum power that the package can dissipate at

a given temperature is illustrated in the

Power Derating

plot in the

Typical Performance Characteristics

section. The power derating curve for any package

can be derived by utilizing the following equation:

θ

ambient, for a given package in °C/W

Layout Considerations

A proper printed circuit layout is essential for achieving

high frequency performance. Comlinear provides eval-

uation boards for the CLC436 (730013 - DIP, 730027-

SOIC) and suggests their use as a guide for high

frequency layout and as an aid for device testing and

characterization.

Supply bypassing is required for optimum performance.

The bypass capacitors provide a low impedance

current return path at the supply pins. They also provide

high frequency filtering on the power supply traces.

Other layout factors also play a major role in high

frequency performance. The following steps are

recommended as a basis for high frequency layout:

1. Include 6.8

µF tantalum and 0.01µF ceramic

bypass capacitors on both supplies.

2. Place the 6.8

µF capacitors within 0.75 inches

of the power pins.

3. Place the 0.01

µF capacitors within 0.1 inches

of the power pins.

4. Remove the ground plane near the input and

output pins to reduce parasitic capacitance.

5. Minimize all trace lengths to reduce series

inductances.

State Variable Filter

The filter shown on the front page offers both a band-

pass and a low pass output. The design equations are

shown below.

The state variable filter can be modified to obtain a

tunable band pass filter. This technique is shown in

the CLC522, Wideband Variable Gain Amplifier,

data sheet.

Transimpedance Application

The low 1.1pA/

√Hz input current noise and unity gain

stability make the CLC436 useful as a photo diode pre-

amplifier. Figure 4 illustrates a transimpedance amplifier.

Figure 4: Transimpedance Amplifier

The feedback capacitance reduces peaking in the fre-

quency response. As the value of the feedback capac-

itance increases from zero, the rolloff of the response

will increase.

P

175

JA

=

°−

()

θ

Q

R

R

A

R

R

, desired mid band gain

f

Q

2R C

, desired resonant frequency

RR

1

3

v

1

4

r

1

23

=

=−

=

=

π

+

-

CLC436

Applications Circuit

-

+

CLC436

436 Fi 5

Photo Diode

Representation

5

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