CLC423 datasheet(6/8 Pages) NSC

6 / 8 page

http://www.national.com

Layout Considerations

A proper printed circuit layout is essential for achieving

high frequency performance. Comlinear provides evalu-

ation boards for the CLC423 (730013 - DIP, 730027-

SOIC) and suggests their use as a guide for high

frequency layout and as an aid for device testing and

characterization.

General layout and supply bypassing play major roles in

high frequency performance. Follow the steps below as

a basis for high frequency layout:

Include 6.8

µF tantalum and 0.1µF ceramic

capacitors on both supplies.

Place the 6.8

µF capacitors within 0.75 inches

of the power pins.

Place the 0.1

µF capacitors less than 0.1 inches

from the power pins.

Remove the ground plane under and around

the part, especially near the input and output

pins to reduce parasitic capacitance.

Minimize all trace lengths to reduce series

inductances.

Use flush-mount printed circuit board pins for

prototyping, never use high profile DIP sockets.

Evaluation Board Information

A data sheet is available for the CLC730013 and

CLC730027 evaluation boards. This 8-pin op amp

evaluation board data sheet provides:

Evaluation board schematics

Evaluation board layouts for both DIP and

SOIC boards

General information about the boards

The data sheet also contains tables of recommended

components to evaluate several of Comlinear’s high

speed amplifiers.

This table for the CLC423 is

illustrated below.

Refer to the evaluation board data

sheet for schematics and further information.

Components Needed to Evaluate

the CLC423 on the Evaluation Board:

Rf, Rg - Use this product data sheet to

select values

Rin, Rout - Typically 50Ω (Refer to the Basic

Operation section of the evaluation board

data sheet for details)

Rt - Optional resistor for inverting gain

configurations (Select Rt to yield desired input

impedance = Rg || Rt)

C1, C2 - 0.1µF ceramic capacitors

C3, C4 - 6.8µF tantalum capacitors

Components not used:

C5, C6, C7, C8

R1 thru R8

The evaluation boards are designed to accommodate

dual supplies. The boards can be modified to provide

single supply operation.

For best performance; 1) do

not connect the unused supply, 2)

provide a wide

jumper across C2. Use a jumper that is equal in width to

the trace connecting pin 4 to C2. This will minimize any

additional inductance caused by the jumper.

SPICE Models

SPICE models provide a means to evaluate amplifier

designs.

Free

SPICE

models

are

available

for

Comlinear’s monolithic amplifiers that:

Support Berkeley SPICE 2G and its many

derivatives

Reproduce typical DC, AC, Transient, and

Noise performance

Support room temperature simulations

The

readme file that accompanies the diskette lists

released models, and provides a list of modeled parame-

ters.

The application note OA-18, Simulation SPICE

Models for Comlinear’s Op Amps, contains schematics

and a reproduction of the readme file.

Typical Application Circuit

The typical application shown on the front page illustrates

the near rail-to-rail performance of the CLC423.

Single Supply Cable Driver

Figure 8 illustrates the CLC423 in a typical single

supply cable driving application. The CLC423 is set for

a gain of +2V/V to compensate for the divide-by-two

voltage drop at Vo.

Figure 8: Single Supply Cable Driver

Multiple Feedback Bandpass Filter

Figure 9 illustrates a bandpass filter and design

equations. The circuit operates from a single supply of

+5V. The voltage divider biases the non-inverting input to

2.5V. The input is AC coupled to prevent the need for

level shifting the input signal at the source.

Use the

design equations to determine R1 and R2 based on the

desired Q and center frequency.

Applications Circuits

CLC423

250

Ω

0.1

µF

6.8

µF

Vin

+5V

250

Ω

0.1

µF

Ω Coaxial

Cable

Ω

0.1

µF

Ω

0.1

µF

CLC423 Datasheet(PDF) 6 Page - National Semiconductor (TI)

CLC423 Datasheet(HTML) 6 Page - National Semiconductor (TI)

Html Pages

1 2 3 4 5 6 7 8

Datasheet Descarga

Enlace URL