clc423 National Semiconductor Corporation, clc423 Datasheet - Page 6

• Manufacturer Part Number: clc423
• Description: Comlinear Clc423 94mhz, Single Supply Voltage Feedback Op Amp
• Manufacturer: National Semiconductor Corporation

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:
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:
The data sheet also contains tables of recommended
components to evaluate several of Comlinear’s high
speed amplifiers.
illustrated below.
sheet for schematics and further information.
Components Needed to Evaluate
the CLC423 on the Evaluation Board:
Components not used:
http://www.national.com
Include 6.8 F tantalum and 0.1 F ceramic
capacitors on both supplies.
Place the 6.8 F capacitors within 0.75 inches
of the power pins.
Place the 0.1 F 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 schematics
Evaluation board layouts for both DIP and
SOIC boards
General information about the boards
R
select values
R
Operation section of the evaluation board
data sheet for details)
R
configurations (Select R
impedance = R
C
C
C
R
f
in
t
1
3
5
1
, R
, C
, C
, C
- Optional resistor for inverting gain
, R
thru R
g
2
4
6
out
, C
- Use this product data sheet to
- 0.1 F ceramic capacitors
- 6.8 F tantalum capacitors
- Typically 50
7
8
, C
Refer to the evaluation board data
8
This table for the CLC423 is
g
|| R
t
)
(Refer to the Basic
t
to yield desired input
6
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)
jumper across C
the trace connecting pin 4 to C
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:
The readme file that accompanies the diskette lists
released models, and provides a list of modeled parame-
ters.
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 V
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 R
desired Q and center frequency.
V
in
0.1 F
The application note OA-18, Simulation SPICE
Support Berkeley SPICE 2G and its many
derivatives
Reproduce typical DC, AC, Transient, and
Noise performance
Support room temperature simulations
5k
0.1 F
Figure 8: Single Supply Cable Driver
Applications Circuits
5k
250
3
2
2
o
. Use a jumper that is equal in width to
CLC423
.
+
-
+5V
7
4
250
6.8 F
0.1 F
+
6
0.1 F
2
. This will minimize any
1
75
and R
75 Coaxial
provide a wide
2
Cable
based on the
75
V
o