4

Schematic Diagram

Application Information

Layout Considerations

The wide bandwidth of the HA-5002 necessitates that high

frequency circuit layout procedures be followed. Failure to

follow these guidelines can result in marginal performance.

Probably the most crucial of the RF/video layout rules is the

use of a ground plane. A ground plane provides isolation and

minimizes distributed circuit capacitance and inductance

which will degrade high frequency performance.

Other considerations are proper power supply bypassing

and keeping the input and output connections as short as

possible which minimizes distributed capacitance and

reduces board space.

Power Supply Decoupling

For optimal device performance, it is recommended that the

positive and negative power supplies be bypassed with

capacitors to ground. Ceramic capacitors ranging in value

from 0.01 to 0.1

µF will minimize high frequency variations in

supply voltage, while low frequency bypassing requires

larger valued capacitors since the impedance of the

capacitor is dependent on frequency.

It is also recommended that the bypass capacitors be

connected close to the HA-5002 (preferably directly to the

supply pins).

Operation at Reduced Supply Levels

The HA-5002 can operate at supply voltage levels as low as

±5V and lower. Output swing is directly affected as well as

slight reductions in slew rate and bandwidth.

Short Circuit Protection

The output current can be limited by using the following circuit:

Capacitive Loading

The HA-5002 will drive large capacitive loads without oscillation

but peak current limits should not be exceeded. Following the

formula I = Cdv/dt implies that the slew rate or the capacitive

load must be controlled to keep peak current below the

maximum or use the current limiting approach as shown. The

HA-5002 can become unstable with small capacitive loads

(50pF) if certain precautions are not taken. Stability is

enhanced by any one of the following: a source resistance in

series with the input of 50

Ω to 1kΩ; increasing capacitive load

an output resistor of 10

Ω to 50Ω; or adding feedback

capacitance of 50pF or greater. Adding source resistance

generally yields the best results.

OUT

IN

OUT

IN

V+

V-

(CONTINUOUS)

R

LIM

V+

I

OUTMAX

--------------------------

V-

I

OUTMAX

--------------------------

==

HA-5002