11

FN7312.5

January 25, 2006

Maximum reliability is maintained if the output current never

exceeds ±60mA. This limit is set by the design of the internal

metal interconnect.

Power Dissipation

With the high output drive capability of the EL5173 and

EL5373 it is possible to exceed the 125°C absolute

maximum junction temperature under certain load current

conditions. Therefore, it is important to calculate the

maximum junction temperature for the application to

determine if the load conditions or package types need to be

modified for the amplifier to remain in the safe operating

area.

The maximum power dissipation allowed in a package is

determined according to:

Where:

•

The maximum power dissipation actually produced by an IC

is the total quiescent supply current times the total power

supply voltage, plus the power in the IC due to the load, or:

Where:

•

application

• i = Number of channels

overheat.

Power Supply Bypassing and Printed Circuit

Board Layout

As with any high frequency device, a good printed circuit

board layout is necessary for optimum performance. Lead

lengths should be as sort as possible. The power supply pin

must be well bypassed to reduce the risk of oscillation. For

connected to the ground plane, a single 4.7µF tantalum

to GND will suffice. This same capacitor combination should

be placed at each supply pin to ground if split supplies are to

supply rail.

For good AC performance, parasitic capacitance should be

kept to minimum. Use of wire wound resistors should be

avoided because of their additional series inductance. Use

of sockets should also be avoided if possible. Sockets add

parasitic inductance and capacitance that can result in

compromised performance. Minimizing parasitic capacitance

at the amplifier’s inverting input pin is very important. The

feedback resistor should be placed very close to the

inverting input pin. Strip line design techniques are

recommended for the signal traces.

Typical Applications

Twisted pair cable driver

PD

MAX

T

JMAX

T

AMAX

–

Θ

JA

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

=

PD

i

V

S

I

SMAX

V

S

∆V

O

R

LD

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

×

+

×







×

=

0

Ω

EL5175/

EL5375

EL5173/

EL5373

50

50

50

Ω

50

Ω

FIGURE 23. TWISTED PAIR CABLE DRIVER

EL5173, EL5373