µPC7073

7

2.

USE CAUTIONS

(1) Combined characteristics of

µPC7073 and µPD9903

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The

µPC7073 is designed to be used in combination with the µPD9903. Therefore, first half of the electrical

characteristics described below are ratings for the

µPC7073 as a discrete unit while the second half are

combined ratings that include the

µPD9903.

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Subscriber circuit constants that are determined by factors such as termination impedance are configured to

enable setting by external order parameters. Consequently, input of an order that is not suitable for the target

impedance may result in failure to obtain the required characteristics.

(2) Absolute maximum ratings

Application of voltage or current in excess of the absolute maximum ratings may result in damage. Be

especially cautious about surges, etc.

(3) Load of by-pass capacitor

Because the

µPC7073 and µPD9903 use several internal high-frequency operational amplifiers, high power

supply impedance can cause instability (such as oscillation) in these internal operational amplifiers. To

0.1

µF) having superior high frequency characteristics as close as possible to the µPC7073’s power supply

(4) Addition of ACOM pin connection capacitor

The voltage of the ACOM pin between the

µPC7073 and µPD9903 is the signal source reference voltage

for the

µPC7073. Superposition of noise on this pin may have adverse effects on transmission character-

istics. Therefore, make the wires between the ACOM pin and the two LSIs as short as possible, and connect

µF) having superior high frequency characteristics as close as possible to

the pins.

(5) Overcurrent prevention measures

Due to its structure, power to the

the

µPC7073 (an overcurrent will not flow if power is input to all power supply pins).

(rated at several

Ω) in the directions described below.

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