R00B

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excellent means of indicating loop availability for

designs with a full time sealing current requirement. In

addition, for pulsed sealing current loops, the status

from this detector when used in conjuntion with the

timing of modem retraining events can be used as an

indicator to determine if the sealing current event is

clearing line impairments.

2.6 On-State Behavior

2.6.1 Typical Conditions

On-state sealing current levels are determined by the

network’s power feed circuit and the loop’s dc

impedance. To compensate for low loop resistance or

very high loop voltage, the CPC1466 limits the

maximum sealing current to 70 mA.

The CPC1466 manages package power dissipation

by shunting excess sealing current through the 2.2 k

Ω

4W power resistor located between the PR+ and PR-

pins.

2.6.2 Over-Voltage Conditions

Potentials in excess of 100 V applied to the tip and

ring interface will cause the CPC1466 to disable the

sealing current hold circuit and enter a standby state

with very little current draw. Once the over-voltage

condition is removed, the CPC1466 automatically

resumes normal operation.