CPC7581

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5

Rev. 2

Table 5. Make-Before-Break Operation (Ringing to Idle/Talk Transition)

Ring

Ring

Break

Return

Access

Switches

Switch

Switch

Input

TSD

State

Timing

1 & 2

3

4

5V

5V/Float

Ringing

-

Open

Closed

Closed

0V

5V/Float

Make-before-break

SW4 waiting for next zero current

Closed

Open

Closed

crossing to turn off. Maximum

time is half of ringing. In this

transition state, current that is

limited to the dc break switch

current limit value will be sourced

from the ring node of the SLIC

0V

5V/Float

Idle / Talk

Zero cross current has occurred

Closed

Open

Open

Table 6. Break-Before-Make Operation (Ringing to Idle/Talk Transition)

Ring

Ring

Break

Return

Access

Switches

Switch

Switch

Input

TSD

State

Timing

1 & 2

3

4

5V

5V/Float

Ringing

-

Open

Closed

Closed

5V

0V

All Off

Hold this state for <=25ms.

Open

Open

Closed

SW4 waiting for zero current to

turn off.

0V

0V

All/Off

Zero current has occurred

Open

Open

Open

SW4 has opened

0V

5V/Float

Idle/Talk

Release Break Switches

Closed

Open

Open