CPC7582

R05

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13

Table” on page 10 and “CPC7582xC Truth Table” on

page 11.

2.2.1 Make-Before-Break Operation - All Versions

To use make-before-break operation, change the logic

inputs to the talk state immediately following the

ringing state. Application of the talk state opens the

ringing return switch (SW3) as the break switches

(SW1 and SW2) close. The ringing switch (SW4)

remains closed until the next zero-crossing of the

ringing supply current. While in the make-before-break

state, ringing potentials in excess of the CPC7582

protection circuitry trigger levels will be diverted to

ground.

2.2.2 Make-Before-Break Operation for All Versions (Ringing to Talk Transition)

2.2.3 Break-Before-Make Operation - CPC7582xA/B

Break-before-make operation of the CPC7582xA/B

can be achieved using two different techniques.

“Break-Before-Make Operation CPC7582xA/B

(Ringing to Talk Transition)” on page 13.

1.

At the end of the ringing state apply the all off

state (0, 0). This releases the ringing return

switch (SW3) while the ringing switch remains

on, waiting for the next zero current event.

2.

Hold the all off state for at least one-half of a

ringing cycle to assure that a zero crossing event

occurs and that the ringing switch (SW4) has

opened.

Break-before-make operation occurs when the ringing

switch opens before the break switches (SW1 and

SW2) close.

2.2.4 Break-Before-Make Operation CPC7582xA/B (Ringing to Talk Transition)

2.2.5 Break-Before-Make Operation - All Versions

The second break-before-make method for the

CPC7582xA/B is also the only method available for

the CPC7582xC. As shown in “CPC7582xA/B Truth

Table” on page 10 and “CPC7582xC Truth Table” on

State

Timing

Break

Switches

Ringing

Return

Switch

(SW3)

Ringing

Switch

(SW4)

Test

Switches

Ringing

1

0

0

Floating

-Off

On

On

Off

Make-

before-

break

00

SW4 waiting for next zero-current

crossing to turn off. Maximum time is

one-half of the ringing cycle. 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.

On

Off

On

Off

Talk

0

0

Zero-cross current has occurred

On

Off

Off

Off

State

Timing

Break

Switches

Ringing

Return

Switch

(SW3)

Ringing

Switch

(SW4)

Test

Switches

Ringing

1

0

0

Floating

-Off

On

On

Off

All-Off

1

1

Hold this state for at least one-half of the

ringing cycle. SW4 waiting for zero

current to turn off.

Off

Off

On

Off

Break-

Before-

Make

1

1

SW4 has opened

Off

Off

Off

Off

Talk

0

0

Close Break Switches

On

Off

Off

Off