CPC7582
Table” on page 10 and “CPC7582xC Truth Table” on
page 11.
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.
2.2.1 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
2.2.2 Make-Before-Break Operation for All Versions (Ringing to Talk Transition)
Ringing
Return
Switches Switch
(SW3)
Ringing
Switch
(SW4)
Break
Test
Switches
IN
IN
T
SD
State
LATCH
Timing
RINGING
TEST
Ringing
1
0
-
Off
On
On
On
Off
Off
On
On
Off
Off
Off
Off
SW4 waiting for next zero-current
crossing to turn off. Maximum time is
one-half of the ringing cycle. In this
Make-
before-
break
0
0
0
0
0
Floating transition state, current that is limited to
the dc break switch current limit value
will be sourced from the ring node of the
SLIC.
Talk
Zero-cross current has occurred
2.2.3 Break-Before-Make Operation - CPC7582xA/B
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 of the CPC7582xA/B
can be achieved using two different techniques.
The first method uses manipulation of the IN
RINGING
and IN
logic inputs as shown in
TEST
“Break-Before-Make Operation CPC7582xA/B
(Ringing to Talk Transition)” on page 13.
Break-before-make operation occurs when the ringing
switch opens before the break switches (SW1 and
SW2) close.
1. At the end of the ringing state apply the all off
state (0, 0). This releases the ringing return
2.2.4 Break-Before-Make Operation CPC7582xA/B (Ringing to Talk Transition)
Ringing
Return
Switches Switch
(SW3)
Ringing
Switch
(SW4)
Break
Test
Switches
IN
IN
T
SD
State
LATCH
Timing
RINGING
TEST
Ringing
All-Off
1
1
0
1
-
Off
On
On
On
Off
Off
Hold this state for at least one-half of the
ringing cycle. SW4 waiting for zero
current to turn off.
Off
Off
0
Floating
Break-
Before-
Make
1
0
1
0
SW4 has opened
Off
On
Off
Off
Off
Off
Off
Off
Talk
Close Break Switches
2.2.5 Break-Before-Make Operation - All Versions
the CPC7582xC. As shown in “CPC7582xA/B Truth
Table” on page 10 and “CPC7582xC Truth Table” on
The second break-before-make method for the
CPC7582xA/B is also the only method available for
page 11, the bidirectional T interface disables all of
SD
R05
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