CPC7582
Table 7. Break-Before-Make Operation (Ringing to Idle/Talk Transition)
Ring
Ring
Break
Switches Switch Switch
Return Access Line Access
Switches
5 & 6
Access Input
TSD
Float
Float
State
Ringing
All Off
Timing
1 & 2
Open
Open
3
4
0V
5V
5V
5V
-
Closed
Open
Closed
Closed
Open
Open
Hold this state for <= 25ms.
SW4 waiting for zero current to
turn off.
5V
0V
5V
0V
Float
Float
All Off
SW4 has opened.
Zero current has occurred.
Open
Open
Open
Open
Open
Open
Open
Idle/Talk
Release Break Switches
Closed
Alternate “Break-Before-Make” Operation
Note that the “break-before-make” operation can also be achieved using TSD as an input. In lines 2 & 3 of Table 7,
instead of using the logic input pins to force the “all off” state, force TSD to ground. This will override the logic inputs
and also force the all off state. Hold this state for 25 ms. During this 25 ms all off state, toggle the inputs from the
ringing state (Input=5V, Access=0V) to the idle/talk state (Input=0V, Access=0V). After 25 ms, release TSD to return
switch control to the input pins which will set the idle talk state.
When using the CPC7582 in this mode, forcing TSD to ground will override the INPUT pins and force an all off state.
Setting TSD to +5V will allow switch control via the logic INPUT pins. However, setting TSD to +5V will also disable
the thermal shutdown mechanism. This is not recommended. Therefore, to allow switch control via the logic INPUT
pins, allow TSD to float.
Thus when using TSD as an input, the two recommended states are 0 (overrides logic input pins and forces all off
state) and float (allows switch control via logic input pins and thermal shutdown mechanism is active). This may
require use of an open collector buffer.
Table 8. Electrical Specifications, Protection Circuitry
Parameters
Conditions
Symbol
Min
Typ
Max
Units
Parameters Related to Diodes
(in Diode Bridge)
Voltage Drop @ Continuous
Current (50/60 Hz)
Voltage Drop @ Surge
Current
Apply +/-dc current limit of break
switches
Apply +/-dynamic current limit of
break switches
Forward
Voltage
Forward
Voltage
-
-
2.1
5
3
-
V
V
Parameters Related to
Protection SCR1
Surge Current
-
-
-
-
-
ITRIG
IHOLD
ITRIG
IHOLD
-
-
Von
-
-
-
-
-
-
60
100
35
70
-
-
-3
-5
*
-
-
-
A
mA
mA
mA
mA
V
µA
V
V
Trigger Current (+25˚C)
Hold Current (+25˚C)
Trigger Current (+85˚C)
Hold Current (+85˚C)
Gate Trigger Voltage
Reverse Leakage Current
ON State Voltage1
60
VBAT - 4
-
Trigger Current
VBAT
0.5A t = 0.5 ms
2.0A t = 0.5 ms
VBAT - 2
1.0
-
-
-
-
-
1 Only for the CPC7581BA.
* Passes GR1089 & ITU-T K.20 with appropriate secondary protection in place.
Rev. 1.0
6
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