CPC7582

14

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R05

the CPC7582 switches when pulled to a logic low.

Although logically disabled, if the ringing switch (SW4)

is active (closed), it will remain closed until the next

current zero crossing event.

As shown in the table “Break-Before-Make Operation

for all Version (Ringing to Talk Transition)” on page 14,

this operation is similar to the one shown in

“Break-Before-Make Operation - All Versions” on

page 13, except in the method used to select the all off

are reconfigured for the talk state.

1.

This opens the ringing return switch (SW3) and

prevents any other switches from closing.

2.

the ringing cycle period to allow sufficient time for

a zero crossing current event to occur and for the

circuit to enter the break before make state.

3.

4.

activate the break switches.

states are 0 (overrides logic input pins and forces an

all off state) and float (allows switch control via logic

input pins and the thermal shutdown mechanism is

active). This requires the use of an open-collector type

buffer.

shutdown circuit and is therefore not recommended as

this could lead to device damage or destruction in the

presence of excessive tip or ring potentials.

2.2.6 Break-Before-Make Operation for all Version (Ringing to Talk Transition)

2.3 Data Latch

The CPC7582 has an integrated data latch. The latch

operation is controlled by logic-level input pin 11

(LATCH). The data input of the latch is pin 10

output of the data latch is an internal node used for

state control. When LATCH control pin is at logic 0, the

data latch is transparent and data control signals flow

directly through to state control. A change in input will

be reflected in the switch state. When LATCH control

pin is at logic 1, the data latch is active and a change

in input control will not affect switch state. The

switches will remain in the position they were in when

the LATCH changed from logic 0 to logic 1 and will not

respond to changes in input as long as the latch is at

2.4 Thermal Shutdown

logic inputs. This setting, however, also disables the

thermal shutdown circuit and is therefore not

recommended. When using logic controls via the input

result, the two recommended states when using pin 7

all-off state, or float, which allows logic inputs to

remain active. This requires the use of an

open-collector type buffer.

2.5 Ringing Switch Zero-Cross Current Turn Off

After the application of a logic input to turn SW4 off,

the ringing switch is designed to delay the change in

state until the next zero-crossing. Once on, the switch

requires a zero-current cross to turn off, and therefore

should not be used to switch a pure DC signal. The

State

Timing

Break

Switches

Ringing

Return

Switch

(SW3)

Ringing

Switch

(SW4)

Test

Switches

Ringing

1

0

0

Floating

-

Off

On

On

Off

All-Off

0

0

0

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

0

0

SW4 has opened

Off

Off

Off

Off

Talk

0

0

Floating

Close Break Switches

On

Off

Off

Off