CPC5620/CPC5621

R05

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11

half-cycle of the ringing signal for the CPC5620. For

the CPC5621, the RING output returns high for a short

period near the zero-crossing of the ringing signal

before returning low during the positive half-cycle. For

both the CPC5620 and CPC5621, the RING output

remains high between ringing signal bursts.

The ringing detection threshold depends on the values

components shown in the application circuits are

recommended for typical operation. The ringing

detection threshold can be changed according to the

following formula:

Where:

data sheet.

the application circuits shown in this data sheet.

this data sheet.

IXYS Integrated Circuits Division Application Note

AN-117 Customize Caller ID Gain and Ring Detect Voltage

Threshold is a spreadsheet for trying different

component values in this circuit. Changing the ringing

detection threshold will also change the caller ID gain

and the timing of the polarity reversal detection pulse,

if used.

3.2.2 Polarity Reversal Detection with

CPC5621 in On-hook State

The full-wave ringing detector in the CPC5621 makes

it possible to detect on-hook tip and ring polarity

reversal using the RING output. When the polarity of

tip and ring reverses, a pulse on RING indicates the

event. Your system logic must be able to discriminate

this single pulse of approximately 1 msec (using the

recommended snoop circuit external components)

from a valid ringing signal.

3.2.3 On-hook Caller ID Signal Reception

On-hook caller ID (CID) signals are processed by

LITELINK by coupling the CID data burst through the

snoop circuit to the LITELINK RX outputs under

control of the CID pin. In North America, CID data

signals are typically sent between the first and second

ringing signal.

In North American applications, follow these steps to

receive on-hook caller ID data via the LITELINK RX

outputs:

1.

Detect the first ringing signal outputs on RING.

2.

Assert CID low.

3.

Process the CID data from the RX outputs.

4.

De-assert CID (high or floating).

Note: Taking LITELINK off-hook (via the OH pin)

disconnects the snoop path from both the receive

outputs and the RING output, regardless of the state

of the CID pin.

CID gain from tip and ring to RX+ and RX- is

determined by:

Where:

sheet

the application circuits in this data sheet

sheet

The recommended components in the application

circuit yield a gain 0.27 dB at 2000 Hz. IXYS

Integrated Circuits Division Application Note AN-117

Customize Caller ID Gain and Ring Detect Voltage Threshold

is a spreadsheet for trying different component values

in this circuit. Changing the CID gain will also change

the ring detection threshold and the timing of the

polarity reversal detection pulse, if used.

750mV

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



TOTAL

+



2

1

f



2

--------------------------------------

+

=



20

TOTAL

+



2

1

fC

SNP



2

--------------------------

+

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log

=