CPC5622A, LITELINK III is a single package silicon telephone line interface (PLI) DAA for voice and data communication applications to connect between low voltage equipment and high voltage telephone network. LITELINK also provides AC and DC telephone line termination, switchhook, 2-wire to 4-wire hybrid, ringing detection, full-time receive on-hook transmission capability.

The CPC5622 is a member of IXYS and is based on IXYS's third-generation LITELINK products from the IC Division with improved insertion loss performance and lower minimum current consumption for telephone lines. The CPC5622 version of LITELINK III provides concurrent ringing detection and CID monitoring for global applications. Two half-waves provide maximum versatility in full-wave ringing detection.

feature

Superior voice solution, low noise and excellent part-to-part gain accuracy

3 kVRMS line isolation

Simultaneous ringing detection and CID monitoring

Suitable for global applications

Provides full-wave ringing detection and half-wave detection ringing detection for maximum versatility

Transmit power up to +10 dBm to 600 

Data Access Arrangement (DAA) Solutions for Modems

Speeds up to V.92

3.3V or 5V power supply

Simple interface to modem ICs and voice codecs

Worldwide Dial-Up Telephone Network Compatibility

The CPC5622 can be used in circuits that comply with

Requirements of TIA/EIA/IS-968 (FCC Part 68), UL60950 (UL1950), EN/IEC 60950-1

Complies with supplementary isolation, IEC60950, EN55022B, CISPR22B, EN55024 and TBR-21

Line side circuits are powered by telephone lines

Compared to other silicon DAA solutions, LITELINK:

Use fewer passive components

Reduce printed circuit board space

Uses less phone line power

is a single IC solution

application

Computer telephony and gateways such as VoIP

PBX

Satellite and cable set-top boxes

V.92 (and other standards) modems

fax machine

voicemail system

Embedded modems for POS terminals, automated banking, remote metering, vending machines, security and surveillance.

CPC5622 block diagram

2. Application circuit

LITELINK can be used with telephone networks all over the world. Some public telephone networks, especially in North America and Japan, require resistive wire termination. Other telephone networks such as Europe, China and elsewhere require a response line termination. The following application circuits are for both types of line termination models. Reactive Power Termination Description The application circuit of TBR-21 is implemented as shown in the figure below. The circuit can be easily adapted to other reactive termination needs.

Resistor Termination Application Circuit Diagram

3. Use LITELINK

As a full-featured telephone line interface, LITELINK

Perform the following functions:

DC termination and V/I slope control

AC Impedance Control

2-wire to 4-wire conversion (mixed)

current limit

Ring detection signal reception

Caller ID signaling reception

switch hook

LITELINK can be adapted to specific application functions without sacrificing basic functionality or performance. App features include but are not

Limited to:

High transmit power operation

pulse dial

ground start

cycle start

Parallel Phone Off-Hook Detection (Line Intrusion)

Battery reversal detection

Line Presence Detection

Global Programmable Operation

This part of the data sheet describes the usual standard configuration operation of LITELINK. IXYS Integrated Circuits Division offers

Additional online application information has the following topics:

Circuit Isolation Considerations

Optimizing LITELINK performance

Data Access Arrangement Architecture

LITELINK circuit description

Surge protection

EMI Considerations

Other specific application materials are also appropriately cited in this section.

Switch hook control (on-hook and off-hook countries)

LITELINK operates in one of two situations on-hook and off-hook. The telephone line is available for calls while on-hook. The phone line is in use while off-hook. The OH control input is used to place the LITELINK in one of these two states. With OH high, LITELINK is on hook and ready to make or receive a call. Also on-hook LITELINK's ring detector and CID amplifier are active.

Asserting OH low causes LITELINK to answer or initiate a call by going off-hook. In the off-hook state, loop current flows through the LITELINK.

On-hook operation: OH = 1

The leakage current of the LITELINK application circuit is less than 10A, and the ring and tip are 100 V, which is equivalent to an on-hook resistance greater than 10M.

Ringing signal received via

snooping circuit

In the on-hook state (OH not asserted), the internal multiplexer uses snooping circuitry. This circuit monitors two telephone lines simultaneously

Condition; incoming call ringing signal and caller ID data bursts.

C7 (CSNP-) and C8 (CSNP+) provide a high voltage isolation barrier between the LITELINK line and the SNP- and SNP+ input pins while coupling the AC signal to the snooping amplifier. The snooping circuit "constantly" snoops on the telephone line although no DC current is drawn. In LITELINK, the incoming ringing signal is compared to a reference level. When the ringing signal exceeds the preset threshold, the internal comparator generates the output RING and RING2 signals LITELINK at pins 9 and 10, respectively. choose

Which output to use depends on the support logic responsible for monitoring and filtering the ring detect signal. Reduce or Eliminate False Ringing The signal detected should be digitally filtered and recognized by the system as a valid ringing signal. A logic low output on RING or RING2 indicates that the LITELINK ringing signal detection threshold has been exceeded. In the absence of any input AC signal

The RING and RING2 outputs remain high.

The CPC5622 RING output signal is generated by a RING2 output is a half-wave ringing detector generated by a full-wave ringing detector. half wave

The output frequency of the ring detector follows the frequency of the input ring signal from the central office (CO) while the output frequency of the full wave ring detector is twice that of the input signal.

Because RING is the output of a half-wave detector, it outputs a logic low pulse frequency per ring cycle. Also, since RING2 is the output of a full wave detector will output two logic low pulses per cycle of the ringing frequency. Therefore, the term RING2 is twice the output pulse.

The setting of the ring detector comparator causes the RING output pulse to remain low for the half cycle of the ring signal in most cases and to remain high for the entire second half cycle of the ring signal. For the RING2 output, the pulse remains low for half of the ringing period for most of the time and returns high for only a short period of time around the zero crossing of the ringing signal. Both ring outputs remain high during the silent interval between rings. LITELINK ringing uses a hysteresis detection circuit to improve noise immunity. Ringing detection threshold depends on the values R3 (RSNPD), R6 and R44 (RSNP-), R7 and R45 (RSNP+),

C7 (CSNP-) and C8 (CSNP+). The components shown in these value application circuits are recommended for typical operation. The non-detection threshold can be changed according to the following formula:

IXYS Integrated Circuits Division Application Notes

AN-117 Custom Caller ID Gain and Ringer Detection Voltage Threshold is a spreadsheet for trying out different component values in this circuit. Changing the ring detection threshold will also change the caller ID gain and polarity reversal detection pulse timing, if used.

Polarity reversal detection in on-hook

The full wave ringing detector in the CPC5622 can detect the polarity reversal of the battery voltage applied to the tip and ring when the on-hook tip and ring batteries use the RING2 output for polarity reversal, a pulse on RING2 representing the event. The system logic must be able to distinguish a single use time pulse of approximately 1 millisecond from a valid ringing signal. Recommended external snooping circuit components.

On-hook caller ID signal reception

On-hook caller IDentity (CID) data burst signals are coupled through the snoop component, buffered through LITELINK and output on RX+ and RXpins. In North America, the CID data signal is usually sent between the first and second ringing signals. The CID information of other countries may arrive at any other signaling state before this. Outbreaks like North America in applications that transmit CID after the first ring, follow these steps to receive on-hook Caller ID data output via LITELINK RX:

1. Detect the first complete ringing signal burst on RING or RING2.

2. Monitor and process CID data output from RX.

Applications for CID may arrive in China and Brazil before the bell, follow the steps below to receive

Output on-hook Caller ID data via LITELINK RX:

1. Simultaneously monitor the CID data output from RX and the ringing on RING or RING2.

2. Process the appropriate signaling data.

NOTE: Remove the LITELINK (via the OH pin) to disconnect the snoop path from the receive output and disable the ring detector output RING and ring 2.

The CID obtained from tip and ring to RX+ and RX- depends on:

The component circuit recommended in the application produces a gain of 0.26 dB at 2000 Hz. IXYS Integrated Circuits Division Application Note AN-117 Custom Caller ID Gain and Ringer Detection Voltage Threshold is a spreadsheet for trying out different component values in this circuit. Changing the CID gain also changes the ringing detection threshold and time polarity reversal detection pulse, if used. For single-ended receive applications where only one RX output is used, the snoop circuit gain can be adjusted back to 0 dB by changing the value of snoop series resistors R6, R7, R44 and R45 from 1.8M to 715k. This change is negligible

Modify the ringing detection threshold.

Off-hook operation: OH = 0

The receive signal path appears from the tip and ring connections of the signal application circuit of the telephone network.

The received signal is extracted by sending the signal and then the LITELINK two-wire to four-wire mixing is converted into infrared light through the receive path LED. The intensity of the light is determined by the barrier that receives the modulated signal and couples the reflection dome through the electrical isolation. On the low voltage side of the barrier, the received signal is converted into a photocurrent by a photodiode. The photocurrent, linearly representing the received signal, is amplified and converted to a differential voltage output on aRX+ and RX-.

Gain variation is controlled to within ±0.4 dB Factory gain trim sets the output to unity gain. To accommodate single supply operation, LITELINK includes a small DC bias of 1.0 Vdc on the RX+ and RX- outputs. Most applications should AC-couple the receive output as shown in Figure 4. LITELINK can be used for differential or single-ended output as shown in Figure 4. Single-ended use results in a signal output amplitude of 6 dB. Do not exceed the output level of the 0 dBm reference 600 (2.2 VP-P) signal standard application circuit. See Application Note AN-157, Adding LITELINK III Transmissions for more information.

send signal path

The transmit signal from the CODEC to the TX+ and TXpins of the LITELINK should pass through the coupling capacitors as shown in Figure 5 to minimize DC offset errors. The differential transmit signal is converted to a single-ended signal in LITELINK and then coupled to the optical transmit amplifier in a similar way to the receive path.

The output of the optical amplifier is coupled to a telephone line loop current through a transconductance voltage-to-current converter that transmits the signal modulated in the stage. As in the receive path, the transmit gain is factory calibrated, limiting insertion loss to 0 ± 0.4 dB. Split and single-ended transmit signals into LITELINK should not exceed 0 dBm signal level with reference to 600 or 2.2 VP-P). For output power levels above 0dBm please refer to Application Note AN-157, which adds LITELINK III transmit power information.