CPC5620/CPC5621

R05

www.ixysic.com

13

Figure 5. Differential and Single-ended Transmit Path Connections to LITELINK

3.4 Start-up Requirements

OH must be de-asserted (set logic high) once after

power-up for at least 50ms to transfer internal gain

trim values within LITELINK. This would be normal

operation in most applications. Failure to comply with

this requirement will result in transmission gain errors

and possibly distortion.

3.5 DC Characteristics

The CPC5620 and CPC5621 are designed for

worldwide application, including use under the

requirements of TBR-21. The ZDC, DCS1, and DCS2

pins control the VI slope characteristics of LITELINK.

assure compliance with DC requirements.

3.5.1 Setting a Current Limit

LITELINK includes a telephone line current limit

feature that is selectable by choosing the desired

IXYS Integrated Circuits Division recommends using

8.2

 for R

telephone line current to 130 mA.

Whether using the recommended value above or

refer to the guidelines for FET thermal management

provided in AN-146, Guidelines for Effective

LITELINK Designs.

3.6 AC Characteristics

3.6.1 Resistive Termination Applications

North American and Japanese telephone line AC

termination requirements are met with a resistive 600

 AC termination. Receive termination is applied to

the LITELINK ZNT pin (pin 29) as a 301

 resistor,

3.6.2 Reactive Termination Applications

Many countries use a single-pole complex impedance

to model the telephone network transmission line

characteristic impedance as shown in the table below.

Proper gain and termination impedance circuits for a

complex impedance requires the use of complex

network on ZNT as shown in the “Reactive Termination

Application Circuit Schematic” on page 8.

LITELINK

LITELINK

TXA1

TXA2

-

+

0.1

µf

Low-Voltage Side CODEC or

Transmit Circuit

Low-Voltage Side CODEC or

Transmit Circuit

TX-

TX+

TXA1

-

+

TX-

TX+

0.1

µf

0.1

µf

0.1

µf

1V

------------- 0.008A

+

=

Line Impedance Model

Australia

China

TBR 21

220



200



270



820



680



750



120 nF

100 nF

150 nF

R

S

R

P

C

P