Features：

• Single supply voltage ring slic: +3.3V to +5.0V
• Integral high efficiency DC/DC converter.
• Highly integrated with ringing generator.
• Tip/Ring polarity reversal.
• 2 / 4 wire conversion
• Constant current feed
• High performance with low price
• Excellent sound quality
• On-Hook Transmission for caller line ID.
• Designed for GSM network
• Easy to use, with a minimum number of external components.

Applications：

• Fixed Cellular Terminals (FCT) applications.
• POS MODEM applications
• Internet Telephony (VoIP) applications.
• Fixed Wireless Terminals (FWT) applications.
• DVB Terminals applications.
• Wireless local loop (WLL) applications.
• GSM gateway

Index：

• unbalanced to ground 60dB(300Hz-3400Hz)
• Two- Wire Impedance 600R
• Four-wire return loss >24Db
• weighted noise -75dB
• Ringing voltage 130VP-P
• Constant current  23-31mA
• Supply Voltage 3.2V-5.5VDC

Description：

The R-TONE RT0805 is a single Subscriber Line Interface Circuit (SLIC).

The combination of features and packaging offers extremely efficient use of board area, saving  significant system size and cost, minimising time to market for Telephony Systems developers.

The RT0805 has been designed to work with loop lengths of typically 1.0km

The RT0805 has integral dc/dc converter and ringing generation thus providing all the line powering requirements from a single supply.24V(off-hook)and 48V(on-hook)and 75V(ringing).

The RT0805 requires a minimum of external components, making it ideal for low line count, short loop length applications, such as WLL Terminal (WLL), Fixed Cellular Terminals (FCT), Fixed Wireless Terminals (FWT) and Internet Telephony (VoIP).

The RT0805 has an integral DC/DC converter, which generates the battery voltage in the device.  This means that only a single supply of between +3.3V to +5.0V is needed, unlike conventional SLICs which will also need a battery voltage of anything between 20V and60V ( 75V for ringing).  This confers a significant cost, space and time to market benefit on the equipment designer.

• Absolute Maximum Ratings：

• DC Electrical Characteristics*

All DC Electrical Characteristics are over the Recommended Operating Conditions with VCC at +5.0V +1%,or +3.3V +1%, unless

otherwise stated.

2) Operating currents are dependent on the users application.

*Typical figures are at 25°C and are for design aid only. Not Guaranteed

• AC Electrical Characteristics*

This applies to 3 phones with tone ringers or 2 phones with mechanical bells.

*Typical figures are at 25°C and are for design aid only.

• Pin Description:

• RT0805 Typical Connection Diagram:

1 Ringing

The ringing signal is generated by switching the SLIC into ringing mode, by setting the RM pin high, and  then toggling the F/R pin or 25Hz pin at the required frequency and cadence. The toggling  of  the  F/R  pin  produces  a  balanced  signal  at  Tip  and  Ring.

During ringing the integral DC/DC converter is switched produce a battery voltage of  75V.The  slope of the edges on the ringing waveform is set internally to give the correct waveform with 20Hz to 25Hz ringing frequency.

2 Tip & Ring Polarity Reversal

If F/R is held at logic (H) (Forward) the d.c. voltage at Ring is negative with respect to Tip. If F/R is taken to logic (L) (Reverse) the voltage at Ring is positive with respect to Tip.

3 Switch Hook Detection

When an “off-hook” condition occurs during ringing, the ring-trip circuit on the RT0805 senses the loop current flowing and signals the off-hook condition on the SHK output. The SHK signal must be “de-bounced” (by the controlling processor) for 10ms to remove any spurious  pulses. 

• RT0805 Product Selector

• Package：(mm ±3mm )
•