AG1171

V1.0 Dec 2006 Data Sheet Silver TELECOM Pb Ag1171 +3.3V / +5.0V Low Power Ringing SLIC 1. Features A highly featured low power SLIC in a 14 pin SIL format. Integral high efficiency DC/DC converter. Single supply voltage: +3.3V to +5.0V. Highly integrated with an on-board ringing generator. Tip/Ring polarity reversal. On-Hook Transmission for caller line ID. Suitable for FCT applications. Easy to use, with a minimum number of external components. Simplified protection in “on-premise” applications. Silver Telecom “design-in” assistance 2. Description The Silver Telecom Ag1171 is a single Subscriber Line Interface Circuit (SLIC) in a 14 pin single in line (SIL) format. 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 Ag1171 has been designed to work with loop lengths of typically 1.0km (470R including telephone). The Ag1171 has integral dc/dc converter and ringing generation thus providing all the line powering requirements from a single supply. The Ag1171 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). © Silver Telecom 2006 V1.0 Dec 2006 Data Sheet Ag1171 +3.3V / +5.0V Low Power Ringing SLIC Table of Contents 1. Features........................................................................................................................... 1 2. Description ....................................................................................................................... 1 Table of Contents ............................................................................................................. 2 Table of Figures ............................................................................................................... 2 3. Ag1171 Product Selector ................................................................................................. 3 4. Pin Description ................................................................................................................. 5 5. Functional Description ..................................................................................................... 6 5.1. Line Interfacing .......................................................................................................... 6 5.2. Battery Feed .............................................................................................................. 6 5.3. Ringing ...................................................................................................................... 6 5.4. Power Down and Synchronisation............................................................................. 7 5.5. The 2-4 Wire (hybrid) Conversion ............................................................................. 8 5.6. Transmit and Receive Gain ....................................................................................... 8 5.7. The 2 Wire Impedance .............................................................................................. 8 5.8. Network Balance Impedance .................................................................................... 8 5.9. Tip & Ring Polarity Reversal ..................................................................................... 8 5.10. On Hook Transmission ............................................................................................ 8 5.11. Switch Hook Detection ............................................................................................ 9 6. Protection of the Ag1171 SLIC ...................................................................................... 10 6.1. Thermal Protection .................................................................................................. 10 6.2. Lightning and Power Cross Protection .................................................................... 10 7. Typical Application ......................................................................................................... 10 8. DC Supply Voltage ........................................................................................................ 10 9. Layout Considerations ................................................................................................... 11 9.1. Power and Ground .................................................................................................. 11 10. Electrical Characteristics.............................................................................................. 12 10.1. Absolute Maximum Ratings* ................................................................................. 12 10.2. Recommended Operating Conditions* .................................................................. 12 10.3. DC Electrical Characteristics* ............................................................................... 13 10.4. AC Electrical Characteristics* ................................................................................ 14 11. Package ....................................................................................................................... 15 Table of Figures Figure 1: Block Diagram ...................................................................................................... 3 Figure 2: Ag1171 Package Format ...................................................................................... 4 Figure 3: Ringing Signal Waveforms ................................................................................... 7 Figure 4: Typical Connection Diagram ................................................................................. 9 Figure 5: Optional EMI Suppression .................................................................................. 11 © Silver Telecom 2006 2 V1.0 Dec 2006 Data Sheet Ag1171 +3.3V / +5.0V Low Power Ringing SLIC 3. Ag1171 Product Selector Part Number Ag1171 Impedance Package Supply Voltage 600 ohm SIL 3.3 to 5.0 Volt Table 1: Ordering Information Marking Figure 1: Block Diagram © Silver Telecom 2006 3 V1.0 Dec 2006 Data Sheet Ag1171 +3.3V / +5.0V Low Power Ringing SLIC Ag1171 Ag1171 Ag1171 1 Figure 2: Ag1171 Package Format © Silver Telecom 2006 4 V1.0 Dec 2006 Data Sheet Ag1171 +3.3V / +5.0V Low Power Ringing SLIC 4. Pin Description Pin # 1 2 3 4 5 6 7 8 9 10 11 12 13 14 Name RING (B) TIP (A) F/R RM SHK NC NC NC VIN VOUT NC GNDPWR +VPWR PD Description Ring. Connects to the subscriber line Ring. Tip. Connects to the subscriber line Tip. Forward/Reverse. A logic (L) will reverse the Tip and Ring voltage polarities. F/R is toggled to produce the ringing output. Ringing Mode. Sets bias conditions during ringing. Must be set to logic (H) during ringing. Logic (L) for other modes. Switch Hook. Indicates an off-hook condition when at logic (H). No Connection. Do not connect to this pin. No Connection. Do not connect to this pin. No Connection. Do not connect to this pin. Audio In. Analog input signal from the Codec (which is output on Tip and Ring). Connect via a 10nF capacitor Audio Out. This is the analog output signal (from Tip and Ring) to the Codec. Connect via a 100nF capacitor. No Connection. Do not connect to this pin. DC/DC Ground. Ground input for the DC/DC converter. DC/DC Supply. +5.0V or +3.3V input for the DC/DC converter. Power Down DC/DC Converter. A logic (L) on this pin powers down the Ag1171. DO NOT put logic (H) on this pin. © Silver Telecom 2006 5 V1.0 Dec 2006 Data Sheet Ag1171 +3.3V / +5.0V Low Power Ringing SLIC 5. Functional Description 5.1. Line Interfacing As well as being used in an electrically demanding environment, the needs of different applications and regulatory standards means that the SLIC must be flexible, and have facilities to ensure robust performance. The Ag1171 SLIC provides a complete and flexible interface to the telephone. 5.2. Battery Feed The Ag1171 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 and 60V ( 75V for ringing). This confers a significant cost, space and time to market benefit on the equipment designer. The battery feed to the telephone line is generated from the positive supply rail. This provides a 48V battery feed to the line driver, which is adjusted automatically to match line conditions. In Forward mode the Ring voltage is negative with respect to the Tip voltage. Power efficiency is good, because the line is supplied with only as much power as is needed. Little excess heat is generated, even on short lines. The loop current is pre-set to a constant 30mA, under the conditions shown in Section 10.3 of this datasheet, which specifies the ‘DC Electrical Characteristics’ for the Ag1171. 5.3. 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 at the required frequency and cadence. The toggling of the F/R pin produces a balanced signal at Tip and Ring. These signal waveforms are shown in Figure 3. Ringing voltage of approximately 60Vrms is applied to a single telephone set. It is important that the RM pin is only set high during ringing and that this pin is set low at all other times. During ringing the integral DC/DC converter is switched by RM (H) to produce a battery voltage of 72V. This will produce greater than 40Vrms into 3 telephones (with tone ringers). The slope of the edges on the ringing waveform is set internally to give the correct waveform with 20Hz to 25Hz ringing frequency. When an “off-hook” condition occurs during ringing, the ring-trip circuit on the Ag1171 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. The DC/DC controller limits the power. The Ag1171 will operate continuously with a ring-trip load (but this is not recommended as the power dissipation is high). The ring-trip function will operate up to a loop resistance of typically 470R (including 300R telephone). © Silver Telecom 2006 6 V1.0 Dec 2006 Data Sheet Ag1171 +3.3V / +5.0V Low Power Ringing SLIC Conditio n 1 - DC ope rat ion No tes 1 0 1 0 NO TE: SH K S HO ULD B E DE-BO UNC ED FO R 1 0ms Si g nal INPUT RM No rin gin g OUTPUT SH K Off hoo k det ected Off Ho ok Conditio n 2 - Ring ing O n- hook 1 1 s ec 3 s ec 1 s ec Conditio n 3 - Ring i ng/Off - hook 3 s ec RM 0 1 F/R (inp ut ) 0 SHK 1 0 Th e p h o n e go es o ff h o o k, an d SH K is d et ect ed at po in t A (lead ing edge). RM mus t b e s wit ch ed lo w in < 5 00 ms (p oint B) , an d t h e r inging cadence s hou ld b e re mo ved fro m F/ R. . A s lo n g as t h e t elep h on e is o ff ho o k, S H K wi l l re ma in hig h . A B Figure 3: Ringing Signal Waveforms 5.4. Power Down and Synchronisation The DC/DC converter can be switched off by applying a logic (L) level to the PD input. The SLIC takes 50ms to power up from this state. Logic outputs are not valid during this time. When using the power down function, it is recommended that the SLIC is polled (powered up periodically) to check for SHK (the subscriber has gone off-hook). If Power Down mode is not required, the PD pin should be left open circuit. The PD input should not be taken to a logic (H) as this may damage the SLIC. Connecting to PD via a diode will ensure it is never taken (H). NOTE: This is a sensitive node, keep connections very short. The DC/DC has an internal oscillator. If desired, the oscillator frequency may be synchronised with an external clock for EMI reasons. To do this, a 64kHz square wave (with 50:50 mark space) should be inputted to the PD pin. See Applications Note: AN11711, for further details. © Silver Telecom 2006 7 V1.0 Dec 2006 Data Sheet Ag1171 +3.3V / +5.0V Low Power Ringing SLIC 5.5. The 2-4 Wire (hybrid) Conversion The Ag1171 SLIC transmits and receives balanced 2 wire analog signals at the Tip and Ring connections. These are converted to a ground referenced output at VOUT and from a ground referenced input at VIN. The VOUT and VIN pins are normally connected to a Codec or telephony DSP for conversion of audio to and from a digital format. 5.6. Transmit and Receive Gain The gain in both the transmit direction (Tip/Ring to VOUT) and the receive direction (VIN to Tip/Ring) is set to 0dB. Normally any gain adjustments required by the user can be made by programming the Codec or telephony DSP. 5.7. The 2 Wire Impedance The 2 Wire impedance at Tip/Ring of the Ag1171 is set to 600R. It requires no external programming resistors. 5.8. Network Balance Impedance The network balance impedance ZB of the Ag1171 is set to 600R and it requires no external programming resistors. 5.9. Tip & Ring Polarity Reversal The Ag1171 can reverse the battery voltage polarity at Tip and Ring via the F/R pin. 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. 5.10. On Hook Transmission The Ag1171 is capable of on-hook transmission if an external resistor is fitted between pins 1 (Ring) and 2 (Tip). This means analog signals can be transmitted from VIN through Tip and Ring and onto the line even when no external loop current is flowing. This can be used when sending Caller Line Identification (CLI) information or for other “no ring” calls. The Ag1171 will provide on hook transmission of audio signals up to 0dBm (0.775V) with a high impedance on Tip/Ring or with AC loads down to 600R. To achieve this the external bias resistor should have a value of 20Kohms. This will increase the VPWR idle current by 35ma. A larger value of resistor will reduce the idle current but the maximum audio signal which can be transmitted will be reduced in proportion e.g. a 39Kohm bias resistor will allow audio signals up to –6dBm (0.387V) with an increase in idle current of 18mA. © Silver Telecom 2006 8 V1.0 Dec 2006 Data Sheet Ag1171 +3.3V / +5.0V Low Power Ringing SLIC Components C1, C3 = 100nF C4 = 10nF C2 = 470uF, 16V Aluminium Electrolytic (standard type) R1 = External DC bias resistor (required for CLI) typically 20K to 39K D1 = BZT03C82 or P6KE82 (only one needed per line card) D2 – 5 = 1N4004 or MB4S bridge D6 = 1N4148 or BAS16 Figure 4: Typical Connection Diagram 5.11. Switch Hook Detection When the subscriber goes “off-hook” loop current will begin to flow. If this current is above the detection threshold the switch hook output, SHK, will switch to a logic (H). It is recommended that software or hardware de-bouncing of the switch hook signal is used. This is to avoid short pulses which can cause a false switch hook output, triggering the incorrect system response. During loop disconnect dialling, SHK will pulse between logic (H) and logic (L) to indicate the digits being dialled. Again it is recommended that software de-bouncing of the pulse edges is used to avoid false detection of digits © Silver Telecom 2006 9 V1.0 Dec 2006 Data Sheet Ag1171 +3.3V / +5.0V Low Power Ringing SLIC 6. Protection of the Ag1171 SLIC 6.1. Thermal Protection Should the SLIC be operated incorrectly, for example by accidentally shorting Tip and Ring to each other or to ground, the power dissipation is automatically limited by the DC/DC converter This feature means that the SLIC will always operate within its power limits, without overheating. When operating on very short lines the battery voltage is regulated to a low value. This limits the power dissipation and ensures the Ag1171 operates with a minimum temperature rise. 6.2. Lightning and Power Cross Protection The Ag1171 is designed for use short loop “on-premise” applications, such as FCT, FWT, WLL and VoIP. In this case power cross and lightning protection is not required. The only protection which should be required is for ESD (Electro Static Discharge) caused by handling during installation. The Ag1171 has been designed to be able to use low cost ESD protection components. A typical circuit is shown in Figure 4. This circuit is suitable for most “on-premise” applications. 7. Typical Application The Ag1171 has been designed to interface to telephony Codecs or DSPs. Applications drawings for many codecs and DSP chips are available. Please contact Silver Telecom or visit our website www.silvertel.com. An example is shown in figure 4. The status outputs from the SLIC are passed to the micro-controller. These signals can then be processed as necessary by the system software. The audio signals which are on the 4 wire side of the connection are coupled by capacitors to avoid d.c. level problems between the two devices. 8. DC Supply Voltage During operation the DC Supply Voltage MUST be regulated within the limits shown in the Electrical Characteristics – Section 10.0 of this datasheet. Use of a “clean” power supply is extremely important. Should the VCC supply rail go above the Absolute Maximum Rating of 7.0V, for even a short time, then permanent damage to the Ag1171 is likely to result. We also advise that the designer performs a full system evaluation, under all possible performance conditions, to ensure that the VCC Maximum rating is not exceeded. © Silver Telecom 2006 10 V1.0 Dec 2006 Data Sheet Ag1171 +3.3V / +5.0V Low Power Ringing SLIC In some applications, additional EMI suppression may be needed. In this instance capacitors can be added to filter out the higher frequencies of the DC-DC converter. See figure 5 for details. Values between 1nF and 10nF are suitable. TIP TIP RING 1nF 1nF RING Figure 5: Optional EMI Suppression 9. Layout Considerations 9.1. Power and Ground Tracks to the +VPWR and GNDPWR should be made as thick as possible. To maximise the performance of the device, signal tracks should be kept as short as possible. To reduce DC/DC noise capacitors up to 10nF may be connected to ground at Tip and Ring. © Silver Telecom 2006 11 V1.0 Dec 2006 Data Sheet Ag1171 +3.3V / +5.0V Low Power Ringing SLIC 10. Electrical Characteristics 10.1. Absolute Maximum Ratings* Parameter 1 2 3 4 DC Supply Voltage Maximum Power Dissipation, Off Hook @ 25oC Storage Temperature Duty Cycle for RM(H) Symbol VCC PSLIC TS -40 Min -0.3 Max 7.0 1.2 +100 33 Units V W O C % *Exceeding the above ratings may cause permanent damage to the product. Functional operation under these conditions is not implied. Maximum ratings assume free airflow. 10.2. Recommended Operating Conditions* All Voltages are with respect to ground unless otherwise stated. Parameter 1 2 DC Supply Voltage Operating Temperature Symbol VCC TOP Min 3.1 0 Typ Max 5.5 Units V O 25 70 C *Typical figures are at 25°C with nominal +5.0V/+3.3V supplies and are for design use only. They are not guaranteed It is important that the user performs a full system evaluation, under all possible performance conditions, to ensure that the VCC Maximum rating is not exceeded. © Silver Telecom 2006 12 V1.0 Dec 2006 Data Sheet Ag1171 +3.3V / +5.0V Low Power Ringing SLIC 10.3. DC Electrical Characteristics* DC Characteristic 1 Supply Current, on-hook @ 5.0V @ 3.3V Supply current ringing 1 REN @ 5.0V @ 3.3V Supply current, off-hook @ 5.0V @ 3.3V Supply current during ring trip (