AG2120 ETC1
Document overview
- Manufacturer or author: Provided By www.digicamel.com(FREE DATASHEET DOWNLOAD SITE)
- PDF pages: 14
Technical content
V2.0October 2002 Advance data Sheet © Silver Telecom 2002
DESCRIPTION
The Ag2120 is a self-contained highly integrated PSTN Interface Circuit in a single SIL or DIL Module. In addition to the features listed, the Ag2120 allows flexible programming of many functions, including the dc voltage mask and impedances. The Ag2120 meets international safety and regulatory requirements. The device requires a minimum of external components and has been specified for ease of use, to reduce time to market. The Ag2120 is designed for all applications, including those where there is a high level of common mode interference, such as PABX, long loop applications and systems without a ground. Ag2120 FULLY FEATURED PSTN INTERFACE
FEATURES
- A highly featured PSTN Interface (COIC, FXO, DAA, Trunk Interface) in a single DIL or 12mm high SIL device. +5V or +3.3V supply. Transformer isolation providing high common mode rejection (CMRR) for use in un-grounded systems. Highly integrated with on board loop switch and integral diode bridge. Loop start circuit, ringing detect and loop current detection. Parallel phone detect. Tip-ring polarity reversal detect (for Caller Line ID and remote metering) and on-hook reception. Meets requirements of EN60950/UL1950, and FCC Pt68. Low cost power cross protection. Programmable d.c. mask, line and network impedances. Silver Telecom “design-in” assistance. Silver T E L E C O M VIN VOUT TIP RING TRUNK Control and Supervision
V2.0 October 2002 Advance Data Sheet © Silver Telecom 2002 Page 3 Ag2120 FULLY FEATURED PSTN INTERFACE
1.0 Pin Description
1.1 DIL Pin-Out
Pin # Name Description 1 TIP (A) Tip. Connects to the subscriber line Tip. 2 RING (B) Ring. Connects to the subscriber line Ring. 3 CATHODE Cathode. For power cross protection connect to protection device cathode. 4 ANODE Anode. For power cross protection connect to protection device anode. 5 DMa DC Mask a. A resistor is connected between this pin and DMb to adjust the d.c. characteristics of the termination. 6 DMb DC Mask b. A resistor is connected between this pin and DMa to adjust the d.c. characteristics of the termination. 7 GATE Gate. For power cross protection connect to protection device gate. 8 GND Analog ground. Normally connected to system ground. 9 VCC Positive supply. Must be connected to +5V or +3.3V.
10 ZT2
2 Wire matching network 2. The 2 wire impedance matching network is connected between this pin and ZT1. The compensation impedance Zc is connected between this pin and Zb.
11 ZT1
2 Wire matching network 1. The 2 wire impedance matching network is connected between this pin and ZT2. 12 Zb Balance network. The network balance matching components are connected between this pin, VIN and GND.
13 VIN
Audio In. This is the analog input signal from the Codec (which is output on Tip and Ring). Connected via a 100nF capacitor. 14 nc No connect. This pin is not used and can be left open circuit.
15 VOUT
Audio Out. This is the analog output signal (from Tip and Ring) to the Codec. Connected via a 100nF capacitor. 16 F/R Forward/reverse. A logic 1 indicates that the Tip and Ring polarities are reversed. i.e. Tip is negative with respect to Ring. 17 LC Loop current. A logic 1 Indicates that loop current is flowing. 18 LSC Loop switch control. Applying a logic 1 closes the integral loop switch. 19 RS Ringing signal. A logic 0 indicates the presence of ringing voltage on the telephone line. Toggles at ringing frequency.
20 VREF
Reference voltage. Used with VTR to detect off-hook parallel phone. Normally left open circuit. Approx. +1.9V
21 VTR
Tip/Ring voltage. Indicates the voltage at Tip/Ring. Divided by 50 and relative to Vref.
V2.0 October 2002 Advance Data Sheet © Silver Telecom 2002 Page 4 Ag2120 FULLY FEATURED PSTN INTERFACE
1.2 SIL Pin-Out
Pin # Name Description 1 RING (B) Ring. Connects to the subscriber line Ring. 2 TIP (A) Tip. Connects to the subscriber line Tip. 3 CATHODE Cathode. For power cross protection connect to protection device cathode. 4 ANODE Anode. For power cross protection connect to protection device anode. 5 GATE Gate. For power cross protection connect to protection device gate. 6 DMb DC Mask b. A resistor is connected between this pin and DMa to adjust the d.c. characteristics of the termination. 7 DMa DC Mask a. A resistor is connected between this pin and DMb to adjust the d.c. characteristics of the termination. 8 LC Loop current. A logic 1 Indicates that loop current is flowing.
9 VIN
Audio In. This is the analog input signal from the Codec (which is output on Tip and Ring). Connected via a 100nF capacitor.
10 VOUT
Audio Out. This is the analog output signal (from Tip and Ring) to the Codec. Connected via a 100nF capacitor. 11 LSC Loop switch control. Applying a logic 1 closes the integral loop switch. 12 GND Analog ground. Normally connected to system ground. 13 VCC Positive supply. Must be connected to +5V or +3.3V. 14 F/R Forward/reverse. A logic 1 indicates that the Tip and Ring polarities are reversed. i.e. Tip is negative with respect to Ring. 15 Zb Balance network. The network balance matching components are connected between this pin, VIN and GND.
16 ZT2
2 Wire matching network 2. The 2 wire impedance matching network is connected between this pin and ZT1. The compensation impedance Zc is connected between this pin and Zb.
17 ZT1
2 Wire matching network 1. The 2 wire impedance matching network is connected between this pin and ZT2. 18 RS Ringing signal. A logic 0 indicates the presence of ringing voltage on the telephone line. Toggles at ringing frequency.
19 VREF
Reference voltage. Used with VTR to detect off-hook parallel phone. Normally left open circuit. Approx. +1.9V
20 VTR
Tip/Ring voltage. Indicates the voltage at Tip/Ring. Divided by 50 and relative to Vref.
V2.0 October 2002 Advance Data Sheet © Silver Telecom 2002 Page 5 Ag2120 FULLY FEATURED PSTN INTERFACE
2.0 Line Interfacing
The Ag2120 line interface provides a flexible and robust interface to the telephone line. It has been designed to meet regulatory standards whilst providing a space and power efficient solution. 2.1 D.C. Termination. Any equipment terminating a telephone line must present the correct d.c. resistance to the line. This ensures that the correct current flows to be able to detect the off hook condition, avoids excessive power dissipation in the Subscriber Line Interface (SLIC) and the Subscriber’s equipment, and minimises the size of power supply needed to drive the SLIC. The Ag2120 has been designed to meet the requirements of many network operators. This is done by making the d.c. characteristic adjustable. These are controlled by connecting the DM pins on the line side of the circuit. Table 1 shows how these are connected. Table 1 Set Up of the DM Pins Market DMa DMb North America (EIA 464, Resistive) Connect together through 390K resistor Europe (CTR21) Connect together through 390K resistor Far East Connect together through 390K resistor 2.2 Signalling and Loop Status. The Ag2120 provides facilities to monitor and control the telephone line. This allows the device to be used with a variety of loop signalling schemes and minimises the number of external components needed to implement a complete line interface. In order to implement ground start applications please contact Silver Telecom or our local representative.
2.2.1 The On-Board Loop Switch
The Ag2120 implements the loop start protocol when initiating and answering a call. This means that a switch must be closed to allow loop current to flow, signalling to the SLIC that the terminating equipment has gone “off-hook”. This has been done historically by a relay. The Ag2120 uses an integral optically isolated switch to do this, eliminating the need for an external relay, so space and cost is saved for the user. The on-board Loop Switch is controlled by the LSC pin. A logic 1 applied to the pin closes the loop switch. This is done when the terminating equipment wishes to begin a call or in response to the reception of the ringing signal. The LSC pin can be controlled by the output drive pins of a Codec or from a micro controller device. Once the Loop Switch has been closed confirmation that loop current is flowing is provided by the LC pin. This can be used for fault detection and for call clear detection. 2.2.2 Ringing Detection and Sensitivity. The terminal equipment must be capable of detecting and responding to an incoming call in the same way as a telephone set. The termination circuitry must, therefore, detect the presence of the ringing signal. The Ag2120 provides an output, RS, which indicates the presence of ringing by switching from a logic 1 to logic 0. The RS output will toggle at the ringing frequency. A capacitor to ground can also be added if ringing cadence is needed rather than the ringing frequency. The sensitivity to ringing is set internally to 22V RMS when VCC is +5V, or 14VRMS when VCC is +3.3V.
2.2.3 Reversal Detect
The reversal of the battery polarity is used as a signalling technique. The Ag2120 can detect this condition and provides an output on the F/R pin, whether in the on-hook or off-hook state. One example of this type of signalling is in Caller Line ID in the United Kingdom, where a battery polarity reversal precedes the transmission of data before the ringing signal is applied to the line. Another example is in some systems in the US where a reversal is used to indicate far end answer. 3.0 The 2-4 Wire (Hybrid) Conversion. The Ag2120 transmits and receives balanced 2-wire analog signals at the Tip and Ring connections. These are converted to a ground referenced output at V OUT and from a ground referenced signal at VIN. VOUT and V IN are normally connected to a Codec (via d.c. blocking capacitors) for conversion to and from a Pulse Code Modulated (PCM) stream. 3.1 Transmit and Receive Gain. The gain in both the transmit and receive directions is set at 0dB. Any gain adjustments can be made using the Codec functionality. This is either by hardware or software depending upon the Codec used.
V2.0 October 2002 Advance Data Sheet © Silver Telecom 2002 Page 6 Ag2120 FULLY FEATURED PSTN INTERFACE eg. 2-wire Impedance ZT ZC Network Balance Impedance Zb1 Zb2 Zb3 C3 Notes 1 600Ω 300Ω 47K 600Ω 100K 0R --- --- USA Short Line, Far East, Middle East
2 CTR21 TBA TBA CTR21 TBA TBA TBA TBA Europe
3 600Ω 300Ω TBA AT&T compromise TBA TBA TBA TBA USA Long Line
3.2 The 2 Wire Impedance
The input impedance, Z IN, of the Ag2120 can be programmed. This is achieved by connecting an impedance matching network between Z T1 and Z T2. This network is the line impedance to be matched minus 300Ω. For example to match 600 Ω, fit a 300 Ω resistor. Other common line impedances, and the corresponding programming components are listed in Table 2. In addition to the programming network, an impedance, Z FC, must be fitted between ZT2 and Zb to provide frequency compensation. An alternative method of programming the 2 wire impedance is to choose a codec where the internal filter characteristics can be programmed to provide the correct matching. In order to generate the filter coefficients a model of the Ag2120 must be used. This file, in .CIR format is available on request from Silver Telecom or one of our representatives. Full details on how the Codec is programmed must be obtained from the Codec manufacturer.
3.3 Network Balance Impedance
The setting of the network balance impedance is very similar to that of the 2 wire impedance. Again this can be done by programming of the Codec, using the .CIR file, or it can be done by hardware components.
3.4 On-Hook Reception
The need to provide the facility for data exchange On-Hook is becoming increasingly common, whether for Caller Line I.D. or for telemetry purposes. TheFor 600ΩΩΩΩ application: R1 = 390K Zb1 = 100K Zb2 = 0R Zb3 = NF ZT = 300R ZC = 47k C1, C2 = 100nF C3 = NF Table 2: Line and Network Balance Impedance Examples Figure 4: Line Impedance and Network Balance Components VCC Zb1 Ag2120 VIN VOUT RS LC LSC RING TIP DMa VCC Zb DMb GND GND Silver T E L E C O M Codec Zb2 GND F/R Zb3 ZT ZC ZT1 ZT2 GATE ANODE CATHODE
V2.0 October 2002 Advance Data Sheet © Silver Telecom 2002 Page 7 Ag2120 FULLY FEATURED PSTN INTERFACE Ag2120 can receive signals On-Hook, presenting a high impedance to the line, i.e. while drawing a very small current (5µµµµA approx) from the line.
3.5 Ringer Load Networks
The “dummy ringer” is usually a capacitive/resistive load which is connected across TIP/RING. During a call it is of sufficiently high impedance not to affect the operation of the interface. The Ag2120 meets the dummy ringer requirements for CTR21 (Europe), USA and Asia. 4.0 Device Protection. As with many of the requirements which must be met by the Ag2120 the device protection is dependent upon regulatory standards in the market in which the equipment is deployed. Some examples are given below, but these are not exhaustive. For a more comprehensive overview of protection refer to the Silver Telecom protection applications note, which is available directly form Silver Telecom, via our web-site (www.silvertel.com), or through our local representative. 4.1 FCC Pt 68 Requirements. To withstand the FCC Pt68 longitudinal voltage surge of 1500V no protection is required as the barrier will withstand 1500V peak voltage to GND. To withstand the FCC Pt68 metallic surges at 800V requires a 130V AC varistor (which clamps at 300V which is the rating of the loop switch transistor). A 14mm device should be used to withstand the two 100A 10/560us surges. Examples of suitable devices are:- Joyin JVR-14N201K; Walsin VZ14D201KBS Note: If varistors to ground are used for added protection (e.g. more than 1500V) customers should be aware that the FCC test generator for longitudinal tests is rated at up to 1000A. 10 Ω 2W wire wound surge limiting resistors will also be needed. 4.2 UL1459 and UL1950 Protection. To meet the UL1459 and UL1950 mains cross test 22Ω 2W wire wound surge resistors and 0.35A special fuses (Bussman C515 or Littelfuse 220003) in a balanced configuration are required. Alternatively a Teccor F1250T fuse may be used without surge limiting resistors. It is also possible to use PTC thermistors to meet these tests. The Raychem TR600-150 is designed for this application. See Raychem application notes for further details. A typical application is shown in figure 6a. 4.3 Other Standards. The Ag2120 has provision for low cost mains cross protection (CCITT K21): a 47 Ω 2W wire wound surge resistor and a PTC thermistor are sufficient to meet regulatory approvals. A suitable device is the Walsin PTD3A350H26. (Metallic protection with a single device is all that is required as the Ag2120 will withstand longitudinal voltages up to 1000Vrms to ground without additional protection). As an option, for improved off-hook power cross Figure 5: Typical Application VIN VOUT RS LC LSC Z b DMa DMb TIP RING GND LOUT LIN Processor Interface Protection Circuit VCC Protection circuit depends upon precise application VCC T E L E C O M Silver Zb2 Zb1 PTC Ag2120 AGPIO F/R VoicePump VP140 DSP Protection Circuit For 600R line and balance impedance: R1 = 390k Zb1 = 100k Zb2 = 0R ZT = 300 ΩΩΩΩ ZC = 47k C1, C2, C4 = 100nF C3 = NF C5 = 10uF Typical protection: PTC = TR600-150 (Raychem) X1 = TVB200SA (Raychem) PTC ZC ZT ZT1 ZT2 VoicePump DSP shown for illustration purposes. Ag2120 can interface to any codec
V2.0 October 2002 Advance Data Sheet © Silver Telecom 2002 Page 8 Ag2120 FULLY FEATURED PSTN INTERFACE protection, the Ag2120 has been designed to interface directly to the STM TPP25011. This protection arrangement is shown in figure 6b.
5.0 Regulatory Standards
There are some aspects of international standards which are not fully met by the Ag2120. These are shown below. It is Silver Telecom’s policy to bring to the attention of customers all known exceptions. The Ag2120 meets the requirements of EN60950 (1992) paragraph 6.2.1.2 for all countries except Norway and Sweden. Please contact Silver Telecom if the product is needed for Norway or Sweden. User/Network safety from mains power voltage be provided externally by a power supply with reinforced or double insulation.
6.0 Layout
Signal tracks should be kept as short as possible. Special attention should be paid to DMa and DMb, as these are sensitive nodes. Figure 6: Protection Options Ag2120 RING TIP GATE ANODE CATHODE Central Office Line TPP250 hook PTC Central Office Line Ag2120 RING TIP GATE ANODE CATHODE PTC Fig 6a: Standard Protection Fig 6b: Protection for Off-hook
V2.0 October 2002 Advance Data Sheet © Silver Telecom 2002 Page 9 Ag2120 FULLY FEATURED PSTN INTERFACE
7.0 Absolute Maximum Ratings*
All Voltages are with respect to ground unless otherwise stated. Parameter Sym Min Max Units 1 DC supply voltage V CC -0.3 6.0 V
2 DC battery voltage present between Tip and Ring (on-hook) V TR 300 V
3 Maximum voltage on programmable pin, LSC -0.3 6.0 V 4 Maximum power dissipation per trunk @ 25°C PTRUNK 0.75 W 5 Maximum power dissipation per module @ 25°C PTOT 3.0 W
6 Maximum loop current I LOOP 90 mA
7 Maximum ringing current (for 0.5 second) I RING 185 mA
8 Storage Temperature T S -40 +100
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 air flow.
8.0 Recommended Operating Conditions*
All Voltages are with respect to ground unless otherwise stated. Parameter Symbol Min Typ Max Units 1 DC supply voltage (+5V operation) V CC 4.75 5.0 5.25 V 2 DC supply voltage (+3.3V operation) V CC 3.0 3.3 3.6 V
3 DC battery voltage on Tip and Ring
(on-hook) VTIP VRING -48 -120 -120 V V
4 DC loop current I LOOP 02 5 8 5 m A
5 Operating Temperature T OP 02 5 7 0
O C *Typical figures are at 25°C with nominal +5V supplies and are for design use only.
V2.0 October 2002 Advance Data Sheet © Silver Telecom 2002 Page 10 Ag2120 FULLY FEATURED PSTN INTERFACE 9.0 DC Electrical Characteristics. Characteristic Sym Min Typ Max Units Test Comments
1 Supply current (per trunk),
3 ICC 2.5 4.0 mA 2 Loop current range I LOOP 14.0 85.0 mA Status outputs, RS, F/R Output low voltage Output high voltage V OL VOH 4.5 0.4 V V +5V operation @ 50µA @ -50µA Status outputs, RS, F/R Output low voltage Output high voltage VOL VOH 2.8 0.4 V V +3.3V operation @ 50µA @ -50µA Control input, LSC Input low voltage Input high voltage VIL VIH 4.5 0.3 V V +5V operation Control input, LSC Input low current Input high current IIL IIH 500 100 µA µA +5V operation Control input, LSC Input low voltage Input high voltage VIL VIH 2.8 0.3 V V +3.3V operation Control input, LSC Input low current Input high current IIL IIH 500 100 µA mA +3.3V operation Status output LC Output low voltage Output high voltage VOL VOH 4.5 0.5 V V +5V operation @ 50µA @ -50µA Status outputs LC Output low voltage Output high voltage V OL VOH 2.8 0.5 V V +3.3V operation @ 50µA @ -50µA 9 Off-hook DC voltage 5.7 V ILOOP = 20mA DMa-DMb = TBA
10 Leakage current, Tip and Ring to
analog ground ILA 35 µA 100VDC
11 Leakage current on-hook, Tip to
Ring ILTR 35 µA All DC Electrical Characteristics are over the Recommended Operating Conditions with V CC at +5.0V +5%, unless otherwise stated.
1 For test circuit details please contact Silver Telecom
2 Typical figures are at 25°C with nominal +5V supply and 25mA loop current, unless otherwise stated. These figures are for de sign aid only. 3 Operating currents are dependant on the users application.
V2.0 October 2002 Advance Data Sheet © Silver Telecom 2002 Page 11 Ag2120 FULLY FEATURED PSTN INTERFACE 10.0 AC Electrical Characteristics. Characteristic Sym Min Typ* Max Units Test Comments
1 Ringing voltage: detect
Ringing voltage: no detect VRD 26 22 22 18 VRMS +5V operation
2 Ringing voltage: detect
Ringing voltage: no detect VRD 18 14 14 10 VRMS +3.3V operation
3 Ringing frequency FR 15 68 Hz
4 Input Impedance at V IN 100 kΩ
5 Output impedance at V out 10 Ω
6 Absolute voltage gain, 2 Wire to
-0.5 +0.5 dB Off-hook
7 Absolute voltage gain, VIN to
2 Wire -0.5 +0.5 dB Off-Hook 8 On-hook gain, 2 Wire to V OUT -0.5 +0.5 dB
9 Relative gain, referenced to
1kHz. 2Wire - Vout, Vin - 2Wire -0.5 +0.5 dB 200 - 3400 Hz
10 Total harmonic distortion @
THD 0.1 1.0 % @0dBm, 1kHz
11 Overload distortion @2 Wire and
12 Common mode rejection ratio CMRR 70 75 dB 50 – 500Hz
V CM = 60VRMS
13 Common mode overload level CMOL 250 300 VRMS 50 – 60Hz
14 Idle channel noise
NC 12.0 dBrnC @2 Wire & VOUT
15 Power supply rejection ratio
PSRR 25 dB Ripple 0.1V, 1kHz on V CC
16 Return loss
17 Transhybrid loss
18 Metallic to longitudinal balance 60
19 Leakage current, Tip or Ring to
analog ground ILA 5 mARMS 1000V ac All AC Electrical Characteristics are over the Recommended Operating Conditions with V CC at +5.0V +5%, unless otherwise stated. *Typical figures are at 25°C with nominal 5V supply and 25mA loop current unless otherwise stated. These figures are for desig n aid only. 1 For test circuit details please contact Silver Telecom. 2 These figures fpr+5V operation. For +3.3V operation, OD is typically 5% at +3dBm.
3 In the off-hook condition
4 Into a 600Ω impedance
V2.0 October 2002 Advance Data Sheet © Silver Telecom 2002 Page 12 Ag2120 FULLY FEATURED PSTN INTERFACE
11.0 Mechanical Specification and Pin Assignation
11.1 Ag2120D – DIL Package
Tip (A) Ring (B) Cathode Anode DMa DMb GateGND Z b NC F/R LSC VTR RS LC V OU T VIN VCC 89 7 2120 Pin Names Top View Tip (A) Ring (B) Cathode Anode DMa DMb GateGND Z b NC F/R LSC VTR RS LC V OU T VIN VCC ZT1ZT2 ZT2 ZT1 VREF VREF Silver Telecom recommends the use of 2mm sockets, especially on prototype and pre-production boards. Recommended PCB hole diameter = 0.9 ± 0.05 mm 19.0 54.0 2.0mm 11.002.0mm 3.5mm Bottom View 42.0m 5.0 mm 5.0 mm Not To Scale
V2.0 October 2002 Advance Data Sheet © Silver Telecom 2002 Page 13 Ag2120 FULLY FEATURED PSTN INTERFACE
11.1 Ag2120S – SIL Package
Information published in this data sheet is believed to be correct and accurate. Silver Telecom assumes no liability for errors which may occur or for liability otherwise arising out of use of this information or infringement of patents which may occur as a result of such use. No license is granted by this document under patents owned by Silver Telecom or licensed from third parties by Silver Telecom. The products, their specifications and information appearing in this document are subject to change by Silver Telecom without notice. Ag2120SAg2120S pin 1 Ring (B) Tip (A) Cathode Anode Gate DMb DMa LC V IN VOUT LSC GND V CC F/R Z B ZT2 ZT1 RS VTR VRE F 12.0mm 61mm 4.0 Ag2120SAg2120S 1.6mm 0.6 ± 0.05 11.0mm 2.8mm Silver Telecom recommends the use of 2.54mm sockets, especially on prototype and pre-production boards. Recommended PCB hole diameter = 1.1 ± 0.05 mm
V2.0 October 2002 Advance Data Sheet © Silver Telecom 2002 Page 14 Ag2120 FULLY FEATURED PSTN INTERFACE
12.0 Change Sheet
Number Description of Change Change implemented 8 Aug 2002 V1.0 First issue. CB
27 Sept 02
7 Oct 2002
V1.1 V2.0 Include VREF on DIL, and VREF and VTR on SIL Fill in various TBA’s CB SE