MH88612BV-K Subscriber Line Interface Circuit (SLIC) Advance Information Features • • • • • • • • • DS5066 Transformerless 2-wire to 4-wire conversion Battery and ringing feed to line. Off-hook and dial pulse detection. . Ring ground over-current protection. Constant current feed with constant voltage foldover. Relay driver. Power Denial. Wide Operating Range. Pin for pin compatible 600R and 900R variants. Applications Line interface for: • • • • ISSUE 2 January 1999 Ordering Information MH88612BV-K MH88612BV-4K 20 Pin SIL Package (600R) 20 Pin SIL Package (900R) 0°C to 70°C Description The SLIC provides a complete interface between a switching system and a subscriber loop. Functions provided include battery feed and ringing feed to the subscriber line, 2-Wire to 4-Wire hybrid interfacing, constant current feed with constant voltage foldback, and dial pulse detection. The device is fabricated using thick film hybrid technology in a 20-pin single in-line package. PABX Intercoms Key Telephone Systems Control Systems LPGND VBAT PD VCC VEE AGND Constant Voltage Foldback TF TIP RING RF Power Management RV VRLY RC RD CD 2-Wire to 4-Wire Conversion Current and Voltage Sensing VR VX Over Current Protection Relay Drive Circuit Constant Current Feed Loop Supervision CAP SHK Figure 1 - Functional Block Diagram 1 MH88612BV-K Advance Information TF LPGND VR IC VEE AGND PD VX TIP RING RF VCC RC RD RV VRLY CD VBAT CAP SHK 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 Figure 2 - Pin Connections Pin Description Pin # Name Description 1 2 TF LPGND 3 4 5 6 7 8 9 10 11 VR IC VEE AGND PD VX TIP RING RF 12 13 14 15 VCC RC RD RV 16 17 18 VRLY CD VBAT 19 CAP Tip Feed. Connects to external diode for protection Loop Ground. Is the system ground reference with respect to VBAT. Normally connected to AGND. Voice Receive (Input). The 4 wire analog signal to the device. Internal Connection. No connection should be made to this pin Negative Power Supply Voltage (-5V). Analog Ground. Connects to System Ground (Earth). Power Denial (Input). A logic high will isolate the battery voltage to Tip/Ring. Voice Transmit (Output). The 4-wire analog signal from the device. Tip Lead. Connects to the "Tip" lead of the telephone line. Ring Lead. Connects to the "Ring" lead of the telephone line. Ring Feed (Input). Normally connected to Ring relay for negative battery feed voltage and ringing voltage input. Positive Power Supply Voltage (+5V). Relay Control (Input). Active high. Relay Drive. Open collector sinks current when RC is at logic high. Ring Feed Voltage. Normally connected to pin 11 (RF) through a normally closed relay and to external diode protection. Relay voltage Supply (+5V). Clamping Diode. Normally connected to AGND. Negative Battery Feed Supply Voltage (-48V). Battery supply for the Subscriber Line. Typically -48VDC is applied to this pin. Ring Trip Filter Capacitor. Normally connected via an external capacitor to ground to prevent false ring trip. Must be open circuit to allow dial pulse detection. 20 SHK Switch Hook Detect (Output). A logic level 1 will indicate that the Subscriber Line is in the ’Off-Hook’ state. Note 1: C4 in Figure 3 can be added permanently to this pin for certain dial pulse applications. 2 MH88612BV-K Advance Information Functional Description The SLIC performs a transformerless 2-wire to 4wire conversion of the analog signal. The 2-wire circuit is the balanced line going to the subscriber loop, while the 4-wire circuit is the audio signal going to and from devices such as the voice codec or switching circuit. The SLIC also provides a switch hook (SHK) status output which goes high when the telephone is set off-hook. Constant Current Feed The MH88612BV-K family employs complex feedback circuits to supply a constant current feed or, if necessary, constant voltage feed to the line. With a nominal -48V battery the device will supply a constant current of typically 25mA to a line up to 1100Ω. For longer lines there is insufficient battery voltage so the device automatically switches to constant voltage mode where Tip and Ring will stay at their minimum and maximum voltage levels and the supplied current will be reduced accordingly. The maximum line resistance supported is 2000Ω including the telephone set. Switch Hook Detection The SHK pin will go to logic 1 to indicate that a telephone connected to the line has gone off-hook (on-line). Off-hook will not be indicated if the loop resistance (including the telephone set) is too high for the device to support. The SHK output will toggle to indicate dial pulses on the line. If the capacitor on CAP (Pin 19) has not been switched out of circuit the dial pulses will be distorted. disconnect the ringing voltage from pin 11 and reconnect to pin 15. At that time the SLIC will revert to constant current feed operation. For applications requiring Dial Pulse Detection the Capacitor connection to ground C1 should be controlled such that the capacitor is disconnected during Pulse Dialling. If the signalling method is unknown, a capacitor of approximately 56nf should be permanently fitted between CAP (pin 19) and ground. This should be in addition to the capacitor mentioned in the above paragraph. During off-hook conditions (on-line), the capacitor (C1) should not have a low impedance path to ground. This can be achieved using a transistor (Q1) and resistor (R2) as shown in Figure 3, with R2 providing a high impedance path for C1. When ringing is applied (RC = 5V) the transistor will short circuit R2 which will give C1 a low impedance path to ground and provide the required filtering. Other methods can be used to switch out C1, such as a relay or a codec system drive output (with a similar configuration as above). For applications using DTMF signalling, C1 can be permanently connected to ground. Current Limit The Tip or Ring of the telephone line may accidentally be shorted to ground. In such a case, current will only flow through the feed resistor. This high current will be sensed and reduced by the current limit circuit to a lower value to protect the internal circuitry. Power Denial Ringing And Ring Trip Detection In Figure 3 a ringing signal (e.g.90 Vrms and -48Vdc) is applied to the line by disconnecting pin 15 (RV) from pin 11(RF), and connecting the ringing voltage at pin 11 (RF) by use of the relay K1. The SLIC can detect an off-hook condition during ringing but there is a large AC component which must be filtered out to give a true off-hook condition at SHK. The power denial function is a feature of the MH88612 which allows for powering down of the subscriber loop. A logic high voltage applied to the power denial input effectively removes the battery voltage from the loop driver circuitry. The resulting ILOOP is negligible and power consumption is minimised. The power denial function is useful for disabling a loop which may have a ground fault. A 1.0µF capacitor connected from pin 19 (CAP) to ground will provide adequate attenuation when ringing is applied. Once an off-hook condition has been detected a logic low should be applied to pin 13 (RC) which will deactivate the relay (K1) to 3 MH88612BV-K R1 Advance Information K1 11 RF MH88612BV-K VBAT ~ + D3 D4 90 VRMS 15 D1 D2 48V 1 2 9 TIP TF RV VR LPGND VX 8 TIP Protection Circuit SHK 10 RING RING 3 PD 13 20 7 RC 16 +5V VRLY 19 C1 C2 14 K1 CAP RD 17 CD Q1 -+ R3 R2 C4 VBAT VCC VEE 12 5 18 R4 AGND 6 C3 -48V +5V -5V Component List R1 = earth = ground 200Ω + 10%, 1/4W R2 470kΩ + 5%, 1/4W R3, R4 10kΩ + 5%, 1/4W C1 1.0µF, + 10%, 25V electrolytic capacitor C2, C3 0.1µF, + 20%, 50V ceramic de-coupling capacitors D1,D2, D3, D4 Diode rectifier 200V, 1A, IN4003 Q1 General purpose switching transistor K1 Relay E/M, 5V or 6V, 1 Form C C4 10nF - 56nF 20% 16V capacitor Protection Circuit - Depending on the application the Protection circuit may need to provide over-voltage and/or over-current protection. In certain circumstances no protection will be required. Figure 3 - Typical Application Circuit . 4 RC (Pin 13) MH88612BV-K Advance Information Absolute Maximum Ratings* Parameter 1 DC Supply Voltage LPGND = AGND 2 3 Storage Temperature Package Power Dissipation Symbol Min Max Units VCC VEE VBAT VRLY TS PD -0.3 -9 -60 -0.3 -40 9 0.3 0.3 40 100 2 V V V V °C W * Exceeding these values may cause permanent damage. Functional operation under these conditions is not implied. Recommended Operating Conditions Characteristics 1 Operating Supply Voltage 2 Relay Driver Current 3 Sym Min Typ‡ Max Units VCC VEE VBAT VRLY IRLY 4.75 -5.25 -54 5.0 -5.0 -48 5 5.25 -4.75 -42 100 V V V V mA To 0 70 °C Test Conditions ‡Typical figures are at 25˚C with nominal 5V supplies and are for design aid only. DC Electrical Characteristics† - Voltages are with respect to GNDA unless otherwise stated. Characteristics 1 Supply Current Sym VCC VEE VBAT ICC IEE IBAT 2 Power Consumption 3 Constant Current Line Feed ILoop 4 Operating Loop Resistance RLoop 5 Ring Ground Over-Current protection Off-Hook Detect Output Low Voltage (On-hook) Output High Voltage (Off-hook) RC, PD Control Input Input Low Volt (no activation) Input High Volt (activation) RC, PD control Input Input Low Current (no activation) Input high current (activation) PD Control Input Input Low Current Input High Current 6 7 8 9 Min Max 7.5 -5.1 23 15 3 160 1600 25 16.5 Units 27 19 mA mA µA mA mW mW mA mA 2000 Ω 45 mA 0.4 V V 0.7 V V 800 PC VOL VOH Typ‡ 2.7 Test Conditions PD = Logic High PD = Logic Low, Idle Standby VBAT = -48V Active (Off Hook) RLoop <1100Ω RLoop ≤2000Ω VBAT = -48V VBAT = -48V @ ILoop = 16mA, RLoopincludes telephone set VBAT = 48V Active high logic IOL = 8mA IOL = -100mA Active high logic VIL VIH 2.0 IIL 50 µA IIH 0.5 mA IIL IIH 0.5 0.3 mA mA LSTTL compatible † DC Electrical Characteristics are over recommended operating supply voltages. ‡Typical figures are at 25˚C with nominal 5V supplies and are for design aid only. 5 MH88612BV-K Advance Information AC Electrical Characteristics Characteristics 1 2 3 4 Ringing Voltage Frequency Ringer Equivalence Number Ring Trip Detect time Input AC Impedance 2-wire 5 6 7 Input Impedance at VR Output Impedance at VX Gain 2-wire to VX 8 90 25 2 300 Vrms Hz Gain relative to Gain @ 1kHz Gain VR to 2-wire -0.3 -1.3 -1.0 +0.3 -0.7 dB Gain relative to Gain @ 1kHz -0.3 +0.3 dB 11 Longitudinal to Metallic Balance Total Harmonic Distortion at VX at Tip and Ring Common Mode Rejection Ratio 2-wire to VX Idle channel Noise Power supply rejection ratio VCC VEE VBAT Zin THL Test Conditions Superimposed on VBAT = -48V MH88612BV-K MH88612BV-4K Input + 3dBm, 1kHz across Tip and Ring 300-3400 Hz Input 0.5Vrms 1kHz at VR ZLoad = 600Ω 300 - 3400 Hz 20 30 dB Input 0.5Vrms, 1kHz across Tip and Ring ZLoad= 600Ω 300-3400 Hz ZLoad= 600Ω 20 30 dB 40 46 55 55 dB dB 300-600Hz 600-3400Hz Input + 3dBm, 1kHz across Tip and Ring Input 1.0Vrms 1kHz at VR THD 0.1 1.0 % 0.1 1.0 % dB CMRR 40 Nc Input 0.5Vrms, 1kHz 50 +14 dBrnC @ 2 Wire and VX C- Message weighted PSRR ‡Typical figure are at 25°C and are for design aid only. 6 Units -0.7 Transhybrid Loss 15 17 Max -1.3 10 14 VRING FRING REN Typ‡ ms Ω Ω kΩ Ω dB 2-wire Return Loss over 300-3400Hz 13 Min 200 600 900 100 10 -1.0 9 12 Sym 26 26 26 dB dB dB 100 mVPP ripple, 1kHz on VCC/VEE/VBAT, measure at VX and across Tip and Ring MH88612BV-K Advance Information 0.08 Max 0.12 Max (2.03 Max)(3.05 Max) 2.02 Max (51.30 Max) 0.50 max (12.70 max) 1 0.18 + 0.02 (4.57 + 0.51) 0.02 + 0.005 (0.51 + 0.13) 0.01 + 0.002 (0.25 + 0.05) *0.05 + 0.02 (1.27+ 0.51) * 0.10+ 0.01 (2.54 + 0.25) Notes: 1) Not to scale 2) Dimensions in inches. (Dimensions in millimetres) 3) Pin tolerances are non-accumulative. 4) Recommended soldering conditions: wave soldering max. temp: 260˚C for 10 secs. * Dimensions to centre of pin. Figure 4 - Mechanical Data 7 http://www.mitelsemi.com World Headquarters - Canada Tel: +1 (613) 592 2122 Fax: +1 (613) 592 6909 North America Tel: +1 (770) 486 0194 Fax: +1 (770) 631 8213 Asia/Pacific Tel: +65 333 6193 Fax: +65 333 6192 Europe, Middle East, and Africa (EMEA) Tel: +44 (0) 1793 518528 Fax: +44 (0) 1793 518581 Information relating to products and services furnished herein by Mitel Corporation or its subsidiaries (collectively “Mitel”) is believed to be reliable. However, Mitel assumes no liability for errors that may appear in this publication, or for liability otherwise arising from the application or use of any such information, product or service or for any infringement of patents or other intellectual property rights owned by third parties which may result from such application or use. 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