Obsolescence Notice This product is obsolete. This information is available for your convenience only. For more information on Zarlink’s obsolete products and replacement product lists, please visit http://products.zarlink.com/obsolete_products/ MH88500 Hybrid Subscriber Line Interface Circuit (SLIC) Preliminary Information ISSUE 5 Features April 1995 Ordering Information • • • Differential to single ended conversion No transformers required Minimum installation space • • • • • • • Off-Hook detection and LED indicator drive Relay drive output Battery and ringing feed to line Logic interface: MUTE, OFHK, RC Mute of incoming audio Dial pulse detection Voltage surge protection Applications Line Interface for: • PABX • Intercoms • Key Systems VA1 MH88500 20 Pin SIL Package 0°C to 70°C Description The Zarlink MH88500 Subscriber Line Interface Circuit provides a complete interface between the telephone line and a speech switch requiring only single bidirectional switch per crosspoint. The functions provided by the MH88500 include bidirectional differential to single ended conversion in the speech path, line battery feed, ringing feed and loop and dial pulse detection. The device is fabricated as a thick film hybrid in a 20-pin ‘single-inline’ package allowing optimum circuit board packing density. VA2 VC1 VB GND TIP RING RING FEED Loop Feed/ Ring Feed JUNCTOR Speech Circuit VA2 VB MUTE CD OFHK RD RC RGND Loop Detection Relay Drive Circuit LED THRESH ADJ VC2 Figure 1 - Functional Block Diagram 1 MH88500 Preliminary Information TIP VA1 RING RING FEED IC VC1 GND VB LED OFHK THRESH ADJ VA2 GND VC2 MUTE JUNCTOR RD RGND RC CD 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 2 Pin # Name Description 1 TIP Tip Lead. Connects to the “Tip” lead (A-wire) of the telephone line. 2 VA1 Positive Line Feed Supply Voltage. Normally connected to VA2. 3 RING 4 RING FEED 5 IC Internal Connection. Leave open circuit. Use for testing only. 6 VC1 Sense Input. Normally connected to negative line feed voltage supply. 7 GND 8 VB 9 LED 10 OFHK 11 THRESH ADJ 12 VA2 13 GND 14 VC2 15 MUTE 16 JUNCTOR 17 RD 18 RGND Ground for Relay Drive Circuit. 19 RC Ring Control Input. Active high. 20 CD Clamping Diode. Normally connected to relay positive voltage. Ring Lead. Connects to the “Ring” lead (B-wire) of the telephone line. Negative Line Feed Voltage and Ringing Input. Normally connected to Ring Relay. Analog ground (0V). Internally connected to pin 13. Negative Analog Supply Voltage. LED Drive Output. Drives an LED directly. Off-Hook condition, logic low. Logic Low Output. Indicates closed loop condition (Off-Hook and dial pulsing). Allows adjustment of OFHK detection threshold. Positive Power Supply Voltage. Normally connected to VA1. Analog Ground (0V). Internally connected to pin 7. Loop Detector Voltage Supply.Connected to negative line feed voltages supply. Input mutes the incoming audio. Active low. Receive/transmit audio speech path. (referenced to 0V GND) Relay Drive Output. Open collector sinks current when RC high. Diode clamp protected. Preliminary Information MH88500 Functional Description Line Feed/Ring Feed Circuit Speech Circuit The line feed circuit provides loop current and the ability to apply ringing onto TIP and RING. The impedance from Ring Feed to GND is 600Ω which gives the loop current as: The speech circuit converts the bidirectional TIP and RING line pair to a bidirectional single ended junctor line. Figure 3 illustrates a typical connection between two SLIC’s through two crosspoint switches. This configuration gives optimum transhybrid loss as seen from Figure 4 given that the output impedance of the Junctor line is 604Ω . The MUTE input mutes signals coming from TIP and RING to the junctor line while allowing the signal from the junctor to the tip-ring pair to be transmitted. Loop Detection The loop detection circuit determines whether a low enough impedances is across TIP and RING to be recognized as an off-hook condition. IL = Voltage at RING FEED pin Telephone Impedance + 600 Amps The positive supply for the line feed circuit is VA1 through the loop current is determined from RING FEED and GND. Relay Drive Circuit The relay drive circuit switches ringing onto RING FEED (Fig.7). The diode is present to suppress voltage transients during relay switches caused by the inductive coils of the relay. Ringing voltage includes AC ringing (90V typically) an dDC line feed voltage (-24V typically). (Threshold impedance = 5.4kΩ with no adjustment) This threshold level can be adjusted by the use of external resistors as shown in Figure 6. OFHK has low output drive capability so it may drive CMOS operating with different power supplies. MH88500 75Ω 1 TIP 16 TIP JUNC RING 3 CROSSPOINT SWITCH RING MH88500 1 TIP 75Ω TIP 16 JUNC RING 3 RING CROSSPOINT SWITCH Figure 3 - SLIC Crosspoint Switch Connection 3 MH88500 Preliminary Information Absolute Maximum Ratings† Parameter 1 Symbol Voltage Supplies - VRef to GND Min Max VA1, VA2 V VB -18 VC1, VC2 -35 2 Clamp Diode Breakdown Voltage-VRef to RGND VCD 3 Operating Temperature TAMB 4 Storage Temperature TSTG 5 Power Dissipation Units +18 V V +15 V 0 +70 ˚C -40 +100 ˚C 1.2 Watt PD † Exceeding these values may cause permanent damage. Functional operation under these conditions is not implied. AC Electrical Characteristics† Voltages are with respect to ground (VSS), TA = 25˚C, unless otherwise stated. Test conditions unless noted, VA1=VA2=+7V, VB=8V, VC2=-24V(+5%). Characteristics Sym Min Typ‡ Max Units Test Conditions 1 Junctor to differential output (tipring) gain. AJL 2.18 2.25 7 2.32 V/V dB 1kHz, 400mVRMS source on pin 16. Note 2 2 Differential Input (tip-ring) to junctor gain ALJ 0.303 0.321 0.321 V/V dB 1kHz, 1VRMS Source on pins 1&3. Note 1,2 3 On/Off Hook Detection Threshold RThresh IThresh 4.0 3.6 5.4 4.0 6.0 5.3 kΩ mA Note 1. Note 1 Loop Resist Loop Current 4 Trans Hybrid Loss 55 dB Notes 1,2. See Figure 2 5 Passband Linearity +1 dB Notes 1,2 6 Power Supply Rejection Ratio (VC to Junctor) PSRR 40 dB Notes 1,2 7 Common Mode Rejection Ratio (Tip and Ring to Junctor) CMRR 40 dB Notes 1,2 8 Low Frequency Cutoff (3dB) Junctor to Line Line to Junctor FLLJ FLJL 53 20 Hz Hz Notes 1,2 Notes 1,2 High Frequency Cutoff (3dB) Line to Junctor Junctor to Line FHLJ FHJL 800 500 kHz kHz Notes 1,2 Notes 1,2 65 dB Note 1 ZI 300 Ω ZOJ 604 Ω 9 10 Longitudinal Balance 11 Tip (or Ring) to ground AC input impedance 12 Junctor output impedance † Exceeding these values may cause permanent damage. Functional operation under these conditions is not implied. ‡ Typical figures are at 25°C with nominal+ 5V supplies and are for design aid only: not guaranteed and not subject to production testing. Note 1: 754Ω connected between JUNCTOR (pin 16) and OV. Note 2: 604Ω connected between TIP (pin 1) and RING (pin 3). 4 Preliminary Information MH88500 . DC Electrical Characteristics Characteristics 1 2 Operating Supply Voltages S U P P L Y 3 Sym Min Typ‡ VA1,VA2 VB VC1,VA2 -13 -30 -24 Max Units +13 V V V Test Conditions -20 Operating Supply Currents 7 8 6 .2 .1 IA1 IA2 IB IC1 IC2 mA mA mA mA mA High Level Input Voltage MUTE RC VIH Low Level Input Voltage MUTE RC .8 1 V VIL High Level Input Current MUTE RC IIH IIH -28 700 µA µA Low Level input Current MUTE RC IIL IIL 100 1 µA µA ILED IRD 2 65 6 100 mA mA VOFHK, -6V CD=RC=5V,RGD=0V VRRD<1.5V Diode Clamp Current IRLY 65 100 mA RC=RGND=0V, CD=5V VRRD <1.5V High Level Output Voltage VOH 6 V LED Unconnected Low Level Output Voltage OFHK VOL -6.5 V LED Unconnected 11 High Level Output Current IOH 10 µA 12 Low Level Output Current IOL 10 µΑ 4 5 I N P U T S 6 7 9 10 VIL V V 4.2 3 Sink Current LED RD 8 VIH O U T P U T S ‡ Typical figures are at 25°C with nominal+ 5V supplies and are for design aid only: not guaranteed and not subject to production testing. TRANSHYBRID LOSS (dB) 10 20 30 40 50 60 550 600 650 700 750 800 850 900 950 LOAD IMPEDANCE ON JUNCTOR (Ω) Figure 4 - Return Loss VS Junctor Load Impedance 5 MH88500 Preliminary Information VO 754Ω 5 1 VTR 604Ω 54Ω 1 200Ω 16 VTR 5 604Ω 10µF MH88500 MH88500 VS 10H VX 3 16 3 CAN BE MEASURED THAT TRANSHYBRID LOSS = - 20LOG (VO) (b) 2VS VTP=2VX=2VTR (a) Figure 5 - Transhybrid Loss Test Circuit R and RTHRESH (kΩ ) R and RTHRESH (kΩ) GND (a) VC2 (a) R R MH88500 11 MH88500 11 THRESH ADJ THRESH ADJ (48 x RTHRESH) -28.8 R= 5.4 - RTHRESH R (kΩ) R= (912 x RTHRESH) +604 RTHRESH - 5.4 R (kΩ) 2000 120 100 80 1000 60 40 20 1 2 3 4 5 6 10 RTHRESH (kΩ) (a) Figure 6 - Off-Hook Threshold Adjust 6 20 30 40 RTHRESH (kΩ) (b) Preliminary Information MH88500 VA1 TIP LINE FEED/ RING FEED RING -24VDC -24VDC RING FEED +90VAC +V MH88500 CLAMP DIODE CD RELAY COIL RD RELAY DRIVE CIRCUIT RC RGND Figure 7 - Relay Drive Circuit 7 MH88500 Preliminary Information +7v +5V +5V CONTROL 00 01 02 03 04 05 06 07 A0 A1 A2 LOGIC -24VDC 90VAC -24VDC 2 12 ADDRESS OUT 1 TIP MH88500 19 3 RING 10 16 MD74SC137 1 OF 8 DECODER 9 20 17 4 15 8 6 14 7 -8V -24V 0V +5V +7V +5V 5 MORE SLICS -24VDC 90VAC -24VDC 00 01 A0 A1 A2 12 9 20 17 4 TIP 1 03 04 05 15 19 MH88500 3 06 07 10 02 2 8 16 -8V MD74SC137 1 OF 8 DECODER 6 14 -24V +7V +5V RING 7 0V +5V -24VDC 90VAC -24VDC 5 MORE SLICS A0-A2/D0-D3 J0 MT8812 J1 Crosspoint J2 Switch J3 -L7 L0 A0 A1 A2 CMOS 4512 8-INPUT MUX SELECT OUTPUT D0 D1 D2 | | D7 2 15 12 9 20 17 4 19 10 MH88500 RING 16 8 -8V Figure 8 - PABX Typical Application 8 1 TIP 6 14 -24V 7 0V 3 MH88500 Preliminary Information 0.080 Max (2.0 Max) Side View 2.00 + 0.020 (50.8 + 0.5) 0.52+0.02 (13.2+0.5) 1 2 3 4 19 20 0.010 + 0.002 (0.25 + 0.05) 0.12 Max (3.1 Max) Notes: 1) Not to scale 2) Dimensions in inches). 3) (Dimensions in millimetres). *Dimensions to centre of pin & tolerance non accumulative. 0.05 + 0.01 (1.3 + 0.5) * 0.05 + 0.02 (1.3 + 0.05) * 0.020 + 0.05 (0.51 + 0.13) * 0.18 + 0.02 (4.6 + 0.5) 0.100 + 0.10 (2.54 + 0.13) Figure 9 -Mechanical Data 9 MH88500 Notes: 10 Preliminary Information For more information about all Zarlink products visit our Web Site at www.zarlink.com Information relating to products and services furnished herein by Zarlink Semiconductor Inc. or its subsidiaries (collectively “Zarlink”) is believed to be reliable. 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