MH88615 ONS Subscriber Line Interface Circuit Advance Information Features ISSUE 1 • ONS SLIC • Variants April 1995 Ordering Information MH88615-1 MH88615-3 MH88615-7 - 1 Germany - 3 UK 20 Pin SIL Package 20 Pin SIL Package 20 Pin SIL Package - 7 North America • Transformerless 2W to 4W conversion • Battery Feed to line • Off-Hook and dial pulse detection • Tip and Ring ground over-current protection • Power Denial • Integral Ringing Amplifier • Programmable Loop Current • Wide V BAT Operating Range Description The Mitel MH88615 ONS SLIC provides a complete interface between a switching system and a subscriber loop. The functions provided by the MH88615 include battery feed and integral ringing amplifier feed to the subscriber line, 2W to 4W conversion current feed, off-hook and dial pulse detection. The device is fabricated as a thick film hybrid in a 20 pin single-in-line package. Applications Line Interface for • PABX • Pair Gain Systems • Satellite Communication Systems • Key Telephone Systems • Marine Systems • Cordless Local Loop PD RING DCRI VBat Power Denial TIP 0°C to 70°C Tip & Ring Drivers RV Ringing Control 2-Wire to 4-Wire Conversion RC VR VX VRef Loop Supervision Constant Current Feed CAP SHK Figure 1 - Block Diagram 2-139 MH88615 Advance Information TIP RING NC DCRI LPGND VBat NC VDD AGND VEE RC PD NC SHK VR VRef CAP VX NC RV 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 Figure 2 - Pin Description Pin Description Pin # Name 1 TIP 2 RING 3 NC 4 DCRI 5 LPGND 6 VBat 7 NC 8 VDD Positive Supply Voltage. +5V dc supply rail. 9 AGND Analogue Ground. VDD and VEE return path. 10 VEE Negative Supply Voltage. -5V dc supply rail. 11 RC Ringing Control. This input enables the ringing voltage feed to Tip and Ring for subscriber line. 12 PD Power Denial. A logic high will isolate the battery voltage for Tip and Ring. 13 NC No Connection. This pin may be used for internal connections. 14 SHK Switch Hook Detect. A logic high indicates when subscriber line has gone off-hook. 15 VR 16 VRef Reference Voltage. A dc reference voltage is applied to this pin to set the constant current feed to subscriber line. This pin may also be grounded for normal 25mA loop current. 17 CAP Ring Trip Filter Capacitor. A capacitor is normally connected from this pin to ground and filters out low frequency ringing signals, preventing false off-hook conditions. 18 VX Transmit Signal. This is the 4 wire analogue signal transmitted from subscriber’s set. 19 NC No Connection. This pin may be used for internal connections. 20 RV Ringing Voltage. 1.5 Vrms signal is injected to this pin. 2-140 Description Tip Lead. Connects to the “Tip” lead of subscriber line. Ring Lead. Connects to the “Ring” lead of subsriber line. No Connection. This pin may be used for internal connections. DC Ringing Voltage Input. A continuous 120 Vdc is applied to this pin. This voltage is the positive supply rail for the internal ringing amplifier for subscriber line. Battery Ground. VBat return path for subscriber line. Connects to the systems’s energy dumping ground. Battery Voltage. Battery supply feed for subscriber line. Typically -48Vdc is applied to this pin. No Connection. This pin may be used for internal connections. Receive Signal. This is the 4 wire analogue signal received at subscriber’s set. MH88615 Advance Information Functional Description Power Denial The Mitel MH88615 ONS SLIC provides a complete interface between a switching system and a subscriber loop. The functions provided by the MH88615 include battery feed and integral ringing amplifier feed to the subscriber line, 2W to 4W conversion, constant current feed, off-hook and dial pulse detection. The device is fabricated as a thick film hybrid in a 20 pin single-in-line package. A logic high voltage applied to the power denial input effectively removes the battery voltage from the loop driver circuitry. The resulting loop current is negligible and power consumption is minimised. The power denial function is useful for disabling a loop which may have a ground fault. The MH88615 is intended for applications where low cost and basic functionality is important. The MH88615 features an integral ringing amplifier which enables a system designer to provide typically 60 Vrms ringing without having to generate a high voltage, high current ac signal. The SLIC uses a transformerless 2-4 wire converter which can be connected to a CODEC to interface the 2 wire subscriber loop to a TDM (time division multiplex) PCM (pulse code modulation) digital link. Powering of the subscriber line is provided though precision battery feed resistors on the hybrid. The thick film hybrid circuit also contains control, signalling and status circuits which combine to provide a complete functional solution. A power denial facility is provided which isolates the Battery Feed from Tip and Ring. The MH88615 is designed to meet German regulatory approvals, UK regulatory approvals (BS6305), and capable of meeting the approvals for the USA (FCC Part 68/EIA 464). The SLIC is capable of detecting and indicating offhook and unbalanced conditions as well as inhibiting ringing while in power denial. Input and Network Impedance The Input and Network Balance Impedances are defined by the variant type on the MH88615. MH88615-1Germany Zin = 220Ω + (820Ω//115nF) Znet = 220Ω +(820Ω//115nF) MH88615-3 UK Zin = 370Ω + (620Ω//310nF) Znet = 300Ω + (1000Ω//220nF) MH88615-7 North America Zin = 600Ω Znet = 350Ω (1kΩ//210nF) Ringing Amplifier The loop current is programmed by the dc reference voltage applied to VRef. The MH88615 incorporates an integral ringing amplifier. A nominal 1.5Vrms ac signal is applied to the RV pin and this produces a ringing signal of typically 60 Vrms. This should ensure that the SLIC can support a REN of 5. Switch Hook Detection Transmit Gain When the dc current exceeds an internal threshold level, the switch hook output (SHK) will go high. If the loop resistance is so high that V Bat can no longer supply the required loop current, the output SHK will go low. This indicates that the loop resistance is too high and the line is on hook. Transmit gain (Tip-Ring to Vx) is fixed at 0.dB. A dcbias on the ac input signal does not effect the ringing signal. DC Loop Current Limit Receive Gain (VR to TIP-RING) is fixed at 0dB. Constant Current Feed Under Tip or Ring ground conditions the loop current is nominally limited to 42mA. Receive Gain For correct gain, the SLIC input impedance must match the line impedance 2-141 MH88615 Advance Information Absolute Maximum Ratings*- Voltages are with respect to AGND. Parameter 1 2 Supply Voltages Symbol Min Max Units Comments VBat VDD VEE VDCRI 0.3 -0.3 0.3 -0.3 65 6 -6 140 V V V V With respect LPGND TS -55 125 °C Storage Temperature With respect LPGND * Exceeding these values may cause permanent damage. Functional operation under these conditions is not implied. Recommended Operating Conditions Characteristics Sym Min Typ* Max Units VBat VDD VEE VDCRI -20 4.75 -4.75 0 -48 5.0 -5.0 48 -60 5.25 -5.25 130 V V V V 0 20 70 °C 60 90 68 VRMS Hz 1 Supply Voltages 2 Operating Temperature TOP 3 AC Ring Generator Voltage Frequency VR FR Comments VBAT= -48V 17 * Typical figures are at 25°C with nominal +5V supplied and are for design aid only. DC Electrical Characteristics* Characteristics 1 Supply Current Sym Min Typ IDD IEE IBat 2 Power Consumption PC 3 Constant Current Line Feed ILoop 23 4 Adjustable Loop Current Range ILoop 18 5 Maximum Operating Loop Resistance RLoop 1200 6 Ring Ground Over-Current 7 Off-Hook Detect Output Low Voltage Output High Voltage VOL VOH Off-Hook Detect Output Low Current Output High Current 8 9 10 Units 10 5 2.5 mA mA mA PD on 150 1700 mW mW Standyby Active 27 mA V Ref = AGND 30 mA Ω 42 mA 0.4 V V IOL IOH 4 -400 mA µA RC, PD Control Input Input Low Voltage Input High Voltage VOL VOH 0.7 V V RC, PD Control Input Input Low Current Input High Voltage IIL IIH -500 500 µA µA * -48V and are for design aid only 2-142 25 Max Test Comments VBat=-48V @ ILoop=18mA, RLoop=includes telephone set Active High Logic 2.7 Active High Logic 2.0 MH88615 Advance Information AC Electrical Characteristics* Characteristics 1 Ringing voltage Sym Min VR FR 17 Typ‡ Max Units Test Comments 68 Vrms Hz Superimposed on VBat= -48V. RV=1.5 Vrms 38 2 Ring Trip Detect Time 3 Input Impedance at VR 4 Output Impedance at Vx 5 Gain 2-wire to Vx -0.25 0 0.25 dB 6 Frequency Response 2-wire to Vx -0.15 0 0.15 dB 7 Gain Vr to 2-wire -0.25 0 0.25 dB 8 Frequency Response Vr to 2-wire -0.15 0 0.15 dB 9 Total Harmonic Distortion 0.5 % 10 Common Mode Rejection Ratio 11 Idle Channel Noise 12 Power Supply Rejection Ratio at 2Wire or VX 47 100 ms 100 kΩ Ω 10 THD CMRR 50 Relative to 1kHz 300 Hz to 3.4 kHz dB Nc PSRR Relative to 1kHz 300Hz to 3.4 kHz 12 25 dBrnC dB Ripple 0.1V 1kHz @ VDD * Exceeding these values may cause permanent damage. Functional operation under these conditions is not implied. ‡ Typical figures are at 25°C and are for design aid only. Note 1: All of the above test conditions use a test source impedance which matches the device’s impedance. Note 2: THD is measured with “A Weight” filter. AC Electrical Characteristics*- MH88615-1 Characteristics Sym Min REN 5 Typ Max Units Test Comments 1 Ringer Equivalence 2 Return Loss RL 20 24 20 3 Transhybrid Loss THL 24 dB 300 Hz - 3.4 kHz 4 Longitudinal to Metallic Balance 32 54 dB dB 50 Hz - 300 Hz 300 Hz - 4 kHz 1 REN= 8000Ω @ 25 Hz dB dB dB 200 Hz - 500 Hz 500 Hz - 2.5 kHz 2.5kHz - 3.4 kHz * Exceeding these values may cause permanent damage. Functional operation under these conditions is not implied. Note: Return Loss reference impedance are defined by variant type. Transhybrid Loss is measured when terminated with network impedance. AC Electrical Characteristics*- MH88615-3 Characteristics Sym Min REN 4 Typ Max Units Test Comments 1 Ringer Equivalence 2 Return Loss RL 20 dB 300 Hz - 3.4 kHz 3 Transhybrid Loss THL 20 dB 300 Hz - 3.4 kHz 4 Longitudinal to Metallic Balance 52 dB 300 Hz - 3.4 kHz 4 REN= 2200Ω @ 25 Hz * Exceeding these values may cause permanent damage. Functional operation under these conditions is not implied. Note: Return Loss reference impedance are defined by variant type. Transhybrid Loss is measured when terminated with network impedance. 2-143 MH88615 Advance Information AC Electrical Characteristics*- MH88615-7 Characteristics Sym Min REN 5 Typ Max Units Test Comments 1 Ringer Equivalence 2 Return Loss RL 24 dB 300 Hz - 3.4 kHz 3 Transhybrid Loss THL 20 dB 300 Hz - 3.4 kHz 4 Longitudinal to Metallic Balance 52 dB 300 Hz - 3.4 kHz 1 REN= 5000Ω @ 30 Hz * Exceeding these values may cause permanent damage. Functional operation under these conditions is not implied. Note: Return Loss reference impedance are defined by variant type. Transhybrid Loss is measured when terminated with network impedance. Side View 0.25 Max (6.4 Max) 0.29 Max (7.4 Max) 2.1 Max. (106.7 Max.) 0.750 Max. (19.0 Max.) 1 2 3 19 20 4 0.010 + 0.005 (0.25 + 0.13) 0.12 Max * Notes: 1) Not to scale 2) Dimensions in inches). 3) (Dimensions in millimetres). *Dimensions to centre of pin & tolerance non accumulative. 0.05 + 0.02 (1.3 + 0.5) * 0.05 + 0.020 (1.25 + 0.5) 0.020 + 0.005 (0.5 + 0.13) Figure 3 - Mechanical Data 2-144 0.100 + 0.010 (2.54 + 0.25) 0.180 + 0.02 (4.6 + 0.5)