MH88634B Central Office Interface Circuit Advance Information Features • • • • • • • • • • • • DS5061 January 1999 Ordering Information MH88634BV-2 21 Pin SIL Package MH88634BT-2 21 Pin 90° L/F Package MH88634BV-4 21 Pin SIL Package Loop Start Trunk Interface 600Ω & 900Ω Input Impedance 2-4 Wire Conversion Line state Detection Outputs: - Forward Loop - Reverse Loop - Ringing Voltage - Switch Hook One Relay Driver On-Hook Reception Small footprint area Meets FCC Part 68 Leakage Current Requirements 0°C to 70°C Description The Mitel MH88634-2 Central Office Interface Circuit trunk provides a complete analogue and signalling link between audio switching equipment and a telephone Line. The device is available in a single in line package for high packing densities or with a lead frame formed at 90° for low clearance applications. The device is fabricated as a thick film hybrid incorporating various technologies for optimum circuit design and very high reliability. Applications Interface to Central Office for: • PABX • Key Telephone Systems • Channel Bank • Voice Mail • Terminal Equipment • Digital Loop Carrier • Optical Multiplexer RV ISSUE 6 FL RL SHK This part supercedes the MH88634-2 and is pin for pin compatible. We advise that the B rev parts are fully tested. However, we do not expect to see changes between MH88634-2 and MH88634BV-2. The component design has been changed to improve the general performance of the part. It is also now capable of operating at a 24V battery. VCC XLA XLB XLC XLD VEE AGND Status Detection TIP Dummy Ringer LRC Loop Relay Driver RX Transmit Gain TX 2 - 4 Wire Hybrid Line Termination RING LRD Receive Gain Impedance Matching Network Balance VRLY Figure 1 - Functional Block Diagram 2-265 MH88634B Advance Information TIP RING XLA XLD XLB XLC IC IC IC SHK RX VEE TX RV FL RL VCC AGND LRC VRLY LRD 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 Figure 2 - Pin Connections Pin Description Pin # Name 1 TIP 2 RING 3 XLA Loop Relay Contact A. Connects to XLB through the Loop relay (K1) contacts when the relay is activated. 4 XLD Loop Relay Contact D. Connects to XLC through the loop relay (K1) contacts, when the relay is activated. 5 XLB Loop Relay Contact B. Connects to XLA through the loop relay (K1) contacts, when the relay is activated. 6 XLC Loop Relay Contact C. Connects to XLD through the loop relay (K1) contacts, when the relay is activated. 7-9 IC 10 SHK 11 RX 12 VEE 13 TX Transmit (Output). 4-Wire ground (AGND) referenced analog output. 14 RV Ringing Voltage Detect (Output). A logic low indicates that ringing voltage is across the Tip and Ring leads. 15 FL Forward Loop Detect (Output). In the on-hook state, a logic 0 output indicates that forward loop battery is present. In the off-hook state, a logic 0 indicates that forward loop current is present. 16 RL Reverse Loop Detect (Output). In the on-hook state, a logic 0 output indicates that reverse loop battery is present. In the off-hook state, a logic 0 output indicates that reverse loop current is present. 17 VCC 2-266 Description Tip Lead. Connects to the "Tip" lead of a Telephone Line. Ring Lead. Connects to the "Ring" lead of a Telephone Line. Internal Connection. No connection should be made to this pin. Switch Hook (Output). A logic 0 indicates the presence of forward or reverse battery voltage when LRC is logic 0 and the presence of forward or reverse loop current when LRC is logic 1. Receive (Input). 4-Wire ground (AGND) referenced analog input. Negative Supply Voltage. -5V DC Positive Supply Voltage. +5V DC MH88634B Advance Information Pin Description (continued) 18 AGND Analog Ground. 4-wire ground (AGND). Normally connected to system ground. 19 LRC Loop Relay Control (Input). A logic 1 activates the Loop Relay Driver output (LRD). 20 VRLY Relay Positive Supply Voltage. Typically +5V. Connects to the relay supply voltage. 21 LRD Loop Relay Drive (Output). Connects to the Loop Relay Coil. When LRC is at a logic 1 an open collector output at LRD sinks current and energizes the relay. Functional Description Line Termination The MH88634 is a Central Office Interface Circuit (COIC). It is used to correctly terminate a Central Office 2-wire telephone line. The device provides a signalling link and a 2-4 Wire line interface between the Telephone Line and subscriber equipment. The subscriber equipment can include Private Branch Exchanges (PBXs), Key Telephone Systems, Terminal Equipment, Digital Loop Carriers and Wireless Local Loops. When LRC is at a logic 1, LRD will sink current which energizes the Loop Relay (K1), connecting XLA to XLB and XLC to XLD. This places a line termination across Tip and Ring. The device can be considered to be in an off-hook state and DC loop current will flow. The line termination consists of a DC resistance and an AC impedance. When LRC is at a logic 0, the line termination is removed from across Tip and Ring. All descriptions assume that the device is connected as in the application circuit shown in Figure 3. An internal Dummy Ringer is permanently connected across Tip and Ring which is a series AC load of (17kΩ+330nF). This represents a mechanical telephone ringer and allows ringing voltages to be sensed. This load can be considered negligible when the line has been terminated. Isolation Barrier The MH88634 provides an isolation barrier which is designed to meet FCC Part 68 (November 1987) Leakage Current Requirements. External Protection Circuit An external Protection Circuit Device assists in preventing damage to the device and the subscriber’s equipment, due to over-voltage conditions. The type of protection required is dependant upon the application and regulatorary standards. Further details should be obtained from the specific country’s regulatorary body. Typically you will need lightening protection supplied by resettable fuses or PTCTM and mains crossover protection via a foldover diode. Suitable Markets The MH88634BV-2/BT-2 has fixed 600Ω line and network balance impedance for use in North America and Asia. The MH88634BV-4 has a fixed 900R impedance and is also suitable for some applications in North and South America Depending on the Network Protocol being used the Line Termination can terminate an incoming call, seize the line for an outgoing call, or if applied and disconnected at the correct rate can be used to generate dial pulse signals. The DC line termination circuitry provides the line with an active DC load termination which is equivalent to a DC resistance of 280Ω at 20mA Ringing Equivalent Number The Ringing Equivalent Number (REN) is application specific. See the governing regulatory body specification for details. Input Impedance The input impedance (Zin) is the AC impedance that the MH88634 places across Tip and Ring to terminate the Telephone line. This is fixed at 600Ω on the -2 variant and 900R on the -4. 2-267 MH88634B Advance Information Network Balance Impedance The MH88634BV-2/BT-2’s Impedance is fixed at 600Ω. Network Balance The MH88634BV-4 Network Balance Impedance is fixed at 900R. Ringing Voltage Detect Output (RV) The RV output provides a logic 0 when ringing voltage is detected across Tip and Ring. This detector includes a filter which ensures that the output toggles at the ringing cadence and not at the ringing frequency. Typically this output switches to a logic 0 after 50ms of applied ringing voltage and remains at a logic 0 for 50ms after ringing voltage is removed. 2-4 Wire Conversion The device converts the balanced 2-Wire input, presented by the line at Tip and Ring, to a ground referenced signal at TX. This circuit operates with or without loop current; signal reception with no loop current is required for on-hook reception enabling the detection of Caller Line Identification (CLI) signals. Conversely the device converts the ground referenced signal input at RX, to a balanced 2-Wire signal across Tip and Ring. The 4-Wire side (TX and RX) can be interfaced to a filter/codec, such as the Mitel MT896X, for use in digital voice switched systems During full duplex transmission, the signal at Tip and Ring consists of both the signal from the device to the line and the signal from the line to the device. The signal input at RX, being sent to the line, must not appear at the output TX. In order to prevent this, the device has an internal cancellation circuit. The measure of attenuation is Transhybrid Loss (THL). The threshold is different on the two variants. The 900R part has been designed to meet the ring sensitivity requirements of TR57, 30 not detecting ringin below 35Vrms. Forward Loop and Reverse Loop Detect Outputs (FL & RL) The FL output provides a logic 0 when either forward loop battery or forward loop current is detected, that is the Ring pin voltage is more negative than the Tip pin voltage. The RL output provides a logic 0 when either reverse loop battery or reverse loop current is detected, that is the Tip pin voltage is more negative than the Ring pin voltage. Switch Hook (SHK) The SHK output is active if either forward loop or reverse loop current is detected, or if forward or reverse battery voltage is detected. Control Input Transmit and Receive Gain The Transmit Gain of the device is the gain from the balanced signal across Tip and Ring to the ground referenced signal at TX. It is set at 0dB. The Receive Gain of the device is the gain from the ground referenced signal at RX to the balanced signal across Tip and Ring. It is set at -2dB. The MH88634 accepts a control signal from the system controller at the Loop Relay Control input (LRC). This energises the relay drive output Loop Relay Drive (LRD). The output is active low and has an internal clamp diode to VRLY. The intended use of this relay driver is to add and remove the Line Termination from across Tip and Ring, as shown in Figure 3. Supervision Features Line Status Detection Outputs The MH88634 supervisory circuitry provides the signalling status outputs which are monitored by the system controller. The supervisory circuitry is capable of detecting: Ringing Voltage; Forward and Reverse loop battery; Forward and Reverse loop current; and Switch Hook. 2-268 If this Control input and the Supervisory Features are used as indicated in Figure 3, Loop-Start Signalling can be implemented. Mechanical Data See Figure 9 specification. for details of the mechanical MH88634B Advance Information MH88634 +5V 1 Tip TIP VCC Protection Circuit 2 Ring TX 21 LRD RX 20 19 Loop Relay Control 5 3 K1 LRC XLB FL XLA 6 XLC 4 13 11 Analog Out Analog In VRLY RV K1 C1 RING +5V K1 17 RL SHK 14 15 16 10 Ringing Detect Forward Loop Reverse Loop Switch Hook XLD AGND VEE 18 C2 12 NOTES: 1) K1 Electro Mechanical 2 Form A 2) C1 and C2 are decoupling capacitors -5V Figure 3 - Typical LS Application Circuit 2-269 MH88634B Advance Information Absolute Maximum Ratings* Parameters 1 DC Supply Voltages 2 3 4 DC Ring Relay Voltage Storage Temperature Ring Trip Current Sym Min Max Units VCC VEE VRLY -0.3 0.3 -0.3 -55 7 -7 18 +125 180 V V V ˚C mArms TS Comments ITRIP 250ms 10% duty cycle or 500ms *Exceeding these values may cause permanent damage. Functional operation under these conditions is not implied. single shot Recommended Operating Conditions Parameters Sym Min Typ‡ Max Units 4.75 -4.75 5.0 -5.0 5.25 -5.25 V V 0 5.0 25 15 70 V ˚C 1 DC Supply Voltages 2 DC Ring Relay Voltage VCC VEE VRLY 3 Operating Temperature TOP ‡ Typical figures are at 25°C with nominal 5V supplies and are o f r design aid only. s DC Electrical Characteristics† Characteristics 1 Min Typ‡ Max Units 5 2.5 37.5 13 13 137 0.5 VBAT not connected IOL = 4mA IOH = 0.4mA VOL = 0.35V not continuous, LRC=5V Power Consumption ICC IEE PC Low Level Output Voltage High Level Output Voltage VOL VOH 2.4 4 FL RL SHK RV LRD mA mA mW V V Sink Current, Relay to VCC Clamp Diode Current IOL ICD 100 150 mA mA 5 LRC Low Level Input Voltage High Level Input Voltage High Level Input Current Low Level Input Current VIL VIH IIH IIL 2 3 6 Supply Current Sym LRC 0.8 2.0 40 40 † Electrical Characteristics are over recommended operating conditions unless otherwise stated. ‡ Typical figures are at 25°C with nominal 5V supplies and are o f r design aid only. 2-270 V V µA µA Test Conditions VIH = 5.0V MH88634B Advance Information DC Electrical Characteristics† Characteristics Symbol Min Typ‡ Max Units Test Conditions 90 150 Vrms -2 Variant only 17 to 68Hz -4 Variant only -4 Variant only 16-33Hz (TR57 compliant) 1 Ringing Voltage VR 40 2 Detect No Detect VR 60 106 35 Vrms 3 4 5 Operating Loop Current Off-Hook DC Resistance Leakage Current (Tip-Ring to AGND) SHK & FL Threshold Tip-Ring (On-hook) Tip-Ring Current (Off-Hook) SHK & RL Threshold Tip-Ring (On-Hook) Tip-Ring Current (Off-Hook) 16 70 280 7 mA Ω mArms 12 5 21 15 Vdc mA LRC = 0V LRC = 5V 12 -5 21 -15 Vdc mA LRC = 0V LRC = 5V 6 7 270 @ 20mA Note 1 @ 1000VAC † Electrical Characteristics are over recommended operating conditions unless otherwise stated. ‡ Typical figures are at 25°C with nominal 5V supplies and are o f r design aid only. Note 1: Maximum figure of 282Ω at 0°C 2-271 MH88634B Advance Information AC Electrical Characteristics† Characteristics Symbol 1 2-wire Input Impedance Zin 2 Return Loss at 2-wire RL 3 Longitudinal to Metallic Balance 4 5 Transhybrid Loss Gain, 2 wire to TX 6 Relative Gain Gain, Rx to 2 wire 7 8 9 10 THL Relative Gain Input impedance at RX Output impedance at TX Signal Overload Level at 2-wire at TX Total Harmonic Distortion at 2-wire Min Typ‡ 12 13 14 Idle Channel Noise at 2-Wire at TX Power Supply Rejection Ratio at 2-wire and TX VCC VEE On-Hook Gain, 2-Wire to TX Relative to Off-Hook Gain Met. to Long. Balance Ω 20 29 dB 58 55 53 20 60 60 58 27 dB dB dB dB -0.25 -0.3 0 0 0.25 0.3 dB dB -2.25 -0.3 -2 0 10 5 -1.75 0.3 dB dB kΩ Ω dBm dBm 1.0 % 1.0 % 16.5 16.5 dBrnC dBrnC Input 0.5V, 1kHz @ RX Input 0.5V, 1kHz @ Tip-Ring NC 15 15 PSRR Ripple 0.1V, 1kHz 25 25 -1 48 47 0 1 dB dB dB Input 1000Hz @ 0.5V Test Circuit as Fig. 8 CMRR 60 40 55 40 48 62 48 62 48 55 † Electrical Characteristics are over recommended operating conditions unless otherwise stated. ‡ Typical figures are at 25°C with nominal 5V supplies and are o f r design aid only. 2-272 -2 Variant -4 Variant Test Circuit as Fig 6 200-3400 Hz Test Circuit as Fig 7 200Hz 1000Hz 3400Hz 200-3400Hz Test Circuit as Fig 4 1000Hz 200-3400Hz Test Circuit as Fig 5 1000Hz 200-3400Hz THD -4 Variant Common Mode Rejection Ratio Test Conditions % THD < 5% @ 20mA 4.0 1.7 -2 Variant 15 Units 600 900 at TX 11 Max dB 200-1000Hz 1000-3400Hz 200-1000Hz 1000-3400Hz Test Circuit as Fig. 7 1000Hz, FL = 0V, ILoop = 25mA MH88634B Advance Information -V +5V -5V VCC VEE 10H 300Ω XLA 100uF XLB RING + I = 25mA XLC XLD ~ Vs = 0.5V 600Ω 100uF Vtx TX TIP + RX V AGND 10H 300Ω Gain = 20 * Log (Vtx/Vs) Figure 4 - 2-4 Wire Gain Test Circuit +5V -5V VCC VEE -V 10H 300Ω XLA 100uF XLB RING I = 25mA + XLC XLD VZ Z = 600Ω 100uF TX TIP RX + Vs = 0.5V ~ AGND 10H 300Ω Gain = 20 * Log (Vz/Vs) Figure 5 - 4-2 Wire Gain Test Circuit 2-273 MH88634B Advance Information +5V -5V VCC VEE -V 10H 300Ω XLA 100uF XLB RING 600Ω + I = 25mA XLC 368Ω Vs = 0.5V XLD V1 368Ω ~ 100uF TX TIP RX + AGND 10H 300Ω Return Loss = 20 * Log (V1\Vs) Figure 6 - Return Loss Test Circuit +5V -5V VCC VEE -V 10H 300Ω XLA 100uF XLB RING + I = 25mA XLC 368Ω XLD V1 368Ω Vtx VEX V 100uF TX TIP RX AGND + 10H 300Ω Long to Met Bal. = 20 * Log (V1\Vs) CMRR = 20 * Log (Vtx\Vs) - ( 2-4W Gain) Figure 7 - Longitudinal to Metallic Balance and CMRR Test Circuit 2-274 Vs = 0.5V ~ MH88634B Advance Information +5V -5V VCC VEE -V 10H 300Ω XLA 100uF XLB RING + I = 25mA 368Ω XLC XLD Vs = 0.5V ~ 510Ω V1 100uF TX TIP RX 368Ω + AGND 10H 300Ω Met to Long Bal. = 20 * Log (V1\Vs) Figure 8 - Metallic to Longitudinal Balance Test Circuit 0.13 Max (3.3 Max) 0.14 Max (3.6 Max) 2.120 Max (53.85 Max) 0.625 Max (15.9 Max) 1 0.180 + 0.020 (4.57 + 0.51) 0.010 + 0.002 (0.25 + 0.05) *0.250+0.020 (6.35+0.51) 0.020 +0.005 (0.5 +0.13) * 0.100 + 0.010 (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 tempetature 260˚C for 10 secs. * Dimensions to centre of pin. Figure 9 - Mechanical Data 2-275 MH88634B Advance Information 2.12 Max (53.85 Max) 0.62 Max (15.75 Max) 1 0.080 +0.020 (2.03 +0.51) 0.170 Max (4.32 Max) 0.080 Max (2.03 Max) Notes: 1) Not to scale 0.260 +0.015 (6.60 +0.38) 2) Dimensions in inches. (Dimensions in millimetres) 3) Pin tolerances are non-accumulative. 4) Recommended soldering conditions: Wave Soldering Max temp at pins 260˚ for 10 secs. * Dimensions to centre of pin. * 0.100 0.010 (2.54 0.25) 0.250 0.020 (6.35 0.51) Figure 10 - MH88634T-2 Mechanical Information 2-276 0.020 +0.005 (0.51 +0.13) 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. 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