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| (R) MH88614 Programmable CODEC SLIC Advance Information Features * * * * * * * * * * * * Transformerless 2-wire to 4-wire conversion Battery Feed Ringing & Messaging Facility Power Down with Wake Up output Automatic Ring Trip Programmable Constant Current Earth Ground Button detection Switch Hook detection Interface for a programmable CODEC Ring ground over-current protection Impedance reflection Loop Length Indication MH88614 ISSUE 2 April 1995 Ordering Information 30 Pin SIL Package 0C to 70C Description The SLIC provides a complete interface between an industry standard programmable CODEC or DSP and a subscriber loop. Functions provided include battery feed, zero crossing ring control, programmable current feed, power down with wake up signal, cadenced messaging facility, switch hook & dial pulse detection, loop length indication and the capability of reflecting a programmable CODEC's impedance or supplying a standard 600 ohm impedance to the line. The device is fabricated as a thick film hybrid using various technologies for optimum circuit design high reliability. Applications Line Interface for * PABX * * * Intercoms Key Telephone Systems Control Systems VX VR Loop SHK EGB LA WU LCA RE MSE PD 2W-4W Converter Line Drivers & Battery Feed TIP RING Loop Supervision Constant Current Control Switch Circuits VMSG VRNG VEE VDD VBAT AGND BGND Figure 1 - Functional Block Diagram 2-129 MH88614 IC IC TIP IC RING LOOP BGND WU EGB IC VBAT IC PD AGND VDD VEE IC VR IC VX 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 IC LCA IC LA IC VRING VMSE RE MSE SHK Advance Information 21 22 23 24 25 26 27 28 29 30 Figure 2 - Pin Connections Description Pin Description Pin # 1 2 3 4 5 6 7 Name IC IC TIP IC RING LOOP BGND Internal Connection Internal Connection Connects to the "Tip" lead of the telephone line. Internal Connection Connects to the "Ring" lead of the telephone line Loop Length Indication. The output on this pin is proportional to the loop length / resistance, and is valid for off hook conditions only. Battery Ground. This pin is the return pin for the battery feed to the line and also for the message voltage supply and the Ring Voltage supply. This pin should normally be connected to AGND. Wake Up(Output). When in the power down mode this pin goes high to indicate the phone has gone off hook. When this occurs the power down signal should be removed. Earth Ground Button Detection (Output) This output goes low when the ring lead or tip lead is grounded. Internal Connection Battery Feed Supply. This pin is the supply for the line feed. (Typically -48V). Internal Connection Power Down (Input) Applying a logic 0 (Active low) will Power down the hybrid. This may be used, but must be removed to allow a call to be made or to reduce power consumption. Analog Ground. This pin is the return pin for the positive and negative supplies and is normally connected to BGND. Positive Supply. (Typically +5V). Negative Supply. (Typically -5V). Internal Connection Receive (Input). The audio input signal is applied to this pin from the programmable CODEC. This signal is internally a.c. coupled 8 9 10 11 12 13 14 15 16 17 18 WU EGB IC VBAT IC PD AGND VDD VEE IC VR 2-130 Advance Information Pin Description- (Continued) Pin # 19 20 21 22 23 24 Name IC VX IC LCA IC LA Internal Connection Description MH88614 Transmit (Output). The audio output signal appears on this pin and is internally a.c. coupled. This signal is applied to the programmable CODEC. Internal Connection Loop Current Adjust (input). The circuit has two constant current settings that are logic selectable Internal Connection Loop Alarm (Output) When the loop impedance exceeds the maximum limits that the SLIC can support for a specified voltage & current this output will go low. This indicates that the SLIC will no longer support the line. Note: This pin will also pulse low if Loop Disconnect Dialling is performed, and goes low when the phone is on hook. Internal Connection Ring Voltage Supply. This pin is the supply for the Ringing signal to the telephone. (Typically 90VRMS on -48V battery). Message Voltage Supply. This pin is the supply for the message signal to the telephone. (Typically -100V) Ring Enable (Input). The ringing signal is applied across Tip & Ring by applying a logic 1 to this pin while the phone is "On Hook". Ringing will be automatically stopped when the phone goes "Off Hook" regardless of the state of the RE pin. Message Signal Enable (Input). A cadenced signal can be applied to this pin which will switch the VMSG voltage onto Tip & Ring. The output voltage is internally conditioned to prevent bell tinkle on the telephone. This is automatically switched off when the phone goes off hook. Switch Hook (Output). The output of this pin goes low when the phone goes "Off Hook" and can be used externally to switch MSE off. 25 26 27 28 IC VRING VMSE RE 29 MSE 30 SHK Functional Description The MH88614 is an ONS SLIC for use with a programmable / intelligent CODEC or DSP. The SLIC performs all of the normal interface functions between the CODEC and the analog telephone set whilst having such additional features as Earth Ground Button Detection, message switching and Ringing switching with zero crossing. The MH88614 is available as a 30 pin SIL package to increase board densities. Loop Supervision The Loop Supervision circuit monitors the state of the phone line and provides three different output stages. When the phone goes "Off Hook" the SHK pin goes low to indicate this state. This pin reverts to a high state when the phone goes back "On Hook" (see figure 3). When the phone is off hook the circuitry can also detect two other features of the line status namely Earth Ground Button & Loop Alarm. A logic low signal on the Earth Ground Button output indicates that an earth ground path has been applied to the Tip or Ring lead of the telephone. This function can be used for recall operations on phone sets with Earth Ground Buttons. The Loop Alarm signal low to indicate that the R Loop has been exceeded and that the circuit will no longer support the line. 2 Wire to 4 Wire Conversion The hybrid performs 2 wire to 4 wire conversion by taking the 4 wire signal from the programmable CODEC at VR and converting it to a 2 wire differential signal at Tip & Ring. The 2 wire signal applied across Tip & Ring by the phone is converted to 4 wire signal at Vx which is the output from the SLIC to the programmable CODEC. Both the VR input & Vx output are internally a.c. coupled. 2-131 MH88614 The hybrid also provides an output which is proportional to the loop length / resistance. LA must be high for ILoop to be valid. R Loop = - [(10 x VLoop)-1.5] ILoop Advance Information Europe by allowing an impedance to be reflected through the SLIC from the CODEC or DSP module. The outputs at tip & ring protected from short term over voltage between tip & gnd, ring to gnd or tip to ring reducing the requirement for secondary protection circuitry. There is also long term protection on the outputs against short circuits applied across tip & ring, tip to gnd, ring to gnd and tip & ring to gnd. - 82 Where VLoop = the voltage at Loop ILoop = the programmed line current Constant Current Control Whilst working within the RLoop maximum limit set by the I Loop & VBat levels chosen the circuit allows the loop current to be set to one of the two discrete levels by the use of the loop current adjust pin. Applying a logic low to this pin sets the constant current to the lowest level. By changing the level to a logic high the constant current is set to the highest level. This feature can be used with the loop alarm signal when setting up the line to chose the loop current setting most suitable. Switch circuits There are three switches built into the functionality of this circuit, they are Ringing Enable, Message Signal Enable and Power Denial. Ringing Enable allows a logic level to be applied to a pin and the ringing voltage superimposed on a d.c. level to then be switched onto the line. The ringing signal applied to the line at zero voltage crossing and switched off at zero current. (see figure 3). The ringing signal can be terminated by either returning the Ringing Enable pin to a logic low level or it will automatically stop when the phone goes off hook regardless of the state of the input pin. The Message Signal Enable pin provides the switching control of the message voltage. A logic high on the MSE pin applies the message voltage to the line. Internal circuitry allows the input signal to MSE to be cadenced, causing the output signal to be cadenced, without causing bell tinkle. This is possible by conditioning the rising and falling edges of the output signal. Message Signal Enable also has auto trip facility. Line Drivers & Battery Feed The Line Drivers & Battery Feed circuit provide power to the line and allow bi-directional audio transmission. The line impedance present by the line driver circuitry is a nominal 600 ohms, allowing the circuit to be used on its own in a PABX application. The nominal impedance can be modified to look like a complex impedance such as those used within RE IRING SHK 1 0 30/45mA ILOOP 0mA On Hook tt Off Hook tt Figure 3 - Call Supervision 2-132 Advance Information MH88614 MSE Uncadenced trdr MSE cadenced trdr trda RE trda - MSE should be removed at least 200ms before applying RE. trdr - RE should be removed at least 120ms before applying MSE. Figure 4 - Call & Message Indication When applying ringing and message signal to the phone the two signals should be applied separately to minimise total power consumption. Figure 4 indicates how the timing of this process could best be achieved for cadenced and uncadenced message signalling. Power Denial can be applied at any time to remove the line from service. The Power Denial input enables the line to be isolated from the battery under fault conditions or for maintenance purposes. A logic low will remove the battery feed whilst a logic high will provide power to the line. Absolute Maximum Ratings* Parameter 1 DC Supply Voltage Symbol VDD VEE VBAT VRING VMSG Min -0.3 +0.3 0.3 Max +15 -15 -60 130 -180 300 IRING IMSG 45 6 60 Units V V V VRMS V V mA mA mA VDC + AC PEAK MAX 1ms (with power on) Comments 2 3 4 5 6 7 Ringing Voltage Message Voltage Overvoltage Tip/Gnd Ring/Gnd, Tip/Ring Ringing Current Message Current Short Circuit current (continuous), Tip/Gnd, Ring/Gnd, Tip/Ring Storage Temp Package Power Dissipation 8 9 TSTG PDISS -40 +100 2.5 C W TAMB 70C max * Exceeding these values may cause permanent damage. Functional operation under these conditions is not implied. 2-133 MH88614 Recommended Operating Conditions Characteristics 1 Operating Supply Voltage VDD VEE VBat VRING 4.75 -4.75 -22 50 5.00 -5.00 -48 90 5.25 -5.25 -60 100 Sym Min Typ* Max Advance Information Units V V V VRMS Comments 2 Ringing Voltage 3 4 Message Voltage Operating Temperature VMSG TO 0 -100 25 -130 70 V C 17 to 55 Hz on a DC bias of -22V to -60V VDC + AC PEAK VBat ILoop -48V 45mA * Typical figures are at 25C with nominal+ 5V supplies and are for design aid only: not guaranteed and not subject to production testing. DC Electrical Characteristics - Voltages are with respect to GNDA unless otherwise stated. Characteristics 1 Supply Current Sym IDD IEE IBat PC Min Typ* 10 10 10 300 1800 50 25 40 RLoop 30 45 Max 15 15 60 400 Units mA mA mA mW mW mW mA mA mA mA 200 1.5 4 5 A mA V MSE = LOW MSE = HIGH VMSG = -100V IMSG = 3mA Test Conditions PD =High Standby, VBat = -48V LCA = Low, (Off Hook) PD = Low LCA=Low LCA=High ILoop = 45mA ILoop = 30mA VBAT = -48V ILoop = 30mA VBAT =-22V 2 Power Consumption 3 4 Constant Current Line Feed Operating Loop (Inclusive of Tele. Set) 35 50 750 1150 400 5 6 7 8 9 10 Off Hook Detection Threshold Unbalanced Detection VMSG Leakage Current VMSG Bias Current VMSG Voltage Drop LCA, MSE, RE, PD Input Low Voltage Input High Voltage EGB, SHK, LA, WU Output Low Voltage Output High Voltage Loop Output Voltage VLoop 0 -5 10 SHK 10 EGB 2 VIL VIH 2.0 0.4 2.4 0.8 V V IiI = -2mA Iih = 0.4mA 11 VOL VOH 0.4 2.4 V V V lol = 2mA loh = -0.4mA PD = High SHK = Low (Off Hook) VBat = -48V 12 Averaged level with no load applied, and a cadence of 1s "On", 3s "Off". * Typical figures are at 25C with nominal+ 5V supplies and are for design aid only: not guaranteed and not subject to production testing. 2-134 Advance Information AC Electrical Characteristics Characteristics 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 Auto Ring Trip/Message Trip Detect Time Impedance (2W) Return Loss (2W) Transhybrid Loss Impedance at VR Impedance at VX Gain VR to 2W @ 1kHz Gain Relative to 1kHz Gain 2W to VX @ 1kHz Gain Relative to 1KHz Longitudinal to Metallic Balance at 2W Harmonic Distortion @ VX and 2W Max. Signal Level @ VX and 2W Common Mode Rejection Ratio @ 2W Idle Channel Noise @ 2W @ VX Power Supply Rejection 2W and VX CMRR Nc 12 15 PSRR VDD VEE V BAT 25 25 25 35 35 40 4 5 dBrnc dBrmc dB dB dB Vrms 40 LCL THD 48 -0.3 -0.3 Sym tt Zin RL THL MH88614 Min Typ* 100 600 22 18 30 20 100k 10 0 +0.3 0 +0.3 56 0.1 1.1 50 1 0.3 0.3 Max 150 Units ms dB dB dB dB dB dB dB % Vrms dB Test Conditions VBAT -48V No External Feedback AC coupled via 0.1F AC coupled via 0.1F ZTERM @ 2W = 600 ZSOURCE @ VR < 10 300-3400Hz ZSOURCE @ 2W = 600 ZLOAD @ VR > 100k 300-3400Hz 300-3400Hz 0.1Vrms @ 1kHz 1kHz THD < 10% 0.5Vrms @ 1kHz CMess. Filter CMess. Filter 0.3Vp-p @ 1kHz 16 17 VRING Voltage Drop I RNG = 10mA RMS * Typical figures are at 25C with nominal+ 5V supplies and are for design aid only: not guaranteed and not subject to production testing. The 2W impedance and THL are modified to the required value by external feedback applied by the programmable codec to the hybrid where required. Values quoted are for the hybrid on its own with no external feedback. Ref. 600, 300Hz to 3400Hz 2-135 MH88614 Applications This SLIC has been designed to be used with minimal external components in applications where programmable CODEC's or DSP's are used. Advance Information Figures 5& 6 show a typical application where the MH88614 is connected to a programmable CODEC and a phone. Secondary Protection Circuit MH88614 Vx CODEC VR Tip SD4-7 Ring SDO-3 Figure 5 - Typical System Application Loop Tip Ring MH88614 VX VR SHK EGB LA WU LCA RE PD MSE VIN VOUT SD0 SD1 SD2 SD3 SD4 SD5 SD6 SD7 PROGRAMMABLE CODEC VMSG BGND VDD AGND VRNG VSS VDD VSS GND +5V -100V 90VRMS (on -48V) -5V GND Figure 6 - Interconnection Diagram 2-136 Advance Information MH88614 Side View 0.1 Max (2.54 Max) Note 4 3.00 + 0.02 (76.2 + 0.5) 0.600 Max (15.0 Max) 1 30 0.010 + 0.002 (0.25 + 0.13) 0.175 Max (4.45 Max) * 0.05 typ (1.25 typ) * Notes: 1) Not to scale 2) Dimensions in inches). 3) (Dimensions in millimetres). *Dimensions to centre of pin & tolerance non accumulative. 0.050 + 0.02 (1.25 + 0.5) 0.020 + 0.005 (0.51 + 0.13) * 0.18+ 0.02 (4.6+ 0.5) 0.100 + 0.010 (2.54 + 0.26) Figure 7- Mechanical Diagram 2-137 MH88614 Notes: Advance Information 2-138 |
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