HC55185 TM Data Sheet November 2001 VoIP Ringing SLIC Family Features The RSLIC-VoIP family of ringing subscriber line interface circuits (RSLIC) supports analog Plain Old Telephone Service (POTS) in short and medium loop length, wireless and wireline applications. Ideally suited for remote subscriber units, this family of products offers flexibility to designers with high ringing voltage and low power consumption system requirements. • Onboard Ringing Generation The RSLIC-VoIP family operates to 100V which translates directly to the amount of ringing voltage supplied to the end subscriber. With the high operating voltage, subscriber loop lengths can be extended to 500Ω (i.e., 5,000 feet) and beyond. Other key features across the product family include: low power consumption, ringing using sinusoidal or trapezoidal waveforms, robust auto-detection mechanisms for when subscribers go on or off hook, and minimal external discrete application components. Integrated test access features are also offered on selected products to support loopback testing as well as line measurement tests. There are five product offerings of the HC55185 with each version providing voltage grades of high battery voltage and longitudinal balance. The voltage feed amplifier design uses low fixed loop gains to achieve high analog performance with low susceptibility to system induced noise. File Number 4831.8 • Compatible with Existing HC5518x Devices • Low Standby Power Consumption (75V, 65mW) • Reduced Idle Channel Noise • Programmable Transient Current Limit • Improved Off Hook Software Interface • Integrated MTU DC Characteristics • Low External Component Count • Silent Polarity Reversal • Pulse Metering and On Hook Transmission • Tip Open Ground Start Operation • Balanced and Unbalanced Ringing • Thermal Shutdown with Alarm Indicator • 28 Lead Surface Mount Packaging • Reduced Footprint Micro Leadframe Packaging • Dielectric Isolated (DI) High Voltage Design Applications • Voice Over Internet Protocol (VoIP) • Cable Modems • Voice Over DSL (VoDSL) • Short Loop Access Platforms Block Diagram • Remote Subscriber Units POL ILIM CDC DC CONTROL VBL VBH BATTERY SWITCH • Terminal Adapters RINGING PORT VRS Related Literature • AN9814, User’s Guide for Development Board TIP RING TL SW+ SW- • AN9824, Modeling of the AC Loop 2-WIRE PORT TRANSIENT CURRENT LIMIT TEST ACCESS TRANSMIT SENSING 4-WIRE PORT VRX VTX -IN VFB • Interfacing to DSP CODECs (Contact Factory) • TB379 Thermal Characterization of Packages for ICs • AN9922, Thermal Characterization and Modeling of the RSLIC18 in the Micro Leadframe Package DETECTOR LOGIC CONTROL LOGIC RTD RD E0 DETALM BSEL SWC 1 F2 F1 F0 CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures. 1-888-INTERSIL or 321-724-7143 | Intersil (and design) is a trademark of Intersil Americas Inc. Copyright © Intersil Americas Inc. 2001. All Rights Reserved. RSLIC18™ is a trademark of Intersil Americas Inc. HC55185 Ordering Information LONGITUDINAL BALANCE HIGH BATTERY (VBH) PART NUMBER 100V 85V 75V • HC55185AIM • HC55185BIM FULL TEST TEMP. RANGE oC PACKAGE • • -40 to 85 28 Ld PLCC N28.45 • • -40 to 85 28 Ld PLCC N28.45 • • -40 to 85 28 Ld PLCC N28.45 • • -40 to 85 28 Ld PLCC N28.45 58dB 53dB • HC55185CIM • HC55185DIM HC55185ECM • • 0 to 75 28 Ld PLCC HC55185ECR • • 0 to 75 32 Pad MLFP HC55185FCM • • • 0 to 85 28 Ld PLCC HC55185FCR • • • 0 to 85 32 Pad MLFP PACKAGE NO. N28.45 L32.7x7/A † N28.45 L32.7x7/A † HC55185GCM • • • 0 to 85 28 Ld PLCC N28.45 HC55185GCR • • • 0 to 85 32 pad MLFP L32.7x7/A † HC5518XEVAL1 Evaluation board platform, including CODEC. Also available in Tape and Reel † Reference “Special Considerations for the MLF Package” text. Device Operating Modes MODE F2 F1 F0 E0 = 1 E0 = 0 HC55185A HC55185B HC55185C HC55185D HC55185E HC55185F HC55185G Low Power Standby 0 0 0 SHD GKD • • • • • • • Forward Active 0 0 1 SHD GKD • • • • • • • Unbalanced Ringing 0 1 0 RTD RTD Reverse Active 0 1 1 SHD GKD • • • • • • • Ringing 1 0 0 RTD RTD • • • • • • • Forward Loop Back 1 0 1 SHD GKD • • • • • • Tip Open 1 1 0 SHD GKD • • • • • • Power Denial 1 1 1 n/a n/a • • • • • • • • Device Pinouts 4 SW+ SW- 3 2 1 28 27 6 RD NC RING NC TIP †† 32 31 30 29 28 27 26 25 26 5 BGND †† VBL VBH ILIM HC55185 (MLFP) TOP VIEW RD RING TIP BGND VBL VBH HC55185 (PLCC) TOP VIEW SW+ 1 24 ILIM 25 RTD SW- 2 23 RTD 24 CDC SWC 3 22 CDC F2 4 F1 5 21 VCC 20 -IN SWC 7 23 VCC F2 8 22 -IN F0 6 19 VFB F1 9 21 VFB E0 7 18 VTX 17 18 AGND BSEL TL POL VRS 2 NC TL VRS 16 POL 15 BSEL 14 AGND 13 17 VRX 9 10 11 12 13 14 15 16 ALM 12 †† 8 DET 19 VRX 11 ALM E0 20 VTX 10 DET F0 NC †† CAUTION: Tabs connected to substrate / VBH. †† HC55185 Absolute Maximum Ratings TA = 25oC Thermal Information θJA (oC/W) Maximum Supply Voltages VCC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -0.5V to +7V VCC - VBH . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 110V Uncommitted Switch Voltage . . . . . . . . . . . . . . . . . . . . . . . . -110V Maximum Tip/Ring Negative Voltage Pulse (Note 8) . . . . . . VBH -15V Maximum Tip/Ring Positive Voltage Pulse (Note 8) . . . . . . . . . . . .+8V ESD (Human Body Model). . . . . . . . . . . . . . . . . . . . . . . . . . . . 500V Thermal Resistance (Typical) Operating Conditions Die Characteristics Temperature Range Commercial (C suffix) . . . . . . . . . . . . . . . . . . . . . . . . . . 0oC to 85oC Industrial (I suffix). . . . . . . . . . . . . . . . . . . . . . . . . . . . -40oC to 85oC Positive Power Supply (VCC). . . . . . . . . . . . . . . . . . . . . . . +5V, ±5% Low Battery Power Supply (VBL) . . . . . . . . . . . . . -16V to -52V, ±5% High Battery Power Supply (VBH) AIM, CIM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . VBL to 100V, ±5% BIM, DIM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . VBL to -85V, ±10% EIM. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . VBL to -75V, ±10% Uncommitted Switch (loop back or relay driver) . . . . . +5V to -100V Substrate Potential . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . VBH Process . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Bipolar-DI PLCC (Note 1) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53 MLFP (Note 2) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 Maximum Junction Temperature Plastic . . . . . . . . . . . . . . . . 150oC Maximum Storage Temperature Range . . . . . . . . . . -65oC to 150oC Maximum Lead Temperature (Soldering 10s) . . . . . . . . . . . . 300oC (PLCC - Lead Tips Only) CAUTION: Stresses above those listed in “Absolute Maximum Ratings” may cause permanent damage to the device. This is a stress only rating and operation of the device at these or any other conditions above those indicated in the operational sections of this specification is not implied. NOTES: 1. θJA for the PLCC package is measured with the component mounted on a low effective thermal conductivity test board in free air. See Tech Brief TB379 for details. 2. θJA for the MLFP package is measured in free air with the component mounted on a high effective thermal conductivity test board with direct attach features including conductive thermal vias. See Tech Brief 379 and AN9922 for additional information and board layout considerations. Unless Otherwise Specified, TA = -40oC to 85oC for industrial (I) grade and TA = 0oC to 85oC for commercial (C) grade, VBL = -24V, VBH = -100V, -85V or -75V, VCC = +5V, AGND = BGND = 0V, loop current limit = 25mA. All AC parameters are specified at 600Ω 2-wire terminating impedance over the frequency band of 300Hz to 3.4kHz. Protection resistors = 0Ω. Electrical Specifications PARAMETER TEST CONDITIONS MIN TYP MAX UNITS RINGING PARAMETERS VRS Input Impedance (Note 3) Differential Ringing Gain (Note 4) 450 - - kΩ 78 80 82 V/V Tip, Referenced to VBH/2 + 0.5 (Note 9) - ± 2.5 - V Ring, Referenced to VBH/2 + 0.5 - ± 2.5 - V Balanced Ringing, VRS Input = 0.840VRMS - 67 - Balanced Ringing, VRS to 2-Wire, RLOAD = ∞ Unbalanced Ringing, VRS to 2-Wire, RLOAD = ∞ Centering Voltage Accuracy Open Circuit Ringing Voltage 40 Unbalanced Ringing, VRS Input = 0.840VRMS V/V 33.5 - - VRMS VRMS Ringing Voltage Total Distortion RL = 1.3 kΩ, VT-R = |VBH| -5 3.0 % 4-Wire to 2-Wire Ringing Off Isolation Active Mode, Referenced to VRS Input - 90 - dB 2-Wire to 4-Wire Transmit Isolation Ringing Mode Referenced to the Differential Ringing Amplitude - 80 - dB 160 - - kΩ AC TRANSMISSION PARAMETERS Receive Input Impedance (Note 3) - - 1 Ω 4-Wire Port Overload Level THD = 1% 3.1 3.5 - VPK 2-Wire Port Overload Level THD = 1% 3.1 3.5 - VPK 2-Wire Return Loss 300Hz - 24 - dB 1kHz - 40 - dB 3.4kHz - 21 - dB Forward Active, Grade A and B 58 62 - dB Forward Active, Grade C, D and E 53 59 - dB Forward Active, Grade A and B 58 67 - dB Forward Active, Grade C, D and E 53 64 - dB Transmit Output Impedance (Note 3) 2-Wire Longitudinal Balance (Notes 5, 6) 4-Wire Longitudinal Balance (Notes 5, 6) 3 HC55185 Unless Otherwise Specified, TA = -40oC to 85oC for industrial (I) grade and TA = 0oC to 85oC for commercial (C) grade, VBL = -24V, VBH = -100V, -85V or -75V, VCC = +5V, AGND = BGND = 0V, loop current limit = 25mA. All AC parameters are specified at 600Ω 2-wire terminating impedance over the frequency band of 300Hz to 3.4kHz. Protection resistors = 0Ω. (Continued) Electrical Specifications MIN TYP MAX 2-Wire to 4-Wire Level Linearity 4-Wire to 2-Wire Level Linearity Referenced to -10dBm PARAMETER +3 to -40dBm, 1kHz TEST CONDITIONS - ±0.025 - UNITS dB -40 to -50dBm, 1kHz - ±0.050 - dB -50 to -55dBm, 1kHz - ±0.100 - dB Longitudinal Current Capability Per Wire (Note 3) Test for False Detect 20 - - mARMS Test for False Detect, Low Power Standby 10 - - mARMS 4-Wire to 2-Wire Insertion Loss -0.20 0.00 +0.20 dB 2-Wire to 4-Wire Insertion Loss -6.22 -6.02 -5.82 dB 4-Wire to 4-Wire Insertion Loss -6.22 -6.02 -5.82 dB Forward Active Idle Channel Noise (Note 6) 2-Wire C-Message, T = 25oC - 10 13 dBrnC 4-Wire C-Message, T = 25oC - 4 7 dBrnC Reverse Active Idle Channel Noise (Note 6) 2-Wire C-Message, T = 25oC - 11 14 dBrnC 4-Wire C-Message, T = 25oC - 5 8 dBrnC DC PARAMETERS Off Hook Loop Current Limit Programming Accuracy -8.5 - +8.5 % Programming Range 15 - 45 mA Programming Accuracy -10 - +10 % Programming Range 40 - 100 mA Loop Current During Low Power Standby Forward Polarity Only 18 - 26 mA Open Circuit Voltage (|Tip - Ring|) VBL = -16V - 8.0 - VDC VBL = -24V 14 15.5 17 VDC VBH > -60V 43 49 - VDC Low Power Standby, Open Circuit Voltage (Tip - Ring) VBL = -48V - 44.5 - VDC VBH > -60V 43 51.5 - VDC Absolute Open Circuit Voltage VRG in LPS and FA; VTG in RA; VBH > -60V - -53 -56 VDC Off Hook Transient Current Limit TEST ACCESS FUNCTIONS IOL = 45mA Switch On Voltage Loopback Max Battery - 0.30 0.60 V - - 52 V mA LOOP DETECTORS AND SUPERVISORY FUNCTIONS Switch Hook Programming Range 5 - 15 -10 - +10 % - 1.0 - % Ring Trip Comparator Threshold 2.3 2.5 2.9 V Ring Trip Programming Current Accuracy -10 - +10 % Ground Key Threshold - 12 - mA E0 Transition, DET Output Delay - 20 - µs 175 - oC V Switch Hook Programming Accuracy Assumes 1% External Programming Resistor Dial Pulse Distortion Thermal Alarm Output IC Junction Temperature - LOGIC INPUTS (F0, F1, F2, E0, SWC, BSEL) Input Low Voltage - - 0.8 Input High Voltage 2.0 - - V Input Low Current VIL = 0.4V -20 -10 - µA Input High Current VIH = 2.4V - - 1 µA Output Low Voltage IOL = 5mA - .15 0.4 V Output High Voltage IOH = 100µA 2.4 3.5 - V mA LOGIC OUTPUTS (DET, ALM) SUPPLY CURRENTS Low Power Standby, BSEL = 1 Forward or Reverse Active, BSEL = 0 4 ICC - 3.9 6.0 IBH - 0.66 0.90 mA ICC - 4.9 6.5 mA IBL - 1.2 2.5 mA HC55185 Unless Otherwise Specified, TA = -40oC to 85oC for industrial (I) grade and TA = 0oC to 85oC for commercial (C) grade, VBL = -24V, VBH = -100V, -85V or -75V, VCC = +5V, AGND = BGND = 0V, loop current limit = 25mA. All AC parameters are specified at 600Ω 2-wire terminating impedance over the frequency band of 300Hz to 3.4kHz. Protection resistors = 0Ω. (Continued) Electrical Specifications PARAMETER Forward Active, BSEL = 1 Ringing, BSEL = 1 (Balanced Ringing, 100) Ringing, BSEL = 1 (Unbalanced Ringing, 010) Forward Loopback, BSEL = 0 Tip Open, BSEL = 0 Power Denial, BSEL = 0 or 1 MIN TYP MAX UNITS ICC TEST CONDITIONS - 7.0 9.5 mA IBL - 0.9 2.0 mA IBH - 2.2 3.0 mA ICC - 6.4 9.0 mA IBL - 0.3 1.0 mA IBH - 2.0 3.0 mA ICC - 9.3 mA IBL - 0.3 mA IBH - 2.4 ICC - 10.3 13.5 mA IBL - 23.5 32 mA ICC - 3.8 5.5 mA IBL - .3 1.0 mA ICC - 4.0 6.0 mA IBL - 0.22 0.5 mA 1 mA ON HOOK POWER DISSIPATION (Note 7) Forward or Reverse VBL = -24V - 55 - mW Low Power Standby VBH = -100V - 85 - mW VBH = -85V - 75 - mW Ringing VBH = -75V - 65 - mW VBH = -100V - 250 - mW VBH = -85V - 230 - mW VBH = -75V - 225 - mW VBL = -24V - 305 - mW f = 300Hz - 40 - dB OFF HOOK POWER DISSIPATION (Note 7) Forward or Reverse POWER SUPPLY REJECTION RATIO VCC to 2-Wire VCC to 4-Wire f = 1kHz - 35 - dB f = 3.4kHz - 28 - dB dB f = 300Hz - 45 - f = 1kHz - 43 - dB f = 3.4kHz - 33 - dB dB VBL to 2-Wire 300Hz ≤ f ≤ 3.4kHz - 30 - VBL to 4-Wire 300Hz ≤ f ≤ 3.4kHz - 35 - dB VBH to 2-Wire 300Hz ≤ f ≤ 3.4kHz - 33 - dB VBH to 4-Wire 300Hz ≤ f ≤ 1kHz - 40 - dB 1kHz < f ≤ 3.4kHz - 45 - dB NOTES: 3. These parameters are controlled via design or process parameters and are not directly tested. These parameters are characterized upon initial design release and upon design changes which would affect these characteristics. 4. Differential Ringing Gain is measured with VRS = 0.795VRMS for -100V devices, VRS = 0.663 VRMS for -85V devices and VRS = 0.575VRMS for -75V devices. 5. Longitudinal Balance is tested per IEEE455-1985, with 368Ω per Tip and Ring terminal. 6. These parameters are tested 100% at room temperature. These parameters are guaranteed not tested across temperature via statistical characterization and design. 7. The power dissipation is based on actual device measurements and will be less than worst case calculations based on data sheet supply current limits. 8. Characterized with 2 x 10µs, and 10 x 1000µs first level lightning surge waveforms (GR-1089-CORE) 9. For Unbalanced Ringing the Tip terminal is offset to 0V and the Ring terminal is centered at Vbh/2 + 0.5V. 5 HC55185 Special Considerations for the MLFP Package calculate RS for other combinations of termination and protection resistance. The new MLFP package offers a significant footprint reduction (65%) and improved thermal performance with respect to the 28 lead PLCC. To realize the thermal enhancements and maintain the high voltage (-100V) performance the exposed leadframe should be soldered to a power/heat sink plane that is electrically connected to the high battery supply (VBH) within the application board. This approach distributes the heat evenly across the board and is accomplished by using conductive thermal vias. Reference technical brief TB379 and AN9922 for additional information on thermal characterization and board layout considerations. The CFB capacitor must be non-polarized for proper device operation in Reverse Active. Ceramic surface mount capacitors (1206 body style) are available from Panasonic with a 6.3V voltage rating. These can be used for CFB since it is internally limited to approximately ±3V. The CDC capacitor may be either polarized or non polarized. Product Family Cross Reference The following table provides an ordering and functional cross reference for the existing HC55180 through HC55184 products and the new and improved HC55185 product. TABLE 1. PRODUCT CROSS REFERENCE Parametric Improvements The most significant parametric improvement of the HC55185 is reduction in Idle Channel Noise. This improvement was accomplished by redistributing gains in the impedance matching loop. The impact to the application circuit is the change in the impedance programming resistor RS. The redistribution of gains also improves AC performance at the upper end of the voice band. Functional Improvements HC55180CIM, HC55180DIM None Offered In addition to parametric improvements, internal circuit changes and application circuit changes have been made to improve the overall device functionality. HC55181AIM, HC55182AIM HC55185AIM Off Hook Interface HC55181BIM, HC55182BIM HC55185BIM HC55181CIM, HC55182CIM HC55185CIM HC55181DIM, HC55182DIM HC55185DIM HC55183ECM, HC55184ECM HC55185ECM The transient behavior of the device in response to mode changes has been significantly improved. The benefit to the application is reduction or more likely elimination of DET glitches when off hook events occur. In addition to internal circuit modifications, the change of CFB value contributes to this functional improvement. EXISTING DEVICES FUNCTIONAL EQUIVALENT Any of the HC55185 products may be used without the battery switch function by shorting the supply pins VBL and VBH together. This provides compatibility with HC55180 type applications which do not require the battery switch. Application Circuit Modifications The HC55185 basic application circuit is nearly identical to that of the HC55180 through HC55184.The HC55185 requires an additional resistor to program the transient current limit feature. This programming resistor is connected from pin 16 (TL) to ground. In addition some component values have been changed to improve overall device performance. The table below lists the component value changes required for the HC55185 application circuit. TABLE 2. COMPONENT VALUE CHANGES REFERENCE HC55180 - 184 HC55185 RS 210kΩ 66.5kΩ RP1 ≥ 35Ω ≥ 49Ω RP2 ≥ 35Ω ≥ 49Ω CFB 0.47µ 4.7µ The value of RS is based on a 600Ω termination impedance and RP1 = RP2 = 49.9Ω. Design equations are provided to 6 Transient Current Limit The drive current capability of the output amplifiers is determined by an externally programmable output current limit circuit which is separate from the DC loop current limit function and programmed at the pin TL. The current limit circuit works in both the source and sink direction, with an internally fixed offset to prevent the current limit functions from turning on simultaneously. The current limit function is provided by sensing line current and reducing the voltage drive to the load when the externally set threshold is exceeded, hence forcing a constant source or sink current. SOURCE CURRENT PROGRAMMING The source current is externally programmed as shown in Equation 1. 1780 R TL = ------------I SRC (EQ. 1) For example a source current limit setting of 50mA is programmed with a 35.6kΩ resistor connected from pin 16 of the device to ground. This setting determines the maximum amount of current which flows from Tip to Ring during an off hook event until the DC loop current limit responds. In addition this setting also determines the amount of current which will flow from Tip or Ring when external battery faults occur. HC55185 SINK CURRENT PROGRAMMING The sink current limit is internally offset 20% higher than the externally programmed source current limit setting. (EQ. 2) I SNK = 1.20 × ISRC If the source current limit is set to 50mA, the sink current limit will be 60mA. This setting will determine the maximum current that flows into Tip or Ring when external ground faults occur. FUNCTIONAL DESCRIPTION Each amplifier is designed to limit source current and sink current. The diagram below shows the functionality of the circuit for the case of limiting the source current. A similar diagram applies to the sink current limit with current polarity changed accordingly. IO/K IREF = 1.21/TL IERR 200K TIP or RING - + 20 ISIG VB/2 IO FIGURE 1. CURRENT LIMIT FUNCTIONAL DIAGRAM During normal operation, the error current (IERR) is zero and the output voltage is determined by the signal current (ISIG) multiplied by the 200K feedback resistor. With the current polarity as shown for ISIG, the output voltage moves positive with respect to half battery. Assuming the amplifier output is driving a load at a more negative potential, the amplifier output will source current. 7 During excessive output source current flow, the scaled output current (IO/K) exceeds the reference current (IREF) forcing an error current (IERR). With the polarity as shown the error current subtracts from the signal current, which reduces the amplifier output voltage. By reducing the output voltage the source current to the load is decreased and the output current is limited. DETERMINING THE PROPER SETTING Since this feature programs the maximum output current of the device, the setting must be high enough to allow for detection of ring trip or programmed off hook loop current, whichever is greater. To allow for proper ring trip operation, the transient current limit setting should be set at least 25% higher than the peak ring trip current setting. Setting the transient current 25% higher should account for programming tolerances of both the ring trip threshold and the transient current limit. If loop current is larger than ring trip current (low REN applications) then the transient current limit should be set at least 35% higher than the loop current setting. The slightly higher offset accounts for the slope of the loop current limit function. Attention to detail should be exercised when programming the transient current limit setting. If ring trip detect does not occur while ringing, then re-examine the transient current limit and ring trip threshold settings. HC55185 Design Equations 4-WIRE TO 2-WIRE GAIN Loop Supervision Thresholds SWITCH HOOK DETECT The switch hook detect threshold is set by a single external resistor, RSH . Equation 3 is used to calculate the value of RSH. (EQ. 3) R SH = 600 ⁄ I SH The 4-wire to 2-wire gain is defined as the receive gain. It is a function of the terminating impedance, synthesized impedance and protection resistors. Equation 8 calculates the receive gain, G42. ZL G 42 = – 2 ------------------------------------------ Z O + 2R P + Z L (EQ. 8) The term ISH is the desired DC loop current threshold. The loop current threshold programming range is from 5mA to 15mA. When the device source impedance and protection resistors equals the terminating impedance, the receive gain equals unity. GROUND KEY DETECT 2-WIRE TO 4-WIRE GAIN The ground key detector senses a DC current imbalance between the Tip and Ring terminals when the ring terminal is connected to ground. The ground key detect threshold is not externally programmable and is internally fixed to 12mA regardless of the switch hook threshold. The 2-wire to 4-wire gain (G24) is the gain from tip and ring to the VTX output. The transmit gain is calculated in Equation 9. RING TRIP DETECT When the protection resistors are set to zero, the transmit gain is -6dB. The ring trip detect threshold is set by a single external resistor, RRT. IRT should be set between the peak ringing current and the peak off hook current while still ringing. In (EQ. 4) R RT = 1800 ⁄ IRT ZO G 24 = – ------------------------------------------ Z O + 2R P + Z L (EQ. 9) TRANSHYBRID GAIN The transhybrid gain is defined as the 4-wire to 4-wire gain (G44). addition, the ring trip current must be set below the transient current limit, including tolerances. The capacitor CRT, in parallel with RRT, will set the ring trip response time. ZO G 44 = – --------------------------------------- Z + 2R + Z O P L Loop Current Limit When the protection resistors are set to zero, the transhybrid gain is -6dB. The loop current limit of the device is programmed by the external resistor RIL. The value of RIL can be calculated using Equation 5. 1760 R IL = ------------I LIM (EQ. 5) COMPLEX IMPEDANCE SYNTHESIS Substituting the impedance programming resistor, RS, with a complex programming network provides complex impedance synthesis. The term ILIM is the desired loop current limit. The loop current limit programming range is from 15mA to 45mA. Impedance Matching 2-WIRE NETWORK C2 R1 The impedance of the device is programmed with the external component RS . RS is the gain setting resistor for the feedback amplifier that provides impedance matching. If complex impedance matching is required, then a complex network can be substituted for RS . RESISTIVE IMPEDANCE SYNTHESIS The source impedance of the device, ZO , can be calculated in Equation 6. (EQ. 6) R S = 133.3 ( Z O ) The required impedance is defined by the terminating impedance and protection resistors as shown in Equation 7. (EQ. 7) Z O = Z L – 2RP 8 (EQ. 10) PROGRAMMING NETWORK CP RS R2 RP FIGURE 2. COMPLEX PROGRAMMING NETWORK The reference designators in the programming network match the evaluation board. The component RS has a different design equation than the RS used for resistive impedance synthesis. The design equations for each component are provided below. R S = 133.3 × ( R 1 – 2 ( R P ) ) (EQ. 11) R P = 133.3 × R 2 (EQ. 12) · C P = C 2 ⁄ 133.3 (EQ. 13) HC55185 Low Power Standby Overview The low power standby mode (LPS, 000) should be used during idle line conditions. The device is designed to operate from the high battery during this mode. Most of the internal circuitry is powered down, resulting in low power dissipation. If the 2-wire (tip/ring) DC voltage requirements are not critical during idle line conditions, the device may be operated from the low battery. Operation from the low battery will decrease the standby power dissipation. TABLE 3. DEVICE INTERFACES DURING LPS INTERFACE ON OFF NOTES Receive x Ringing x AC transmission, impedance matching and ringing are disabled during this mode. Transmit x 2-Wire x Amplifiers disabled. Loop Detect x Switch hook or ground key. 2-Wire Interface During LPS, the 2-wire interface is maintained with internal switches and voltage references. The Tip and Ring amplifiers are turned off to conserve power. The device will provide MTU compliance, loop current and loop supervision. Figure 3 represents the internal circuitry providing the 2-wire interface during low power standby. GND voltage exceeds the MTU reference of -49V (typically), the Ring terminal will be clamped by the internal reference. The same Ring relationships apply when operating from the low battery voltage. For high battery voltages (VBH) less than or equal to the internal MTU reference threshold: V RING = V BH + 4 Loop Current During LPS, the device will provide current to a load. The current path is through resistors and switches, and will be function of the off hook loop resistance (RLOOP). This includes the off hook phone resistance and copper loop resistance. The current available during LPS is determined by Equation 15. I LOOP = ( – 1 – ( – 49 ) ) ⁄ ( 600 + 600 + R LOOP ) TIP AMP TIP RING RING AMP 600Ω MTU REF FIGURE 3. LPS 2-WIRE INTERFACE CIRCUIT DIAGRAM (EQ. 15) Internal current limiting of the standby switches will limit the maximum current to 20mA. Another loop current related parameter is longitudinal current capability. The longitudinal current capability is reduced to 10mARMS per pin. The reduction in longitudinal current capability is a result of turning off the Tip and Ring amplifiers. On Hook Power Dissipation The on hook power dissipation of the device during LPS is determined by the operating voltages and quiescent currents and is calculated using Equation 16. P LPS = V BH × I BHQ + V BL × I BLQ + V CC × I CCQ 600Ω (EQ. 14) (EQ. 16) The quiescent current terms are specified in the electrical tables for each operating mode. Load power dissipation is not a factor since this is an on hook mode. Some applications may specify a standby current. The standby current may be a charging current required for modern telephone electronics. Standby Current Power Dissipation Any standby line current, ISLC , introduces an additional power dissipation term PSLC . Equation 17 illustrates the power contribution is zero when the standby line current is zero. (EQ. 17) MTU Compliance P SLC = I SLC × ( V BH – 49 + 1 + I SLC x1200 ) Maintenance Termination Unit or MTU compliance places DC voltage requirements on the 2-wire terminals during idle line conditions. The minimum idle voltage is 42.75V. The high side of the MTU range is 56V. The voltage is expressed as the difference between Tip and Ring. If the battery voltage is less than -49V (the MTU clamp is off), the standby line current power contribution reduces to Equation 18. The Tip voltage is held near ground through a 600Ω resistor and switch. The Ring voltage is limited to a maximum of -49V (by MTU REF) when operating from either the high or low battery. A switch and 600Ω resistor connect the MTU reference to the Ring terminal. When the high battery Most applications do not specify charging current requirements during standby. When specified, the typical charging current may be as high as 5mA. 9 P SLC = I SLC × ( V BH + 1 + I SLC x1200 ) (EQ. 18) HC55185 Forward Active filter is set by the external capacitor CDC . The value of the external capacitor should be 4.7µF. On-Hook Transmission The primary purpose of on hook transmission will be to support caller ID and other advanced signalling features. The transmission over load level while on hook is 3.5VPEAK . When operating from the high battery, the DC voltages at Tip and Ring are MTU compliant. The typical Tip voltage is -4V and the Ring voltage is a function of the battery voltage for battery voltages less than -60V as shown in Equation 19. (EQ. 19) V RING = V BH + 4 Loop supervision is provided by the switch hook detector at the DET output. When DET goes low, the low battery should be selected for DC loop feed and voice transmission. Feed Architecture The design implements a voltage feed current sense architecture. The device controls the voltage across Tip and Ring based on the sensing of load current. Resistors are placed in series with Tip and Ring outputs to provide the current sensing. The diagram below illustrates the concept. RB RA VIN RCS - VOUT Most applications will operate the device from low battery while off hook. The DC feed characteristic of the device will drive Tip and Ring towards half battery to regulate the DC loop current. For light loads, Tip will be near -4V and Ring will be near VVBL + 4V. The following diagram shows the DC feed characteristic. VTR(OC) m = (∆VTR/∆IL) = 11.1kΩ ILOOP (mA) ILIM FIGURE 5. DC FEED CHARACTERISTIC The point on the y-axis labeled VTR(OC) is the open circuit Tip to Ring voltage and is defined by the feed battery voltage. (EQ. 20) V TR ( OC ) = V BL – 8 The curve of Figure 5 determines the actual loop current for a given set of loop conditions. The loop conditions are determined by the low battery voltage and the DC loop impedance. The DC loop impedance is the sum of the protection resistance, copper resistance (ohms/foot) and the telephone off hook DC resistance. IA ISC IB ILIM ILOOP (mA) The forward active mode (FA, 001) is the primary AC transmission mode of the device. On hook transmission, DC loop feed and voice transmission are supported during forward active. Loop supervision is provided by either the switch hook detector (E0 = 1) or the ground key detector (E0 = 0). The device may be operated from either high or low battery for onhook transmission and low battery for loop feed. VTR , DC (V) Overview + RL 2RP RC RLOOP (Ω) RKNEE FIGURE 6. ILOOP vs RLOOP LOAD CHARACTERISTIC - + KS FIGURE 4. VOLTAGE FEED CURRENT SENSE DIAGRAM By monitoring the current at the amplifier output, a negative feedback mechanism sets the output voltage for a defined load. The amplifier gains are set by resistor ratios (RA , RB , RC) providing all the performance benefits of matched resistors. The internal sense resistor, RCS , is much smaller than the gain resistors and is typically 20Ω for this device. The feedback mechanism, KS , represents the amplifier configuration providing the negative feedback. DC Loop Feed The feedback mechanism for monitoring the DC portion of the loop current is the loop detector. A low pass filter is used in the feedback to block voice band signals from interfering with the loop current limit function. The pole of the low pass 10 The slope of the feed characteristic and the battery voltage define the maximum loop current on the shortest possible loop as the short circuit current ISC. V TR ( OC ) – 2R P I LIM I SC = I LIM + -----------------------------------------------------1.1e4 (EQ. 21) The term ILIM is the programmed current limit, 1760/RIL. The line segment IA represents the constant current region of the loop current limit function. V TR ( OC ) – R LOOP I LIM I A = I LIM + -------------------------------------------------------------1.1e4 (EQ. 22) The maximum loop impedance for a programmed loop current is defined as RKNEE . V TR ( OC ) R KNEE = -----------------------I LIM (EQ. 23) HC55185 When RKNEE is exceeded, the device will transition from constant current feed to constant voltage, resistive feed. The line segment IB represents the resistive feed portion of the load characteristic. V TR ( OC ) I B = -----------------------R LOOP of the signal injected at VRX . The echo must be cancelled to maintain voice quality. Most applications will use a summing amplifier in the CODEC front end as shown below to cancel the echo signal. (EQ. 24) R Voice Transmission VRX RA VTX RB R R 1:1 TA RF RS + The feedback mechanism for monitoring the AC portion of the loop current consists of two amplifiers, the sense amplifier (SA) and the transmit amplifier (TA). The AC feedback signal is used for impedance synthesis. A detailed model of the AC feed back loop is provided below. RX OUT + TX IN +2.4V -IN CODEC HC5518x R VRX 20 TIP FIGURE 8. TRANSHYBRID BALANCE INTERFACE - R + 1:1 20 RING VTX + - TA - + RS R 4R 3R -IN CFB 4R 4R 4R 8K - + VFB VSA 3R FIGURE 7. AC SIGNAL TRANSMISSION MODEL The gain of the transmit amplifier, set by RS , determines the programmed impedance of the device. The capacitor CFB blocks the DC component of the loop current. The ground symbols in the model represent AC grounds, not actual DC potentials. The resistor ratio, RF /RB , provides the final adjustment for the transmit gain, GTX . The transmit gain is calculated using Equation 27. R F - TX = – G 24 ------ R B (EQ. 27) Most applications set RF = RB , hence the device 2-wire to 4-wire equals the transmit gain. Typically RB is greater than 20kΩ to prevent loading of the device transmit output. The resistor ratio, RF /RA , is determined by the transhybrid gain of the device, G44 . RF is previously defined by the transmit gain requirement and RA is calculated using Equation 28. RB R A = ---------G 44 (EQ. 28) Power Dissipation The sense amp output voltage, VSA , as a function of Tip and Ring voltage and load is calculated using Equation 25. The power dissipated by the device during on hook transmission is strictly a function of the quiescent currents for each supply voltage during Forward Active operation. 30 V SA = – ( V T – V R ) -----ZL P FAQ = V BH × I (EQ. 25) The transmit amplifier provides the programmable gain required for impedance synthesis. In addition, the output of this amplifier interfaces to the CODEC transmit input. The output voltage is calculated using Equation 26. RS V VTX = – V SA ---------- 8e3 (EQ. 26) Once the impedance matching components have been selected using the design equations, the above equations provide additional insight as to the expected AC node voltages for a specific Tip and Ring load. BHQ + V BL × I BLQ + V CC × I CCQ (EQ. 29) Off hook power dissipation is increased above the quiescent power dissipation by the DC load. If the loop length is less than or equal to RKNEE , the device is providing constant current, IA , and the power dissipation is calculated using Equation 30. P FA ( IA ) = P FA ( Q ) + ( V BL xI A ) – ( R LOOP xI 2 A ) (EQ. 30) If the loop length is greater than RKNEE , the device is operating in the constant voltage, resistive feed region. The power dissipated in this region is calculated using Equation 31. Transhybrid Balance P FA ( IB ) = P FA ( Q ) + ( V BL xI B ) – ( R LOOP xI 2 B ) The final step in completing the impedance synthesis design is calculating the necessary gains for transhybrid balance. The AC feed back loop produces an echo at the VTX output Since the current relationships are different for constant current versus constant voltage, the region of device operation is critical to valid power dissipation calculations. 11 (EQ. 31) HC55185 Reverse Active Ringing Overview Overview The reverse active mode (RA, 011) provides the same functionality as the forward active mode. On hook transmission, DC loop feed and voice transmission are supported. Loop supervision is provided by either the switch hook detector (E0 = 1) or the ground key detector (E0 = 0). The device may be operated from either high or low battery. The ringing mode (RNG, 100) provides linear amplification to support a variety of ringing waveforms. A programmable ring trip function provides loop supervision and auto disconnect upon ring trip. The device is designed to operate from the high battery during this mode. During reverse active the Tip and Ring DC voltage characteristics exchange roles. That is, Ring is typically 4V below ground and Tip is typically 4V more positive than battery. Otherwise, all feed and voice transmission characteristics are identical to forward active. The device provides linear amplification to the signal applied to the ringing input, VRS . The differential ringing gain of the device is 80V/V. The circuit model for the ringing path is shown in the following figure. Architecture R Silent Polarity Reversal Changing from forward active to reverse active or vice versa is referred to as polarity reversal. Many applications require slew rate control of the polarity reversal event. Requirements range from minimizing cross talk to protocol signalling. 20 TIP The internal circuitry used to set the polarity reversal time is shown below. I1 POL 75kΩ CPOL I2 FIGURE 9. REVERSAL TIMING CONTROL During forward active, the current from source I1 charges the external timing capacitor CPOL and the switch is open. The internal resistor provides a clamping function for voltages on the POL node. During reverse active, the switch closes and I2 (roughly twice I1) pulls current from I1 and the timing capacitor. The current at the POL node provides the drive to a differential pair which controls the reversal time of the Tip and Ring DC voltages. ∆time C POL = ---------------75000 (EQ. 32) Where ∆time is the required reversal time. Polarized capacitors may be used for CPOL . The low voltage at the POL pin and minimal voltage excursion ±0.75V, are well suited to polarized capacitors. Power Dissipation The power dissipation equations for forward active operation also apply to the reverse active mode. 12 - + - + 5:1 20 + RING The device uses an external low voltage capacitor, CPOL , to set the reversal time. Once programmed, the reversal time will remain nearly constant over various load conditions. In addition, the reversal timing capacitor is isolated from the AC loop, therefore loop stability is not impacted. R/8 - VRS 600K + VBH 2 R FIGURE 10. LINEAR RINGING MODEL The voltage gain from the VRS input to the Tip output is 40V/V. The resistor ratio provides a gain of 8 and the current mirror provides a gain of 5. The voltage gain from the VRS input to the Ring output is -40V/V. The equations for the Tip and Ring outputs during ringing are provided below. V BH V T = ----------- + ( 40 × VRS ) 2 (EQ. 33) V BH V R = ----------- – ( 40 × VRS ) 2 (EQ. 34) When the input signal at VRS is zero, the Tip and Ring amplifier outputs are centered at half battery. The device provides auto centering for easy implementation of sinusoidal ringing waveforms. Both AC and DC control of the Tip and Ring outputs is available during ringing. This feature allows for DC offsets as part of the ringing waveform. Ringing Input The ringing input, VRS , is a high impedance input. The high impedance allows the use of low value capacitors for AC coupling the ring signal. The VRS input is enabled only during the ringing mode, therefore a free running oscillator may be connected to VRS at all times. When operating from a battery of -100V, each amplifier, Tip and Ring, will swing a maximum of 95VP-P . Hence, the maximum signal swing at VRS to achieve full scale ringing is approximately 2.4VP-P . The low signal levels are compatible with the output voltage range of the CODEC. The digital nature of the CODEC ideally suits it for the function of programmable ringing generator. See Applications Section. HC55185 Logic Control Unbalanced Ringing Ringing patterns consist of silent intervals. The ringing to silent pattern is called the ringing cadence. During the silent portion of ringing, the device can be programmed to any other operating mode. The most likely candidates are low power standby or forward active. Depending on system requirements, the low or high battery may be selected. The HC55185GCM offers a new Unbalanced Ringing mode (010). This feature has been added to accommodate some Analog PBX Trunk Lines that require the Tip terminal to be held near ground for the duration of the ringing bursts. The Tip terminal is offset to 0V’s with an internal current source that is applied to the inverting input of the Tip amplifier. This reduces the differential ringing gain to 40V/V. The Ring terminal will center at Vbh/2 and swing from -Vbh to ground. As in Balanced Ringing, off hook detection is accomplished by sensing the peak current and comparing it to a preset threshold. This allows the same sensing, comparing and threshold circuitry to be used in both Ringing modes. This mode of operation does not require any additional external components. Loop supervision is provided with the ring trip detector. The ring trip detector senses the change in loop current when the phone is taken off hook. The loop detector full wave rectifies the ringing current, which is then filtered with external components RRT and CRT. The resistor RRT sets the trip threshold and the capacitor CRT sets the trip response time. Most applications will require a trip response time less than 150ms. Three very distinct actions occur when the devices detects a ring trip. First, the DET output is latched low. The latching mechanism eliminates the need for software filtering of the detector output. The latch is cleared when the operating mode is changed externally. Second, the VRS input is disabled, removing the ring signal from the line. Third, the device is internally forced to the forward active mode. Power Dissipation The power dissipation during ringing is dictated by the load driving requirements and the ringing waveform. The key to valid power calculations is the correct definition of average and RMS currents. The average current defines the high battery supply current. The RMS current defines the load current. The cadence provides a time averaging reduction in the peak power. The total power dissipation consists of ringing power, Pr , and the silent interval power, Ps . tr ts P RNG = P r × -------------- + P s × -------------tr + ts tr + ts P r ( Q ) = V BH × I BHQ + V BL × I BLQ + V CC × I CCQ (EQ. 36) The total power during the ringing interval is the sum of the quiescent power and loading power: 2 V RMS P r = P r ( Q ) + V BH × I AVG – -----------------------------------------Z +R (EQ. 37) LOOP For sinusoidal waveforms, the average current, IAVG, is defined in Equation 38. (EQ. 38) The silent interval power dissipation will be determined by the quiescent power of the selected operating mode. 13 The Forward Loop Back mode (FLB, 101) provides test capability for the device. An internal signal path is enabled allowing for both DC and AC verification. The internal 600Ω terminating resistor has a tolerance of ±20%. The device is intended to operate from only the low battery during this mode. Architecture When the forward loop back mode is initiated internal switches connect a 600Ω load across the outputs of the Tip and Ring amplifiers. TIP TIP AMP 600Ω RING AMP The quiescent power of the device in the ringing mode is defined in Equation 36. V RMS × 2 2 I AVG = --- ----------------------------------------- π Z REN + R LOOP Overview (EQ. 35) The terms tR and tS represent the cadence. The ringing interval is tR and the silent interval is tS . The typical cadence ratio tR :tS is 1:2. REN Forward Loop Back RING FIGURE 11. FORWARD LOOP BACK INTERNAL TERMINATION DC Verification When the internal signal path is provided, DC current will flow from Tip to Ring. The DC current will force DET low, indicating the presence of loop current. In addition, the ALM output will also go low. This does not indicate a thermal alarm condition. Rather, proper logic operation is verified in the event of a thermal shutdown. In addition to verifying device functionality, toggling the logic outputs verifies the interface to the system controller. AC Verification The entire AC loop of the device is active during the forward loop back mode. Therefore a 4-wire to 4-wire level test capability is provided. Depending on the transhybrid balance implementation, test coverage is provided by a one or two step process. HC55185 System architectures which cannot disable the transhybrid function would require a two step process. The first step would be to send a test tone to the device while on hook and not in forward loop back mode. The return signal would be the test level times the gain RF /RA of the transhybrid amplifier. Since the device would not be terminated, cancellation would not occur. The second step would be to program the device to FLB and resend the test tone. The return signal would be much lower in amplitude than the first step, indicating the device was active and the internal termination attenuated the return signal. System architectures which disable the transhybrid function would achieve test coverage with a signal step. Once the transhybrid function is disable, program the device for FLB and send the test tone. The return signal level is determined by the 4-wire to 4-wire gain of the device. automatically shut down. When the device cools, ALM will go high and DET will reflect the loop status. If the thermal fault persists, ALM will go low again and the part will shut down. Programming power denial will permanently shutdown the device and stop the self cooling cycling. Battery Switching Overview The integrated battery switch selects between the high battery and low battery. The battery switch is controlled with the logic input BSEL. When BSEL is a logic high, the high battery is selected and when a logic low, the low battery is selected. All operating modes of the device will operate from high or low battery except forward loop back. Functionality The logic control is independent of the operating mode decode. Independent logic control provides the most flexibility and will support all application configurations. Tip Open Overview The tip open mode (110) is intended for compatibility for PBX type interfaces. Used during idle line conditions, the device does not provide transmission. Loop supervision is provided by either the switch hook detector (E0 = 1) or the ground key detector (E0 = 0). The ground key detector will be used in most applications. The device may be operated from either high or low battery. Functionality During tip open operation, the Tip switch is disabled and the Ring switch is enabled. The minimum Tip impedance is 30kΩ. The only active path through the device will be the Ring switch. In keeping with the MTU characteristics of the device, Ring will not exceed -56V when operating from the high battery. Though MTU does not apply to tip open, safety requirements are satisfied. When changing device operating states, battery switching should occur simultaneously with or prior to changing the operating mode. In most cases, this will minimize overall power dissipation and prevent glitches on the DET output. The only external component required to support the battery switch is a diode in series with the VBH supply lead. In the event that high battery is removed, the diode allows the device to transition to low battery operation. Low Battery Operation All off hook operating conditions should use the low battery. The prime benefit will be reduced power dissipation. The typical low battery for the device is -24V. However this may be increased to support longer loop lengths or high loop current requirements. Standby conditions may also operate from the low battery if MTU compliance is not required, further reducing standby power dissipation. High Battery Operation Power Denial Overview The power denial mode (111) will shutdown the entire device except for the logic interface. Loop supervision is not provided. This mode may be used as a sleep mode or to shut down in the presence of a persistent thermal alarm. Switching between high and low battery will have no effect during power denial. Functionality During power denial, both the Tip and Ring amplifiers are disabled, representing high impedances. The voltages at both outputs are near ground. Thermal Shutdown In the event the safe die temperature is exceeded, the ALM output will go low and DET will go high and the part will 14 Other than ringing, the high battery should be used for standby conditions which must provide MTU compliance. During standby operation the power consumption is typically 85mW with -100V battery. If ringing requirements do not require full 100V operation, then a lower battery will result in lower standby power. High Voltage Decoupling The 100V rating of the device will require a capacitor of higher voltage rating for decoupling. Suggested decoupling values for all device pins are 0.1µF. Standard surface mount ceramic capacitors are rated at 100V. For applications driven at low cost and small size, the decoupling scheme shown below could be implemented. HC55185 0.22µ TIP 0.22µ RING VBL VBH HC5518X TEST LOAD SW+ FIGURE 12. ALTERNATE DECOUPLING SCHEME It is important to place the external diode between the VBH pin and the decoupling capacitor. Attaching the decoupling capacitor directly to the VBH pin will degrade the reliability of the device. Refer to Figure 12 for the proper arrangement. This applies to both single and stacked and decoupling arrangements. If VBL and VBH are tied together to override the battery switch function, then the external diode is not needed and the decoupling may be attached directly to VBH. Uncommitted Switch Overview SWC SW- FIGURE 14. TEST LOAD SWITCHING The diode in series with the test load blocks current from flowing through the uncommitted switch when the polarity of the Tip and Ring terminals are reversed. In addition to the reverse active state, the polarity of Tip and Ring are reversed for half of the ringing cycle. With independent logic control and the blocking diode, the uncommitted switch may be continuously connected to the Tip and Ring terminals. Basic Application Circuit The uncommitted switch is a three terminal device designed for flexibility. The independent logic control input, SWC, allows switch operation regardless of device operating mode. The switch is activated by a logic low. The positive and negative terminals of the device are labeled SW+ and SW- respectively. CPS1 CPS2 D1 CPS3 VCC VBL VBH CRX Relay Driver RP1 The uncommitted switch may be used as a relay driver by connecting SW+ to the relay coil and SW- to ground. The switch is designed to have a maximum on voltage of 0.6V with a load current of 45mA. U1 TIP HC55185 RP2 RING SW+ +5V RELAY CRT SW- RRT RTD RD SWC RIL ILIM FIGURE 13. EXTERNAL RELAY SWITCHING Since the device provides the ringing waveform, the relay functions which may be supported include subscriber disconnect, test access or line interface bypass. An external snubber diode is not required when using the uncommitted switch as a relay driver. Test Load CRS VTX RS CTX -IN CFB VFB BSEL E0 F0 CDC VCC VRS SWC RSH SW+ SW- VRX CDC F1 POL F2 CPOL DET RTL TL AGND ALM BGND FIGURE 15. HC55185 BASIC APPLICATION CIRCUIT The switch may be used to connect test loads across Tip and Ring. The test loads can provide external test termination for the device. Proper connection of the uncommitted switch to Tip and Ring is shown below. 15 HC55185 TABLE 4. BASIC APPLICATION CIRCUIT COMPONENT LIST COMPONENT U1 - Ringing SLIC VALUE TOL TABLE 4. BASIC APPLICATION CIRCUIT COMPONENT LIST (Continued) RATING HC55185 N/A N/A RTL 18.7kΩ 1% 0.1W RRT 23.7kΩ 1% 0.1W RSH 49.9kΩ 1% 0.1W RIL 71.5kΩ 1% 0.1W RS 66.5kΩ 1% 0.1W 10V CRX , CRS , CTX , CRT , CPOL 0.47µF 20% CDC, CFB 4.7µF 20% 10V CPS1 0.1µF 20% >100V CPS2 , CPS3 0.1µF 20% 100V COMPONENT D1 VALUE TOL RATING 1N400X type with breakdown > 100V. RP1 , RP2 Standard applications will use ≥ 49Ω per side. Protection resistor values are application dependent and will be determined by protection requirements. Design Parameters: Ring Trip Threshold = 76mAPEAK , Switch Hook Threshold = 12mA, Loop Current Limit = 24.6mA, Synthesize Device Impedance = (3*66.5kΩ)/400 = 498.8Ω, with 49.9Ω protection resistors, impedance across Tip and Ring terminals = 599Ω. Transient current limit = 95mA. Pin Descriptions PLCC MLFP SYMBOL 1 29 TIP 2 30 BGND DESCRIPTION TIP power amplifier output. Battery Ground - To be connected to zero potential. All loop current and longitudinal current flow from this ground. Internally separate from AGND but it is recommended that it is connected to the same potential as AGND. 3 31 VBL Low battery supply connection. 4 32 VBH High battery supply connection for the most negative battery. 5 1 SW+ Uncommitted switch positive terminal. 6 2 SW- Uncommitted switch negative terminal. 7 3 SWC Switch control input. This TTL compatible input controls the uncommitted switch, with a logic “0” enabling the switch and logic “1” disabling the switch. 8 4 F2 Mode Control Input - MSB. F2-F0 for the TTL compatible parallel control interface for controlling the various modes of operation of the device. 9 5 F1 Mode control input. 10 6 F0 Mode control input. 11 7 E0 Detector Output Selection Input. This TTL input controls the multiplexing of the SHD (E0 = 1) and GKD (E0 = 0) comparator outputs to the DET output based upon the state at the F2-F0 pins (see the Device Operating Modes table shown on page 2). 12 9 DET Detector Output - This TTL output provides on-hook/off-hook status of the loop based upon the selected operating mode. The detected output will either be switch hook, ground key or ring trip (see the Device Operating Modes table shown on page 2). 13 10 ALM Thermal Shutdown Alarm. This pin signals the internal die temperature has exceeded safe operating temperature (approximately 175oC) and the device has been powered down automatically. 14 11 AGND Analog ground reference. This pin should be externally connected to BGND. 15 12 BSEL Selects between high and low battery, with a logic “1” selecting the high battery and logic “0” the low battery. 16 13 TL 17 14 POL External capacitor on this pin sets the polarity reversal time. 18 15 VRS Ringing Signal Input - Analog input for driving 2-wire interface while in Ring Mode. 19 17 VRX Analog Receive Voltage - 4-wire analog audio input voltage. AC couples to CODEC. 20 18 VTX Transmit Output Voltage - Output of impedance matching amplifier, AC couples to CODEC. 21 19 VFB Feedback voltage for impedance matching. This voltage is scaled to accomplish impedance matching. 22 20 -IN 23 21 VCC Positive voltage power supply, usually +5V. 24 22 CDC DC Biasing Filter Capacitor - Connects between this pin and VCC. 25 23 RTD Ring trip filter network. 26 24 ILIM Loop Current Limit programming resistor. 27 25 RD Switch hook detection threshold programming resistor. 28 27 RING Programming pin for the transient current limit feature, set by an external resistor to ground. Impedance matching amplifier summing node. RING power amplifier output. 16 HC55185 Micro Lead Frame Plastic Package (MLFP) 2X L32.7x7 0.15 C A 32 LEAD MICRO LEAD FRAME PLASTIC PACKAGE (COMPLIANT TO JEDEC MO-220-VKKC-1 ISSUE C) D A D/2 MILLIMETERS D1 D1/2 2X N 6 0.50 DIA. 0.15 C B 1 2 3 E1/2 E/2 E1 0.15 C A MAX NOTES - 0.90 - A1 - - 0.05 - A2 - - 0.70 - 0.35 5, 8 0.20 REF 0.23 7.00 BSC - 6.75 BSC - 4.55 E2 0 A NX A3 SIDE VIEW A1 4X P 4.70 0.25 L 0.50 0.60 7, 8 - - - 0.75 8 2 0.10 M C A B Nd 8 3 8 Ne 8 3 7 NX k D2 2 N P - - 0.60 - θ - - 12 - 4X P Rev. 2 7/01 1 NOTES: 2 3 (Ne-1)Xe REF. E2 E2/2 NX L 1. Dimensioning and tolerancing per ASME Y14.5-1994. 7 2. N is the number of terminals. 8 3. Nd is the number of terminals in the X direction, and Ne is the number of terminals in the Y direction. 4. Controlling dimension: Millimeters. Converted dimensions to inches are not necessarily exact. Angles are in degrees. e (Nd-1)Xe REF. BOTTOM VIEW CL 4.85 32 D2 8 - 0.65 BSC k 7, 8 N 5 NX b 4.85 6.75 BSC 4.55 e 0.05 C 4.70 7.00 BSC E1 C - D E A2 0.28 D1 D2 2X SEATING PLANE NOMINAL - b B TOP VIEW MIN A A3 E 0.15 C B 2X SYMBOL 5. Dimension b applies to the plated terminal and is measured between 0.20mm and 0.25mm from the terminal tip. C C A1 NX b CL 5 6. The Pin #1 identifier exists on the top surface as an indentation mark in the molded body. SECTION "C-C" e e TERMINAL TIP FOR ODD TERMINAL/SIDE FOR EVEN TERMINAL/SIDE 17 7. Dimensions D2 and E2 are the maximum exposed pad dimensions for improved grounding and thermal performance. 8. Nominal dimensions provided to assist with PCB Land Pattern Design efforts, see Technical Brief TB389. HC55185 Micro Lead Frame Plastic Package (MLFP) 2X L32.7x7A 0.15 C A 32 LEAD MICRO LEAD FRAME PLASTIC PACKAGE (COMPLIANT TO JEDEC MO-220-VKKC-1 ISSUE C) D A D/2 MILLIMETERS D1 D1/2 2X N 6 0.50 DIA. 0.15 C B 1 2 3 E1/2 E/2 E1 0.15 C A MAX NOTES - 0.90 - A1 - - 0.05 - A2 - - 0.70 - 0.35 5, 8 0.20 REF 0.23 7.00 BSC - 6.75 BSC - 4.95 E2 0 A NX A3 SIDE VIEW A1 4X P 5.10 0.25 L 0.50 0.60 7, 8 - - - 0.75 8 2 0.10 M C A B Nd 8 3 8 Ne 8 3 7 NX k D2 2 N P - - 0.60 - θ - - 12 - 4X P Rev. 0 11/01 1 NOTES: 2 3 (Ne-1)Xe REF. E2 E2/2 NX L 1. Dimensioning and tolerancing per ASME Y14.5-1994. 7 2. N is the number of terminals. 8 3. Nd is the number of terminals in the X direction, and Ne is the number of terminals in the Y direction. 4. Controlling dimension: Millimeters. Converted dimensions to inches are not necessarily exact. Angles are in degrees. e (Nd-1)Xe REF. BOTTOM VIEW CL 5.25 32 D2 8 - 0.65 BSC k 7, 8 N 5 NX b 5.25 6.75 BSC 4.95 e 0.05 C 5.10 7.00 BSC E1 C - D E A2 0.28 D1 D2 2X SEATING PLANE NOMINAL - b B TOP VIEW MIN A A3 E 0.15 C B 2X SYMBOL 5. Dimension b applies to the plated terminal and is measured between 0.20mm and 0.25mm from the terminal tip. C C A1 NX b CL 5 6. The Pin #1 identifier exists on the top surface as an indentation mark in the molded body. SECTION "C-C" e e TERMINAL TIP FOR ODD TERMINAL/SIDE FOR EVEN TERMINAL/SIDE 18 7. Dimensions D2 and E2 are the maximum exposed pad dimensions for improved grounding and thermal performance. 8. Nominal dimensions provided to assist with PCB Land Pattern Design efforts, see Technical Brief TB389. HC55185 Plastic Leaded Chip Carrier Packages (PLCC) 0.042 (1.07) 0.048 (1.22) PIN (1) IDENTIFIER N28.45 (JEDEC MS-018AB ISSUE A) 0.042 (1.07) 0.056 (1.42) 0.004 (0.10) C 0.025 (0.64) R 0.045 (1.14) 0.050 (1.27) TP C L D2/E2 C L E1 E D2/E2 VIEW “A” A1 A D1 D 0.020 (0.51) MAX 3 PLCS 0.020 (0.51) MIN 28 LEAD PLASTIC LEADED CHIP CARRIER PACKAGE INCHES MILLIMETERS SYMBOL MIN MAX MIN MAX NOTES A 0.165 0.180 4.20 4.57 - A1 0.090 0.120 2.29 3.04 - D 0.485 0.495 12.32 12.57 - D1 0.450 0.456 11.43 11.58 3 D2 0.191 0.219 4.86 5.56 4, 5 E 0.485 0.495 12.32 12.57 - E1 0.450 0.456 11.43 11.58 3 E2 0.191 0.219 4.86 5.56 4, 5 N 28 28 6 Rev. 2 11/97 SEATING -C- PLANE 0.026 (0.66) 0.032 (0.81) 0.045 (1.14) MIN 0.013 (0.33) 0.021 (0.53) 0.025 (0.64) MIN VIEW “A” TYP. NOTES: 1. Controlling dimension: INCH. Converted millimeter dimensions are not necessarily exact. 2. Dimensions and tolerancing per ANSI Y14.5M-1982. 3. Dimensions D1 and E1 do not include mold protrusions. Allowable mold protrusion is 0.010 inch (0.25mm) per side. Dimensions D1 and E1 include mold mismatch and are measured at the extreme material condition at the body parting line. 4. To be measured at seating plane -C- contact point. 5. Centerline to be determined where center leads exit plastic body. 6. “N” is the number of terminal positions. All Intersil U.S. products are manufactured, assembled and tested utilizing ISO9000 quality systems. Intersil Corporation’s quality certifications can be viewed at www.intersil.com/design/quality Intersil products are sold by description only. Intersil Corporation reserves the right to make changes in circuit design, software and/or specifications at any time without notice. Accordingly, the reader is cautioned to verify that data sheets are current before placing orders. Information furnished by Intersil is believed to be accurate and reliable. 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