Data Sheet November 1999 L7582 Tip Ring Access Switch Features ■ Small size/surface-mount packaging ■ Monolithic IC reliability ■ Low impulse noise ■ Make-before-break, break-before-make operation ■ Clean, bounce-free switching ■ Low, matched ON-resistance ■ Built-in current limiting, thermal shutdown, and SLIC protection ■ 5 V only operation, very low power consumption ■ Battery monitor, all OFF state upon loss of battery ■ No EMI ■ Latched logic level inputs, no drive circuitry ■ Only one external protector required Applications ■ Central office ■ DLC ■ PBX ■ DAML ■ HFC/FITL Description The L7582 Tip Ring Access Switch is a monolithic solid-state device that provides the switching functionality of a 2 form C switch. The L7582 is designed to provide power ringing access to tip and ring in central office, digital loop carrier, private branch exchange, digitally added main line, and hybrid fiber coax/fiber-in-the-loop ana- log line card applications. An additional pair of solidstate contacts provides access to the telephone loop for line test access or message waiting in the PBX application. The L7582 has four states: the idle talk state (line break switches closed, ringing and loop access switches open), the power ringing state (ringing access switches closed, line break and loop access switches open), loop access state (loop access switches closed, line break and ringing access switches open), and an all OFF state. The L7582 offers break-before-make or make-beforebreak switching, with simple logic level input control. Because of the solid-state construction, voltage transients generated when switching into an inductive ringing load during ring cadence or ring trip are minimized, possibly eliminating the need for external zero cross switching circuitry. State control is via logic level inputs so no additional driver circuitry is required. The line break switch is a linear switch that has exceptionally low ON-resistance and an excellent ON-resistance matching characteristic. The ringing access switch has a breakdown voltage rating >480 V which is sufficiently high, with proper protection, to prevent breakdown in the presence of a transient fault condition (i.e., passing the transient on to the ringing generator). Incorporated into the L7582Axx is a diode bridge/ SCR clamping circuit, current-limiting circuitry, and a thermal shutdown mechanism to provide protection to the SLIC device and subsequent circuitry during fault conditions (see Figure 1). Positive and negative lightning is reduced by the current-limiting circuitry and steered to ground via diodes and the integrated SCR. Power cross is also reduced by the currentlimiting and thermal shutdown circuits. Data Sheet November 1999 L7582 Tip Ring Access Switch The L7582Bxx version provides only an integrated diode bridge along with current limiting and thermal shutdown as shown in Figure 2. This will cause positive faults to be directed to ground and negative faults to battery. In either polarity, faults are reduced by the current-limit and/or thermal shutdown mechanisms. To protect the L7582 from an overvoltage fault condition, use of a secondary protector is required. The secondary protector must limit the voltage seen at the tip/ ring terminals to prevent the breakdown voltage of the switches from being exceeded. To minimize stress on the solid-state contacts, use of a foldback- or crowbartype secondary protector is recommended. With proper choice of secondary protection, a line card using the L7582 will meet all relevant ITU-T, LSSGR, FCC, or UL* protection requirements. The L7582 operates from a 5 V supply only. This gives the device extremely low idle and active power dissipation and allows use with virtually any range of battery voltage. This makes the L7582 especially appropriate for remote power applications such as DAML or FOC/FITL or other Bellcore TA 909 applications where power dissipation is particularly critical. Pin Information FGND 1 TBAT 2 TLINE TRINGING SCR AND TRIP CKT 16 VBAT 15 RBAT SW1 SW2 SW3 SW4 SW5 SW6 14 RLINE 3 13 RRINGING 4 TACCESS 5 12 RACCESS VDD 6 11 LATCH TSD 7 DGND 8 CONTROL LOGIC Description (continued) 10 INRING 9 INACCESS 12-2306.i (F) Note: Shown with A version protection. The 16-pin SOG is available with either A or B version protection. Figure 1. 16-Pin, Plastic SOG A battery voltage is also used by the L7582, only as a reference for the integrated protection circuit. The L7582 will enter an all OFF state upon loss of battery. The L7582 device is packaged in a 16-pin, plastic DIP package (L7582AC/BC) and a 16-pin, plastic SOG package (L7582AAE/BAE). The L7582AAE/BAE are pin compatible with the L7542AAE/BAE. *UL is a registered trademark of Underwriters Laboratories, Inc. FGND 1 TBAT 2 TLINE TRINGING 16 VBAT 15 RBAT SW1 SW2 SW3 SW4 SW5 SW6 14 RLINE 3 13 RRINGING 4 TACCESS 5 12 RACCESS VDD 6 11 LATCH TSD 7 DGND 8 CONTROL LOGIC During power ringing, to turn on and maintain the ON state, the ring access switch will draw a nominal 2 mA or 4 mA from the ring generator. 10 INRING 9 INACCESS 12-2306.c (F) Note: Shown with B version protection. The 16-pin DIP is available with either A or B version protection. Figure 2. 16-Pin, Plastic DIP 2 Lucent Technologies Inc. Data Sheet November 1999 L7582 Tip Ring Access Switch Pin Information (continued) Table 1. Pin Descriptions DIP SOG Symbol Description 1 1 FGND Fault ground. 2 3 4 2 3 4 TBAT TLINE TRINGING 5 6 5 6 TACCESS VDD 7 7 TSD 8 8 DGND DIP 16 SOG 16 Symbol Description VBAT Battery voltage. Used as a reference for protection circuit. RBAT Connect to RING on SLIC side. R LINE Connect to RING on line side. RRINGING Connect to ringing generator. Connect to TIP on SLIC side. 15 Connect to TIP on line side. 14 Connect to return ground for ring- 13 ing generator. Test access. 12 5 V supply. 11 15 14 13 10 10 RACCESS Test access. LATCH Data latch control, active-high, transparent low. INRING Logic level input switch control. 9 9 INACCESS Logic level input switch control. Temperature shutdown pin. Can be used as a logic level input or output. See Table 13, Truth Table, and the Switching Behavior section of this data sheet for input pin description. As an output, will read 5 V when device is in its operational mode and 0 V in the thermal shutdown mode. To disable the thermal shutdown mechanism, tie this pin to 5 V (not recommended). Digital ground. 12 11 Absolute Maximum Ratings Handling Precautions Stresses in excess of the absolute maximum ratings can cause permanent damage to the device. These are absolute stress ratings only. Functional operation of the device is not implied at these or any other conditions in excess of those given in the operational sections of the data sheet. Exposure to absolute maximum ratings for extended periods can adversely affect device reliability. Although protection circuitry has been designed into this device, proper precautions should be taken to avoid exposure to electrostatic discharge (ESD) during handling and mounting. Lucent Technologies Microelectronics Group employs a human-body model (HBM) and a charged-device model (CDM) for ESDsusceptibility testing and protection design evaluation. ESD voltage thresholds are dependent on the circuit parameters used to define the model. No industry-wide standard has been adopted for CDM. However, a standard HBM (resistance = 1500 Ω, capacitance = 100 pF) is widely used and therefore can be used for comparison purposes. The HBM ESD threshold presented here was obtained by using these circuit parameters. Table 2. Absolute Maximum Ratings Parameters Parameter Operating Temperature Range Storage Temperature Range Relative Humidity Range Pin Soldering Temperature (t = 10 s max) 5 V Power Supply Battery Supply Logic Input Voltage Input-to-output Isolation Pole-to-pole Isolation Lucent Technologies Inc. Min –40 –40 5 — Max 110 150 95 260 Unit °C °C % °C — — — — — 7 –85 7 330 330 V V V V V Table 3. HBM ESD Threshold Voltage Device L7582 Rating 1000 V 3 Data Sheet November 1999 L7582 Tip Ring Access Switch Electrical Characteristics TA = –40 °C to +85 °C, unless otherwise specified. Minimum and maximum values are testing requirements. Typical values are characteristics of the device and are the result of engineering evaluations. Typical values are for information purposes only and are not part of the testing requirements. Table 4. Power Supply Specifications Supply VDD VBAT* Min 4.5 –19 Typ 5 — Max 5.5 –72 Unit V V * VBAT is used only as a reference for internal protection circuitry. If VBAT rises above –10 V, the device will enter an all OFF state and will remain in the all OFF state until the battery voltage drops below –15 V. Table 5. Break Switches, 1 and 2 Parameter OFF-state Leakage Current: +25 °C +85 °C –40 °C ON-resistance (SW1, SW2): +25 °C +85 °C –40 °C ON-resistance Match ON-state Voltage* dc Current Limit: +85 °C –40 °C Dynamic Current Limit (t = < 0.5 µs) Isolation: +25 °C +85 °C –40 °C dV/dt Sensitivity† Test Condition Measure Min Typ Max Unit Vswitch (differential) = –320 V to Gnd Vswitch (differential) = –60 V to +260 V Vswitch (differential) = –330 V to Gnd Vswitch (differential) = –60 V to +270 V Vswitch (differential) = –310 V to Gnd Vswitch (differential) = –60 V to +250 V Iswitch — — 1 µA Iswitch — — 1 µA Iswitch — — 1 µA TLINE = ±10 mA, ±40 mA, TBAT = –2 V TLINE = ±10 mA, ±40 mA, TBAT = –2 V TLINE = ±10 mA, ±40 mA, TBAT = –2 V Per ON-resistance test condition of SW1, SW2 Iswitch = ILIMIT @ 50 Hz/60 Hz ∆ VON ∆ VON ∆ VON Magnitude RON SW1 – RON SW2 VON — — — — 19.5 — 14.5 0.2 — 28 — 1.0 Ω Ω Ω Ω — — 220 V Vswitch (on) = ±10 V Vswitch (on) = ±10 V Break switches in ON state; ringing access switches off; apply ±1000 V at 10/1000 µs pulse; appropriate secondary protection in place Iswitch Iswitch Iswitch 80 — — — — 2.5 — 250 — mA mA A Vswitch (both poles) = ±320 V, Logic inputs = Gnd Vswitch (both poles) = ±330 V, Logic inputs = Gnd Vswitch (both poles) = ±310 V, Logic inputs = Gnd — Iswitch — — 1 µA Iswitch — — 1 µA Iswitch — — 1 µA — — 200 — V/µs * This parameter is not tested in production. Choice of secondary protector should ensure this rating is not exceeded. † Applied voltage is 100 Vp-p square wave at 100 Hz. 4 Lucent Technologies Inc. Data Sheet November 1999 L7582 Tip Ring Access Switch Electrical Characteristics (continued) Table 6. Ring Return Switch, 3 Parameter OFF-state Leakage Current (SW3): +25 °C +85 °C –40 °C dc Current Limit Dynamic Current Limit (t = < 0.5 µs) ON-resistance ON-state Voltage* Isolation: +25 °C +85 °C –40 °C Test Condition Vswitch (differential) = –320 V to Gnd Vswitch (differential) = –60 V to +260 V Vswitch (differential) = –330 V to Gnd Vswitch (differential) = –60 V to +270 V Vswitch (differential) = –310 V to Gnd Vswitch (differential) = –60 V to +250 V Vswitch (on) = ±10 V Break switches in ON state; ringing access switches off; apply ±1000 V at 10/1000 µs pulse; appropriate secondary protection in place Iswitch (on) = ±0 mA, ±10 mA Iswitch = ILIMIT @ 50 Hz/60 Hz dV/dt Sensitivity† Vswitch (both poles) = ±320 V, Logic inputs = Gnd Vswitch (both poles) = ±330 V, Logic inputs = Gnd Vswitch (both poles) = ±310 V, Logic inputs = Gnd — Measure Min Typ Max Unit Iswitch — — 1 µA Iswitch — — 1 µA Iswitch — — 1 µA Iswitch Iswitch — — 200 2.5 — — mA A ∆ VON VON — — — — 100 130 Ω V Iswitch Iswitch Iswitch — — — — — — — — 200 1 1 1 — µA µA µA V/µs * This parameter is not tested in production. Choice of secondary protector should ensure this rating is not exceeded. † Applied voltage is 100 Vp-p square wave at 100 Hz. Table 7. Ringing Access Switch, 4 Parameter OFF-state Leakage Current (SW4): +25 °C +85 °C –40 °C ON Voltage Ring Generator Current During Ring Steady-state Current† Surge Current† Release Current ON-resistance Isolation: +25 °C +85 °C –40 °C dV/dt Sensitivity‡ Test Condition Measure Min Vswitch (differential) = –255 V to +210 V Vswitch (differential) = +255 V to –210 V Vswitch (differential) = –270 V to +210 V Vswitch (differential) = +270 V to –210 V Vswitch (differential) = –245 V to +210 V Vswitch (differential) = +245 V to –210 V Iswitch (on) = ±1 mA VCC = 5 V INACCESS = 0 — — — Iswitch (on) = ±70 mA, ±80 mA Iswitch — — 1 µA Iswitch — — 1 µA Iswitch — — 1 µA — IRINGSOURCE — — — * 3 — V mA — — — ∆ Von — — — — — — 500 150 2 — 12 mA A µA Ω Iswitch Iswitch Iswitch — — — — — — — — 200 1 1 1 — µA µA µA V/µs Vswitch (both poles) = ±320 V, Logic inputs = Gnd Vswitch (both poles) = ±330 V, Logic inputs = Gnd Vswitch (both poles) = ±310 V, Logic inputs = Gnd — Typ Max Unit * At the time of publication of this data sheet, the current device design will be a nominal 4 mA. Devices are being redesigned to reduce this current to less than 2 mA nominally. Consult your Lucent Technologies Microelectronics Group account executive for additional details. † Choice of secondary protector and series current-limit resistor should ensure these ratings are not exceeded. ‡ Applied voltage is 100 Vp-p square wave at 100 Hz. Lucent Technologies Inc. 5 Data Sheet November 1999 L7582 Tip Ring Access Switch Electrical Characteristics (continued) Table 8. Loop Access Switches, 5 and 6 Parameter OFF-state Leakage Current: +25 °C +85 °C –40 °C dc Current Limit: +85 °C –40 °C Dynamic Current Limit (t = <0.5 µs) ON-resistance: +25 °C +85 °C –40 °C ON-state Voltage* Isolation: +25 °C +85 °C –40 °C dV/dt Sensitivity† Test Condition Measure Min Typ Max Unit Vswitch (differential) = –320 V to Gnd Vswitch (differential) = –60 V to +260 V Vswitch (differential) = –330 V to Gnd Vswitch (differential) = –60 V to +270 V Vswitch (differential) = –310 V to Gnd Vswitch (differential) = –60 V to +250 V Iswitch — — 1 µA Iswitch — — 1 µA Iswitch — — 1 µA Vswitch (on) = ±10 V Vswitch (on) = ±10 V Break switches in ON state; ringing access switches off; apply ±1000 V at 10/1000 µs pulse; appropriate secondary protection in place Iswitch Iswitch Iswitch 80 — — — — 2.5 — 250 — mA mA A Iswitch (on) = ±10 mA, ±40 mA Iswitch (on) = ±10 mA, ±40 mA Iswitch (on) = ±10 mA, ±40 mA Iswitch = ILIMIT @ 50 Hz/60 Hz ∆ VON ∆ VON ∆ VON VON — — — — 45 — 33 — — 70 — 130 Ω Ω Ω V Vswitch (both poles) = ±320 V, Logic inputs = Gnd Vswitch (both poles) = ±330 V, Logic inputs = Gnd Vswitch (both poles) = ±310 V, Logic inputs = Gnd — Iswitch Iswitch Iswitch — — — — — — — — 200 1 1 1 — µA µA µA V/µs * This parameter is not tested in production. Choice of secondary protector should ensure this rating is not exceeded. † Applied voltage is 100 Vp-p square wave at 100 Hz. 6 Lucent Technologies Inc. Data Sheet November 1999 L7582 Tip Ring Access Switch Electrical Characteristics (continued) Table 9. Additional Electrical Characteristics Parameter Digital Input Characteristics: Input Low Voltage Input High Voltage Input Leakage Current (high) Input Leakage Current (low) Power Requirements: Power Dissipation VDD Current VBAT Current Test Condition Measure Min Typ — — VDD = 5.5 V, VBAT = –75 V, Vlogicin = 5 V VDD = 5.5 V, VBAT = –75 V, Vlogicin = 0 V — — llogicin — 3.5 — — — — 1.5 — 1 V V µA llogicin — — 1 µA IDD, IBAT IDD — — 3 6 5 10 mW mW IDD IDD — — 560 900 0.750 1.9 µA mA IBAT IBAT — — 4 4 10 10 µA µA — — 110 10 125 — 150 25 °C °C VDD = 5 V, VBAT = –48 V, idle/talk state or all OFF state, ringing state or access state VDD = 5 V, idle/talk state or all OFF state, ringing state or access state VBAT = –48 V, idle/talk state or all OFF state, ringing state or access state Temperature Shutdown Requirements*: Shutdown Activation Temperature Shutdown Circuit Hysteresis — — Max Unit * Temperature shutdown flag (TSD) will be high during normal operation and low during temperature shutdown state. Zero Cross Current Turn Off Switching Behavior The ring access switch (SW4) is designed to turn off on the next zero current crossing after application of the appropriate logic input control. This switch requires a current zero cross to turn off. Switch 4, once on, will remain in the ON state (regardless of logic input) until a current zero cross. Therefore, to ensure proper operation of switch 4, this switch should be connected, via proper impedance, to the ringing generator or some other ac source. Do not attempt to switch pure dc with switch 4. When switching from the power ringing state to the idle/talk state via simple logic level input control, the L7582 is able to provide control with respect to the timing when the ringing access contacts are released relative to the state of the line break contacts. For a detailed explanation of the operation of switch 4, please refer to the An Introduction to L758X Series of Line Card Access Switches Application Note. Lucent Technologies Inc. Make-before-break operation occurs when the line break switch contacts are closed (or made) before the ringing access switch contact is opened (or broken). Break-before-make operation occurs when the ringing access contact is opened (broken) before the line break switch contacts are closed (made). Using the logic level input pins INring and INaccess, either make-before-break or break-before-make operation of the L7582 is easily achieved. The logic sequences for either mode of operation are given in Table 10 and Table 11. See the Truth Table (Table 13) for an explanation of the logic states. 7 Data Sheet November 1999 L7582 Tip Ring Access Switch Switching Behavior (continued) The SCR may turn on if: When using an L7582 in the make-before-break mode, during the ring-to-idle transition, for a period of up to one-half the ringing frequency, the ring break switch and the pnpn-type ring access switch can both be in the ON state. This is the maximum time after the logic signal at INRING has transitioned that the ring access switch is waiting for the next zero current cross, so it can close. During this interval, current that is limited to the dc break switch current-limit value will be sourced from the ring node of the SLIC. This current is presented to the internal protection circuit. ■ The SCR-type protector is used (A code) ■ By random probability the ring-to-idle transition occurs during a portion of the ring cycle when the ringing voltage exceeds the protection circuit SCR turn-on voltage. ■ Current in excess of the SCR’s turn-on current is also available. Once the SCR is triggered on, if the SLIC is capable of supplying current in excess of the holding current, the SCR may be latched on by the SLIC. The probability of this event depends on the characteristics of the given SLIC and of the holding current of the L7582A device. The SCR hold current distribution is designed to be safely away from the test limit of 80 mA. The higher the distribution, the lower the probability of the latch. If this situation is of concern for a given board design, either use the A series device in the break-before-make mode (eliminates the original 25 ms current pulse) or use a B series device (eliminates the SCR). Table 10. Make-Before-Break Operation ACCESS INPUT TSD 8 0V 0V 5V 0V 0V 0V State Timing Float Power Ringing — Float Make-before- SW4 waiting for next zero break current crossing to turn off maximum time—one-half of ringing. In this transition state, current that is limited to the dc break switch current-limit value will be sourced from the ring node of the SLIC. Float Idle/Talk Zero cross current has occurred. Break Switches 1&2 Ring Return Switch 3 Line Ring Access Access Switch Switches 5&6 4 Open Closed Closed Open Closed Closed Open Open Closed Open Open Open Lucent Technologies Inc. Data Sheet November 1999 L7582 Tip Ring Access Switch Switching Behavior (continued) Table 11. Break-Before-Make Operation ACCESS INPUT 0V 5V 5V 5V 5V 5V 0V 0V TSD State Timing Float Power — Ringing Float All Off Hold this state for ≤25 ms. SW4 waiting for zero current to turn off. Float All Off Zero current has occurred and SW4 has opened. Float Idle/Talk Release break switches. Break Switches 1&2 Ring Return Switch 3 Ring Access Switch 4 Line Access Switches 5&6 Open Closed Closed Open Open Open Closed Open Open Open Open Open Closed Open Open Open Notes: Break-before-make operation can also be achieved using TSD as an input. In lines two and three of Table 11, instead of using the logic input pins to force the all OFF state, force TSD to ground. This will override the logic inputs and also force the all OFF state. Hold this state for 25 ms. During this 25 ms all OFF state, toggle the inputs from 10 (ringing state) to 00 (idle/talk state). After 25 ms, release TSD to return switch control to the input pins which will set the idle talk state. When using the L7582 in this mode, forcing TSD to ground will override the INPUT pins and force an all OFF state. Setting TSD to 5 V will allow switch control via the logic INPUT pins. However, setting TSD to 5 V will also disable the thermal shutdown mechanism. This is not recommended. Therefore, to allow switch control via the logic INPUT pins, allow TSD to float. Thus, when using TSD as an input, the two recommended states are 0 (overrides logic input pins and forces all OFF state) and float (allows switch control via logic input pins and thermal shutdown mechanism is active). This may require use of an open collector buffer. Also note that TSD operation in L7582 is different than TSD operation of the L7581, where application of 5 V does not disable the thermal shutdown mechanism. Power Supplies Both the 5 V and battery supply are brought onto the L7582. The L7582 requires only the 5 V supply for switch operation; that is, state control is powered exclusively off of the 5 V supply. Because of this, the L7582 offers extremely low power dissipation, both in the idle and active states. The battery voltage is not used for switch state control. The battery is used as a reference voltage by the integrated secondary protection circuit. When the voltage at TBAT or RBAT drops 2 V to 4 V below the battery, the integrated SCR will trigger, thus preventing fault-induced overvoltage situations at the TBAT/RBAT nodes. Loss of Battery Voltage The L7582 is designed such that the device will enter the all OFF state if the battery rises above –10 V and will remain off until the battery drops below –15 V. Monitoring the battery for the automatic shutdown feature will draw a small current from the battery, typically 4 µA. This will add slightly to the overall power dissipation of the device. Impulse Noise Using the L7582 will minimize and possibly eliminate the contribution to the overall system impulse noise that is associated with ringing access switches. Because of this characteristic of the L7582, it may not be necessary to incorporate a zero cross switching scheme. This ultimately depends upon the characteristics of the individual system and is best evaluated at the board level. As an additional protection feature, the L7582 monitors the battery voltage. Upon loss of battery voltage, the L7582 will automatically enter an all OFF state and remain in that state until the battery voltage is restored. Lucent Technologies Inc. 9 L7582 Tip Ring Access Switch Protection Integrated SLIC Protection Diode Bridge/SCR In the L7582Axx version, protection to the SLIC device or other subsequent circuitry is provided by a combination of current-limited break switches, a diode bridge/ SCR clamping circuit, and a thermal shutdown mechanism. In the L7582Bxx version, protection to the SLIC device or other subsequent circuitry is provided by a combination of current-limited break switches, a diode bridge, and a thermal shutdown mechanism. In both versions, during a positive lightning event, fault current is directed to ground via steering diodes in the diode bridge. Voltage is clamped to a diode drop above ground. In the A version, negative lightning causes the SCR to conduct when the voltage goes 2 V to 4 V more negative than the battery. Fault currents are then directed to ground via the SCR and steering diodes in the diode bridge. Note that for the SCR to foldback or crowbar, the ON voltage (see Table 11) of the SCR must be less negative than the battery reference voltage. If the battery voltage is less negative than the SCR ON voltage, the SCR will conduct fault currents to ground; however, it will not crowbar. In the B version, negative lightning is directed to battery via steering diodes in the diode bridge. For power cross and power induction faults, in both versions, the positive cycle of the fault is clamped a diode drop above ground and fault currents are steered to ground. In the A version, the negative cycle will cause the SCR to trigger when the voltage exceeds the battery reference voltage by 2 V to 4 V. When the SCR triggers, fault current is steered to ground. In the B version, the negative cycle of the power cross is steered to battery. Current Limiting During a lightning event, the current that is passed through the break switches and presented to the integrated protection circuit and subsequent circuitry is limited by the dynamic current-limit response of the break switches (assuming idle/talk state). When the voltage seen at the TLINE/RLINE nodes is properly clamped by an external secondary protector, upon application of a 1000 V 10 x 1000 pulse (LSSGR lightning), the current seen at the TBAT/RBAT nodes will typically be a pulse of magnitude 2.5 A and duration less than 0.5 µs. 10 Data Sheet November 1999 During a power cross event, the current that is passed through the break switches and presented to the integrated protection circuit and subsequent circuitry is limited by the dc current-limit response of the break switches (assuming idle/talk state). The dc current limit is specified over temperature between 100 mA and 250 mA. Note that the current-limit circuitry has a negative temperature coefficient. Thus, if the device is subjected to an extended power cross, the value of current seen at TBAT/RBAT will decrease as the device heats due to the fault current. If sufficient heating occurs, the temperature shutdown mechanism will activate and the device will enter an all off mode. Temperature Shutdown Mechanism When the device temperature reaches a minimum of 110 °C, the thermal shutdown mechanism will activate and force the device into an all OFF state, regardless of the logic input pins. Pin TSD, when used as an output, will read 0 V when the device is in the thermal shutdown mode and +VDD during normal operation. During a lightning event, due to the relatively short duration, the thermal shutdown will not typically activate. During an extended power cross, the device temperature will rise and cause the device to enter the thermal shutdown mode. This forces an all off mode, and the current seen at TBAT/RBAT drops to zero. Once in the thermal shutdown mode, the device will cool and exit the thermal shutdown mode, thus reentering the state it was in prior to thermal shutdown. Current, limited to the dc current-limit value, will again begin to flow and device heating will begin again. This cycle of entering and exiting thermal shutdown will last as long as the power-cross fault is present. If the magnitude of power is great enough, the external secondary protector could trigger, thereby shunting all current to ground. In the L7582, the thermal shutdown mechanism can be disabled by forcing the TSD pin to +VDD. This functionality differs from the L7581, whose thermal shutdown mechanism cannot be disabled. Lucent Technologies Inc. Data Sheet November 1999 Protection (continued) Integrated SLIC Protection (continued) External Secondary Protector With the above integrated protection features, only one overvoltage secondary protection device on the loop side of the L7582 is required. The purpose of this device is to limit fault voltages seen by the L7582 so as not to exceed the breakdown voltage or input-output isolation rating of the device. To minimize stress on the L7582, use of a foldback- or crowbar-type device is recommended. A detailed explanation and design equations on the choice of the external secondary protection device are given in the An Introduction to L758X Series of Line Card Access Switches Application Note. Basic design equations governing the choice of external secondary protector are given below: ■ ■ ■ L7582 Tip Ring Access Switch where: VBATmax—Maximum magnitude of battery voltage. Vbreakovermax—Maximum magnitude breakover voltage of external secondary protector. Vbreakovermin—Minimum magnitude breakover voltage of external secondary protector. Vbreakdownmin(break)—Minimum magnitude breakdown voltage of L7582 break switch. Vbreakdownmin(ring)—Minimum magnitude breakdown voltage of L7582 ring access switch. Vringingpeakmax—Maximum magnitude peak voltage of ringing signal. Series current-limiting fused resistors or PTCs should be chosen so as not to exceed the current rating of the external secondary protector. Refer to the manufacturer’s data sheet for requirements. |VBATmax| + |Vbreakovermax| < |Vbreakdownmin(break)| |Vringingpeakmax| + |VBATmax| + |Vbreakovermax| < |Vbreakdownmin(ring)| |Vringingpeakmax| + |VBATmax| < |Vbreakovermin| Table 12. Electrical Specifications, Protection Circuitry Parameters Related to Diodes (in Diode Bridge) Parameter Test Condition Measure Min Voltage Drop @ Continuous CurApply ±dc current limit Forward — rent (50 Hz/60 Hz) of break switches Voltage Voltage Drop @ Surge Apply ±dynamic curForward — Current rent limit of break Voltage switches Parameters Related to Protection SCR Surge Current — — — — — — Gate Trigger Current*† † Gate Trigger Current Temperature — — — Coefficient Hold Current — — 70 Gate Trigger Voltage Trigger current — VBAT – 4 Reverse Leakage Current VBAT — — § ON-State Voltage 0.5 A, t = 0.5 µs VON — 2.0 A, t = 0.5 µs — — Typ — Max 3 Unit V 5 — V — 25 –0.5 ‡ A mA %/°C — — — –3 –5 50 — — VBAT – 2 1.0 — — mA V µA V V * Previous versions of this data sheet specified a Trigger Current of 50 mA minimum. Trigger Current is defined as the minimum current drawn from tip and ring to turn on the SCR. The specification in this data sheet is Gate Trigger Current, which is defined as the maximum current that can flow into the battery before the SCR turns on. † Typical at 25 °C. ‡ Twice ± dynamic current limit of break switches. § In some instances, the typical ON-state voltage can range as low as –25 V. Lucent Technologies Inc. 11 Data Sheet November 1999 L7582 Tip Ring Access Switch Typical Performance Characteristics CURRENT LIMITING +I ILIMIT 2/3 RON dc CURRENT-LIMIT BREAK SWITCHES VBAT – 2 VBAT – 4 RON –1.5 V VBAT –V VON <1 µA 3V 1.5 V RON +V 2/3 RON ILIMIT CURRENT LIMITING 50 mA –I 12-2311 (F) dc CURRENT LIMIT (OF BREAK SWITCHES) Figure 5. Switches 1—3 IH 12-2309.f (F) Figure 3. Protection Circuit A Version +I RON dc CURRENT-LIMIT BREAK SWITCHES –VOS –V VBAT – 3 +VOS +V VBAT <1 µA 3V –I 12-2312 (F) dc CURRENT LIMIT (OF BREAK SWITCHES) Figure 6. Switch 4 12-2309.b (F) Figure 4. Protection Circuit B Version 12 Lucent Technologies Inc. Data Sheet November 1999 L7582 Tip Ring Access Switch Application VBAT REFERENCE TIP SW5 LINE TEST ACCESS R1 SW3 RINGING RETURN TIP SW1 BREAK SCR AND TRIP CKT CROWBAR PROTECTION R2 BATTERY FEED SW2 BREAK SW6 LINE TEST ACCESS RING RING SW4 RINGING ACCESS RING GENERATOR BATTERY 12-2366.c (F) Figure 7. Typical TRAS Application, Idle, or Talk State Shown Table 13. Truth Table Input Access 0V 0V 5V 0V 0V 5V 5V 5V Don’t Care Don’t Care 1. 2. 3. 4. 5. 6. TSD 5 V/Float1 5 V/Float1 5 V/Float1 5 V/Float1 0 V2 Tip Break Switch On Off Off Off Off Ring Break Switch On Off Off Off Off Ringing Return Switch Off On Off Off Off Ring Switch Off On Off Off Off Tip Access Switch Off Off On Off Off Ring Access Switch Off3 Off4 On5 Off6 Off6 If TSD = 5 V, the thermal shutdown mechanism is disabled. If TSD is floating, the thermal shutdown mechanism is active. Forcing TSD to ground overrides the logic input pins and forces an all OFF state. Idle/Talk state. Power ringing state. Test out or message waiting state. All OFF state. A parallel in/parallel out data latch is integrated into the L7582. Operation of the data latch is controlled by the logic level input pin LATCH. The data input to the latch is the INRING and INACCESS pins of the L7582, and the output of the data latch is an internal node used for state control. When the LATCH control pin is at logic 0, the data latch is transparent and data control signals flow directly from INRING and INACCESS, through the data latch to state control. Any changes in INRING and INACCESS will be reflected in the state of the switches. Lucent Technologies Inc. When the LATCH control pin is at logic 1, the data latch is active—the L7582 will no longer react to changes at the INRING and INACCESS control pins. The state of the switches is now latched; that is, the state of the switches will remain as they were when the LATCH input transitioned from logic 0 to logic 1. The switches will not respond to changes in INRING and INACCESS as long as LATCH is held high. Note that the TSD input is not tied to the data latch. TSD is not affected by the LATCH input. TSD input will override state control via INRING, INACCESS, and LATCH. 13 Data Sheet November 1999 L7582 Tip Ring Access Switch Outline Diagrams 16-Pin, Plastic SOG (L7582AAE/BAE) Note: The dimensions in this outline diagram are intended for informational purposes only. For detailed schematics to assist your design efforts, please contact your Lucent Technologies Sales Representative. L N B 1 PIN #1 IDENTIFIER ZONE W H SEATING PLANE 0.10 1.27 TYP 0.51 MAX 0.61 0.28 MAX Number of Pins (N) Maximum Length (L) Maximum Width Without Leads (B) Maximum Width Including Leads (W) Maximum Height Above Board (H) 16 10.49 7.62 10.64 2.67 5-4414 (F) 14 Lucent Technologies Inc. Data Sheet November 1999 L7582 Tip Ring Access Switch Outline Diagrams (continued) 16-Pin, Plastic DIP (L7582AC/BC) Note: The dimensions in this outline diagram are intended for informational purposes only. For detailed schematics to assist your design efforts, please contact your Lucent Technologies Sales Representative. L N B 1 W PIN #1 IDENTIFIER ZONE H SEATING PLANE 0.38 MIN 2.54 TYP 0.58 MAX Number of Pins (N) Maximum Length (L) Maximum Width Without Leads (B) Maximum Width Including Leads (W) Maximum Height Above Board (H) 16 20.57 6.48 7.87 5.08 5-4410 (F) Lucent Technologies Inc. 15 Data Sheet November 1999 L7582 Tip Ring Access Switch Ordering Information Device Part No. ATTL7582AAE ATTL7582AAE-TR* ATTL7582AC ATTL7582BAE ATTL7582BAE-TR* ATTL7582BC Description Tip Ri ng Access Switch Tip Ri ng Access Switch Tip Ri ng Access Switch Tip Ri ng Access Switch Tip Ri ng Access Switch Tip Ri ng Access Switch Package 16-pin SOG 16-pin SO G (Tape & Reel) 16-pin DIP 16-pin SOG 16-pin SO G (Tape & Reel) 16-pin DIP Comcode 107338543 107338576 107394181 107394231 107394256 107394207 *Devices o n tape an d reel must be ordered i n 1000-piece inc rement s. For additi onal INTERNET: E-MAIL: N. AMERICA: info rm ation, contact your Microelectronics Group Acc ount Manager or the followi ng: http://www.lucent.com/micro [email protected] Microelectronics Grou p, Lucent Technologies Inc., 555 Union Boul evard, Room 30L-15 P-BA, Allent own , PA 18103 1-800-372-2447, FAX 610-712-4106 (In CANADA: 1-800-553-2448, FAX 610-712-4106) ASIA PACIFIC: Microelectronics Grou p, Lucent Technologies Singapore Pt e. Ltd., 77 Science Park Drive, #03-18 Cintech III , ore Singa 118256 p Tel. (65) 778 8833, FAX (65) 777 7495 CHINA: Micr oelectronics Group, Lucent Techn ologies (China) Co., Lt d., A-F2, 23/F, Zao Fong Univers e Building, 1800 Zho ng Shan Road,XiShang hai 200233 P. R. China Tel. (86) 21 6440 0468, ext. 316, FAX (86) 21 6440 0652 JAPAN: Micr oelectronics Group, Lucent Technolog ies Japan Ltd., 7-18, Higashi-Gotanda 2-chome, Shinagawa-ku, Tokyo 141, Japan Tel. (81) 3 5421 1600, FAX (81) 3 5421 1700 EUROPE: Data Requ ests: MICROELECTRONICS GROUP DATALINE:Tel. (44) 7000 582 368, FAX (44) 1189 328 148 Technical Inquiries: GERMANY: (49) 89 95086 0 (Munich), UNITED KINGDOM:(44) 1344 865 900 (Ascot), FRANCE: (33) 1 40 83 68 00 (Paris), SWEDEN: (46) 8 594 607 00 (Sto ckholm), FINLAND (358) : 9 4354 2800 (Hels inki), ITALY: (39) 02 6608131 (Milan), SPAIN: (34) 1 807 1441 (Madrid) Lucent Techn ologies I nc. re ser ves t he right t o make chan ges to the p roduct (s) or in formation c ontain ed he rein with outono liability tice. Ni s assum ed as a res ult of t heir us e or applicatio n. No rights unde r any pa tent acc ompa ny the s ale of a ny such p roduct (s) or in formation. Copyright © 1999 Luce nt Technologie s Inc. All Rights Res er ved November 1999 DS00-051ALC (Replaces DS99-015ALC)