L6720 L6721 MINITEL INTERFACE ADVANCE DATA ONE NON INVERTING LINE DRIVER ONE NON INVERTING LINE RECEIVER LINE TRANSCEIVER: (TOWARDS PERIPHERALS) - non inverter from Minitel to peripherals - inverter from peripherals to Minitel POWER SUPPLY - not regolated output voltage - internal low drop power switch with antisaturation circuit - output protected against short circuit - standby mode operation with an external signal AUDIO AMPLIFIER - one input, one output - one pin for supply rejection - internal fixed gain THERMAL SHUTDOWN DESCRIPTION This device performs the functions of a complete interface for Minitel peripheral plug. Powerdip 16+2+2 ORDERING NUMERS: L6720 L6721 It integrates one line driver, one line receiver, one line transceiver, a power supply for peripherals, and an audio amplifier, Two version are provided: - L6720 which needs a negative supply. - L6721 which doesn’t use a negative supply. PIN CONNECTIONS L6720 L6721 November 1991 This advanced information on a new product now in development or undergoing evaluation. Details are subject to change without notice. 1/9 L6720 - L6721 BLOCK DIAGRAMS 2/9 L6720 - L6721 ABSOLUTE MAXIMUM RATINGS Test Conditions Unit +Vs ,(Vs) Symbol Positive Supply Voltage Parameter +15 V -Vs Negative Supply Voltage -13 V VOC Open Collectors Voltage max 20 V IOC Open Collectors Current max 10 mA Ptot Total Power Dissipation at Tamb = 70°C 1.25 W TJ Junction Temperature 150 °C Top Operating Temperature Range 0 to 70 °C THERMAL DATA Symbol Description Value Unit R thj-case Thermal Resistance Junction-case Max 14 °C/W Rthj-amb Thermal Resistance Junction-ambient Max (*)65 °C/W (*) Mounted on board with minimized dissipating copper area PIN FUNCTIONS Pin Name 1 AFI Audio Frequency input Function 2 AGND Audio Amplifier Ground 3 AFO 4 +Vs,(Vs) Audio amplifier output 5 –V S ,(GND) Negative Supply (GND for L6721) 6 –V S ,(GND) Negative Supply (GND for L6721) 7 PT 8 N.C. Not Connected (L6720) 7 PT1 Transceiver Output (to plug) (L6721) Power Supply Input (to plug) Transceiver Input/Output (L6720) 8 PT2 9 PSout Transceiver Input (from plug) (L6721) 10 M/V Inhibition of peripheral output power 11 GND Ground pin 12 PTS Line Transceiver Input (from Minitel) 13 PTE Line Transceiver Output (to Minitel) 14 EDP Line Driver Input (from Minitel) 15 –V S ,(GND) Negative Supply (GND for L6721) 16 –V S ,(GND) Negative Supply (GND for L6721) 17 TX 18 RDP 19 RX 20 SVR Power Supply Output (to plug) Line Driver Output (to plug) Line Receiver Output (to Minitel) Line Receiver Input Supply Voltage Rejection 3/9 L6720 - L6721 APPLICATION DIAGRAMS 4/9 L6720 - L6721 ELECTRICAL CHARACTERISTICS I) LINE DRIVER, LINE RECEIVER, LINE TRANCEIVER L6720: with negative supply Test Conditions: 10V < +Vs < 12V, -8V <- Vs < -4V, Tj = 25°C unless otherwise specified Symbol Parameter VIL Input Low Level (Pins Rx, EDP, PTS, PT) VIH Input High Level (pins Rx, EDP, PTS, PT) IG Pull-up Current Generator on Pins Rx, PT ZI Input Impedance on pins RX, Tx, PT Pins VS and –VS open Output Low Level (pins Tx, PT, PTE) ILOAD = 6mA VOL IR tPLH, tPHL tr, tf Test Condition Min. Typ. Unit 0.8 V 2 160 V 250 340 68 ILOAD = 6mA Cout = 50pF 3 Output Rise and Fall Time µA KΩ Output Leakage Current (pins Tx, RDP, PTE) Propagation Delay Time Max. 0.4 V 10 µA 5 µs µs 1 L6721: without negative supply Test Conditions: 10V < Vs < 12V, Tj = 25°C unless otherwise specified Symbol Parameter VIL Input Low Level (Pins Rx, EDP, PTS, PT2) VIH Input High Level (pins Rx, EDP, PTS, PT2) IG Pull-up Current Generator on Pins Rx, PT2 ZI Input Impedance on pins RX, Tx, PT2 Pins VS and GND open VOL Output Low Level (pins Tx, PT1) ILOAD = 6mA 0.15 V VOL Output Low Level (pins RDP, PTE) ILOAD = 6mA 0.4 V IR Output Leakage Current (pins Tx, RDP, PT1, PTE) 10 µA 5 µs tPLH, tPHL tr, tf Test Condition Min. Typ. Max. Unit 0.8 V 2 160 V 250 340 68 µA KΩ Propagation Delay Time ILOAD = 6mA Cout = 50pF 3 Output Rise and Fall Time ILOAD = 6mA Cout = 50pF 1 µs II) POWER SUPPLY L6720: +Vs = 12V, -Vs = -8V L6721: Vs = 12V Tj = 25°C unless otherwise specified Symbol VI - VO ISC Parameter Dropout Voltage Test Condition Min. ILOAD = 1A Short Circuit Current 1 Typ. Max. Unit 0.4 0.8 V 1.1 1.2 A 0.8 V M/VL Low Level Disable Pin (1) M/VH High Level Disable Pin (1) IL Disable Pin Input Current M/V = 0 100 µA Quiescent Current ILOAD = 1A ILOAD = 0.25A 60 23 mA mA IQ 2 V Note (1) Power supply is disabled when a zero level voltage is applied on M/V Pin 5/9 L6720 - L6721 III) AUDIO AMPLIFIER (2) L6720: +Vs = 12V, -Vs = -8V L6721: Vs = 12V Tj = 25°C unless otherwise specified Symbol Parameter Test Condition Min. Zi Input Impedance 20 AV Voltage Gain 28 BW Bandwidth PO Output Power Distortion = 10%, f = 1KHz R LOAD = 32Ω, 10V < VCC < 14V Typ. Max. 30 32 Unit KΩ dB 10 KHz 250 mW Note (2): The output of the audio amplifier is protected against short circuits toward positive power supply and ground IV) PROTECTIONS 1) L6720 (With negative supply) Pins Rx, Tx, PT are protected against any DC voltage ranging from -18V to +18V, with the device supplied or not, without extra components. 2) L6721 (Without negative supply) Pins Tx, PT1 are not protected: an external schottky diode must be added to protect them from 18V to +18V (see application diagram). Pins Rx, PT2 are protected against any DC voltage ranging from -18V to +18V. 3) In Both Options P. Supply pin is not protected: an external diode must be inserted to protect it (see application diagram). The suggested electrical characteristic of the external diode are: - VREVERSE > 20V - Voltage drop at 1A max. 1.2V 4) Thermal Protection This protection is operating when the chip temperature typically raises above 150°C (hysteresis 20°C Typ; this indicated value is valid with the application circuit on pag. 4), turning off both the power switch and the audio amplifier. APPLICATION INFORMATION The external diode on the output of the power switch has the fundamental function of protecting this pin against positive overvoltages. However the voltage drop on this diode is also important in the correct definition of the thermal hysteresis. This can be understood by considering the circuit applied on the output of the power switch, which has the function of withstanding negative overvoltages. Let’s refer to fig. 1: Figure 1 DEXT: EXTERNAL DIODE; PWR: POWER TRANSISTOR; I1, I2: CURRENT GENERATORS; R: RESISTANCE; D1, D2, D3: DIODES; Q1, Q2: SIGNAL TRANSISTORS 6/9 L6720 - L6721 When VOUT = 0.7V Q2 and D3 turn on and also Q1 whose saturation turns off the power PWR. In this condition (BVCBO) it can withstand the maximum negative overvoltage (-18V). If we now have an overload on VOUT (after the diode) for example with VIN = 12V, VOUT = 8V, Pd = 4W, the temperature of the chip increases to the thermal shutdown intervention, so that VOUT = 0. However Q1 and Q2 cannot turn on because we have 2 diodes (D1 and D2) against 3 diodes (D3, DEXT, Base-Emitter of Q2). If the over load is on point VO (before the external diode) as before the chip temperature increases until shutdown. But in that condition (with VOUT = 0) we have now 2 diodes (D1, D2) against other 2 diodes (D3, Q2 Base-Emitter); than the power switch doesn’t turn on because of a slight difference between the thermal coefficient of the 4 diodes. THERMAL CHARACTERISTICS The transient thermal resistance of the 16+2+2 powerdip package is shown in Fig. 2: a typical Rth j-amb of 50° C/W roughly can be seen.To be able to well sink out the heast from the inside of the package, the four control pins can be closely connected to a p.c.b. copper side. By considering the two square sides of Fig. 4, the thermal resistance junction-ambient can be reduced according to Fig. 3. Figure 2: DIP 16+2+2 Transient Thermal Resistance for single pulses. Figure 3: Typical Rth j-a of Powerdip 16+2+2 vs side 1 for heat sink on the PCB lower side. We will have the new switching-on of power switch only when the chip temperature decreases of about 80°C (being kept off by Q1 and Q2). In conclusion with or without the external diode the absolute value of the thermal shutdown is the same, but the hysteresis is higher without the external diode. Figure 4: Two ”On Board” square heat sink 7/9 L6720 - L6721 POWERDIP20 PACKAGE MECHANICAL DATA mm DIM. MIN. a1 0.51 B 0.85 b b1 TYP. MAX. MIN. TYP. MAX. 0.020 1.40 0.033 0.50 0.38 0.055 0.020 0.50 D 0.015 0.020 24.80 0.976 E 8.80 0.346 e 2.54 0.100 e3 22.86 0.900 F 7.10 0.280 I 5.10 0.201 L Z 8/9 inch 3.30 0.130 1.27 0.050 L6720 - L6721 Information furnished is believed to be accurate and reliable. However, SGS-THOMSON Microelectronics assumes no responsibility for the consequences of use of such information nor for any infringement of patents or other rights of third parties which may result from its use. No license is granted by implication or otherwise under any patent or patent rights of SGS-THOMSON Microelectronics. Specifications mentioned in this publication are subject to change without notice. This publication supersedes and replaces all information previously supplied. SGS-THOMSON Microelectronics products are not authorized for use as critical components in life support devices or systems without express written approval of SGS-THOMSON Microelectronics. 1994 SGS-THOMSON Microelectronics - All Rights Reserved SGS-THOMSON Microelectronics GROUP OF COMPANIES Australia - Brazil - France - Germany - Hong Kong - Italy - Japan - Korea - Malaysia - Malta - Morocco - The Netherlands - Singapore Spain - Sweden - Switzerland - Taiwan - Thaliand - United Kingdom - U.S.A. 9/9