MC1488 RS232C QUAD LINE DRIVER .. . .. CURRENT LIMITED OUTPUT 10mA TYP. POWER-OFF SOURCE IMPEDANCE 300 MIN. SIMPLE SLEW RATE CONTROL WITH EXTERNAL CAPACITOR FLEXIBLE OPERATING SUPPLY RANGE INPUTS ARE TTL AND P COMPATIBLE N DIP14 (Plastic Package) ORDER CODES : DESCRIPTION D SO14 (Plastic Micropackage) MC1488P (Plastic DIP) MC1488L (Ceramic DIP) MC1488D (SO14) The MC1488 is a monolithic quad line driver designed to interface data terminal equipment with data communications equipment in conformance PIN CONNECTIONS (top view) April 1993 LOGIC DIAGRAM 1/9 MC1488 ABSOLUTE MAXIMUM RATINGS Symbol VS VEE VIR VO Tamb Tstg Parameter Power Supply Voltage Power Supply Voltage Input Voltage Range Output Signal Voltage Operating Ambient Temperature Storage Temperature Range Test Conditions 15 -15 -15 VIR 7 15 0 to 75 -65 to 150 Unit V V V V o C o C THERMAL DATA Symbol Rth j-amb Parameter Thermal Resistance Junction-ambient Max. Plastic DIP14 200oC/W Ceramic DIP14 165oC/W SO14 165oC/W ELECTRICAL CHARACTERISTICS VS= 9 10%V, VE E= -9 10%V ,Tamb= 0 to 75oC, unless otherwise specified Symbol IIL IIH VOH VOL IOS + * - IOS * RO Is Parameter Input Current Input Current Output Voltage Output Voltage Positive Output Short-circuit Current Negative Output Short-circuit Current Output Resistance Positive Supply Current (R i = ) IEE Negative Supply Current (R L = ) Pc Power Consumption Test Conditions Min. Low Logic State VIL = 0V High Logic State VIH = 5V High Logic State RL = 3k 6 VIL = 0.8V, V S = 9V, VEE = -9V 9 VIL = 0.8V, V S = 13.2V, VEE = -13.2V Low Logic State -6 VIH = 1.9V, VEE = -9V, VS = 9V VIH = 1.9V, VEE = -13.2V, VS = 13.2V -9 -6 300 Typ. Max. Unit Fig. 1 1.6 mA 1 10 A 1 V 7 2 10.5 2 V -7 2 2 10.5 mA 3 10 12 mA 3 -10 -12 4 15 20 4.5 6 19 25 5.5 7 mA 5 34 12 -13 -17 mA -15 A -18 -23 mA -15 A 5 -34 mA -2.5 mA 333 mW 567 Min. Typ. Max. Unit Fig. 6 VS = VEE = 0 VIH = 1.9V VIL = 0.8V VIH = 1.9V VIL = 0.8V VIH = 1.9V VIL = 0.8V VIH = 1.9V VIL = 0.8V VIH = 1.9V VIL = 0.8V VIH = 1.9V VIL = 0.8V VS = 9V VS = 12V Vol = 2V Vs = 9V Vs = 9V Vs = 12V Vs = 12V Vs = 15V Vs = 15V Vs = -9V Vs = -9V Vs = -12V Vs = -12V Vs = -15V Vs = -15V VEE = -9V VEE = -12V SWITCHING CHARACTERISTICS VS= 9 1V, VE E= -9 1%V ,Tamb= 25oC Symbol Parameter Test Conditions tPHL Propagation Delay Time Zi = 3k and 15pF 275 350 ns 6 tTHL Fall Time Zi = 3k and 15pF 45 75 ns 6 tPHL Propagation Delay Time Zi = 3k and 15pF 110 175 ns 6 tTHL Rise Time Zi = 3k and 15pF 55 100 ns 6 * Maximum package power dissipation may be exceeded if all outputs are shorted simultaneously. 2/9 MC1488 TEST CIRCUITS Figure 1 : Input Current Figure 2 : Output Voltage Figure 3 : Output Short-Circuit Current Figure 4 : Output Resistance (power off) Figure 5 : Power Supply Currents Figure 6 : Switching Response 3/9 MC1488 Figure 7 : Transfer Characteristics versus Power Supply Voltage Figure 8 : Short-Circuit Output Current versus Temperature Figure 9 : Output Slew-Rate Load Capacitance Figure 10 : Output Voltage and Current Limiting Characteristics Figure 11 : Maximum Operating Temperature versus Power Supply Voltage 4/9 MC1488 TYPICAL APPLICATION : RS232C Data Transmission APPLICATION INFORMATION The Electronic Industries Association (EIA) has released the RS232C specification detailing the requirements for the interface between data processing equipment. This standard specifies not only the number and type of interface leads, but also the voltage levels to be used. The MC1488 quad driver and its companion circuit, the MC1489 quad receiver, provide a complete interface system between DTL or TTL logic levels and the RS232C defined levels. The RS232C requirements as applied to drivers are discussed herein. The required driver voltages are defined as between 5 and 15 V in magnitude and are positive for a logic "0" and negative for a logic "1". These voltages are so defined when the drivers are terminated with a 3000 to 7000 resistor. The MC1488 meets this voltage requirement by converting a DTL/TTL logic level into RS232C levels with one stage of inversion. The RS232C specification further requires that during transitions, the driver output slew rate must not exceed 30 V per s. The inherent slew rate of the MC1488 is much too fast for this requirement. The current limited output of the device can be used to control this slew rate by connecting a capacitor to each driver output. The required capacitor can be easily determined by using the relationship C = IOS x T/ V from which Figure 12 is derived. Accordingly, a 330 pF capacitor on each output will guarantee a worst case slew rate of 30 V per s. The interface driver is also required to withstand an accidental short to any other conductor in an interconnectingcable. The worst possible signal on any conductor would be another driver using a plus or minus 15 V, 500 mA source. The MC1488 is designed to indefinitely withstand such a short to all four outputsin a package as long as the power-supply voltages are greater than 9.0 V (i.e., VS 9.0 V ; VEE - 9.0 V). In some power-supply designs, a loss of system power causes a low impedance on the power-supply outputs. When this occurs, a low impedance to ground would exist at the power inputs to the MC1488 effectively shorting the 300 output resistor to ground. If all four outputs were then shorted to plus or minus 15 V, the power dissipation in these resistors would be excessive. Therefore, if the system is designed to permit low impedances to ground at the power-suppies of the drivers, a diode should be placed in each powersupply lead to prevent over-heating in this fault condition. These two diodes, as shown in Figure 13, could be used to decouple all the driver packages in a system. (These same diodes will allow the MC1488 to withstand momentary shorts to the 15 V limits specified in the earlier Standard RS232B). The addition of the diodes also permits the MC1488 to withstand faults with power-supplies of less than the 9.0 V stated above. The maximum short-circuit current allowable under fault conditions is more than guaranteed by the previouslymentioned 10 mA output current limiting. 5/9 MC1488 Figure 12 : Slew Rate versus Capacitance for Isc = 10mA Figure 13 : Power Supply Protection to Meet Power-off Fault Conditions OTHER APPLICATION The MC1488 is an extremely versatile line driver with a miriad of possible applications. Several features of the drivers enhance this versatility : 1. Output Current Limiting - this enables the circuit designer to define the ouptut voltage levels independent of power-supplies and can be accomplished by diode clamping of the output pins. 2. Power-Supply Range - as can be seen from the schematic drawing of the drivers, the positive and negative driving elements of the device are essentially independent and do not require matching 6/9 power-supplies. Infact, the positive supplycan very from a minimum seven volts (required for driving the negative pulldown section) to the maximum specified 15 V. The negative supply can vary from approximately - 2.5 V to the minimum specified 15 V. The MC1488 will drive the ouptut to within 2 V of the positive or negative supplies as long as the current output limits are not exceeded. The combination of the current-limiting and supply-voltage features allow a wide combination of possible outputs within the same quad package. MC1488 DIP14 PACKAGE MECHANICAL DATA mm DIM. MIN. a1 0.51 B 1.39 TYP. inch MAX. MIN. TYP. MAX. 0.020 1.65 0.055 0.065 b 0.5 0.020 b1 0.25 0.010 D 20 0.787 E 8.5 0.335 e 2.54 0.100 e3 15.24 0.600 F 7.1 0.280 I 5.1 0.201 L Z 3.3 1.27 0.130 2.54 0.050 0.100 7/9 MC1488 SO14 PACKAGE MECHANICAL DATA mm DIM. MIN. TYP. A a1 inch MAX. TYP. 1.75 0.1 MAX. 0.069 0.25 a2 0.004 0.009 1.6 0.063 b 0.35 0.46 0.014 0.018 b1 0.19 0.25 0.007 0.010 C 0.5 0.020 c1 45 (typ.) D 8.55 8.75 0.336 0.344 E 5.8 6.2 0.228 0.244 e 1.27 e3 0.050 7.62 0.300 F 3.8 4.0 0.15 0.157 L 0.4 1.27 0.016 0.050 M S 8/9 MIN. 0.68 0.027 8 (max.) MC1488 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 pub lication 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