======================================================================== 74F243 QUAD BUS TRANSCEIVER (WITH 3-STATE OUTPUTS) ======================================================================== Family: Fairchild FAST (Advanced Schottky TTL) Source: 1980 Fairchild FAST Data Book, pages 4-70 ... 4-72 (shared data sheet with the 'F242) Status: PRELIMINARY -- page 4-70 carries a "Preliminary" watermark. Ratings: Vcc = +5.0 V +/-5%, TA = 0 to +70 deg C DESCRIPTION ----------- The 'F242 and 'F243 are quad bus transmitters/receivers designed for 4-line asynchronous 2-way data communications between data buses. o Hysteresis at inputs to improve noise immunity o 2-way asynchronous data bus communication o Input clamp diodes limit high speed termination effects CONNECTION DIAGRAM (14-pin DIP) ------------------------------- Pin Function Pin Function --- ------------------- --- ------------------- 1 /E1 Enable input 14 Vcc 2 NC no connection 13 E2 Enable input 3 A1 Bus A, bit 1 12 NC no connection 4 A2 Bus A, bit 2 11 B1 Bus B, bit 1 5 A3 Bus A, bit 3 10 B2 Bus B, bit 2 6 A4 Bus A, bit 4 9 B3 Bus B, bit 3 7 GND 8 B4 Bus B, bit 4 /E1 is the Enable input for one direction (active LOW); E2 is the Enable input for the other direction (active HIGH). Each of the four channels contains a back-to-back pair of non-inverting 3-state buffers, one enabled by /E1 (A -> B direction) and the other by E2 (B -> A direction). Pins 2 and 12 are no-connect. Pin-for-pin identical to the 'F242. TRUTH TABLES ------------ /E1 direction (active LOW enable), A -> B ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ /E1 D Output --- --- ------ L L L L H H H X Z E2 direction (active HIGH enable), B -> A ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ E2 D Output --- --- ------ L X Z H L L H H H H = HIGH voltage level; L = LOW voltage level; X = immaterial; Z = high impedance. INPUT LOADING / FAN-OUT ----------------------- Pin Names Description U.L. HIGH/LOW --------- -------------------------- ------------- /E1 Enable Input (Active LOW) 0.5 / 0.625 E2 Enable Input (Active HIGH) 0.5 / 0.625 Inputs 1.75 / 1.0 Outputs 75 / 40 DC CHARACTERISTICS OVER OPERATING TEMPERATURE RANGE --------------------------------------------------- Test conditions are keyed by number and listed below the table. Symbol Parameter Min Typ Max Units Cond --------- ---------------------------------- ---- --- ---- ----- ---- VOH Output HIGH Voltage 2.4 V (1) VOH Output HIGH Voltage 2.0 V (2) VOH Output HIGH Voltage 2.0 V (3) VOL Output LOW Voltage 0.55 V (4) VOL Output LOW Voltage 0.55 V (5) VT+ - VT- Hysteresis Voltage 0.2 0.4 V (6) IOZH Output OFF Current HIGH 70 uA (7) IOZH Output OFF Current HIGH 100 uA (8) IOZL Output OFF Current LOW -1.6 mA (9) IOS Output Short Circuit Current -100 -225 mA (10) ICC Power Supply Current, outputs HIGH 64 mA (11) ICC Power Supply Current, outputs LOW 64 mA (11) ICC Power Supply Current, outputs OFF 71 mA (11) Conditions (grade shown first where the data sheet gives one): (1) XM, XC: IOH = -3.0 mA, Vcc = Min, VIN = VIH or VIL (2) XM: IOH = -12 mA; VIH = 2.0 V, Vcc = Min, VIL = 0.5 V (3) XC: IOH = -15 mA; VIH = 2.0 V, Vcc = Min, VIL = 0.5 V (4) XM: IOL = 48 mA; VIN = VIH or VIL, Vcc = Min (5) XC: IOL = 64 mA; VIN = VIH or VIL, Vcc = Min (6) Vcc = Min (7) VOUT = 2.7 V; VIN = VIH or VIL, Vcc = Max (8) VOUT = 5.5 V; VIN = VIH or VIL, Vcc = Max (9) Vcc = Max, VIN = VIH or VIL, VOUT = 0.4 V (10) Vcc = Max, VOUT = 0 V (11) Vcc = Max AC CHARACTERISTICS ------------------ Symbol Parameter Min Typ Max Units ------ -------------------------------- --- --- --- ----- tPLH Propagation Delay Data to Output -- 4.5 -- ns tPHL Propagation Delay Data to Output -- 4.5 -- ns tPZH Output Enable Time -- 6.0 -- ns tPZL Output Enable Time -- 10 -- ns tPHZ Output Disable Time * -- 10 -- ns tPLZ Output Disable Time * -- 6.0 -- ns * Disable times measured with CL = 5.0 pF, RL = 90 ohms.