MC74F257A QUAD 2-INPUT MULTIPLEXER WITH 3-STATE OUTPUTS The MC74F257 is a quad 2-input multiplexer with 3-state outputs. Four bits of data from two sources can be selected using a common Data Select input. The four outputs present the selected data in true (non-inverted) form. The outputs may be switched to a high impedance state with a HIGH on the common Output Enable (OE) input, allowing the outputs to interface directly with bus oriented systems. • Multiplexer Expansion by Tying Outputs Together • Non-Inverting 3-State Outputs • Input Clamp Diodes Limit High-Speed Termination Effects • AC Enhanced Version of the F257 QUAD 2-INPUT MULTIPLEXER WITH 3-STATE OUTPUTS FAST SCHOTTKY TTL J SUFFIX CERAMIC CASE 620-09 CONNECTION DIAGRAM VCC OE I0c I1c Zc I0d I1d Zd 16 15 14 13 12 11 10 9 16 1 N SUFFIX PLASTIC CASE 648-08 16 1 2 3 4 5 6 7 8 S I0a I1a Za I0b I1b Zb GND I1c I0d 1 LOGIC DIAGRAM OE I0a I1a I0b I1b I0c I1d D SUFFIX SOIC CASE 751B-03 S 16 1 ORDERING INFORMATION MC54FXXXAJ Ceramic MC74FXXXAN Plastic MC74FXXXAD SOIC LOGIC SYMBOL 1 Za Zb Zc S Zd Select Input OE S Data Inputs Outputs H X I0 X I1 X Z L H X L L L H X H H 7 Zb I0b I1b 12 Zc I0c 14 9 I1c I0d 13 Zd I1d L L L X L 10 L L H X H Z H = HIGH Voltage Level L = LOW Voltage Level X = Don’t Care Z = High Impedance FAST AND LS TTL DATA 4-127 VCC = PIN 16 GND = PIN 8 15 Za FUNCTION TABLE Output Enable OE I0a I1a 4 2 3 5 6 11 MC74F257A GUARANTEED OPERATING RANGES Symbol Parameter Min Typ Max Unit VCC Supply Voltage 74 4.5 5.0 5.5 V TA Operating Ambient Temperature Range 74 0 25 70 °C IOH Output Current — High 74 –3.0 mA IOL Output Current — Low 74 24 mA DC CHARACTERISTICS OVER OPERATING TEMPERATURE RANGE (unless otherwise specified) Limits Symbol Parameter VIH Input HIGH Voltage VIL Input LOW Voltage VIK Input Clamp Diode Voltage VOH Output HIGH Voltage Min Typ Max 2.0 Unit Test Conditions V Guaranteed Input HIGH Voltage 0.8 V Guaranteed Input LOW Voltage –1.2 V IIN = –18 mA VCC = MIN 74 2.4 3.3 V IOH = –3.0 mA VCC = 4.50 V 74 2.7 3.3 V IOH = –3.0 mA VCC = 4.75 V 0.5 V IOL = 24 mA VCC = MIN VOL Output LOW Voltage 0.35 IOZH Output OFF Current — HIGH 50 µA VOUT = 2.7 V VCC = MAX IOZL Output OFF Current — LOW –50 µA VOUT = 0.5 V VCC = MAX IIH Input HIGH Current 20 µA VIN = 2.7 V VCC = MAX 100 IIL Input LOW Current IOS Output Short Circuit Current (Note 2) –60 ICCH 9.0 VIN = 7.0 V –0.6 mA VIN = 0.5 V VCC = MAX –150 mA VOUT = 0 V VCC = MAX 15 S, I1x = 4.5 V OE, I0x = GND ICCL Power Supply Current 14.5 22 mA I1x = 4.5 V VCC = MAX OE, I0x, S = GND ICCZ 15 23 S, I0x = GND OE, I1x = 4.5 V NOTES: 1. For conditions shown as MIN or MAX, use the appropriate value specified under guaranteed operating ranges. 2. Not more than one output should be shorted at a time, nor for more than 1 second. FUNCTIONAL DESCRIPTION The F257A is a quad 2-input multiplexer with 3-state outputs. It selects four bits of data from two sources under control of a Common Data Select input. When the Select input is LOW, the I0x inputs are selected and when Select is HIGH, the I1x inputs are selected. The data on the selected inputs appears at the outputs in true (non-inverted) form. The device is the logic implementation of a 4-pole, 2-position switch where the position of the switch is determined by the logic levels supplied to the Select input. The logic equations for the outputs are shown below: Za = OE • (I1a • S + I0a • S) Zb = OE • (I1b • S + I0b • S) Zc = OE • (I1c • S + I0c • S) Zd = OE • (I1d • S + I0d • S) When the Output Enable input (OE) is HIGH, the outputs are forced to a high impedance OFF state. If the outputs are tied together, all but one device must be in the high impedance state to avoid high currents that would exceed the maximum ratings. Designers should ensure the Output Enable signals to 3-state devices whose outputs are tied together are designed so there is no overlap. FAST AND LS TTL DATA 4-128 MC74F257A AC CHARACTERISTICS Symbol Parameter 74F 74F TA = +25°C TA = 0°C to 70°C VCC = +5.0 V VCC = 5.0 V ± 10% CL = 50 pF CL = 50 pF Min Max Min Max Unit 6.0 ns tPLH Propagation Delay 1.5 5.5 1.5 tPHL In to Zn 2.0 5.5 2.0 6.0 tPLH Propagation Delay 3.0 9.5 3.0 10.5 tPHL S to Zn 2.5 7.0 2.5 8.0 tPZH Output Enable Time 2.0 6.5 2.0 7.0 2.5 7.0 2.5 8.0 2.0 6.0 2.0 7.0 2.0 6.0 2.0 7.0 tPZL tPHZ Output Disable Time tPLZ FAST AND LS TTL DATA 4-129 ns ns ns