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| 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 CONNECTION DIAGRAM VCC 16 OE 15 I0c 14 I1c 13 Zc 12 I0d 11 I1d 10 Zd 9 16 1 QUAD 2-INPUT MULTIPLEXER WITH 3-STATE OUTPUTS FASTTM SCHOTTKY TTL J SUFFIX CERAMIC CASE 620-09 16 N SUFFIX PLASTIC CASE 648-08 1 1 S 2 I0a 3 I1a 4 Za 5 I0b 6 I1b 7 Zb 8 GND LOGIC DIAGRAM OE I0a I1a I0b I1b I0c I1c I0d I1d S 16 1 D SUFFIX SOIC CASE 751B-03 ORDERING INFORMATION MC54FXXXAJ Ceramic MC74FXXXAN Plastic MC74FXXXAD SOIC LOGIC SYMBOL 1 Za Zb Zc Zd 4 Za Zb Zc Zd S OE I0a I1a I0b I1b I0c I1c I0d I1d 15 2 3 5 6 14 13 11 10 FUNCTION TABLE Output Enable OE H L L L L Select Input S X H H L L Data Inputs I0 X X X L H I1 X L H X X Outputs Z Z L H L H H = HIGH Voltage Level L = LOW Voltage Level X = Don't Care Z = High Impedance 7 12 9 VCC = PIN 16 GND = PIN 8 FAST AND LS TTL DATA 4-127 MC74F257A GUARANTEED OPERATING RANGES Symbol VCC TA IOH IOL Supply Voltage Operating Ambient Temperature Range Output Current -- High Output Current -- Low Parameter 74 74 74 74 Min 4.5 0 Typ 5.0 25 Max 5.5 70 -3.0 24 Unit V C mA mA DC CHARACTERISTICS OVER OPERATING TEMPERATURE RANGE (unless otherwise specified) Limits Symbol VIH VIL VIK VOH Parameter Input HIGH Voltage Input LOW Voltage Input Clamp Diode Voltage Output HIGH Voltage 74 74 VOL IOZH IOZL IIH Output LOW Voltage Output OFF Current -- HIGH Output OFF Current -- LOW Input HIGH Current 2.4 2.7 3.3 3.3 0.35 0.5 50 -50 20 100 IIL IOS ICCH Input LOW Current Output Short Circuit Current (Note 2) -60 9.0 -0.6 -150 15 mA mA Min 2.0 0.8 -1.2 Typ Max Unit V V V V V V A A A Test Conditions Guaranteed Input HIGH Voltage Guaranteed Input LOW Voltage IIN = -18 mA IOH = -3.0 mA IOH = -3.0 mA IOL = 24 mA VOUT = 2.7 V VOUT = 0.5 V VIN = 2.7 V VIN = 7.0 V VIN = 0.5 V VOUT = 0 V S, I1x = 4.5 V OE, I0x = GND ICCL Power Supply Current 14.5 22 mA I1x = 4.5 V 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. VCC = MIN VCC = 4.50 V VCC = 4.75 V VCC = MIN VCC = MAX VCC = MAX VCC = MAX VCC = MAX VCC = MAX VCC = MAX 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 74F TA = +25C VCC = +5.0 V CL = 50 pF Symbol tPLH tPHL tPLH tPHL tPZH tPZL tPHZ tPLZ Output Disable Time Propagation Delay In to Zn Propagation Delay S to Zn Output Enable Time Parameter Min 1.5 2.0 3.0 2.5 2.0 2.5 2.0 2.0 Max 5.5 5.5 9.5 7.0 6.5 7.0 6.0 6.0 74F TA = 0C to 70C VCC = 5.0 V 10% CL = 50 pF Min 1.5 2.0 3.0 2.5 2.0 2.5 2.0 2.0 Max 6.0 6.0 10.5 8.0 7.0 8.0 7.0 7.0 ns ns ns Unit ns FAST AND LS TTL DATA 4-129 |
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