74AC257 QUAD 2 CHANNEL MULTIPLEXER (3-STATE) ■ ■ ■ ■ ■ ■ ■ ■ ■ HIGH SPEED: tPD = 4.5ns (TYP.) at VCC = 5V LOW POWER DISSIPATION: ICC = 4µA(MAX.) at TA=25°C HIGH NOISE IMMUNITY: VNIH = V NIL = 28 % VCC (MIN.) 50Ω TRANSMISSION LINE DRIVING CAPABILITY SYMMETRICAL OUTPUT IMPEDANCE: |IOH| = IOL = 24mA (MIN) BALANCED PROPAGATION DELAYS: tPLH ≅ tPHL OPERATING VOLTAGE RANGE: VCC (OPR) = 2V to 6V PIN AND FUNCTION COMPATIBLE WITH 74 SERIES 257 IMPROVED LATCH-UP IMMUNITY DESCRIPTION The 74AC257 is an advanced high-speed CMOS QUAD 2-CHANNEL MULTIPLEXER (3-STATE) fabricated with sub-micron silicon gate and double-layer metal wiring C2MOS tecnology. It is composed of four independent 2-channel multiplexer with common SELECT and ENABLE (OE) inputs. It is a non-inverting multiplexer. When the OE input is held HIGH,all the output become in DIP SOP TSSOP ORDER CODES PACKAGE TUBE DIP SOP TSSOP 74AC257B 74AC257M T&R 74AC257MTR 74AC257TTR high impedance state. If SELECT input is held LOW, ”A” data is selected, when SELECT input is held HIGH, ”B” data is chosen. All inputs and outputs are equipped with protection circuits against static discharge, giving them 2KV ESD immunity and transient excess voltage. PIN CONNECTION AND IEC LOGIC SYMBOLS April 2001 1/11 74AC257 INPUT AND OUTPUT EQUIVALENT CIRCUIT PIN DESCRIPTION PIN No SYMBOL NAME AND FUNCTION 1 SELECT 2, 5, 11, 14 1A to 4A 3, 6, 10, 13 1B to 4B 4, 7, 9, 12 15 1Y to 4Y OE 8 16 GND VCC Common Data Select Inputs Data Inputs From Source A Data Inputs From Source B Multiplexer Outputs 3 State Output Enable Inputs (Active LOW) Ground (0V) Positive Supply Voltage TRUTH TABLE INPUTS OE SELECT A B Y H L L L L X L L H H X L H X X X X X L H L L H L H X : Don’t Care Z : High Impedance LOGIC DIAGRAM This logic diagram has not be used to estimate propagation delays 2/11 OUTPUT 74AC257 ABSOLUTE MAXIMUM RATINGS Symbol V CC Parameter Supply Voltage Value Unit -0.5 to +7 V -0.5 to VCC + 0.5 -0.5 to VCC + 0.5 V DC Input Diode Current ± 20 mA IOK DC Output Diode Current ± 20 mA IO DC Output Current VI DC Input Voltage VO DC Output Voltage IIK ICC or IGND DC VCC or Ground Current Tstg Storage Temperature TL Lead Temperature (10 sec) V ± 50 mA ± 200 mA -65 to +150 °C 300 °C Absolute Maximum Ratings are those values beyond which damage to the device may occur. Functional operation under these conditions is not implied. RECOMMENDED OPERATING CONDITIONS Symbol V CC Parameter Supply Voltage Value Unit 2 to 6 V VI Input Voltage 0 to VCC V VO Output Voltage 0 to VCC V Top Operating Temperature -55 to 125 °C 8 ns/V dt/dv Input Rise and Fall Time VCC = 3.0, 4.5 or 5.5V (note 1) 1) VIN from 30% to 70% of VCC 3/11 74AC257 DC SPECIFICATIONS Test Condition Symbol VIH V IL VOH VOL II Ioz ICC IOLD IOHD Parameter High Level Input Voltage Low Level Input Voltage High Level Output Voltage Low Level Output Voltage TA = 25°C VCC (V) 3.0 4.5 5.5 3.0 4.5 5.5 Value VO = 0.1 V or VCC-0.1V Min. Typ. 2.1 3.15 3.85 1.5 2.25 2.75 1.5 2.25 2.75 VO = 0.1 V or VCC-0.1V Max. -55 to 125°C Min. Min. Max. 2.1 3.15 3.85 0.9 1.35 1.65 2.1 3.15 3.85 0.9 1.35 1.65 Unit Max. V 0.9 1.35 1.65 3.0 IO=-50 µA 2.9 2.99 2.9 2.9 4.5 IO=-50 µA 4.4 4.49 4.4 4.4 5.5 IO=-50 µA 5.4 5.49 5.4 5.4 3.0 IO =-12 mA 2.56 2.46 2.4 4.5 IO =-24 mA 3.86 3.76 3.7 5.5 IO =-24 mA 4.86 4.76 4.7 3.0 IO=50 µA 0.002 0.1 0.1 0.1 4.5 IO=50 µA 0.001 0.1 0.1 0.1 5.5 IO=50 µA 0.001 0.1 0.1 0.1 3.0 IO =12 mA 0.36 0.44 0.5 4.5 IO =24 mA 0.36 0.44 0.5 5.5 IO =24 mA 0.36 0.44 0.5 V V V Input Leakage Current High Impedance Output Leakage Current Quiescent Supply Current 5.5 VI = VCC or GND ± 0.1 ±1 ±1 µA 5.5 VI = VIH or VIL VO = VCC or GND ± 0.5 ±5 ± 10 µA 5.5 VI = VCC or GND 4 40 80 µA Dynamic Output Current (note 1, 2) 5.5 VOLD = 1.65 V max 75 50 mA VOHD = 3.85 V min -75 -50 mA 1) Maximum test duration 2ms, one output loaded at time 2) Incident wave switching is guaranteed on transmission lines with impedances as low as 50Ω 4/11 -40 to 85°C 74AC257 AC ELECTRICAL CHARACTERISTICS (CL = 50 pF, RL = 500 Ω, Input tr = tf = 3ns) Test Condition Symbol Parameter tPLH tPHL Propagation Delay Time A, B to Y tPLH tPHL Propagation Delay Time SELECT to Y tPZL tPZH Output Enable Time tPLZ tPHZ Output Disable Time Value TA = 25°C VCC (V) -40 to 85°C -55 to 125°C Min. Typ. Max. Min. Max. Min. Max. (*) 1.5 5.5 8.5 1.5 9.0 1.5 9.0 5.0(**) 1.5 4.5 6.0 1.5 7.0 1.5 7.0 3.3 (*) 1.5 7.0 10.5 1.5 11.5 1.5 11.5 (**) 5.0 1.5 5.5 7.5 1.5 8.5 1.5 8.5 3.3 (*) 1.5 5.5 9.0 1.5 100 1.5 100 5.0(**) 1.5 4.5 7.5 1.5 8.5 1.5 8.5 3.3 (*) 1.5 7.0 10.0 1.5 11.0 1.5 13.0 (**) 1.5 5.5 9.0 1.5 10.0 1.5 11.0 3.3 5.0 Unit ns ns ns ns (*) Voltage range is 3.3V ± 0.3V (**) Voltage range is 5.0V ± 0.5V CAPACITIVE CHARACTERISTICS Test Condition Symbol Parameter Value TA = 25°C VCC (V) Min. Typ. Max. -40 to 85°C -55 to 125°C Min. Min. Max. Unit Max. Input Capacitance 5.0 5 pF C OUT Output Capacitance 5.0 8 pF C PD Power Dissipation Capacitance (note 1) 5.0 20 pF CIN fIN = 10MHz 1) CPD is defined as the value of the IC’s internal equivalent capacitance which is calculated from the operating current consumption without load. (Refer to Test Circuit). Average operating current can be obtained by the following equation. ICC(opr) = CPD x VCC x fIN + ICC/4 (per circuit) 5/11 74AC257 TEST CIRCUIT TEST tPLH, tPHL SWITCH Open tPZL, tPLZ 2V CC tPZH, tPHZ Open C L = 50pF or equivalent (includes jig and probe capacitance) R L = R1 = 500Ω or equivalent R T = ZOUT of pulse generator (typically 50Ω) WAVEFORM 1: PROPAGATION DELAYS FOR INVERTING CONDITIONS (f=1MHz; 50% duty cycle) 6/11 74AC257 WAVEFORM 2: PROPAGATION DELAYS FOR NON-INVERTING CONDITIONS (f=1MHz; 50% duty cycle) WAVEFORM 3: OUTPUT ENABLE AND DISABLE TIME (f=1MHz; 50% duty cycle) 7/11 74AC257 Plastic DIP-16 (0.25) MECHANICAL DATA mm DIM. MIN. a1 0.51 B 0.77 TYP. inch MAX. MIN. TYP. MAX. 0.020 1.65 0.030 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 17.78 0.700 F 7.1 0.280 I 5.1 0.201 L Z 3.3 0.130 1.27 0.050 P001C 8/11 74AC257 SO-16 MECHANICAL DATA mm DIM. MIN. TYP. A a1 inch MAX. MIN. TYP. 1.75 0.1 0.068 0.2 a2 MAX. 0.004 0.007 1.65 0.064 b 0.35 0.46 0.013 0.018 b1 0.19 0.25 0.007 0.010 C 0.5 0.019 c1 45 (typ.) D 9.8 10 0.385 0.393 E 5.8 6.2 0.228 0.244 e 1.27 0.050 e3 8.89 0.350 F 3.8 4.0 0.149 0.157 G 4.6 5.3 0.181 0.208 L 0.5 1.27 0.019 0.050 M S 0.62 0.024 8 (max.) P013H 9/11 74AC257 TSSOP16 MECHANICAL DATA mm DIM. MIN. inch TYP. A MAX. MIN. MAX. 1.1 0.433 A1 0.05 0.10 0.15 0.002 0.004 0.006 A2 0.85 0.9 0.95 0.335 0.354 0.374 b 0.19 0.30 0.0075 0.0118 c 0.09 0.20 0.0035 0.0079 D 4.9 5 5.1 0.193 0.197 0.201 E 6.25 6.4 6.5 0.246 0.252 0.256 E1 4.3 4.4 4.48 0.169 0.173 0.176 e 0.65 BSC 0.0256 BSC K 0o 4o 8o 0o 4o 8o L 0.50 0.60 0.70 0.020 0.024 0.028 A A2 A1 b e K c E1 PIN 1 IDENTIFICATION 1 L E D 10/11 TYP. 74AC257 Information furnished is believed to be accurate and reliable. However, STMicroelectronics assumes no responsibility for the consequences of use of such information nor for any infringe ment of patents or other righ ts of third parties which may result from its use. No license is granted by implication or otherwise under any patent or patent rights of STMicroelectronics. Specifications mentioned in this pub lication are subject to change without notice. Thi s pub lication supersedes and replaces all information previously supplied. STMicroelectronics prod ucts are not authori zed for use as critical components in life suppo rt devices or systems without express written approval of STMicroelectronics. The ST logo is a registered trademark of STMicroelectronics 2001 STMicroelectronics - Printed in Italy - All Rights Reserved STMicroelectronics GROUP OF COMPANIES Australia - Brazil - China - Finland - France - Germany - Hong Kong - India - Italy - Japan - Malaysia - Malta - Morocco Singapore - Spain - Sweden - Swit zerland - United Kingdom http://w ww.st.com 11/11