CD74AC238 3-LINE TO 8-LINE DECODER/DEMULTIPLEXER SCHS331 – FEBRUARY 2003 D D D D D D D D M PACKAGE (TOP VIEW) AC Types Feature 1.5-V to 5.5-V Operation and Balanced Noise Immunity at 30% of the Supply Voltage Speed of Bipolar F, AS, and S, With Significantly Reduced Power Consumption Designed Specifically for High-Speed Memory Decoders and Data-Transmission Systems Incorporates Three Enable Inputs to Simplify Cascading and/or Data Reception Balanced Propagation Delays ±24-mA Output Drive Current – Fanout to 15 F Devices SCR-Latchup-Resistant CMOS Process and Circuit Design Exceeds 2-kV ESD Protection Per MIL-STD-883, Method 3015 A B C G2A G2B G1 Y7 GND 1 16 2 15 3 14 4 13 5 12 6 11 7 10 8 9 VCC Y0 Y1 Y2 Y3 Y4 Y5 Y6 description/ordering information The CD74AC238 decoder/demultiplexer is designed for high-performance memory-decoding and data-routing applications that require very short propagation-delay times. In high-performance memory systems, this decoder can be used to minimize the effects of system decoding. When employed with high-speed memories utilizing a fast enable circuit, the delay times of this decoder and the enable time of the memory usually are less than the typical access time of the memory. This means that the effective system delay introduced by the decoder is negligible. The conditions at the binary-select inputs and the three enable inputs select one of eight output lines. Two active-low and one active-high enable inputs reduce the need for external gates or inverters when expanding. A 24-line decoder can be implemented without external inverters, and a 32-line decoder requires only one inverter. An enable input can be used as a data input for demultiplexing applications (see Application Information). ORDERING INFORMATION TA PACKAGE† ORDERABLE PART NUMBER TOP-SIDE MARKING –55°C to 125°C SOIC – M Tape and reel CD74AC238M96 AC238M † Package drawings, standard packing quantities, thermal data, symbolization, and PCB design guidelines are available at www.ti.com/sc/package. Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet. Copyright 2003, Texas Instruments Incorporated PRODUCTION DATA information is current as of publication date. Products conform to specifications per the terms of Texas Instruments standard warranty. Production processing does not necessarily include testing of all parameters. POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 1 CD74AC238 3-LINE TO 8-LINE DECODER/DEMULTIPLEXER SCHS331 – FEBRUARY 2003 FUNCTION TABLE SELECT INPUTS ENABLE INPUTS G1 G2A G2B C B X X H X X X X H X X A OUTPUTS Y0 Y1 Y2 Y3 Y4 X L X L Y5 Y6 L L L L L L L L L L L L L L L X X X X X L L L L L L L L H L L L L L H L L L L L L L H L L L L H L H L L L L L L H L L L H L L L H L L L L L H L L L H H L L L H L L L L H L L H L L L L L L H L L L H L L H L H L L L L L H L L H L L H H L L L L L L L H L H L L H H H L L L L L L L H logic diagram (positive logic) 15 A Y0 1 14 Y1 13 Select Inputs B Y2 2 12 11 3 Y3 Data Outputs Y4 C 10 9 G2A Enable Inputs G2B G1 2 Y7 4 7 5 6 POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 Y5 Y6 Y7 CD74AC238 3-LINE TO 8-LINE DECODER/DEMULTIPLEXER SCHS331 – FEBRUARY 2003 absolute maximum ratings over operating free-air temperature range (unless otherwise noted)† Supply voltage range, VCC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . –0.5 V to 6 V Input clamp current, IIK (VI < 0 V or VI > VCC) (see Note 1) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ±20 mA Output clamp current, IOK (VO < 0 V or VO > VCC) (see Note 1) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ±50 mA Continuous output current, IO (VO > 0 V or VO < VCC) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ±50 mA Continuous current through VCC or GND . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ±200 mA Package thermal impedance, θJA (see Note 2) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73°C/W Storage temperature range, Tstg . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . –65°C to 150°C † Stresses beyond those listed under “absolute maximum ratings” may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated under “recommended operating conditions” is not implied. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability. NOTES: 1. The input and output voltage ratings may be exceeded if the input and output current ratings are observed. 2. The package thermal impedance is calculated in accordance with JESD 51-7. recommended operating conditions (see Note 3) TA = 25°C VCC VIH Supply voltage High-level input voltage –40°C to 85°C UNIT MIN MAX MIN MAX MIN MAX 1.5 5.5 1.5 5.5 1.5 5.5 VCC = 1.5 V VCC = 3 V 1.2 1.2 1.2 2.1 2.1 2.1 VCC = 5.5 V VCC = 1.5 V 3.85 VIL Low-level input voltage VI VO Input voltage 0 Output voltage 0 IOH IOL High-level output current ∆t/∆v Input transition rise or fall rate Low-level output current –55°C to 125°C VCC = 3 V VCC = 5.5 V 3.85 V 3.85 0.3 0.3 0.3 0.9 0.9 0.9 1.65 VCC VCC 1.65 0 0 V VCC VCC V 1.65 0 0 VCC VCC V V VCC = 4.5 V to 5.5 V VCC = 4.5 V to 5.5 V –24 –24 –24 mA 24 24 24 mA VCC = 1.5 V to 3 V VCC = 3.6 V to 5.5 V 50 50 50 20 20 20 ns/V NOTE 3: All unused inputs of the device must be held at VCC or GND to ensure proper device operation. Refer to the TI application report, Implications of Slow or Floating CMOS Inputs, literature number SCBA004. POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 3 CD74AC238 3-LINE TO 8-LINE DECODER/DEMULTIPLEXER SCHS331 – FEBRUARY 2003 electrical characteristics over recommended operating free-air temperature range (unless otherwise noted) PARAMETER TEST CONDITIONS VCC MIN IOH = –50 µA VOH VI = VIH or VIL IOH = –4 mA IOH = –24 mA IOH = –50 mA† IOH = –75 mA† IOL = 50 µA VOL II ICC VI = VIH or VIL VI = VCC or GND VI = VCC or GND, –55°C to 125°C TA = 25°C MAX MIN –40°C to 85°C MAX MIN 1.5 V 1.4 1.4 1.4 2.9 3V 2.9 2.9 4.5 V 4.4 4.4 4.4 3V 2.58 2.4 2.48 4.5 V 3.94 3.7 3.8 5.5 V UNIT MAX V 3.85 5.5 V 3.85 1.5 V 0.1 0.1 0.1 3V 0.1 0.1 0.1 4.5 V 0.1 0.1 0.1 IOL = 12 mA IOL = 24 mA IOL = 50 mA† 3V 0.36 0.5 0.44 4.5 V 0.36 0.5 0.44 IOL = 75 mA† 5.5 V 5.5 V 5.5 V IO = 0 5.5 V Ci V 1.65 1.65 ±0.1 ±1 ±1 µA 8 160 80 µA 10 10 10 pF † Test one output at a time, not exceeding 1-second duration. Measurement is made by forcing indicated current and measuring voltage to minimize power dissipation. Test verifies a minimum 50-Ω transmission-line drive capability at 85°C and 75-Ω transmission-line drive capability at 125°C. switching characteristics over recommended operating free-air temperature range, VCC = 1.5 V, CL = 50 pF (unless otherwise noted) (see Figure 1) FROM (INPUT) TO (OUTPUT) tPLH tPHL A B A, B, C Any Y tPLH tPHL G1 Any Y tPLH tPHL G2A G2B G2A, Any Y PARAMETER 4 POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 –55°C to 125°C MIN MAX –40°C to 85°C MIN UNIT MAX 187 170 187 170 208 189 208 189 149 135 149 135 ns ns ns CD74AC238 3-LINE TO 8-LINE DECODER/DEMULTIPLEXER SCHS331 – FEBRUARY 2003 switching characteristics over recommended operating free-air temperature range, VCC = 3.3 V ± 0.3 V, CL = 50 pF (unless otherwise noted) (see Figure 1) FROM (INPUT) TO (OUTPUT) tPLH tPHL A B A, B, C Any Y tPLH tPHL G1 Any Y tPLH tPHL G2A G2B G2A, Any Y PARAMETER –55°C to 125°C –40°C to 85°C MIN MAX MIN MAX 5.3 21 5.4 19.1 5.3 21 5.4 19.1 5.8 23.2 6 21.1 5.8 23.2 6 21.1 4.2 16.7 4.3 15.2 4.2 16.7 4.3 15.2 UNIT ns ns ns switching characteristics over recommended operating free-air temperature range, VCC = 5 V ± 0.5 V, CL = 50 pF (unless otherwise noted) (see Figure 1) FROM (INPUT) TO (OUTPUT) tPLH tPHL A B A, B, C Any Y tPLH tPHL G1 Any Y tPLH tPHL G2A G2B G2A, Any Y PARAMETER –55°C to 125°C –40°C to 85°C MIN MAX MIN MAX 3.8 15 3.9 13.6 3.8 15 3.9 13.6 4.2 16.6 4.3 15.1 4.2 16.6 4.3 15.1 3 11.9 3.1 10.7 3 11.9 3.1 10.7 UNIT ns ns ns operating characteristics, VCC = 5 V, TA = 25°C PARAMETER Cpd Power dissipation capacitance POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 TYP UNIT 110 pF 5 CD74AC238 3-LINE TO 8-LINE DECODER/DEMULTIPLEXER SCHS331 – FEBRUARY 2003 PARAMETER MEASUREMENT INFORMATION S1 R1 = 500 Ω† From Output Under Test 2 × VCC Open GND CL = 50 pF (see Note A) R2 = 500 Ω† TEST S1 tPLH/tPHL tPLZ/tPZL tPHZ/tPZH Open 2 × VCC GND tw VCC † When VCC = 1.5 V, R1 = R2 = 1 kΩ Input 50% VCC 50% VCC 0V LOAD CIRCUIT VOLTAGE WAVEFORMS PULSE DURATION CLR Input VCC Reference Input VCC 50% VCC 50% VCC 0V 0V tsu trec Data 50% Input 10% VCC 50% VCC CLK 90% VOLTAGE WAVEFORMS RECOVERY TIME tf VCC 50% VCC 50% VCC tPLH tPHL 50% 10% 90% 90% tr tPHL Out-of-Phase Output VCC 50% VCC 10% 0 V VOLTAGE WAVEFORMS SETUP AND HOLD AND INPUT RISE AND FALL TIMES 0V In-Phase Output 90% tr 0V Input th 90% VOH 50% VCC 10% VOL tf Output Waveform 1 S1 at 2 × VCC (see Note B) tPLH 50% VCC 10% tf 50% 10% 90% tr VOH VOL VOLTAGE WAVEFORMS PROPAGATION DELAY AND OUTPUT TRANSITION TIMES VCC Output Control 50% VCC 50% VCC 0V tPLZ tPZL 50% VCC tPHZ tPZH Output Waveform 2 S1 at GND (see Note B) ≈VCC 20% VCC VOL 50% VCC VOH 80% VCC ≈0 V VOLTAGE WAVEFORMS OUTPUT ENABLE AND DISABLE TIMES NOTES: A. CL includes probe and test-fixture capacitance. B. Waveform 1 is for an output with internal conditions such that the output is low except when disabled by the output control. Waveform 2 is for an output with internal conditions such that the output is high except when disabled by the output control. C. All input pulses are supplied by generators having the following characteristics: PRR ≤ 1 MHz, ZO = 50 Ω, tr = 3 ns, tf = 3 ns. Phase relationships between waveforms are arbitrary. D. For clock inputs, fmax is measured with the input duty cycle at 50%. E. The outputs are measured one at a time with one input transition per measurement. F. tPLH and tPHL are the same as tpd. G. tPZL and tPZH are the same as ten. H. tPLZ and tPHZ are the same as tdis. I. All parameters and waveforms are not applicable to all devices. Figure 1. Load Circuit and Voltage Waveforms 6 POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 CD74AC238 3-LINE TO 8-LINE DECODER/DEMULTIPLEXER SCHS331 – FEBRUARY 2003 APPLICATION INFORMATION CD74AC238 BIN/OCT 1 2 3 VCC 0 1 1 2 2 4 6 3 & 4 4 EN 5 5 6 7 15 14 13 12 11 10 9 7 0 1 2 3 4 5 6 7 CD74AC238 BIN/OCT 1 A0 2 A1 3 A2 1 2 2 4 6 A3 0 1 3 & 4 4 A4 EN 5 5 6 7 15 14 13 12 11 10 9 7 8 9 10 11 12 13 14 15 CD74AC238 BIN/OCT 1 2 3 6 0 1 1 2 2 4 3 & 4 4 5 EN 5 6 7 15 14 13 12 11 10 9 7 16 17 18 19 20 21 22 23 Figure 2. 24-Bit Decoding Scheme POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 7 CD74AC238 3-LINE TO 8-LINE DECODER/DEMULTIPLEXER SCHS331 – FEBRUARY 2003 APPLICATION INFORMATION CD74AC238 BIN/OCT 1 A0 2 A1 3 A2 1 1 2 2 4 6 VCC 0 3 & 4 4 A3 EN 5 A4 5 6 7 15 14 13 12 11 10 9 7 0 1 2 3 4 5 6 7 CD74AC238 BIN/OCT 1 2 3 0 1 1 2 2 4 6 3 & 4 4 EN 5 5 6 7 15 14 13 12 11 10 9 7 8 9 10 11 12 13 14 15 CD74AC238 BIN/OCT 1 2 3 0 1 1 2 2 4 6 3 & 4 4 EN 5 5 6 7 15 14 13 12 11 10 9 7 16 17 18 19 20 21 22 23 CD74AC238 BIN/OCT 1 2 3 6 0 1 1 2 2 4 3 & 4 4 5 EN 5 6 7 Figure 3. 32-Bit Decoding Scheme 8 POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 15 14 13 12 11 10 9 7 24 25 26 27 28 29 30 31 PACKAGE OPTION ADDENDUM www.ti.com 30-Mar-2005 PACKAGING INFORMATION Orderable Device Status (1) Package Type Package Drawing CD74AC238M96 ACTIVE SOIC D Pins Package Eco Plan (2) Qty 16 2500 Pb-Free (RoHS) Lead/Ball Finish MSL Peak Temp (3) CU NIPDAU Level-2-260C-1 YEAR/ Level-1-235C-UNLIM (1) The marketing status values are defined as follows: ACTIVE: Product device recommended for new designs. LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect. NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in a new design. PREVIEW: Device has been announced but is not in production. Samples may or may not be available. OBSOLETE: TI has discontinued the production of the device. (2) Eco Plan - The planned eco-friendly classification: Pb-Free (RoHS) or Green (RoHS & no Sb/Br) - please check http://www.ti.com/productcontent for the latest availability information and additional product content details. TBD: The Pb-Free/Green conversion plan has not been defined. Pb-Free (RoHS): TI's terms "Lead-Free" or "Pb-Free" mean semiconductor products that are compatible with the current RoHS requirements for all 6 substances, including the requirement that lead not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, TI Pb-Free products are suitable for use in specified lead-free processes. Green (RoHS & no Sb/Br): TI defines "Green" to mean Pb-Free (RoHS compatible), and free of Bromine (Br) and Antimony (Sb) based flame retardants (Br or Sb do not exceed 0.1% by weight in homogeneous material) (3) MSL, Peak Temp. -- The Moisture Sensitivity Level rating according to the JEDEC industry standard classifications, and peak solder temperature. Important Information and Disclaimer:The information provided on this page represents TI's knowledge and belief as of the date that it is provided. TI bases its knowledge and belief on information provided by third parties, and makes no representation or warranty as to the accuracy of such information. Efforts are underway to better integrate information from third parties. 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