(cid:1)(cid:2)(cid:3)(cid:4)(cid:5)(cid:6)(cid:7)(cid:8)(cid:3)(cid:9)(cid:10) (cid:1)(cid:2)(cid:9)(cid:4)(cid:5)(cid:6)(cid:7)(cid:8)(cid:3)(cid:9) (cid:11)(cid:12)(cid:13)(cid:14)(cid:15)(cid:12)(cid:16)(cid:17)(cid:18) (cid:8)(cid:19)(cid:17)(cid:20)(cid:2)(cid:18) (cid:7)(cid:21) (cid:22)(cid:19)(cid:17)(cid:20)(cid:2)(cid:18) (cid:14)(cid:13)(cid:7)(cid:13) (cid:1)(cid:18)(cid:17)(cid:18)(cid:6)(cid:7)(cid:21)(cid:15)(cid:1)(cid:23)(cid:24)(cid:12)(cid:17)(cid:7)(cid:20)(cid:16)(cid:17)(cid:18)(cid:25)(cid:18)(cid:15)(cid:1) (cid:26)(cid:20)(cid:7)(cid:5) (cid:27)(cid:19)(cid:1)(cid:7)(cid:13)(cid:7)(cid:18) (cid:21)(cid:12)(cid:7)(cid:16)(cid:12)(cid:7)(cid:1) SCLS072D − NOVEMBER 1988 − REVISED SEPTEMBER 2003 (cid:1) Operating Voltage Range of 4.5 V to 5.5 V (cid:1) Low Input Current of 1 µA Max (cid:1) (cid:1) High-Current 3-State Outputs Interface Inputs Are TTL-Voltage Compatible Directly With System Bus (cid:1) Provide Bus Interface From Multiple (cid:1) Typical tpd = 17 ns Sources in High-Performance Systems (cid:1) Low Power Consumption, 80-µA Max I (cid:1) Buffered Inputs and Outputs CC (cid:1) ±6-mA Output Drive at 5 V SN54HCT257... J PACKAGE SN54HCT257...FK PACKAGE SN74HCT257...D OR N PACKAGE (TOP VIEW) (TOP VIEW) 1AA/B NCVCCOE A/B 1 16 VCC 1A 2 15 OE 3 2 1 20 19 1B 4 18 4A 1B 3 14 4A 1Y 5 17 4B 1Y 4 13 4B NC 6 16 NC 2A 5 12 4Y 2A 7 15 4Y 2B 6 11 3A 2B 8 14 3A 2Y 7 10 3B 9 10 1112 13 GND 8 9 3Y Y D CY B 2 N N3 3 G NC − No internal connection description/ordering information The ’HCT257 devices are designed to multiplex signals from 4-bit data sources to 4-output data lines in bus-organized systems. The 3-state outputs do not load the data lines when the output-enable (OE) input is at the high logic level. To ensure the high-impedance state during power up or power down, OE should be tied to V through a pullup CC resistor; the minimum value of the resistor is determined by the current-sinking capability of the driver. ORDERING INFORMATION ORDERABLE TOP-SIDE TA PACKAGE† PART NUMBER MARKING PDIP − N Tube of 25 SN74HCT257N SN74HCT257N Tube of 40 SN74HCT257D −−4400°°CC ttoo 8855°°CC SSOOIICC −− DD Reel of 2500 SN74HCT257DR HHCCTT225577 Reel of 250 SN74HCT257DT CDIP − J Tube of 25 SNJ54HCT257J SNJ54HCT257J −−5555°°CC ttoo 112255°°CC LCCC − FK Tube of 55 SNJ54HCT257FK SNJ54HCT257FK †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 TexasInstruments semiconductor products and disclaimers thereto appears at the end of this data sheet. (cid:12)(cid:2)(cid:17)(cid:18)(cid:1)(cid:1) (cid:21)(cid:7)(cid:5)(cid:18)(cid:15)(cid:26)(cid:20)(cid:1)(cid:18) (cid:2)(cid:21)(cid:7)(cid:18)(cid:14) (cid:28)(cid:29)(cid:30)(cid:31) !"#$%&’(cid:28) #"’(cid:28)((cid:30)’(cid:31) (cid:16)(cid:15)(cid:21)(cid:14)(cid:12)(cid:6)(cid:7)(cid:20)(cid:21)(cid:2) Copyright  2003, Texas Instruments Incorporated (cid:14)(cid:13)(cid:7)(cid:13) (cid:30)’)"*%((cid:28)(cid:30)"’ #$**&’(cid:28) ((cid:31) ") +$,-(cid:30)#((cid:28)(cid:30)"’ !((cid:28)&. (cid:16)*"!$#(cid:28)(cid:31) #"’)"*% (cid:28)" (cid:31)+&#(cid:30))(cid:30)#((cid:28)(cid:30)"’(cid:31) +&* (cid:28)(cid:29)& (cid:28)&*%(cid:31) ") (cid:7)&/((cid:31) (cid:20)’(cid:31)(cid:28)*$%&’(cid:28)(cid:31) (cid:31)(cid:28)(’!(*! 0(**(’(cid:28)1. (cid:16)*"!$#(cid:28)(cid:30)"’ +*"#&(cid:31)(cid:31)(cid:30)’2 !"&(cid:31) ’"(cid:28) ’&#&(cid:31)(cid:31)(*(cid:30)-1 (cid:30)’#-$!& (cid:28)&(cid:31)(cid:28)(cid:30)’2 ") (-- +(*(%&(cid:28)&*(cid:31). POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 1

(cid:1)(cid:2)(cid:3)(cid:4)(cid:5)(cid:6)(cid:7)(cid:8)(cid:3)(cid:9)(cid:10) (cid:1)(cid:2)(cid:9)(cid:4)(cid:5)(cid:6)(cid:7)(cid:8)(cid:3)(cid:9) (cid:11)(cid:12)(cid:13)(cid:14)(cid:15)(cid:12)(cid:16)(cid:17)(cid:18) (cid:8)(cid:19)(cid:17)(cid:20)(cid:2)(cid:18) (cid:7)(cid:21) (cid:22)(cid:19)(cid:17)(cid:20)(cid:2)(cid:18) (cid:14)(cid:13)(cid:7)(cid:13) (cid:1)(cid:18)(cid:17)(cid:18)(cid:6)(cid:7)(cid:21)(cid:15)(cid:1)(cid:23)(cid:24)(cid:12)(cid:17)(cid:7)(cid:20)(cid:16)(cid:17)(cid:18)(cid:25)(cid:18)(cid:15)(cid:1) (cid:26)(cid:20)(cid:7)(cid:5) (cid:27)(cid:19)(cid:1)(cid:7)(cid:13)(cid:7)(cid:18) (cid:21)(cid:12)(cid:7)(cid:16)(cid:12)(cid:7)(cid:1) SCLS072D − NOVEMBER 1988 − REVISED SEPTEMBER 2003 FUNCTION TABLE INPUTS OOUUTTPPUUTT SSEELLEECCTT DATA OOEE YY A/B A B H X X X Z L L L X L L L H X H L H X L L L H X H H logic diagram (positive logic) 15 OE 1 A/B 2 1A 4 1Y 3 1B 5 2A 7 2Y 6 2B 11 3A 9 3Y 10 3B 14 4A 12 4Y 13 4B Pin numbers shown are for the D, J, and N packages. 2 POST OFFICE BOX 655303 • DALLAS, TEXAS 75265

(cid:1)(cid:2)(cid:3)(cid:4)(cid:5)(cid:6)(cid:7)(cid:8)(cid:3)(cid:9)(cid:10) (cid:1)(cid:2)(cid:9)(cid:4)(cid:5)(cid:6)(cid:7)(cid:8)(cid:3)(cid:9) (cid:11)(cid:12)(cid:13)(cid:14)(cid:15)(cid:12)(cid:16)(cid:17)(cid:18) (cid:8)(cid:19)(cid:17)(cid:20)(cid:2)(cid:18) (cid:7)(cid:21) (cid:22)(cid:19)(cid:17)(cid:20)(cid:2)(cid:18) (cid:14)(cid:13)(cid:7)(cid:13) (cid:1)(cid:18)(cid:17)(cid:18)(cid:6)(cid:7)(cid:21)(cid:15)(cid:1)(cid:23)(cid:24)(cid:12)(cid:17)(cid:7)(cid:20)(cid:16)(cid:17)(cid:18)(cid:25)(cid:18)(cid:15)(cid:1) (cid:26)(cid:20)(cid:7)(cid:5) (cid:27)(cid:19)(cid:1)(cid:7)(cid:13)(cid:7)(cid:18) (cid:21)(cid:12)(cid:7)(cid:16)(cid:12)(cid:7)(cid:1) SCLS072D − NOVEMBER 1988 − REVISED SEPTEMBER 2003 absolute maximum ratings over operating free-air temperature range (unless otherwise noted)† Supply voltage range, V . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . −0.5 V to 7 V CC Input clamp current, I (V < 0 or V > V ) (see Note 1) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ±20 mA IK I I CC Output clamp current, I (V < 0 or V > V ) (see Note 1) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ±20 mA OK O O CC Continuous output current, I (V = 0 to V ) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ±35 mA O O CC Continuous current through V or GND . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ±70 mA CC Package thermal impedance, θJA (see Note 2): D package . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73°C/W N package . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67°C/W Storage temperature range, T . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . −65°C to 150°C stg †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) SN54HCT257 SN74HCT257 UUNNIITT MIN NOM MAX MIN NOM MAX VCC Supply voltage 4.5 5 5.5 4.5 5 5.5 V VIH High-level input voltage VCC = 4.5 V to 5.5 V 2 2 V VIL Low-level input voltage VCC = 4.5 V to 5.5 V 0.8 0.8 V VI Input voltage 0 VCC 0 VCC V VO Output voltage 0 VCC 0 VCC V tt Input transition (rise and fall) time 500 500 ns TA Operating free-air temperature −55 125 −40 85 °C 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. electrical characteristics over recommended operating free-air temperature range (unless otherwise noted) TA = 25°C SN54HCT257 SN74HCT257 PPAARRAAMMEETTEERR TTEESSTT CCOONNDDIITTIIOONNSS VVCCCC UUNNIITT MIN TYP MAX MIN MAX MIN MAX IOH = −20 µA 4.4 4.499 4.4 4.4 VVOOHH VVII == VVIIHH oorr VVIILL 44..55 VV VV IOH = −6 mA 3.98 4.3 3.7 3.84 IOL = 20 µA 0.001 0.1 0.1 0.1 VVOOLL VVII == VVIIHH oorr VVIILL 44..55 VV VV IOL = 6 mA 0.17 0.26 0.4 0.33 II VI = VCC or 0 5.5 V ±0.1 ±100 ±1000 ±1000 nA IOZ VO = VCC or 0, VI = VIH or VIL 5.5 V ±0.01 ±0.5 ±10 ±5 µA ICC VI = VCC or 0, IO = 0 5.5 V 8 160 80 µA One input at 0.5 V or 2.4 V, ∆ICC‡ Other inputs at 0 or VCC 5.5 V 1.4 2.4 3 2.9 mA 4.5 V Ci to 5.5 V 3 10 10* 10 pF * On products compliant to MIL-PRF-38535, this parameter is not production tested. ‡This is the increase in supply current for each input that is at one of the specified TTL voltage levels, rather than 0 V or VCC. (cid:16)(cid:15)(cid:21)(cid:14)(cid:12)(cid:6)(cid:7) (cid:16)(cid:15)(cid:18)3(cid:20)(cid:18)(cid:26) (cid:30)’)"*%((cid:28)(cid:30)"’ #"’#&*’(cid:31) +*"!$#(cid:28)(cid:31) (cid:30)’ (cid:28)(cid:29)& )"*%((cid:28)(cid:30)4& "* !&(cid:31)(cid:30)2’ +(cid:29)((cid:31)& ") !&4&-"+%&’(cid:28). (cid:6)(cid:29)(*(#(cid:28)&*(cid:30)(cid:31)(cid:28)(cid:30)# !((cid:28)( (’! "(cid:28)(cid:29)&* (cid:31)+&#(cid:30))(cid:30)#((cid:28)(cid:30)"’(cid:31) (*& !&(cid:31)(cid:30)2’ 2"(-(cid:31). (cid:7)&/((cid:31) (cid:20)’(cid:31)(cid:28)*$%&’(cid:28)(cid:31) *&(cid:31)&*4&(cid:31) (cid:28)(cid:29)& *(cid:30)2(cid:29)(cid:28) (cid:28)" #(cid:29)(’2& "* !(cid:30)(cid:31)#"’(cid:28)(cid:30)’$& (cid:28)(cid:29)&(cid:31)& +*"!$#(cid:28)(cid:31) 0(cid:30)(cid:28)(cid:29)"$(cid:28) ’"(cid:28)(cid:30)#&. POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 3

(cid:1)(cid:2)(cid:3)(cid:4)(cid:5)(cid:6)(cid:7)(cid:8)(cid:3)(cid:9)(cid:10) (cid:1)(cid:2)(cid:9)(cid:4)(cid:5)(cid:6)(cid:7)(cid:8)(cid:3)(cid:9) (cid:11)(cid:12)(cid:13)(cid:14)(cid:15)(cid:12)(cid:16)(cid:17)(cid:18) (cid:8)(cid:19)(cid:17)(cid:20)(cid:2)(cid:18) (cid:7)(cid:21) (cid:22)(cid:19)(cid:17)(cid:20)(cid:2)(cid:18) (cid:14)(cid:13)(cid:7)(cid:13) (cid:1)(cid:18)(cid:17)(cid:18)(cid:6)(cid:7)(cid:21)(cid:15)(cid:1)(cid:23)(cid:24)(cid:12)(cid:17)(cid:7)(cid:20)(cid:16)(cid:17)(cid:18)(cid:25)(cid:18)(cid:15)(cid:1) (cid:26)(cid:20)(cid:7)(cid:5) (cid:27)(cid:19)(cid:1)(cid:7)(cid:13)(cid:7)(cid:18) (cid:21)(cid:12)(cid:7)(cid:16)(cid:12)(cid:7)(cid:1) SCLS072D − NOVEMBER 1988 − REVISED SEPTEMBER 2003 switching characteristics over recommended operating free-air temperature range, C = 50 pF L (unless otherwise noted) (see Figure 1) FFRROOMM TTOO TA = 25°C SN54HCT257 SN74HCT257 PPAARRAAMMEETTEERR (INPUT) (OUTPUT) VVCCCC MIN TYP MAX MIN MAX MIN MAX UUNNIITT 4.5 V 20 30 45 38 AA oorr BB YY 5.5 V 17 27 40 34 ttppdd nnss 4.5 V 20 30 45 38 AA//BB YY 5.5 V 17 27 40 34 4.5 V 20 30 45 38 tteenn OOEE YY nnss 5.5 V 17 27 40 34 4.5 V 20 30 45 38 ttddiiss OOEE YY nnss 5.5 V 17 27 40 34 4.5 V 8 15 22 19 tttt AAnnyy nnss 5.5 V 7 14 21 17 switching characteristics over recommended operating free-air temperature range, C = 150 pF L (unless otherwise noted) (see Figure 1) FFRROOMM TTOO TA = 25°C SN54HCT257 SN74HCT257 PPAARRAAMMEETTEERR (INPUT) (OUTPUT) VVCCCC MIN TYP MAX MIN MAX MIN MAX UUNNIITT 4.5 V 22 38 57 48 AA oorr BB YY 5.5 V 19 35 53 44 ttppdd nnss 4.5 V 22 38 57 48 AA//BB YY 5.5 V 19 35 53 44 4.5 V 23 40 60 50 tteenn OOEE YY nnss 5.5 V 20 38 57 48 4.5 V 17 42 63 53 tttt AAnnyy nnss 5.5 V 14 38 57 48 operating characteristics, T = 25°C A PARAMETER TEST CONDITIONS TYP UNIT Cpd Power dissipation capacitance No load 13 pF (cid:16)(cid:15)(cid:21)(cid:14)(cid:12)(cid:6)(cid:7) (cid:16)(cid:15)(cid:18)3(cid:20)(cid:18)(cid:26) (cid:30)’)"*%((cid:28)(cid:30)"’ #"’#&*’(cid:31) +*"!$#(cid:28)(cid:31) (cid:30)’ (cid:28)(cid:29)& )"*%((cid:28)(cid:30)4& "* !&(cid:31)(cid:30)2’ +(cid:29)((cid:31)& ") !&4&-"+%&’(cid:28). (cid:6)(cid:29)(*(#(cid:28)&*(cid:30)(cid:31)(cid:28)(cid:30)# !((cid:28)( (’! "(cid:28)(cid:29)&* (cid:31)+&#(cid:30))(cid:30)#((cid:28)(cid:30)"’(cid:31) (*& !&(cid:31)(cid:30)2’ 2"(-(cid:31). (cid:7)&/((cid:31) (cid:20)’(cid:31)(cid:28)*$%&’(cid:28)(cid:31) *&(cid:31)&*4&(cid:31) (cid:28)(cid:29)& *(cid:30)2(cid:29)(cid:28) (cid:28)" #(cid:29)(’2& "* !(cid:30)(cid:31)#"’(cid:28)(cid:30)’$& (cid:28)(cid:29)&(cid:31)& +*"!$#(cid:28)(cid:31) 0(cid:30)(cid:28)(cid:29)"$(cid:28) ’"(cid:28)(cid:30)#&. 4 POST OFFICE BOX 655303 • DALLAS, TEXAS 75265

(cid:1)(cid:2)(cid:3)(cid:4)(cid:5)(cid:6)(cid:7)(cid:8)(cid:3)(cid:9)(cid:10) (cid:1)(cid:2)(cid:9)(cid:4)(cid:5)(cid:6)(cid:7)(cid:8)(cid:3)(cid:9) (cid:11)(cid:12)(cid:13)(cid:14)(cid:15)(cid:12)(cid:16)(cid:17)(cid:18) (cid:8)(cid:19)(cid:17)(cid:20)(cid:2)(cid:18) (cid:7)(cid:21) (cid:22)(cid:19)(cid:17)(cid:20)(cid:2)(cid:18) (cid:14)(cid:13)(cid:7)(cid:13) (cid:1)(cid:18)(cid:17)(cid:18)(cid:6)(cid:7)(cid:21)(cid:15)(cid:1)(cid:23)(cid:24)(cid:12)(cid:17)(cid:7)(cid:20)(cid:16)(cid:17)(cid:18)(cid:25)(cid:18)(cid:15)(cid:1) (cid:26)(cid:20)(cid:7)(cid:5) (cid:27)(cid:19)(cid:1)(cid:7)(cid:13)(cid:7)(cid:18) (cid:21)(cid:12)(cid:7)(cid:16)(cid:12)(cid:7)(cid:1) SCLS072D − NOVEMBER 1988 − REVISED SEPTEMBER 2003 PARAMETER MEASUREMENT INFORMATION VCC PARAMETER RL CL S1 S2 S1 tPZH 50 pF Open Closed Test ten 1 kΩ or From Output Point RL tPZL 150 pF Closed Open Under Test tPHZ Open Closed CL tdis 1 kΩ 50 pF (see Note A) S2 tPLZ Closed Open 50 pF tpd or tt −− or Open Open 150 pF LOAD CIRCUIT 3 V Output 3 V Input 1.3 V 1.3 V Control 1.3 V 1.3 V (Low-Level 0 V Enabling) 0 V tPLH tPHL tPZL tPLZ In-Phase 90% 90% VOH Output ≈VCC Output 1.3 V 1.3 V Waveform 1 1.3 V 10% 10% tr tfVOL (See Note B) 10% VOL tPHL tPLH tPZH tPHZ Out-of- 90% 90% VOH Output VOH Phase 1.3 V 1.3 V 90% Output 10% 10% Waveform 2 1.3 V VOL (See Note B) ≈0 V tf tr VOLTAGE WAVEFORMS VOLTAGE WAVEFORMS OUTPUT AND 3-STATE BIDIRECTIONAL I/O ENABLE AND DISABLE TIMES FOR 3-STATE OUTPUTS PROPAGATION DELAY TIME 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. Phase relationships between waveforms were chosen arbitrarily. All input pulses are supplied by generators having the following characteristics: PRR ≤ 1 MHz, ZO = 50 Ω, tr = 6 ns, tf = 6 ns. D. The outputs are measured one at a time with one input transition per measurement. E. tPLZ and tPHZ are the same as tdis. F. tPZL and tPZH are the same as ten. G. tPLH and tPHL are the same as tpd. Figure 1. Load Circuit and Voltage Waveforms POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 5

PACKAGE OPTION ADDENDUM www.ti.com 24-Aug-2018 PACKAGING INFORMATION Orderable Device Status Package Type Package Pins Package Eco Plan Lead/Ball Finish MSL Peak Temp Op Temp (°C) Device Marking Samples (1) Drawing Qty (2) (6) (3) (4/5) SN74HCT257D ACTIVE SOIC D 16 40 Green (RoHS CU NIPDAU Level-1-260C-UNLIM -40 to 85 HCT257 & no Sb/Br) SN74HCT257DR ACTIVE SOIC D 16 2500 Green (RoHS CU NIPDAU Level-1-260C-UNLIM -40 to 85 HCT257 & no Sb/Br) SN74HCT257DRE4 ACTIVE SOIC D 16 2500 Green (RoHS CU NIPDAU Level-1-260C-UNLIM -40 to 85 HCT257 & no Sb/Br) SN74HCT257N ACTIVE PDIP N 16 25 Green (RoHS CU NIPDAU N / A for Pkg Type -40 to 85 SN74HCT257N & no Sb/Br) (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) RoHS: TI defines "RoHS" to mean semiconductor products that are compliant with the current EU RoHS requirements for all 10 RoHS substances, including the requirement that RoHS substance do not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, "RoHS" products are suitable for use in specified lead-free processes. TI may reference these types of products as "Pb-Free". RoHS Exempt: TI defines "RoHS Exempt" to mean products that contain lead but are compliant with EU RoHS pursuant to a specific EU RoHS exemption. Green: TI defines "Green" to mean the content of Chlorine (Cl) and Bromine (Br) based flame retardants meet JS709B low halogen requirements of <=1000ppm threshold. Antimony trioxide based flame retardants must also meet the <=1000ppm threshold requirement. (3) MSL, Peak Temp. - The Moisture Sensitivity Level rating according to the JEDEC industry standard classifications, and peak solder temperature. (4) There may be additional marking, which relates to the logo, the lot trace code information, or the environmental category on the device. (5) Multiple Device Markings will be inside parentheses. Only one Device Marking contained in parentheses and separated by a "~" will appear on a device. If a line is indented then it is a continuation of the previous line and the two combined represent the entire Device Marking for that device. (6) Lead/Ball Finish - Orderable Devices may have multiple material finish options. Finish options are separated by a vertical ruled line. Lead/Ball Finish values may wrap to two lines if the finish value exceeds the maximum column width. 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. TI has taken and Addendum-Page 1

PACKAGE OPTION ADDENDUM www.ti.com 24-Aug-2018 continues to take reasonable steps to provide representative and accurate information but may not have conducted destructive testing or chemical analysis on incoming materials and chemicals. TI and TI suppliers consider certain information to be proprietary, and thus CAS numbers and other limited information may not be available for release. In no event shall TI's liability arising out of such information exceed the total purchase price of the TI part(s) at issue in this document sold by TI to Customer on an annual basis. Addendum-Page 2

PACKAGE MATERIALS INFORMATION www.ti.com 19-Mar-2008 TAPE AND REEL INFORMATION *Alldimensionsarenominal Device Package Package Pins SPQ Reel Reel A0(mm) B0(mm) K0(mm) P1 W Pin1 Type Drawing Diameter Width (mm) (mm) Quadrant (mm) W1(mm) SN74HCT257DR SOIC D 16 2500 330.0 16.4 6.5 10.3 2.1 8.0 16.0 Q1 PackMaterials-Page1

PACKAGE MATERIALS INFORMATION www.ti.com 19-Mar-2008 *Alldimensionsarenominal Device PackageType PackageDrawing Pins SPQ Length(mm) Width(mm) Height(mm) SN74HCT257DR SOIC D 16 2500 333.2 345.9 28.6 PackMaterials-Page2

None

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IMPORTANTNOTICE TexasInstrumentsIncorporated(TI)reservestherighttomakecorrections,enhancements,improvementsandotherchangestoits semiconductorproductsandservicesperJESD46,latestissue,andtodiscontinueanyproductorserviceperJESD48,latestissue.Buyers shouldobtainthelatestrelevantinformationbeforeplacingordersandshouldverifythatsuchinformationiscurrentandcomplete. TI’spublishedtermsofsaleforsemiconductorproducts(http://www.ti.com/sc/docs/stdterms.htm)applytothesaleofpackagedintegrated circuitproductsthatTIhasqualifiedandreleasedtomarket.AdditionaltermsmayapplytotheuseorsaleofothertypesofTIproductsand services. ReproductionofsignificantportionsofTIinformationinTIdatasheetsispermissibleonlyifreproductioniswithoutalterationandis accompaniedbyallassociatedwarranties,conditions,limitations,andnotices.TIisnotresponsibleorliableforsuchreproduced documentation.Informationofthirdpartiesmaybesubjecttoadditionalrestrictions.ResaleofTIproductsorserviceswithstatements differentfromorbeyondtheparametersstatedbyTIforthatproductorservicevoidsallexpressandanyimpliedwarrantiesforthe associatedTIproductorserviceandisanunfairanddeceptivebusinesspractice.TIisnotresponsibleorliableforanysuchstatements. BuyersandotherswhoaredevelopingsystemsthatincorporateTIproducts(collectively,“Designers”)understandandagreethatDesigners remainresponsibleforusingtheirindependentanalysis,evaluationandjudgmentindesigningtheirapplicationsandthatDesignershave fullandexclusiveresponsibilitytoassurethesafetyofDesigners'applicationsandcomplianceoftheirapplications(andofallTIproducts usedinorforDesigners’applications)withallapplicableregulations,lawsandotherapplicablerequirements.Designerrepresentsthat,with respecttotheirapplications,Designerhasallthenecessaryexpertisetocreateandimplementsafeguardsthat(1)anticipatedangerous consequencesoffailures,(2)monitorfailuresandtheirconsequences,and(3)lessenthelikelihoodoffailuresthatmightcauseharmand takeappropriateactions.DesigneragreesthatpriortousingordistributinganyapplicationsthatincludeTIproducts,Designerwill thoroughlytestsuchapplicationsandthefunctionalityofsuchTIproductsasusedinsuchapplications. TI’sprovisionoftechnical,applicationorotherdesignadvice,qualitycharacterization,reliabilitydataorotherservicesorinformation, including,butnotlimitedto,referencedesignsandmaterialsrelatingtoevaluationmodules,(collectively,“TIResources”)areintendedto assistdesignerswhoaredevelopingapplicationsthatincorporateTIproducts;bydownloading,accessingorusingTIResourcesinany way,Designer(individuallyor,ifDesignerisactingonbehalfofacompany,Designer’scompany)agreestouseanyparticularTIResource solelyforthispurposeandsubjecttothetermsofthisNotice. TI’sprovisionofTIResourcesdoesnotexpandorotherwisealterTI’sapplicablepublishedwarrantiesorwarrantydisclaimersforTI products,andnoadditionalobligationsorliabilitiesarisefromTIprovidingsuchTIResources.TIreservestherighttomakecorrections, enhancements,improvementsandotherchangestoitsTIResources.TIhasnotconductedanytestingotherthanthatspecifically describedinthepublisheddocumentationforaparticularTIResource. Designerisauthorizedtouse,copyandmodifyanyindividualTIResourceonlyinconnectionwiththedevelopmentofapplicationsthat includetheTIproduct(s)identifiedinsuchTIResource.NOOTHERLICENSE,EXPRESSORIMPLIED,BYESTOPPELOROTHERWISE TOANYOTHERTIINTELLECTUALPROPERTYRIGHT,ANDNOLICENSETOANYTECHNOLOGYORINTELLECTUALPROPERTY RIGHTOFTIORANYTHIRDPARTYISGRANTEDHEREIN,includingbutnotlimitedtoanypatentright,copyright,maskworkright,or otherintellectualpropertyrightrelatingtoanycombination,machine,orprocessinwhichTIproductsorservicesareused.Information regardingorreferencingthird-partyproductsorservicesdoesnotconstitutealicensetousesuchproductsorservices,orawarrantyor endorsementthereof.UseofTIResourcesmayrequirealicensefromathirdpartyunderthepatentsorotherintellectualpropertyofthe thirdparty,oralicensefromTIunderthepatentsorotherintellectualpropertyofTI. TIRESOURCESAREPROVIDED“ASIS”ANDWITHALLFAULTS.TIDISCLAIMSALLOTHERWARRANTIESOR REPRESENTATIONS,EXPRESSORIMPLIED,REGARDINGRESOURCESORUSETHEREOF,INCLUDINGBUTNOTLIMITEDTO ACCURACYORCOMPLETENESS,TITLE,ANYEPIDEMICFAILUREWARRANTYANDANYIMPLIEDWARRANTIESOF MERCHANTABILITY,FITNESSFORAPARTICULARPURPOSE,ANDNON-INFRINGEMENTOFANYTHIRDPARTYINTELLECTUAL PROPERTYRIGHTS.TISHALLNOTBELIABLEFORANDSHALLNOTDEFENDORINDEMNIFYDESIGNERAGAINSTANYCLAIM, INCLUDINGBUTNOTLIMITEDTOANYINFRINGEMENTCLAIMTHATRELATESTOORISBASEDONANYCOMBINATIONOF PRODUCTSEVENIFDESCRIBEDINTIRESOURCESOROTHERWISE.INNOEVENTSHALLTIBELIABLEFORANYACTUAL, DIRECT,SPECIAL,COLLATERAL,INDIRECT,PUNITIVE,INCIDENTAL,CONSEQUENTIALOREXEMPLARYDAMAGESIN CONNECTIONWITHORARISINGOUTOFTIRESOURCESORUSETHEREOF,ANDREGARDLESSOFWHETHERTIHASBEEN ADVISEDOFTHEPOSSIBILITYOFSUCHDAMAGES. UnlessTIhasexplicitlydesignatedanindividualproductasmeetingtherequirementsofaparticularindustrystandard(e.g.,ISO/TS16949 andISO26262),TIisnotresponsibleforanyfailuretomeetsuchindustrystandardrequirements. WhereTIspecificallypromotesproductsasfacilitatingfunctionalsafetyorascompliantwithindustryfunctionalsafetystandards,such productsareintendedtohelpenablecustomerstodesignandcreatetheirownapplicationsthatmeetapplicablefunctionalsafetystandards andrequirements.Usingproductsinanapplicationdoesnotbyitselfestablishanysafetyfeaturesintheapplication.Designersmust ensurecompliancewithsafety-relatedrequirementsandstandardsapplicabletotheirapplications.DesignermaynotuseanyTIproductsin life-criticalmedicalequipmentunlessauthorizedofficersofthepartieshaveexecutedaspecialcontractspecificallygoverningsuchuse. Life-criticalmedicalequipmentismedicalequipmentwherefailureofsuchequipmentwouldcauseseriousbodilyinjuryordeath(e.g.,life support,pacemakers,defibrillators,heartpumps,neurostimulators,andimplantables).Suchequipmentincludes,withoutlimitation,all medicaldevicesidentifiedbytheU.S.FoodandDrugAdministrationasClassIIIdevicesandequivalentclassificationsoutsidetheU.S. TImayexpresslydesignatecertainproductsascompletingaparticularqualification(e.g.,Q100,MilitaryGrade,orEnhancedProduct). Designersagreethatithasthenecessaryexpertisetoselecttheproductwiththeappropriatequalificationdesignationfortheirapplications andthatproperproductselectionisatDesigners’ownrisk.Designersaresolelyresponsibleforcompliancewithalllegalandregulatory requirementsinconnectionwithsuchselection. DesignerwillfullyindemnifyTIanditsrepresentativesagainstanydamages,costs,losses,and/orliabilitiesarisingoutofDesigner’snon- compliancewiththetermsandprovisionsofthisNotice. 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