SN54ALS251, SN74ALS251 1-OF-8 DATA SELECTORS/MULTIPLEXERS WITH 3-STATE OUTPUTS SDAS215A – APRIL 1982 – REVISED DECEMBER 1994 • • • • • 3-State Version of the ′ALS151 3-State Outputs Interface Directly With System Bus Perform Parallel-to-Serial Conversion Complementary Outputs Provide True and Inverted Data Package Options Include Plastic Small-Outline (D) Packages, Ceramic Chip Carriers (FK), and Standard Plastic (N) and Ceramic (J) 300-mil DIPs SN54ALS251 . . . J PACKAGE SN74ALS251 . . . D OR N PACKAGE (TOP VIEW) D3 D2 D1 D0 Y W OE GND 1 16 2 15 3 14 4 13 5 12 6 11 7 10 8 9 VCC D4 D5 D6 D7 A B C description These data selectors/multiplexers contain full binary decoding to select one-of-eight data sources and feature controlled complementary 3-state outputs. D2 D3 NC VCC D4 SN54ALS251 . . . FK PACKAGE (TOP VIEW) The 3-state outputs can interface with and drive data lines of bus-organized systems. With all but one of the common outputs disabled (at the high-impedance state), the low impedance of the signal-enabled output drives the bus line to a high or low logic level. Both outputs are controlled by the output-enable (OE) input. The outputs are disabled when OE is high. 4 3 2 1 20 19 18 5 17 6 16 7 15 8 14 9 10 11 12 13 D5 D6 NC D7 A OE GND NC C B D1 D0 NC Y W The SN54ALS251 is characterized for operation over the full military temperature range of – 55°C to 125°C. The SN74ALS251 is characterized for operation from 0°C to 70°C. NC – No internal connection FUNCTION TABLE INPUTS OUTPUTS SELECT OE C B A Y W X X X H Z Z L L L L D0 D0 L L H L D1 D1 L H L L D2 D2 L H H L D3 D3 H L L L D4 D4 H L H L D5 D5 H H L L D6 D6 H H H L D7 D7 D0, D1, . . . D7 = the level of the respective D input Copyright 1994, 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 SN54ALS251, SN74ALS251 1-OF-8 DATA SELECTORS/MULTIPLEXERS WITH 3-STATE OUTPUTS SDAS215A – APRIL 1982 – REVISED DECEMBER 1994 logic symbol† OE A B C D0 D1 D2 D3 D4 D5 D6 D7 MUX 7 EN 11 0 10 0 G7 9 2 4 3 2 0 5 1 6 2 1 Y W 3 15 4 14 5 13 6 12 7 † This symbol is in accordance with ANSI/IEEE Std 91-1984 and IEC Publication 617-12. Pin numbers shown are for the D, J, and N packages. logic diagram (positive logic) OE D0 D1 D2 D3 Data Inputs 4 3 2 1 5 D4 D5 D6 D7 A Data Select (binary) 7 B C 15 6 14 13 12 11 10 9 Pin numbers shown are for the D, J, and N packages. 2 POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 Y W SN54ALS251, SN74ALS251 1-OF-8 DATA SELECTORS/MULTIPLEXERS WITH 3-STATE OUTPUTS SDAS215A – APRIL 1982 – REVISED DECEMBER 1994 absolute maximum ratings over operating free-air temperature range (unless otherwise noted)† Supply voltage, VCC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 V Input voltage, VI . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 V Voltage applied to a disabled 3-state output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.5 V Operating free-air temperature range, TA: SN54ALS251 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . – 55°C to 125°C SN74ALS251 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0°C to 70°C Storage temperature range . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . – 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. recommended operating conditions SN54ALS251 SN74ALS251 MIN NOM MAX MIN NOM MAX 4.5 5 5.5 4.5 5 5.5 UNIT VCC VIH Supply voltage VIL IOH Low-level input voltage 0.7 0.8 High-level output current –1 – 2.6 mA IOL TA Low-level output current 12 24 mA 70 °C High-level input voltage 2 Operating free-air temperature 2 – 55 125 V V 0 V electrical characteristics over recommended operating free-air temperature range (unless otherwise noted) PARAMETER VIK TEST CONDITIONS VCC = 4.5 V, VCC = 4.5 V to 5.5 V, II = – 18 mA IOH = – 0.4 mA VCC = 4 4.5 5V IOH = – 1 mA IOH = – 2.6 mA VOL 5V VCC = 4 4.5 IOL = 12 mA IOL = 24 mA IOZH IOZL VCC = 5.5 V, VCC = 5.5 V, VO = 2.7 V VO = 0.4 V II IIH VCC = 5.5 V, VCC = 5.5 V, VI = 7 V VI = 2.7 V IIL IO§ VCC = 5.5 V, VCC = 5.5 V, VI = 0.4 V VO = 4.5 V VOH ICC Enabled Disabled VCC = 5 5.5 5V SN54ALS251 TYP‡ MAX MIN SN74ALS251 TYP‡ MAX MIN – 1.5 VCC – 2 2.4 – 1.5 UNIT V VCC – 2 V 3.3 2.4 0.25 – 20 0.4 3.2 0.25 0.4 0.35 0.5 V µA 20 20 – 20 – 20 µA 0.1 0.1 mA 20 20 µA – 0.1 – 0.1 mA – 112 mA – 112 – 30 Inputs at GND 7 10 7 10 Inputs at 4.5 V 9.4 14 9.4 14 mA ‡ All typical values are at VCC = 5 V, TA = 25°C. § The output conditions have been chosen to produce a current that closely approximates one half of the true short-circuit output current, IOS. POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 3 SN54ALS251, SN74ALS251 1-OF-8 DATA SELECTORS/MULTIPLEXERS WITH 3-STATE OUTPUTS SDAS215A – APRIL 1982 – REVISED DECEMBER 1994 switching characteristics (see Figure 1) PARAMETER FROM (INPUT) TO (OUTPUT) VCC = 4.5 V to 5.5 V, CL = 50 pF, R1 = 500 Ω, R2 = 500 Ω, TA = MIN to MAX† SN54ALS251 tPLH tPHL A B A, B, or C Y tPLH tPHL A B A, B, or C W tPLH tPHL An D Any Y tPLH tPHL An D Any W tPZH tPZL OE Y tPZH tPZL OE W tPZH tPZL OE Y tPZH tPZL OE W SN74ALS251 MIN MAX MIN MAX 1 21 5 18 7 34 8 24 5 38 8 24 7 26 7 23 2 15 2 10 3 23 3 15 3 25 3 15 3 20 3 15 3 21 3 15 3 19 3 15 3 21 3 15 3 19 3 15 2 12 2 10 1 18 1 10 2 12 2 10 1 18 1 10 † For conditions shown as MIN or MAX, use the appropriate value specified under recommended operating conditions. 4 POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 UNIT ns ns ns ns ns ns ns ns SN54ALS251, SN74ALS251 1-OF-8 DATA SELECTORS/MULTIPLEXERS WITH 3-STATE OUTPUTS SDAS215A – APRIL 1982 – REVISED DECEMBER 1994 PARAMETER MEASUREMENT INFORMATION SERIES 54ALS/74ALS AND 54AS/74AS DEVICES 7V RL = R1 = R2 VCC S1 RL R1 Test Point From Output Under Test CL (see Note A) From Output Under Test RL Test Point From Output Under Test CL (see Note A) CL (see Note A) LOAD CIRCUIT FOR BI-STATE TOTEM-POLE OUTPUTS LOAD CIRCUIT FOR OPEN-COLLECTOR OUTPUTS 3.5 V Timing Input Test Point LOAD CIRCUIT FOR 3-STATE OUTPUTS 3.5 V High-Level Pulse 1.3 V R2 1.3 V 1.3 V 0.3 V 0.3 V Data Input tw th tsu 3.5 V 1.3 V 3.5 V Low-Level Pulse 1.3 V 0.3 V 1.3 V 0.3 V VOLTAGE WAVEFORMS SETUP AND HOLD TIMES VOLTAGE WAVEFORMS PULSE DURATIONS 3.5 V Output Control (low-level enabling) 1.3 V 1.3 V 0.3 V tPZL Waveform 1 S1 Closed (see Note B) tPLZ [3.5 V 1.3 V tPHZ tPZH Waveform 2 S1 Open (see Note B) 1.3 V VOL 0.3 V VOH 1.3 V 0.3 V [0 V 3.5 V 1.3 V Input 1.3 V 0.3 V tPHL tPLH VOH In-Phase Output 1.3 V 1.3 V VOL tPLH tPHL VOH Out-of-Phase Output (see Note C) 1.3 V 1.3 V VOL VOLTAGE WAVEFORMS PROPAGATION DELAY TIMES VOLTAGE WAVEFORMS ENABLE AND DISABLE TIMES, 3-STATE OUTPUTS NOTES: A. CL includes probe and jig 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. When measuring propagation delay items of 3-state outputs, switch S1 is open. D. All input pulses have the following characteristics: PRR ≤ 1 MHz, tr = tf = 2 ns, duty cycle = 50%. E. The outputs are measured one at a time with one transition per measurement. Figure 1. Load Circuits and Voltage Waveforms POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 5 IMPORTANT NOTICE Texas Instruments and its subsidiaries (TI) reserve the right to make changes to their products or to discontinue any product or service without notice, and advise customers to obtain the latest version of relevant information to verify, before placing orders, that information being relied on is current and complete. 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