SN54AS885, SN74AS885 8-BIT MAGNITUDE COMPARATORS SDAS236A – DECEMBER 1982 – REVISED JANUARY 1995 • • • • • • • Latchable P-Input Ports With Power-Up Clear Choice of Logical or Arithmetic (Two’s Complement) Comparison Data and PLE Inputs Utilize pnp Input Transistors to Reduce dc Loading Effects Approximately 35% Improvement in ac Performance Over Schottky TTL While Performing More Functions Cascadable to n Bits While Maintaining High Performance 10% Less Power Than STTL for an 8-Bit Comparison Package Options Include Plastic Small-Outline (DW) Packages, Ceramic Chip Carriers (FK), and Standard Plastic (NT) and Ceramic (JT) 300-mil DIPs SN54AS885 . . . JT PACKAGE SN74AS885 . . . DW OR NT PACKAGE (TOP VIEW) L/A P < QIN P > QIN Q7 Q6 Q5 Q4 Q3 Q2 Q1 Q0 GND 24 2 23 3 22 4 21 5 20 6 19 7 18 8 17 9 16 10 15 11 14 12 13 VCC PLE P7 P6 P5 P4 P3 P2 P1 P0 P < QOUT P > QOUT SN54AS885 . . . FK PACKAGE (TOP VIEW) P > QIN P < QIN L/A NC VCC PLE P7 description 5 3 2 1 28 27 26 25 6 24 7 23 8 22 9 21 10 20 4 Q7 Q6 Q5 NC Q4 Q3 Q2 19 11 12 13 14 15 16 17 18 P6 P5 P4 NC P3 P2 P1 Q1 Q0 GND NC P > QOUT P < QOUT P0 These advanced Schottky devices are capable of performing high-speed arithmetic or logic comparisons on two 8-bit binary or two’s complement words. Two fully decoded decisions about words P and Q are externally available at two outputs. These devices are fully expandable to any number of bits without external gates. To compare words of longer lengths, the P > QOUT and P < QOUT outputs of a stage handling less significant bits can be connected to the P > QIN and P < QIN inputs of the next stage handling more significant bits. The cascading paths are implemented with only a two-gate-level delay to reduce overall comparison times for long words. Two alternative methods of cascading are shown in application information. 1 NC – No internal connection The latch is transparent when P latch-enable (PLE) input is high; the P-input port is latched when PLE is low. This provides the designer with temporary storage for the P-data word. The enable circuitry is implemented with minimal delay times to enhance performance when cascaded for longer words. The PLE, P, and Q data inputs utilize pnp input transistors to reduce the low-level current input requirement to typically – 0.25 mA, which minimizes dc loading effects. The SN54AS885 is characterized for operation over the full military temperature range of – 55°C to 125°C. The SN74AS885 is characterized for operation from 0°C to 70°C. Copyright 1995, 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 SN54AS885, SN74AS885 8-BIT MAGNITUDE COMPARATORS SDAS236A – DECEMBER 1982 – REVISED JANUARY 1995 FUNCTION TABLE INPUTS OUTPUTS L/A DATA P0 – P7, Q0 – Q7 P > QIN P < QIN P > QOUT Logical H P>Q X X H L Logical Logical† H P<Q X X L H H P=Q H or L H or L H or L H or L Arithmetic L P AG Q X X H L Arithmetic Arithmetic† L Q AG P X X L H COMPARISON P < QOUT L P=Q H or L H or L H or L H or L † In these cases, P > QOUT follows P > QIN and P < QOUT follows P < QIN. AG = arithmetically greater than logic symbol‡ L/A PLE P0 P1 P2 P3 P4 P5 P6 P7 P > QIN P < QIN Q0 Q1 Q2 Q3 Q4 Q5 Q6 Q7 1 23 15 COMP M [LOGIC] M [ARITH, 2s COMP] C1 1D 1=0 0 16 17 18 19 P 20 21 P>Q 22 3 2 11 7 P<Q > < 0 10 9 8 7 Q 6 5 4 7 ‡ This symbol is in accordance with ANSI/IEEE Std 91-1984 and IEC Publication 617-12. Pin numbers shown are for the DW, JT, and NT packages. 2 POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 13 14 P > QOUT P < QOUT SN54AS885, SN74AS885 8-BIT MAGNITUDE COMPARATORS SDAS236A – DECEMBER 1982 – REVISED JANUARY 1995 logic diagram (positive logic) PLE P7 P6 P5 23 P7 = Q7 C1 P7 22 1D P6 = Q6 P7 21 P6 20 P6 P5 P5 = Q5 P5 P4 P3 P2 19 P4 18 P4 P3 17 P3 P2 P3 = Q3 P2 = Q2 P1 = Q1 14 P < QOUT P2 P1 P0 16 P1 15 P1 P0 P0 = Q0 P0 Q7 Q6 4 Q7 5 Q7 Q6 Q5 6 Q4 7 Q3 8 Q2 9 Q1 10 Q0 11 P > QIN 3 P < QIN 2 1 L/A Q6 Q5 13 P > QOUT Q5 Q4 Q4 Q3 Q3 Q2 4MSB = Q2 Q1 Q1 Q0 Q0 ARITH LOGIC Pin numbers shown are for the DW, JT, and NT packages. POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 3 SN54AS885, SN74AS885 8-BIT MAGNITUDE COMPARATORS SDAS236A – DECEMBER 1982 – REVISED JANUARY 1995 absolute maximum ratings over operating free-air temperature range (unless otherwise noted)† Supply voltage, VCC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 V Input voltage, VI . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 V Operating free-air temperature range, TA: SN54AS885 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . – 55°C to 125°C SN74AS885 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 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 SN54AS885 SN74AS885 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 0.8 0.8 V High-level output current –2 –2 mA IOL tsu* Low-level output current 20 20 mA th* TA Hold time, data after PLE↓ High-level input voltage 2 Setup time, data before PLE↓ Operating free-air temperature 2 V V 2 2 ns 4.5 4 ns – 55 125 0 70 °C * On products compliant to MIL-STD-883, Class B, this parameter is based on characterization data but is not production tested. electrical characteristics over recommended operating free-air temperature range (unless otherwise noted) PARAMETER SN54AS885 TYP‡ MAX TEST CONDITIONS MIN VIK VOH VCC = 4.5 V, VCC = 4.5 V to 5.5 V, II = – 18 mA IOH = – 2 mA VOL II VCC = 4.5 V, VCC = 5.5 V, IOL = 20 mA VI = 7 V VCC = 5 5.5 5V V, VI = 2 2.7 7V VCC = 5.5 V, VI = 0.4 V IIH L/A Others – 1.2 VCC – 2 L/A IIL P > QIN, P < QIN SN74AS885 TYP‡ MAX MIN P, Q, PLE – 1.2 VCC – 2 0.35 0.5 UNIT V V 0.5 V 0.1 0.35 0.1 mA 40 40 20 20 –4 –4 –2 –2 –1 –1 µA mA IO§ VCC = 5.5 V, VO = 2.25 V – 20 – 112 – 20 – 112 mA ICC VCC = 5.5 V, See Note 1 130 210 130 210 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. NOTE 1: ICC is measured with all inputs high except L/A, which is low. 4 POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 SN54AS885, SN74AS885 8-BIT MAGNITUDE COMPARATORS SDAS236A – DECEMBER 1982 – REVISED JANUARY 1995 switching characteristics (see Figure 3) VCC = 4.5 V to 5.5 V, CL = 50 pF, RL = 500 Ω, TA = MIN to MAX SN54AS885 SN74AS885 MIN TYP† MAX MIN TYP† MAX PARAMETER FROM (INPUT) TO (OUTPUT) tPLH tPHL P<Q QOUT,, P > QOUT 2 8.5 14 1 8.5 13 L/A 2 7.5 14 1 7.5 13 tPLH tPHL P < QIN,, P > QIN P<Q QOUT,, P > QOUT 2 5 10 1 5 8 2 5.5 10 1 5.5 8 tPLH tPHL Anyy P or Q data input P<Q QOUT,, P > QOUT 2 13.5 21 1 13.5 17.5 2 10 17 1 10 15 UNIT ns ns ns † All typical values are at VCC = 5 V, TA = 25°C. APPLICATION INFORMATION The ′AS885 can be cascaded to compare words longer than eight bits. Figure 1 shows the comparison of two 32-bit words; however, the design is expandable to n bits. Figure 1 shows the optimum cascading arrangement for comparing words of 32 bits or greater. Typical delay times shown are at VCC = 5 V, TA = 25°C and use the standard advanced Schottky load of RL = 500 Ω, CL = 50 pF. Figure 2 shows the fastest cascading arrangement for comparing 16-bit or 24-bit words. Typical delay times shown are at VCC = 5 V, TA = 25°C and use the standard advanced Schottky load of RL = 500 Ω, CL= 50 pF. POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 5 SN54AS885, SN74AS885 8-BIT MAGNITUDE COMPARATORS SDAS236A – DECEMBER 1982 – REVISED JANUARY 1995 APPLICATION INFORMATION PLE L/A H or L 1 PLE 23 15 P0 16 P1 17 P2 18 P3 19 P4 20 P5 21 P6 22 P7 P > QIN 3 P < QIN 2 11 Q0 10 Q1 9 Q2 8 Q3 7 Q4 6 Q5 5 Q6 4 Q7 ′AS885 13 P > QOUT 14 P < QOUT L/A PLE 23 15 P0 16 P1 17 P2 18 P3 19 P4 20 P5 21 P6 22 P7 P > QIN 3 P < QIN 2 11 Q0 10 Q1 9 Q2 8 Q3 7 Q4 6 Q5 5 Q6 4 Q7 H or L L/A H or L 1 PLE 23 15 P0 16 P1 17 P2 18 P3 19 P4 20 P5 21 P6 22 P7 P > QIN 3 P < QIN 2 11 Q0 10 Q1 9 Q2 8 Q3 7 Q4 6 Q5 5 Q6 4 Q7 1 ′AS885 ′AS885 PLE 13 P > QOUT 14 P < QOUT H or L 1 PLE 23 15 P0 16 P1 17 P2 18 P3 19 P4 20 P5 21 P6 22 P7 P > QIN 3 P < QIN 2 11 Q0 10 Q1 9 Q2 8 Q3 7 Q4 6 Q5 5 Q6 H or L Q7 ′AS885 18 P3 19 P4 20 P5 21 P6 P7 22 P > QIN 3 P < QIN 2 Q0 11 Q1 10 Q2 9 8 Q3 7 Q4 6 Q5 5 Q6 Q7 4 13 P > QOUT 14 P < QOUT 4 13.5 ns Typical 13.5 ns Typical Figure 1. 32-Bit to 72 (n)-Bit Magnitude Comparator 6 ′AS885 PLE 23 P0 15 P1 16 P2 17 13 P > QOUT 14 P < QOUT L/A L/A 1 POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 13 P > QOUT 14 P < QOUT P > QOUT P < QOUT SN54AS885, SN74AS885 8-BIT MAGNITUDE COMPARATORS SDAS236A – DECEMBER 1982 – REVISED JANUARY 1995 APPLICATION INFORMATION Latch Enable L/A H or L 1 PLE 23 15 P0 16 P1 17 P2 18 P3 19 P4 P5 20 21 P6 22 P7 P > QIN 3 P < QIN 2 11 LSB Q0 10 Q1 9 Q2 8 Q3 7 Q4 6 Q5 5 Q6 4 Q7 ′AS885 L/A 13 P > QOUT P < QOUT 14 ′AS885 1 PLE 23 15 P0 16 P1 17 P2 18 P3 19 P4 P5 20 21 P6 22 P7 P > QIN 3 P < QIN 2 11 Q0 10 Q1 9 Q2 8 Q3 7 Q4 6 Q5 5 Q6 4 Q7 L/A ′AS885 1 PLE 23 15 P0 16 P1 17 P2 18 P3 19 P4 P5 20 21 P6 22 P7 13 MSB P > QIN 3 P > QOUT P < QIN 2 P < QOUT 14 11 Q0 10 Q1 9 Q2 8 Q3 7 Q4 6 Q5 5 Q6 4 MSB Q7 13 P > QOUT P < QOUT 14 LSP MSP 16 Bit 19 ns Typical 24 Bit 24.4 ns Typical Figure 2. Fastest Cascading Arrangement for Comparing 16-Bit or 24-Bit Words POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 7 SN54AS885, SN74AS885 8-BIT MAGNITUDE COMPARATORS SDAS236A – DECEMBER 1982 – REVISED JANUARY 1995 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 3. Load Circuits and Voltage Waveforms 8 POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 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. All products are sold subject to the terms and conditions of sale supplied at the time of order acknowledgement, including those pertaining to warranty, patent infringement, and limitation of liability. TI warrants performance of its semiconductor products to the specifications applicable at the time of sale in accordance with TI’s standard warranty. Testing and other quality control techniques are utilized to the extent TI deems necessary to support this warranty. Specific testing of all parameters of each device is not necessarily performed, except those mandated by government requirements. CERTAIN APPLICATIONS USING SEMICONDUCTOR PRODUCTS MAY INVOLVE POTENTIAL RISKS OF DEATH, PERSONAL INJURY, OR SEVERE PROPERTY OR ENVIRONMENTAL DAMAGE (“CRITICAL APPLICATIONS”). TI SEMICONDUCTOR PRODUCTS ARE NOT DESIGNED, AUTHORIZED, OR WARRANTED TO BE SUITABLE FOR USE IN LIFE-SUPPORT DEVICES OR SYSTEMS OR OTHER CRITICAL APPLICATIONS. INCLUSION OF TI PRODUCTS IN SUCH APPLICATIONS IS UNDERSTOOD TO BE FULLY AT THE CUSTOMER’S RISK. In order to minimize risks associated with the customer’s applications, adequate design and operating safeguards must be provided by the customer to minimize inherent or procedural hazards. TI assumes no liability for applications assistance or customer product design. TI does not warrant or represent that any license, either express or implied, is granted under any patent right, copyright, mask work right, or other intellectual property right of TI covering or relating to any combination, machine, or process in which such semiconductor products or services might be or are used. TI’s publication of information regarding any third party’s products or services does not constitute TI’s approval, warranty or endorsement thereof. Copyright 1998, Texas Instruments Incorporated