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DM74AS280 9-Bit Parity Generator/Checker October 1986 Revised March 2000 DM74AS280 9-Bit Parity Generator/Checker General Description These universal, 9-bit parity generators/checkers utilize advanced Schottky high performance circuitry and feature odd/even outputs to facilitate operation of either odd or even parity applications. The word length capability is easily expanded by cascading. The DM74AS280 can be used to upgrade the performance of most systems utilizing the '180 parity generator/checker. Although the DM74AS280 is implemented without expander inputs, the corresponding function is provided by the availability of an input at pin 4 and no internal connection at pin 3. This permits the DM74AS280 to be substituted for the '180 in existing designs to produce identical function even if DM74AS280s are mixed with existing '180s. Features s Generates either odd or even parity for nine data lines s Inputs are buffered to lower the drive requirements s Can be used to upgrade existing systems using MSI parity circuits s Cascadable for N-bits s Advanced oxide-isolated, ion-implanted Schottky TTL process s Switching specifications at 50 pF s Switching specifications guaranteed over full temperature and VCC range Ordering Code: Order Number DM74AS280M DM74AS280N Package Number M14A N14A Package Description 14-Lead Small Outline Integrated Circuit (SOIC), JEDEC MS-012, 0.150 Narrow 14-Lead Plastic Dual-In-Line Package (PDIP), JEDEC MS-001, 0.300 Wide Devices also available in Tape and Reel. Specify by appending the suffix letter "X" to the ordering code. Connection Diagram Function Table Number of Inputs (A thru I) that are HIGH 0, 2, 4, 6, 8 1, 3, 5, 7, 9 L = LOW State H = HIGH State Outputs Even H L Odd L H (c) 2000 Fairchild Semiconductor Corporation DS006303 www.fairchildsemi.com DM74AS280 Logic Diagram www.fairchildsemi.com 2 DM74AS280 Absolute Maximum Ratings(Note 1) Supply Voltage Input Voltage Operating Free Air Temperature Range Storage Temperature Range Typical JA N Package M Package 77.0C/W 108.0C/W 7V 7V 0C to +70C -65C to +150C Note 1: The "Absolute Maximum Ratings" are those values beyond which the safety of the device cannot be guaranteed. The device should not be operated at these limits. The parametric values defined in the Electrical Characteristics tables are not guaranteed at the absolute maximum ratings. The "Recommended Operating Conditions" table will define the conditions for actual device operation. Recommended Operating Conditions Symbol VCC VIH VIL IOH IOL TA Supply Voltage HIGH Level Input Voltage LOW Level Input Voltage HIGH Level Output Current LOW Level Output Current Free-Air Operating Temperature 0 Parameter Min 4.5 2 0.8 -2 20 70 Typ 5 Max 5.5 Units V V V mA mA C Electrical Characteristics Over recommended free-air temperature range. All typical values are measured at VCC = 5V, TA = 25C. Symbol VIK VOH VOL II IIH IIL IO ICC Parameter Input Clamp Voltage HIGH Level Output Voltage LOW Level Output Voltage Input Current @ Max Input Voltage HIGH Level Input Current LOW Level Input Current Output Drive Current Supply Current Conditions VCC = 4.5V, II = -18 mA IOH = -2 mA, VCC = 4.5V to 5.5V VCC = 4.5V, IOL = Max VCC = 5.5V, VIH = 7V VCC = 5.5V, VIH = 2.7V VCC = 5.5V, VIL = 0.4V VCC = 5.5V, VO = 2.25V VCC = 5.5V -30 25 VCC - 2 0.35 0.5 0.1 20 -0.5 -112 40 Min Typ Max -1.2 Units V V V mA A mA mA mA Switching Characteristics over recommended operating free air temperature range Symbol tPLH tPHL tPLH tPHL Parameter Propagation Delay Time, LOW-to-HIGH Level Output Propagation Delay Time, HIGH-to-LOW Level Output Propagation Delay Time, LOW-to-HIGH Level Output Propagation Delay Time, HIGH-to-LOW Level Output Data Odd CL = 50 pF, RL = 500 Conditions VCC = 4.5V to 5.5V, From Data To Even Min 3 3 3 3 Max 12 11 12 11.5 Units ns ns ns ns 3 www.fairchildsemi.com DM74AS280 Typical Applications Three DM74AS280s can be used to implement a 25-line parity generator/checker. As an alternative, the outputs of two or three parity generators/checkers can be decoded with a 2-input (AS86) or 3input (S135) exclusive-OR gate for 18 or 27-line parity applications. Longer word lengths can be implemented by cascading DM74AS280s. As shown in Figure 2, parity can be generated for word lengths up to 81 bits. FIGURE 1. 25-Line Parity/Generator Checker FIGURE 2. 81-Line Parity/Generator Checker www.fairchildsemi.com 4 DM74AS280 Physical Dimensions inches (millimeters) unless otherwise noted 14-Lead Small Outline Integrated Circuit (SOIC), JEDEC MS-012, 0.150 Narrow Package Number M14A 5 www.fairchildsemi.com DM74AS280 9-Bit Parity Generator/Checker Physical Dimensions inches (millimeters) unless otherwise noted (Continued) 14-Lead Plastic Dual-In-Line Package (PDIP), JEDEC MS-001, 0.300 Wide Package Number N14A Fairchild does not assume any responsibility for use of any circuitry described, no circuit patent licenses are implied and Fairchild reserves the right at any time without notice to change said circuitry and specifications. LIFE SUPPORT POLICY FAIRCHILD'S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT DEVICES OR SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT OF FAIRCHILD SEMICONDUCTOR CORPORATION. As used herein: 1. Life support devices or systems are devices or systems which, (a) are intended for surgical implant into the body, or (b) support or sustain life, and (c) whose failure to perform when properly used in accordance with instructions for use provided in the labeling, can be reasonably expected to result in a significant injury to the user. www.fairchildsemi.com 6 2. A critical component in any component of a life support device or system whose failure to perform can be reasonably expected to cause the failure of the life support device or system, or to affect its safety or effectiveness. www.fairchildsemi.com |
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