54LS245/DM54LS245/DM74LS245 TRI-STATEÉ Octal Bus Transceiver General Description These octal bus transceivers are designed for asynchronous two-way communication between data buses. The control function implementation minimizes external timing requirements. The device allows data transmission from the A bus to the B bus or from the B bus to the A bus depending upon the logic level at the direction control (DIR) input. The enable input (G) can be used to disable the device so that the buses are effectively isolated. Features Y Y Y Y Y Y Y Y Y Bi-Directional bus transceiver in a high-density 20-pin package TRI-STATE outputs drive bus lines directly PNP inputs reduce DC loading on bus lines Hysteresis at bus inputs improve noise margins Typical propagation delay times, port-to-port 8 ns Typical enable/disable times 17 ns IOL (sink current) 54LS 12 mA 74LS 24 mA IOH (source current) b 12 mA 54LS b 15 mA 74LS Alternate Military/Aerospace device (54LS245) is available. Contact a National Semiconductor Sales Office/ Distributor for specifications. Connection Diagram Dual-In-Line Package TL/F/6413 – 1 Order Number 54LS245DMQB, 54LS245FMQB, 54LS245LMQB, DM54LS245J, DM54LS245W, DM74LS245WM or DM74LS245N See NS Package Number E20A, J20A, M20B, N20A or W20A Function Table Enable G Direction Control DIR L L H L H X Operation B data to A bus A data to B bus Isolation H e High Level, L e Low Level, X e Irrelevant TRI-STATEÉ is a registered trademark of National Semiconductor Corporation. C1995 National Semiconductor Corporation TL/F/6413 RRD-B30M105/Printed in U. S. A. 54LS245/DM54LS245/DM74LS245 TRI-STATE Octal Bus Transceiver June 1989 Absolute Maximum Ratings (Note) If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/Distributors for availability and specifications. Note: 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’’ table are not guaranteed at the absolute maximum ratings. The ‘‘Recommended Operating Conditions’’ table will define the conditions for actual device operation. Supply Voltage 7V Input Voltage DIR or G 7V A or B 5.5V Operating Free Air Temperature Range b 55§ C to a 125§ C DM54LS and 54LS DM74LS 0§ C to a 70§ C b 65§ C to a 150§ C Storage Temperature Range Recommended Operating Conditions Symbol DM54LS245 Parameter VCC Supply Voltage VIH High Level Input Voltage VIL Low Level Input Voltage IOH High Level Output Current IOL Low Level Output Current TA Free Air Operating Temperature DM74LS245 Units Min Nom Max Min Nom Max 4.5 5 5.5 4.75 5 5.25 2 V 2 V 0.7 0.8 V b 12 b 15 mA 24 mA 70 §C 12 b 55 125 0 Electrical Characteristics over recommended operating free air temperature range (unless otherwise noted) Symbol Parameter Conditions Min Typ (Note 1) Max Units b 1.5 V VI Input Clamp Voltage VCC e Min, II e b18 mA HYS Hysteresis (VT a b VTb) VCC e Min VOH High Level Output Voltage VCC e Min, VIH e Min VIL e Max, IOH e b1 mA DM74 VCC e Min, VIL e Min VIL e Max, IOH e b3 mA DM54/DM74 VCC e Min, VIH e Min VIL e 0.5V, IOH e Max DM54/DM74 VCC e Min VIL e Max VIH e Min IOL e 12 mA DM74 0.4 IOL e Max DM54 0.4 DM74 0.5 VCC e Max VIL e Max VIH e Min VO e 2.7V 20 mA VO e 0.4V b 200 mA VOL Low Level Output Voltage IOZH Off-State Output Current, High Level Voltage Applied IOZL Off-State Output Current, Low Level Voltage Applied II Input Current at Maximum Input Voltage VCC e Max 0.2 0.4 V 3.4 V 2.7 2.4 2 A or B VI e 5.5V 0.1 DIR or G VI e 7V 0.1 V mA IIH High Level Input Current VCC e Max, VI e 2.7V 20 mA IIL Low Level Input Current VCC e Max, VI e 0.4V b 0.2 mA IOS Short Circuit Output Current VCC e Max (Note 2) b 225 mA ICC Supply Current Outputs High b 40 VCC e Max 48 70 Outputs Low 62 90 Outputs at Hi-Z 64 95 Note 1: All typicals are at VCC e 5V, TA e 25§ C. Note 2: Not more than one output should be shorted at a time, not to exceed one second duration 2 mA Switching Characteristics VCC e 5V, TA e 25§ C (See Section 1 for Test Waveforms and Output Load) DM54/74 Symbol Parameter Conditions LS245 Min tPLH Propagation Delay Time, Low-to-High-Level Output tPHL Propagation Delay Time, High-to-Low-Level Output tPZL Output Enable Time to Low Level tPZH Output Enable Time to High Level tPLZ Output Disable Time from Low Level tPHZ Output Disable Time from High Level tPLH Propagation Delay Time, Low-to-High-Level Output tPHL Propagation Delay Time, High-to-Low-Level Output tPZL Output Enable Time to Low Level tPZH Output Enable Time to High Level CL e 45 pF RL e 667X CL e 5 pF RL e 667X 3 CL e 150 pF RL e 667X Units Max 12 ns 12 ns 40 ns 40 ns 25 ns 25 ns 16 ns 17 ns 45 ns 45 ns Physical Dimensions inches (millimeters) Ceramic Leadless Chip Carrier Package (E) Order Number 54LS245LMQB NS Package Number E20A 20-Lead Ceramic Dual-In-Line Package (J) Order Number 54LS245DMQB or DM54LS245J NS Package Number J20A 4 Physical Dimensions inches (millimeters) (Continued) 20-Lead Small Outline Molded Package (M) Order Number DM74LS245WM NS Package Number M20B 20-Lead Molded Dual-In-Line Package (N) Order Number DM74LS245N NS Package Number N20A 5 54LS245/DM54LS245/DM74LS245 TRI-STATE Octal Bus Transceiver Physical Dimensions inches (millimeters) (Continued) 20-Lead Ceramic Flat Package (W) Order Number 54LS245FMQB or DM54LS245W NS Package Number W20A LIFE SUPPORT POLICY NATIONAL’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 NATIONAL SEMICONDUCTOR CORPORATION. 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