DM74LS249 BCD to 7-Segment Decoder with Open-Collector Outputs General Description The ’LS249 has active HIGH open-collector outputs and incorporates the Lamp Test and BI/RBO inputs. Additionally, the ’LS249 will light the top bar (segment a) for numeral 6 and the bottom bar (segment d) for numeral 9. Connection Diagram Logic Symbol Dual-In-Line Package TL/F/10213 – 2 TL/F/10213 – 1 VCC e Pin 16 GND e Pin 8 Order Number DM74LS249N See NS Package Number N16E Pin Names A0 – A3 BI LT BI/RBO a–g C1995 National Semiconductor Corporation TL/F/10213 Description BCD Inputs Blanking Input (Active LOW) Lamp Test Input (Active LOW) Blanking Input (Active LOW) or Ripple Blanking Output (Active LOW) Segment Outputs (Active HIGH) RRD-B30M105/Printed in U. S. A. DM74LS249 BCD to 7-Segment Decoder with Open-Collector Outputs February 1992 Absolute Maximum Ratings (Note) Supply Voltage 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. 7V Input Voltage Operating Free Air Temperature Range Storage Temperature Range 7V 0§ C to a 70§ C b 65§ C to a 150§ C Recommended Operating Conditions Symbol Parameter VCC Supply Voltage VIH High Level Input Voltage VIL Low Level Input Voltage IOH High Level Output Current (BI/RBO) IOL Low Level Output Current TA Free Air Operating Temperature Min Nom Max 4.75 5 5.25 Units V 2 V 0 0.8 V b 0.25 mA 8 mA 70 §C 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 VOH High Level Output Voltage (BI/RBO) VCC e Min, IOH e Max VIL e Max ICEX High Level Output Current (a thru g) VCC e Min, VO e 5.5V VOL Low Level Output Voltage VCC e Min, IOL e Max, VIH e Min 0.35 0.5 IOL e 4 mA, VCC e Min 0.25 0.4 II Input Current @ Max Input Voltage VCC e Max, VI e 7V IIH High Level Input Current VCC e Max, VI e 2.7V IIL Low Level Input Current VCC e Max, VI e 0.4V IOS ICC Short Circuit Output Current VCC e Max (Note 2) Supply Current VCC e Max, VIN e 4.5V 2.7 V 250 mA V 0.1 mA 20 mA Inputs b 0.4 BI/RBO b 1.2 b 0.3 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, and the duration should not exceed one second. 2 3.4 mA b 2.0 mA 15 mA Switching Characteristics VCC e a 5.0V, TA e a 25§ C RL e 2 kX Symbol Parameter CL e 15 pF Min Units Max tPLH tPHL Propagation Delay Time An to a–g (54LS RL e 2 kX) 100 100 ns tPLH tPHL Propagation Delay Time BI to a–g (54LS RL e 6 kX) 100 100 ns Numerical DesignationsÐResultant Displays TL/F/10213 – 3 Truth Table Decimal or Function Inputs Outputs LT A3 A2 A1 A0 BI/RBO a b c d e f g 0 1 2 3 H H H H L L L L L L L L L L H H L H L H H H H H H L H H H H H H H H L H H L H H H L H L H L L L L L H H 4 5 6 7 8 H H H H H L L L L H H H H H L L L H H L L H L H L H H H H H L H L H H H L L H H H H H H H L H H L H L L H L H H H H L H H H H L H 9 10 11 12 13 H H H H H H H H H H L L L H H L H H L L H L H L H H H H H H H L L L H H L L H L H L H L L L H H L H L H L L L H L L H H H H H H H 14 15 BI LT H H X L H H X X H H X X H H X X L H X X H H L H L L L H L L L H L L L H H L L H H L L H H L L H H L L H Note 1 1 2 3 Note 1: BI/RBO is wired-AND logic serving as blanking input (BI) and/or ripple-blanking output (RBO). The blanking out (BI) must be open or held at a HIGH level when output functions 0 through 15 are desired. X e input may be HIGH or LOW. Note 2: When a LOW level is applied to the blanking input (forced condition) all segment outputs go to a LOW level, regardless of the state of any other input condition. Note 3: When the blanking input/ripple-blanking output (BI/RBO) is open or held at a HIGH level, and a LOW level is applied to lamp test input, all segment outputs go to a HIGH level. 3 Logic Diagram TL/F/10213 – 4 4 5 DM74LS249 BCD to 7-Segment Decoder with Open-Collector Outputs Physical Dimensions inches (millimeters) 16-Lead Molded Dual-In-Line Package (N) Order Number DM74LS249N NS Package Number N16E 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. As used herein: 1. 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