Revised March 2000 DM74LS47 BCD to 7-Segment Decoder/Driver with Open-Collector Outputs General Description Features The DM74LS47 accepts four lines of BCD (8421) input data, generates their complements internally and decodes the data with seven AND/OR gates having open-collector outputs to drive indicator segments directly. Each segment output is guaranteed to sink 24 mA in the ON (LOW) state and withstand 15V in the OFF (HIGH) state with a maximum leakage current of 250 µA. Auxiliary inputs provided blanking, lamp test and cascadable zero-suppression functions. ■ Open-collector outputs ■ Drive indicator segments directly ■ Cascadable zero-suppression capability ■ Lamp test input Ordering Code: Order Number Package Number Package Description DM74LS47M M16A 16-Lead Small Outline Integrated Circuit (SOIC), JEDEC MS-012, 0.150 Narrow DM74LS47N N16E 16-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. Logic Symbol Connection Diagram VCC = Pin 16 GND = Pin 8 Pin Descriptions Pin Names Description A0–A3 BCD Inputs RBI Ripple Blanking Input (Active LOW) LT Lamp Test Input (Active LOW) BI/RBO Blanking Input (Active LOW) or Ripple Blanking Output (Active LOW) a –g Segment Outputs (Active LOW) (Note 1) Note 1: OC—Open Collector © 2000 Fairchild Semiconductor Corporation DS009817 www.fairchildsemi.com DM74LS47 BCD to 7-Segment Decoder/Driver with Open-Collector Outputs October 1988 DM74LS47 Truth Table Decimal Inputs or Outputs Note Function LT RBI 0 H H L L L L H L L L L L L H (Note 2) 1 H X L L L H H H L L H H H H (Note 2) 2 H X L L H L H L L H L L H L 3 H X L L H H H L L L L H H L 4 H X L H L L H H L L H H L L 5 H X L H L H H L H L L H L L 6 H X L H H L H H H L L L L L 7 H X L H H H H L L L H H H H 8 H X H L L L H L L L L L L L L A3 A2 A1 A0 BI/RBO a b c d e f g 9 H X H L L H H L L L H H L 10 H X H L H L H H H H L L H L 11 H X H L H H H H H L L H H L 12 H X H H L L H H L H H H L L 13 H X H H L H H L H H L H L L 14 H X H H H L H H H H L L L L 15 H X H H H H H H H H H H H H BI X X X X X X L H H H H H H H (Note 3) RBI H L L L L L L H H H H H H H (Note 4) LT L X X X X X H L L L L L L L (Note 5) Note 2: BI/RBO is wire-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, and ripple-blanking input (RBI) must be open or at a HIGH level if blanking or a decimal 0 is not desired. X = input may be HIGH or LOW. Note 3: When a LOW level is applied to the blanking input (forced condition) all segment outputs go to a HIGH level regardless of the state of any other input condition. Note 4: When ripple-blanking input (RBI) and inputs A0, A1, A2 and A3 are LOW level, with the lamp test input at HIGH level, all segment outputs go to a HIGH level and the ripple-blanking output (RBO) goes to a LOW level (response condition). Note 5: 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 LOW level. Functional Description intermediate decoder from an OR gate whose inputs are BI/RBO of the next highest and lowest order decoders. BI/ RBO also serves as an unconditional blanking input. The internal NAND gate that generates the RBO signal has a resistive pull-up, as opposed to a totem pole, and thus BI/ RBO can be forced LOW by external means, using wiredcollector logic. A LOW signal thus applied to BI/RBO turns off all segment outputs. This blanking feature can be used to control display intensity by varying the duty cycle of the blanking signal. A LOW signal applied to LT turns on all segment outputs, provided that BI/RBO is not forced LOW. The DM74LS47 decodes the input data in the pattern indicated in the Truth Table and the segment identification illustration. If the input data is decimal zero, a LOW signal applied to the RBI blanks the display and causes a multidigit display. For example, by grounding the RBI of the highest order decoder and connecting its BI/RBO to RBI of the next lowest order decoder, etc., leading zeros will be suppressed. Similarly, by grounding RBI of the lowest order decoder and connecting its BI/RBO to RBI of the next highest order decoder, etc., trailing zeros will be suppressed. Leading and trailing zeros can be suppressed simultaneously by using external gates, i.e.: by driving RBI of a www.fairchildsemi.com 2 DM74LS47 Logic Diagram Numerical Designations—Resultant Displays 3 www.fairchildsemi.com DM74LS47 Absolute Maximum Ratings(Note 6) Supply Voltage Note 6: 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. 7V Input Voltage 7V 0°C to +70°C Operating Free Air Temperature Range −65°C to +150°C Storage Temperature Range Recommended Operating Conditions Symbol Parameter VCC Supply Voltage VIH HIGH Level Input Voltage VIL LOW Level Input Voltage IOH HIGH Level Output Current Min Nom Max 4.75 5 5.25 Units V 2 V a − g @ 15V = VOH (Note 7) 0.8 V −250 µA IOH HIGH Level Output Current BI /RBO −50 µA IOL LOW Level Output Current 24 mA TA Free Air Operating Temperature 70 °C 0 Note 7: OFF-State at a–g. Electrical Characteristics Over recommended operating free air temperature range (unless otherwise noted) Symbol Parameter Conditions VI Input Clamp Voltage VCC = Min, II = −18 mA VOH HIGH Level VCC = Min, IOH = Max, Output Voltage VIL = Max, BI /RBO IOFF Output HIGH Current Segment Outputs VCC = 5.5V, VO = 15V a − g VOL LOW Level VCC = Min, IOL = Max, Output Voltage VIH = Min, a − g Min 2.7 Typ (Note 8) V 0.35 Input Voltage VCC = Max, VI = 10V µA 0.5 0.5 0.25 V 0.4 IOL = 1.6 mA, BI /RBO VCC = Max, VI = 7V V 250 IOL = 12 mA, a –g Input Current @ Max Units −1.5 3.4 IOL = 3.2 mA, BI /RBO II Max 0.4 µA 100 IIH HIGH Level Input Current VCC = Max, VI = 2.7V 20 µA IIL LOW Level Input Current VCC = Max, VI = 0.4V −0.4 mA IOS Short Circuit VCC = Max (Note 9), Output Current IOS at BI/RBO Supply Current VCC = Max ICC −0.3 −2.0 13 mA mA Note 8: All typicals are at VCC = 5V, TA = 25°C. Note 9: Not more than one output should be shorted at a time, and the duration should not exceed one second. Switching Characteristics at VCC = +5.0V, TA = +25°C RL = 665Ω Symbol Parameter CL = 15 pF Conditions Min Units Max tPLH Propagation Delay 100 tPHL An to a –g 100 tPLH Propagation Delay 100 tPHL RBI to a –g (Note 10) 100 Note 10: LT = HIGH, A0–A3 = LOW www.fairchildsemi.com 4 ns ns DM74LS47 Physical Dimensions inches (millimeters) unless otherwise noted 16-Lead Small Outline Integrated Circuit (SOIC), JEDEC MS-012, 0.150 Narrow Package Number M16A 5 www.fairchildsemi.com DM74LS47 BCD to 7-Segment Decoder/Driver with Open-Collector Outputs Physical Dimensions inches (millimeters) unless otherwise noted (Continued) 16-Lead Plastic Dual-In-Line Package (PDIP), JEDEC MS-001, 0.300 Wide Package Number N16E 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. 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