DM74LS197 Presettable Binary Counters General Description The ’LS197 ripple counter contains divide-by-two and divide-by-eight sections which can be combined to form a modulo-16 binary counter. State changes are initiated by the falling edge of the clock. The ’LS197 has a Master Reset (MR) input which overrides all other inputs and asynchronously forces all outputs LOW. A Parallel Load input (PL) overrides clocked operations and asynchronously loads the data on the Parallel Data inputs (Pn) into the flipflops. This preset feature makes the circuit usable as a programmable counter. The circuit can also be used as a 4-bit latch, loading data from the Parallel Data inputs when PL is LOW and storing the data when PL is HIGH. For detail specifications and functional description, please refer to the ’LS196 data sheet. Features Y Y Y High counting ratesÐTypically 70 MHz Asynchronous preset Asynchronous master reset Connection Diagram Dual-In-Line Package TL/F/10180 – 1 Order Number DM74LS197M or DM74LS197N See NS Package Number M14A or N14A Mode Select Table Pin Names CP0 CP1 MR P0 – P3 PL Q0 Q1 – Q3 Description d 2 Section Clock Input (Active Falling Edge) d 8 Section Clock Input (Active Falling Edge) Asynchronous Master Reset Input (Active LOW) Parallel Data Inputs Asynchronous Parallel Load Input (Active LOW) d 2 Section Output* d 8 Section Outputs Inputs Response MR PL CP L H H X L H X X K Qn Forced LOW Pn x Qn Count Up H e HIGH Voltage Level L e LOW Voltage Level X e Immaterial *Q0 output is guaranteed to drive the full rated fan-out plus the CP1 input. C1995 National Semiconductor Corporation TL/F/10180 RRD-B30M105/Printed in U. S. A. DM74LS197 Presettable Binary Counters February 1992 Absolute Maximum Ratings (Note) 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. If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/Distributors for availability and specifications. Supply Voltage Input Voltage Operating Free Air Temperature Range DM74LS 7V 7V 0§ C to a 70§ C b 65§ C to a 150§ C Storage Temperature Range Recommended Operating Conditions Symbol DM74LS197 Parameter VCC Supply Voltage VIH High Level Input Voltage VIL Low Level Input Voltage IOH High Level Output Voltage IOL Low Level Output Current TA Free Air Operating Temperature Units Min Nom Max 4.75 5 5.25 V 2 V 0.8 V b 0.4 mA 8 mA 70 §C 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 VOH High Level Output Voltage VCC e Min, IOH e Max, VIL e Max 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 IIL IOS ICC 2.7 3.4 V V 0.1 mA VCC e Max, VI e 2.7V 20 mA Low Level Input Current VCC e Max, VI e 0.4V b 0.4 mA Short Circuit Output Current VCC e Max (Note 2) Supply Current VCC e Max b 20 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 b 100 mA 27 mA Switching Characteristics VCC e a 5.0V, TA e a 25§ C Symbol RL e 2 kX CL e 15 pF Parameter Min Units Max fMAX Max CLK Frequency tPLH tPHL Propagation Delay CP0 to Q0 55 15 15 MHz ns tPLH tPHL Propagation Delay CP1 to Q2 34 34 ns tPLH tPHL Propagation Delay P2 to Q2 27 44 ns tPLH tPHL Propagation Delay PL to Q2 39 45 ns tPLH tPHL Propagation Delay CP1 to Q1 15 17 ns tPLH tPHL Propagation Delay CP1 to Q3 55 63 ns tPHL Propagation Delay MR to Q3 42 ns Logic Diagram TL/F/10180 – 4 3 Logic Symbol d 16 State Diagram TL/F/10180 – 2 VCC e Pin 14 GND e Pin 7 TL/F/10180 – 3 4 Physical Dimensions inches (millimeters) 14-Lead Small Outline Molded Package (M) Order Number DM74LS197M NS Package Number M14A 5 DM74LS197 Presettable Binary Counters Physical Dimensions inches (millimeters) (Continued) 14-Lead Molded Dual-In-Line Package (N) Order Number DM74LS197N NS Package Number N14A 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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