74LS90 Datasheet | National Semiconductor

Description Each of these monolithic counters contains four masterslave flip-flops and additional gating to provide a divide-bytwo counter and a three-stage binary counter for which the count cycle length is divide-by-five for the ’LS90 and divideby-eight for the ’LS93 All of these counters have a gated zero reset and the LS90 also has gated set-to-nine inputs for use in BCD nine’s plement applications To use their maximum count length (decade or four bit binary) the B input is connected to the QA output The input count pulses are applied to input A and the outputs are as described in the appropriate truth table A symmetrical divide-by-ten count can be obtained from the ’LS90 counters by connecting the QD output to the A input and applying the input count to the B input which gives a divide-by-ten square wave at output QA Features Typical power dissipation 45 m W Count frequency 42 MHz Connection Diagrams (Dual-In-Line Packages) TL F 6381 - 1 Order Number DM74LS90M or DM74LS90N See NS Package Number M14A or N14A TL F 6381 - 2 Order Number DM74LS93M or DM74LS93N See NS Package Number M14A or N14A C1995 National Semiconductor Corporation TL F 6381 RRD-B30M105 Printed in U S A Absolute Maximum Ratings (Note) If Military Aerospace specified devices are required please contact the National Semiconductor Sales Office Distributors for availability and specifications Supply Voltage Input Voltage (Reset) Input Voltage (A or B) Operating Free Air Temperature Range DM74LS Storage Temperature Range 7V 7V 5 5V 0 C to a 70 C b 65 C to a 150 C 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 ‘‘Remended Operating Conditions’’ table will define the conditions for actual device operation Remended Operating Conditions Symbol VCC...