Part Number : 74LS
Function : Decade and Binary Counters
Package : DIP 14 Pin type
Manufactures : National Semiconductor
DM74LS90 DM74LS93 Decade and Binary Counters General 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 complement 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 Y Y Typical power dissipation 45 mW Count frequency 42 MHz Connection Diagrams (Dual-In-Line Packages).
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 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 Recommended Operating Conditions Symbol Supply Voltage High Level Input Voltage Low Level Input Voltage High Level Output Current Low Level Output Current Clock Frequency (Note 1) Clock Frequency (Note 2) Pulse Width (Note 1) Electrical Characteristics over recommended operating free air temperature range (unless otherwise noted) Symbol VI VOH VOL Parameter Input Clamp Voltage High Level Output Voltage Low Level Outpu […]