74LS168 Datasheet | National Semiconductor

Description The 54LS168 is a fully synchronous 4-state up down counter featuring a preset capability for programmable operation carry lookahead for easy cascading and a U D input to control the direction of counting It counts in the BCD (8421) sequence and all state changes whether in counting or parallel loading are initiated by the LOW-to-HIGH transition of the clock Connection Diagram Dual-In-Line Package Logic Symbol TL F 10207 - 1 TL F 10207 - 2 Order Number 54LS168DMQB 54LS168FMQB or 54LS168LMQB See NS Package Number E20A J16A or W16A VCC e Pin 16 GND e Pin 8 Pin Names CEP CET CP P0- P3 PE U D Q0- Q3 TC Description Count Enable Parallel Input (Active LOW) Count Enable Trickle Input (Active LOW) Clock Pulse Input (Active Rising Edge) Parallel Data Inputs Parallel Enable Input (Active LOW) Up-Down Count Control Input Flip-Flop Outputs Terminal Count Output (Active LOW) C1995 National Semiconductor Corporation TL F 10207 RRD-B30M105 Printed in U S A 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 ‘‘Remended 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 7V Input Voltage 5 5V Operating Free Air Temperature Range b 55 C to a 125 C 54LS b 65 C to a 150 C Storage Temperature Range Remended Operating Conditions Symbol VCC VIH VIL IOH IOL TA ts (H) ts (L) th (H) th (L) ts (H) ts (L) th (H) th (L) ts (H) ts (L) th (H) th (L) tw (H) tw (L) Parameter Min Supply Voltage High Level Input Voltage Low Level Input Voltage High Level Output Current Low Level Output Current Free Air...