DM54LS461 DM74LS461 LS461 DM54LS461J DM74LS461J DM74LS461N C1995 RRD-B30M115

General Description The LS461 is an 8-bit synchronous counter with parallel load clear and hold capability Two function select

DM54LS461 DM54LS461 DM74LS461 DM74LS461 Octal Counter General Description The LS461 LS461 is an 8-bit synchronous counter with parallel load clear and hold capability Two function select inputs (I0 I1) provide one of four operations which occur synchronously on the rising edge of the clock (CK) The LOAD operation loads the inputs (D7 D0) into the output register (Q7 Q0) The CLEAR operation resets the output register to all LOWs The HOLD operation holds the previous value regardless of clock transitions The INCREMENT operation adds one to the output register when the carry-in input is TRUE (CI e LOW) otherwise the operation is a HOLD The carry-out (CO) is TRUE (CO e LOW) when the output register (Q7 Q0) is all HIGHs otherwise FALSE (CO e HIGH) The output register (Q7 Q0) is enabled when OE is LOW and disabled (HI-Z) when OE is HIGH The output drivers will sink the 24 mA required for many bus interface standards Two or more LS461 LS461 octal counters may be cascaded to provide larger counters The operation codes were chosen such that when I1 is HIGH I0 may be used to select between LOAD and INCREMENT as in a program counter (JUMP INCREMENT) Connection Diagram Standard Test Load Features Benefits Y Y Y Y Y Y Y Octal counter for microprogram-counter DMA controller and general purpose counting applications 8 bits match byte boundaries Bus-structured pinout 24-pin Skinny Dip saves space TRI-STATE outputs drive bus lines Low current PNP inputs reduce loading Expandable in 8-bit increments Top View TL L 8334 2 TL L 8334 1 Order Number DM54LS461J DM54LS461J DM74LS461J DM74LS461J or DM74LS461N DM74LS461N See NS Package Number J24F or N24C Function Table OE CK I1 I0 CI D7 D0 Q7 Q0 Operation H L L L L L X X L L H H H X L H L H H X X X X H L X X X D X X Z L Q D Q Q plus 1 HI-Z CLEAR HOLD LOAD HOLD INCREMENT u u u u u TRI-STATE is a registered trademark of National Semiconductor Corp C1995 C1995 National Semiconductor Corporation TL L 8334 RRD-B30M115 RRD-B30M115 Printed in U S A DM54LS461 DM54LS461 DM74LS461 DM74LS461 Octal Counter July 1989 Absolute Maximum Ratings Off-State Output Voltage If Military Aerospace specified devices are required please contact the National Semiconductor Sales Office Distributors for availability and specifications Supply Voltage VCC 5 5V Storage Temperature b 65 C to a 150 C 7V Input Voltage 5 5V Operating Conditions Symbol Military Parameter Min 45 VCC Operating Free-Air Temperature 5 Supply Voltage TA Commercial Typ Units Max Typ Max 55 4 75 5 5 25 V 125 b 55 Min 0 75 C Low 40 35 High 30 25 tW Width of Clock tSU Set Up Time 60 th Hold Time 0 ns 50 b 15 ns 0 b 15 Case Temperature Electrical Characteristics Over Operating Conditions Symbol Parameter Test Conditions Min Typ Max Low-Level Input Voltage VIH High-Level Input Voltage VIC Input Clamp Voltage VCC e MIN II eb18 mA b1 5 V IIL Low-Level Input Current VCC e MAX VI e 0 4V b 0 25 mA IIH High-Level Input Current VCC e MAX VI e 2 4V 25 mA II Maximum Input Current VCC e MAX VI e 5 5V 1 mA VOL Low-Level Output Voltage 05 V VOH High-Level Output Voltage 08 Units VIL 2 VCC e MIN VIL e 0 8V VIH e 2V VCC e MIN VIL e 0 8V VIH e 2V Off-State Output Current Output Short-Circuit Current Supply Current COM IOL e 24 mA MIL IOH eb2 mA COM VCC e 5 0V ICC IOL e 12 mA VCC e MAX VIL e 0 8V VIH e 2V IOS MIL 24 IOZH V IOH eb3 2 mA VCC e MAX IOZL V V VO e 0 4V b 100 VO e 2 4V mA 100 VCC e 0V 120 mA b 130 b 30 mA 180 mA No more than one output should be shorted at a time and duration of the short-circuit should not exceed one second All typical values are at VCC e 5V TA e 25 C Switching Characteristics Over Operating Conditions Symbol Parameter fMAX CBI to CBO Delay tPD Clock to Q tPD Clock to CO tPZX Output Enable Delay tPXZ Military Min Commercial Max Max 60 35 50 ns 35 20 30 ns 55 95 55 80 ns 35 55 35 45 ns 35 55 35 45 ns 10 5 CL e 50 pF R1 e 200 X R2 e 390 X 2 Min Units Typ 20 Output Disable Delay Typ 35 Maximum Clock Frequency tPD Test Conditions (See Test Load) 12 5 MHz Logic Diagram LS461 LS461 TL L 8334 3 3 DM54LS461 DM54LS461 DM74LS461 DM74LS461 Octal Counter Physical Dimensions inches (millimeters) 24-Pin Narrow Ceramic Dual-In-Line Package (J) Order Number DM54LS461J DM54LS461J or DM74LS461J DM74LS461J NS Package J24F LIFE SUPPORT POLICY 24-Pin Narrow Plastic Dual-In-Line Package (N) Order Number DM74LS461N DM74LS461N NS Package N24C 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 As used herein 1 Life support devices or systems are devices or systems which (a) are intended for surgical implant into the body or (b) support or sustain life and whose failure to perform when properly used in accordance with instructions for use provided in the labeling can be reasonably expected to result in a significant injury to the user National Semiconductor Corporation 1111 West Bardin Road Arlington TX 76017 Tel 1(800) 272-9959 Fax 1(800) 737-7018 2 A critical component is any component of a life support device or system whose failure to perform can be reasonably expected to cause the failure of the life support device or system or to affect its safety or effectiveness National Semiconductor Europe Fax (a49) 0-180-530 85 86 Email cnjwge tevm2 nsc com Deutsch Tel (a49) 0-180-530 85 85 English Tel (a49) 0-180-532 78 32 Fran ais Tel (a49) 0-180-532 93 58 Italiano Tel (a49) 0-180-534 16 80 National Semiconductor Hong Kong Ltd 13th Floor Straight Block Ocean Centre 5 Canton Rd Tsimshatsui Kowloon Hong Kong Tel (852) 2737-1600 Fax (852) 2736-9960 National Semiconductor Japan Ltd Tel 81-043-299-2309 Fax 81-043-299-2408 National does not assume any responsibility for use of any circuitry described no circuit patent licenses are implied and National reserves the right at any time without notice to change said circuitry and specifications