GENERAL DESCRIPTION
To use the maximum count length (decade or four-bit binary), the B input is connected to the QA output. A symmetrical divide-by-ten count can be obtained from the counters by connecting the QD output to the A input and applying the input count to the B input which gives a divideby-ten square wave at output QA. FEATURES
s Typical power dissipation 145 mW s Count frequency 42 MHz Ordering Code: Order Number DM7490AN Package Number N14A Package DESCRIPTION
14-Lead Plastic Dual-In-Line Package (PDIP), JEDEC MS-001, 0.300 Wide Connection Diagram © 2000 Fairchild Semiconductor Corporation DS006533 DM7490A Function Tables BCD Count Sequence (Note 1) Count QD 0 1 2 3 4 5 6 7 8 9 L L L L L L L L H H L L L L H H H H L L Outputs QC QB L L H H L L H H L L QA L H L H L H L H L H Logic Diagram BCD Bi-Quinary (5-2) (Note 2) Count QA 0 1 2 3 4 5 6 7 8 9 L L L L L H H H H H L L L L H L L L L H Outputs QD QC L L H H L L L H H L QB L H L H L L H L H L Reset/Count Function Table Reset Inputs R0(1) H H X X L L X H = HIGH Level L = LOW Level X = Don’t Care Note 1: Output QA is connected to input B for BCD count.