7490 Decade and Binary Counter (74HC90/74LS90)

Description

high-speed 4-bit ripple type counters partitioned into two sections. Each counter has a divide-by-two section and either a divide-by-five section which are triggered by a HIGH-to-LOW transition on the clock inputs. Each section can be used separately or tied together (Q to CP) to form BCD, bi-quinary, modulo-12, or modulo-16 counters. All of the counters have a 2-input gated Master Reset (Clear), and the LS90 also has a 2-input gated Master Set (Preset 9) BCD Decade (8421) Counter — The CP1 input must be externally connected to the Q0 output. The CP0 input receives the incoming count and a BCD count sequence is produced. Symmetrical Bi-quinary Divide-By-Ten Counter — The Q3 output must be externally connected to the CP0 input. The input count is then applied to the CP1 input and a divide-by-ten square wave is obtained at output Q0 Specifications No. of Pins: 14 Operating Temperature Range:0°C to +70°C Supply Voltage Range: 4.75 V to 5.25V Package: DIP-14 Symbol pin Description CP0 1 Clock (Active LOW going edge) Input to÷2 Section CP1 14 Clock (Active LOW going edge) Input to÷5 Section MR1,MR2 2,3 Master Reset (Clear) Inputs MS1,MS2 6,7 Master Set (Preset-9, LS90) Inputs Q0 12 Output from ÷2 Section Q1,Q2,Q3 9,8,11 Outputs from ÷5 sections NC 4, 13 data inputs source 2 VCC 5 supply voltage Notes - The Output LOW drive factor is 2.5 U.L. for Military, (54) and 5 U.L. for commercial (74)Temperature Ranges.- The Q0 Outputs are guaranteed to drive the full fan-out plus the CP1 in