74LS139 Dual 1-of-4 Decoder/ Demultiplexer in Pakistan

74LS47 accepts four lines of BCD (8421) input data, generates their complements internally and decodes the data with seven AND/OR gates having open-collector outputs to drive indicator segments directly. Each segment output is guaranteed to sink 24 mA in the ON (LOW) state and withstand 15V in the OFF (HIGH) state with a maximum leakage current of 250 µA. Auxiliary inputs provided blanking, 74LS47 BCD to 7-Segment Decoder/Driver IC.

The 74HC165 is a high-speed Si-gate CMOS device and is pin-compatible with low-power Schottky TTL (LSTTL). They are specified in compliance with JEDEC standard no. 7A. The 74HC165 are 8-bit parallel-load or serial-in shift registers with complementary serial outputs (Q7 and Q7) available from the last stage. When the parallel load (PL) input is LOW, parallel data from the D0 to D7 inputs are loaded into the register asynchronously. When PL is HIGH, data enters the register serially at the Ds input and shifts one place to the right (Q0 –> Q1 –> Q2, etc.) with each positive-going clock transition. This feature allows parallel-to-serial converter expansion by tying the Q7 output to the DS input of the succeeding stage. The clock input is a gated-OR structure that allows one input to be used as an active LOW clock enable (CE) input. The pin assignment for the CP and CE inputs is arbitrary and can be reversed for layout convenience. The LOW-to-HIGH transition of input CE should only take place while CP is HIGH for predictable operation. Either the CP or the CE should be HIGH before the LOW-to-HIGH transition of PL to prevent shifting the data when PL is activated.