74HCT93

Features:

· Various counting modes
· Asynchronous master reset
· Output capability: standard
· ICC category: MSI


Pinout




Description

The 74HCT93 is high-speed Si-gate CMOS devices and are pin compatible with low power Schottky TTL (LSTTL). They are specified in compliance with JEDEC standard no. 7A.

The 74HCT93 is 4-bit binary ripple counters. The devices consist of four master-slave flip-flops internally connected to provide a divide-by-two section and a divide-by-eight section. Each section has a separate clock input (CP0 and CP1) to initiate state changes of the counter on the HIGH-to-LOW clock transition. State changes of the Qn outputs do not occur simultaneously because of internal ripple delays. Therefore, decoded output signals are subject to decoding spikes and should not be used for clocks or strobes.

A gated AND asynchronous master reset (MR1 and MR2) of the 74HCT93 is provided which overrides both clocks and resets (clears) all flip-flops. Since the output from the divide-by-two section is not internally connected to the succeeding stages, the device may be operated in various counting modes. In a 4-bit ripple counter the output Q0 must be connected externally to input CP1.

The input count pulses of the 74HCT93 are applied to clock input CP0. Simultaneous frequency divisions of 2, 4, 8 and 16 are performed at the Q0, Q1, Q2 and Q3 outputs as shown in the function table. As a 3-bit ripple counter the input count pulses are applied to input CP1.

Simultaneous frequency divisions of 2, 4 and 8 are available at the Q1, Q2 and Q3 outputs. Independent use of the first flip-flop is available if the reset function coincides with reset of the 3-bit ripple-through counter.