SN74LS390D

Product Overview

• Category: Integrated Circuit (IC)
• Use: Digital Counter
• Characteristics: Dual 4-bit Decade Counter
• Package: DIP-16 (Dual In-line Package with 16 pins)
• Essence: High-speed TTL logic circuitry
• Packaging/Quantity: Available in tubes of 25 units or reels of 2,500 units

Specifications

• Supply Voltage Range: 4.75V to 5.25V
• Operating Temperature Range: -40°C to +85°C
• Maximum Clock Frequency: 30 MHz
• Output Current: ±8 mA
• Propagation Delay Time: 15 ns
• Power Dissipation: 500 mW

Detailed Pin Configuration

The SN74LS390D has a total of 16 pins, which are assigned as follows:

1. CLK A (Clock Input A)
2. CLK B (Clock Input B)
3. RCO (Ripple Carry Output)
4. QA (Output A, Bit 0)
5. QB (Output B, Bit 1)
6. QC (Output C, Bit 2)
7. QD (Output D, Bit 3)
8. GND (Ground)
9. VCC (Supply Voltage)
10. MR (Master Reset)
11. QA̅ (Inverted Output A, Bit 0)
12. QB̅ (Inverted Output B, Bit 1)
13. QC̅ (Inverted Output C, Bit 2)
14. QD̅ (Inverted Output D, Bit 3)
15. TC (Terminal Count)
16. CLK INH (Clock Inhibit)

Functional Features

• Dual 4-bit decade counter with separate clock inputs and outputs for each counter
• Ripple carry output (RCO) allows cascading multiple counters
• Terminal count (TC) output indicates when the counter reaches its maximum value
• Master reset (MR) input resets the counter to zero
• Clock inhibit (CLK INH) input disables clock pulses

Advantages and Disadvantages

Advantages: - High-speed operation with a maximum clock frequency of 30 MHz - Separate clock inputs and outputs for each counter provide flexibility in cascading multiple counters - Terminal count output simplifies control logic in applications

Disadvantages: - Limited to 4-bit counting, may not be suitable for applications requiring larger counters - Requires external components for proper operation, such as clock source and control logic

Working Principles

The SN74LS390D operates as a dual 4-bit decade counter. It counts from 0 to 9 in binary-coded decimal (BCD) format. The counter advances on each rising edge of the clock input (CLK A or CLK B), depending on the state of the clock inhibit (CLK INH) input. When the counter reaches its maximum value (9), the terminal count (TC) output goes high, indicating that a full cycle has been completed.

The counter can be reset to zero by applying a low signal to the master reset (MR) input. The ripple carry output (RCO) allows multiple counters to be cascaded, enabling larger counting ranges.

Detailed Application Field Plans

The SN74LS390D is commonly used in various digital applications, including:

1. Frequency Dividers: The counter's ability to divide an input clock frequency by powers of 10 makes it suitable for frequency division applications.
2. Digital Timers: By utilizing the counter's clock inputs and outputs, precise timing intervals can be achieved.
3. Event Counters: The counter can be used to keep track of events or occurrences in systems where counting is required.
4. Industrial Control Systems: The SN74LS390D finds applications in control systems that require counting and timing functions.

Detailed and Complete Alternative Models

1. CD4017: Decade counter with 10 outputs, suitable for applications requiring larger counting ranges.
2. SN74HC393: Dual 4-bit binary ripple counter, offering similar functionality but with different characteristics.
3. CD4029: Presettable up/down counter, providing additional features such as preset capability and up/down counting modes.

These alternative models offer different features and specifications, allowing users to choose the most suitable option for their specific requirements.

In conclusion, the SN74LS390D is a dual 4-bit decade counter integrated circuit. It offers high-speed operation, separate clock inputs and outputs for each counter, and a terminal count output. While it has limitations in terms of counting range, it finds applications in various digital systems, including frequency dividers, timers, event counters, and industrial control systems. Users can also consider alternative models with different features and characteristics based on their needs.