SN74LS390N

Product Overview

• Category: Integrated Circuit (IC)
• Use: Digital Logic
• Characteristics: Dual Decade Counter/Divider with Clear and Strobe
• Package: DIP (Dual In-line Package)
• Essence: The SN74LS390N is a versatile integrated circuit used for counting and dividing signals in digital systems.
• Packaging/Quantity: Available in tubes or reels, typically containing 25 or 100 units.

Specifications

• Supply Voltage: 4.75V to 5.25V
• Operating Temperature Range: -55°C to 125°C
• Maximum Clock Frequency: 30 MHz
• Number of Pins: 16
• Logic Family: LS-TTL (Low Power Schottky Transistor-Transistor Logic)

Detailed Pin Configuration

The SN74LS390N has 16 pins, each serving a specific purpose:

1. CLK A: Clock input for counter A
2. CLK B: Clock input for counter B
3. MR (Master Reset): Active low reset input
4. Q0A: Output for the least significant bit of counter A
5. Q1A: Output for the second least significant bit of counter A
6. Q2A: Output for the third least significant bit of counter A
7. Q3A: Output for the most significant bit of counter A
8. GND: Ground reference
9. Q3B: Output for the most significant bit of counter B
10. Q2B: Output for the third least significant bit of counter B
11. Q1B: Output for the second least significant bit of counter B
12. Q0B: Output for the least significant bit of counter B
13. VCC: Positive power supply
14. STROBE: Active high strobe input
15. Q4: Output for the fourth bit of the combined counters
16. Q5: Output for the fifth bit of the combined counters

Functional Features

• Dual Decade Counter/Divider: The SN74LS390N consists of two independent decade counters, A and B, which can be used separately or combined.
• Clear Function: The MR pin allows resetting both counters to zero when pulled low.
• Strobe Function: The STROBE input enables the outputs to be latched and held in their current state until the strobe signal is deactivated.
• Cascadable: Multiple SN74LS390N ICs can be cascaded together to create larger counter configurations.

Advantages and Disadvantages

Advantages: - Versatile and flexible for various counting and dividing applications. - Low power consumption due to LS-TTL technology. - Easy to use and integrate into digital systems.

Disadvantages: - Limited maximum clock frequency compared to some modern counterparts. - DIP package may not be suitable for space-constrained designs.

Working Principles

The SN74LS390N operates by counting the rising edges of the clock signals applied to CLK A and CLK B inputs. Each counter can count from 0 to 9, and the combined counters can count up to 99. The outputs represent the binary representation of the current count value.

The clear function resets the counters to zero when the MR pin is pulled low. The strobe function allows the outputs to be latched and held in their current state until the strobe signal is deactivated.

Detailed Application Field Plans

The SN74LS390N finds applications in various digital systems where counting and dividing functions are required. Some common application areas include:

1. Frequency Division: Dividing high-frequency clock signals to obtain lower frequencies for timing purposes.
2. Event Counting: Counting events or pulses generated by sensors, switches, or other digital signals.
3. Timekeeping: Creating timers and clocks in digital circuits.
4. Digital Displays: Driving multiplexed or segmented displays, such as seven-segment displays.

Detailed and Complete Alternative Models

1. CD4017: Decade counter/divider with 10 outputs and a wide supply voltage range.
2. SN74HC393: Dual 4-bit binary counters with asynchronous reset and parallel load capability.
3. CD4020: 14-stage ripple carry binary counter/divider with built-in oscillator and reset function.

These alternative models offer similar functionality to the SN74LS390N and can be considered based on specific requirements and availability.

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