SA556D

Product Overview

• Category: Integrated Circuit
• Use: Timer and Oscillator
• Characteristics: Dual Precision Timer
• Package: DIP (Dual In-line Package)
• Essence: The SA556D is a dual precision timer integrated circuit that combines two independent 555 timers in a single package.
• Packaging/Quantity: Available in tubes or reels, with 25 units per tube/reel.

Specifications

• Supply Voltage Range: 4.5V to 16V
• Operating Temperature Range: -40°C to +85°C
• Output Current: 200mA
• Maximum Power Dissipation: 600mW
• Trigger Voltage: 1.67V
• Reset Voltage: 0.7V
• Timing Error: ±2%
• Timing Capacitance Range: 100pF to 100μF

Pin Configuration

The SA556D has a total of 14 pins, which are assigned as follows:

1. GND (Ground)
2. TRIG (Trigger Input A)
3. OUT (Output A)
4. RESET (Reset Input A)
5. CTRL (Control Voltage A)
6. THRES (Threshold Input A)
7. DISCH (Discharge Output A)
8. VCC (Positive Supply Voltage)
9. DISCH (Discharge Output B)
10. THRES (Threshold Input B)
11. CTRL (Control Voltage B)
12. RESET (Reset Input B)
13. OUT (Output B)
14. TRIG (Trigger Input B)

Functional Features

• Dual Independent Timers: The SA556D integrates two separate 555 timers, allowing for simultaneous operation or independent timing functions.
• Wide Supply Voltage Range: The IC can operate within a supply voltage range of 4.5V to 16V, providing flexibility in various applications.
• High Output Current: With a maximum output current of 200mA, the SA556D can drive a wide range of loads.
• Accurate Timing: The timing error is limited to ±2%, ensuring precise timing control.
• Adjustable Timing Capacitance: The timing capacitance can be varied from 100pF to 100μF, enabling a wide range of timing intervals.

Advantages and Disadvantages

Advantages

• Dual timer functionality in a single package saves board space and reduces component count.
• Wide supply voltage range allows for compatibility with different power sources.
• Accurate timing control ensures reliable operation in time-critical applications.
• Adjustable timing capacitance provides flexibility in setting desired timing intervals.

Disadvantages

• Limited output current may not be suitable for high-power applications.
• Requires external components (resistors, capacitors) for complete timer functionality.

Working Principles

The SA556D operates based on the principles of the classic 555 timer. Each timer consists of comparators, flip-flops, and a discharge transistor. The timing interval is determined by the charging and discharging of an external capacitor through resistors connected to the control voltage pin. The trigger and threshold inputs control the timing cycle, while the reset input resets the timer. The output stage can drive loads directly or interface with other circuitry.

Detailed Application Field Plans

The SA556D finds applications in various fields, including:

1. Precision Timing: Used in precision clocks, timers, and frequency generators.
2. Pulse Generation: Generates accurate pulses for applications like waveform generation, pulse-width modulation, and frequency division.
3. Oscillator Circuits: Provides stable oscillation for applications such as tone generation, frequency synthesis, and clock synchronization.
4. Sequential Logic Timers: Enables sequential logic circuits, counters, and sequential event control.
5. Motor Control: Used in motor speed control, time-delay circuits, and motor-driven actuators.

Detailed and Complete Alternative Models

1. NE556: Similar to SA556D, but available in different package options.
2. LM556: Dual timer IC with similar functionality, manufactured by Texas Instruments.
3. ICM7556: CMOS version of the dual timer, offering low power consumption and extended temperature range.

These alternative models provide similar features and can be used as replacements for the SA556D in various applications.

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