LM556CM

Product Overview

Category: Integrated Circuit (IC)

Use: Timer and oscillator applications

Characteristics: - Dual timer with independent control circuits - Wide operating voltage range: 4.5V to 16V - Low power consumption - High output current capability - Can operate in astable or monostable mode - Temperature stability: ±0.005% per °C

Package: SOIC (Small Outline Integrated Circuit)

Essence: The LM556CM is a dual timer IC that provides two independent 555 timers in a single package.

Packaging/Quantity: The LM556CM is available in a standard SOIC package. It is typically sold in reels of 2500 units.

Specifications

• Supply Voltage Range: 4.5V to 16V
• Supply Current:
  • Quiescent Current: 500µA (typical)
  • Output Current: 200mA (maximum)
• Operating Temperature Range: -40°C to +85°C
• Timing Error: ±2% (maximum)
• Trigger Voltage:
  • Low Level: 1.33V (maximum)
  • High Level: 3.67V (minimum)
• Threshold Voltage:
  • Low Level: 0.67V (maximum)
  • High Level: 2.33V (minimum)

Pin Configuration

The LM556CM has a total of 16 pins, which are assigned as follows:

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

Functional Features

• Dual independent 555 timers in a single package
• Can be used as a monostable or astable multivibrator
• Wide operating voltage range allows for versatile applications
• Low power consumption makes it suitable for battery-powered devices
• High output current capability enables driving of external components
• Temperature stability ensures accurate timing over a wide temperature range

Advantages and Disadvantages

Advantages: - Dual timer functionality saves board space and cost - Versatile operation modes for various timing applications - Wide operating voltage range allows for compatibility with different power sources - High output current capability enables direct driving of loads - Temperature stability ensures reliable performance in different environments

Disadvantages: - Limited number of timing options compared to more complex timer ICs - Requires external components for certain applications - Not suitable for high-frequency timing applications

Working Principles

The LM556CM is based on the popular 555 timer IC architecture. It consists of two independent 555 timers, each capable of generating precise timing signals. The timers can operate in either monostable or astable mode, depending on the application requirements.

In monostable mode, a trigger signal applied to the TRIG input initiates a timing cycle. The output remains high for a fixed duration determined by external resistors and capacitors. In astable mode, the timers continuously oscillate between high and low states, generating a square wave output with a frequency determined by external components.

The LM556CM provides control voltage inputs (CTRL A and CTRL B) that allow for modulation of the timing characteristics. The threshold (THRES A/B) and reset (RESET A/B) inputs provide additional control over the timing cycle.

Detailed Application Field Plans

The LM556CM is widely used in various applications that require precise timing and oscillation control. Some common application fields include:

1. Pulse Width Modulation (PWM): The LM556CM can be used to generate variable-width pulses for controlling motor speed, LED brightness, or audio volume.
2. Timing Delays: It is commonly employed in applications requiring time delays, such as traffic light control systems, sequential circuitry, and delay circuits for electronic devices.
3. Frequency Generation: The astable mode of operation allows the LM556CM to generate square wave signals with adjustable frequencies, making it suitable for applications like tone generation, frequency synthesis, and clock generation.
4. Precision Timing: The LM556CM's temperature stability and accuracy make it ideal for applications that require precise timing, such as timers, alarms, and precision measurement instruments.

Detailed and Complete Alternative Models

• NE556: