LM1496N

LM1496N Balanced Modulator-Demodulator

Overview

The LM1496N is a high-performance, double-balanced modulator-demodulator integrated circuit designed for precision signal processing applications. It produces an output voltage proportional to the product of an input signal voltage and a switching (carrier) signal. This device is part of the LM1496/LM1596 family, known for their excellent carrier suppression and wide frequency response. The LM1496N is widely used in communication systems, RF applications, and signal processing circuits where accurate modulation or demodulation is required.

Key Features

• Excellent Carrier Suppression: 65 dB typical at 0.5 MHz, 50 dB typical at 10 MHz
• Adjustable Gain and Signal Handling: Allows for flexible circuit design
• Fully Balanced Inputs and Outputs: Reduces noise and improves signal integrity
• Low Offset and Drift: Ensures stable operation over temperature and time
• Wide Frequency Response: Up to 100 MHz, suitable for high-frequency applications
• Versatile Applications: Supports modulation, demodulation, frequency doubling, and more

Applications

The LM1496N is used in a variety of signal processing and communication applications, including:

• Suppressed Carrier Modulation: Ideal for DSB-SC (Double Sideband Suppressed Carrier) systems
• Amplitude Modulation (AM): Can be configured for standard AM signal generation
• Synchronous Detection: Used in coherent demodulation of AM and SSB signals
• FM or PM Detection: Suitable for phase-sensitive demodulation
• Broadband Frequency Doubling: Efficiently doubles input frequencies
• Signal Mixing: Functions as a high-performance analog multiplier

Electrical Characteristics

The following table summarizes the key electrical specifications of the LM1496N:

• Supply Voltage (V+): ±12V (typical), ±15V (maximum)
• Input Signal Voltage Range: ±300 mV (typical)
• Carrier Input Voltage Range: ±60 mV (typical)
• Output Voltage Swing: ±2.5V (minimum into 1kΩ load)
• Carrier Suppression: 65 dB at 0.5 MHz, 50 dB at 10 MHz
• Frequency Response: DC to 100 MHz (-3dB)
• Power Consumption: 170 mW (typical at ±12V)
• Operating Temperature Range: -55°C to +125°C

Package Information

The LM1496N is available in two package options:

• 14-Pin DIP (Dual Inline Package):
  • Package Code: N (for DIP)
  • Dimensions: 19.3mm x 6.35mm (typical)
  • Pin Spacing: 2.54mm (standard DIP spacing)
• Metal Can Package (TO-100):
  • Package Code: H (for metal can)
  • Dimensions: 9.08mm diameter (typical)
  • 10-pin configuration (Note: Pin 10 is connected electrically to the case)

Schematic and Connection Diagrams

The LM1496N features a well-optimized internal architecture for balanced operation:

• DIP Package Pinout:
  • Pins 1,4: Carrier Inputs
  • Pins 2,3: Signal Inputs
  • Pins 5,6: Bias and Gain Adjust
  • Pins 7,8: Negative Supply and Ground
  • Pins 9,10: Output
  • Pins 11,12: Positive Supply and Balance Adjust
  • Pins 13,14: Additional Bias Connections
• Metal Can Package Pinout: Follows a circular arrangement with pin 10 connected to the case

Design Considerations

When implementing the LM1496N in circuit designs, consider the following:

• Impedance Matching: Proper termination of inputs and outputs is critical for optimal performance
• Power Supply Decoupling: Use 0.1μF ceramic capacitors close to the supply pins
• Thermal Management: The metal can package offers better thermal performance for high-power applications
• Balance Adjustment: External potentiometers can be used to fine-tune the balance for maximum carrier suppression
• Grounding: Use a star grounding scheme to minimize noise coupling

Typical Performance Characteristics

The LM1496N exhibits several key performance attributes:

• Linearity: Excellent linearity in the specified input voltage ranges
• Noise Performance: Low noise figure makes it suitable for sensitive receiver applications
• Temperature Stability: Minimal performance variation across the operating temperature range
• Long-Term Reliability: Robust design ensures consistent performance over time

Conclusion

The LM1496N remains a versatile and reliable choice for balanced modulation and demodulation applications. Its excellent carrier suppression, wide bandwidth, and flexible configuration options make it suitable for both traditional and modern communication systems. Whether used in amateur radio equipment, professional broadcasting systems, or test and measurement applications, the LM1496N delivers consistent, high-quality performance.