ICL7117CPL: High-Performance Dual-Slope ADC with 3.5-Digit Resolution

The ICL7117CPL by Harris Corporation is a precision analog-to-digital converter (ADC) engineered for applications demanding high accuracy and reliability. This 3.5-digit dual-slope ADC integrates a display driver, making it a versatile solution for digital panel meters, industrial systems, and test equipment. In this comprehensive guide, we explore its features, specifications, and applications to help you leverage its full potential.

Introduction to the ICL7117CPL

Manufacturer and Availability

Manufactured by Harris Corporation, a pioneer in semiconductor technology, the ICL7117CPL remains an Active product, ensuring long-term availability for your projects.

Product Category

This IC belongs to the Data Acquisition - ADCs/DACs - Special Purpose category, specifically designed as a Display Driver with integrated ADC functionality.

Detailed Technical Specifications

Core Features

• Type: Display Driver with Integrated ADC
• Channels: 1 Channel
• Resolution: 3.5 Digits (High Precision)
• Architecture: Dual-Slope ADC (Noise-Resistant)
• Data Interface: Flexible (Customizable Integration)

Power and Operating Conditions

• Voltage Supply: Single 5V Operation
• Operating Temperature: 0 C to 70 C (Industrial Grade)

Physical Attributes

• Mounting Type: Through Hole (Easy PCB Integration)
• Package: 40-DIP (0.600", 15.24mm) (Robust Construction)

Advanced Applications

The ICL7117CPL excels in precision-critical applications:

1. Digital Panel Meters

Provides stable, accurate readings for voltage, current, or temperature displays in industrial and consumer devices.

2. Industrial Control Systems

Ensures reliable feedback for process automation with its noise-resistant dual-slope architecture.

3. Laboratory Equipment

Enables high-accuracy measurements in multimeters, data loggers, and calibration instruments.

Competitive Advantages

Precision Engineering

The 3.5-digit resolution delivers 1 count accuracy, superior to basic ADCs.

Dual-Slope Technology

Eliminates noise sensitivity common in successive-approximation ADCs.

Design Flexibility

Single 5V supply simplifies power architecture versus dual-supply competitors.

Technical Deep Dive

Dual-Slope Conversion Process

The IC first integrates the input signal for a fixed time, then de-integrates using a reference voltage. This method inherently rejects line-frequency noise (50/60Hz).

Display Drive Capabilities

Directly interfaces with 3.5-digit LCD/LED displays, reducing external component count.

Auto-Zero Cycle

Automatically compensates for offset voltages, maintaining accuracy over temperature.

Design Considerations

Reference Voltage Selection

For optimal performance:

• Use 1V reference for full 1999 count range
• Ensure reference stability with low-TC components

PCB Layout Guidelines

• Keep analog traces short and away from digital lines
• Use ground planes for noise reduction
• Decouple power pins with 100nF ceramic capacitors

Comparison with Modern Alternatives

Feature	ICL7117CPL	Modern Sigma-Delta ADC
Resolution	3.5 Digits	16-24 Bits
Speed	3-10 Samples/sec	1k-100k Samples/sec
Noise Rejection	Excellent	Good
Display Drive	Integrated	Requires External Driver

Purchasing Information

Available through authorized distributors with full manufacturer support. Bulk pricing available for production quantities.

Conclusion

The ICL7117CPL remains a cost-effective solution for applications prioritizing precision over speed. Its integrated display driver and proven architecture make it ideal for upgrading legacy designs or new developments where 3.5-digit resolution suffices.

For engineers seeking reliable performance without complex digital interfaces, this Harris IC delivers exceptional value. Its 40-year production history stands as testament to its enduring utility in measurement systems worldwide.