ADC0817 - 8-Bit Analog-to-Digital Converter with 16-Channel Multiplexer

Overview

The ADC0817 is a monolithic CMOS data acquisition component that integrates an 8-bit analog-to-digital converter (ADC) with a 16-channel multiplexer and microprocessor-compatible control logic. This device is designed for applications requiring high-performance analog signal acquisition and conversion. The ADC0817 employs successive approximation as its conversion technique, delivering reliable and accurate digital outputs from analog inputs.

The component features a high-impedance chopper-stabilized comparator, a 256R voltage divider with an analog switch tree, and a successive approximation register (SAR). The integrated 16-channel multiplexer allows direct access to any of 16 single-ended analog signals, with additional logic for channel expansion. The ADC0817 simplifies signal conditioning by providing direct access to both the multiplexer output and the ADC input, eliminating the need for external zero and full-scale adjustments.

Features

• 8-Bit Resolution: Provides accurate digital conversion of analog signals with 256 discrete levels.
• 16-Channel Multiplexer: Supports up to 16 single-ended analog inputs, with expandable channel options.
• Successive Approximation Conversion: Ensures fast and reliable conversion with a high-impedance comparator.
• Chopper-Stabilized Comparator: Enhances accuracy by minimizing offset errors.
• 256R Voltage Divider: Integrated resistor ladder network for precise voltage scaling.
• No External Adjustments Required: Eliminates the need for manual zero and full-scale calibration.
• Microprocessor-Compatible Interface: Features latched and decoded multiplexer addressing for seamless integration with microcontrollers and processors.
• Single +5V Supply Operation: Simplifies power supply requirements.
• CMOS Technology: Low power consumption and high noise immunity.

Applications

The ADC0817 is suitable for a wide range of applications requiring analog signal acquisition and digitization, including:

• Data Acquisition Systems: Used in industrial and laboratory environments for signal monitoring and logging.
• Process Control: Interfaces with sensors and transducers in automation and control systems.
• Medical Instrumentation: Provides analog-to-digital conversion for patient monitoring devices.
• Automotive Electronics: Supports sensor data processing in vehicle control systems.
• Consumer Electronics: Used in audio processing, instrumentation, and other analog signal applications.
• Test and Measurement Equipment: Enables precise voltage and signal measurements.

Electrical Characteristics

Absolute Maximum Ratings

• Supply Voltage (V_CC): +7V
• Analog Input Voltage Range: -0.3V to V_CC + 0.3V
• Digital Input Voltage Range: -0.3V to V_CC + 0.3V
• Operating Temperature Range: -40°C to +85°C
• Storage Temperature Range: -65°C to +150°C

Key Performance Parameters

• Resolution: 8 bits
• Conversion Time: Typically 100 µs
• Linearity Error: ±0.5 LSB (max)
• Power Consumption: 15 mW (typical)
• Input Impedance: 1 kΩ (typical)
• Reference Voltage Range: 0V to V_CC

Package Information

The ADC0817 is available in multiple package options to suit different application requirements:

• 28-Pin Plastic Dual In-Line Package (PDIP): Industry-standard through-hole mounting.
• 28-Pin Shrink Small Outline Package (SSOP): Compact surface-mount option for space-constrained designs.
• 28-Pin Ceramic Dual In-Line Package (CERDIP): High-reliability option for harsh environments.

Each package includes a built-in latch for the multiplexer address inputs, ensuring stable operation during signal acquisition.

Functional Description

Analog Multiplexer

The 16-channel multiplexer selects one of 16 single-ended analog inputs for conversion. The channel selection is controlled via a 4-bit address input, which can be latched for stable operation. The multiplexer output is directly accessible for external signal conditioning if required.

Successive Approximation ADC

The ADC0817 uses a successive approximation register (SAR) to perform the conversion. The analog input voltage is compared against a reference voltage using the internal 256R voltage divider network. The conversion process is completed in 8 clock cycles, with the result stored in an output latch.

Microprocessor Interface

The device includes control logic for easy interfacing with microprocessors. The start conversion (SC) input initiates the conversion process, while the end-of-conversion (EOC) output signals completion. The output enable (OE) pin allows the digital result to be read by the host system.

Conclusion

The ADC0817 is a versatile and high-performance 8-bit ADC with a 16-channel multiplexer, making it ideal for applications requiring multi-channel analog signal acquisition. Its integrated features, including a chopper-stabilized comparator and microprocessor-compatible interface, simplify system design while delivering reliable performance. Whether used in industrial control, medical devices, or consumer electronics, the ADC0817 provides a robust solution for analog-to-digital conversion needs.