ADC1205/ADC1225 12-Bit Plus Sign CMOS Analog-to-Digital Converter

Overview

The ADC1205 and ADC1225 are high-performance, 12-bit plus sign analog-to-digital converters (ADCs) fabricated in CMOS technology. These devices are designed to provide accurate digital conversion of analog signals while maintaining low power consumption. With their true differential analog voltage inputs and wide operating voltage range, they are suitable for a variety of precision measurement applications. The ADCs are compatible with all microprocessors and feature TTL/MOS input/output compatibility, making them versatile for both industrial and embedded systems.

Key Features

• Microprocessor Compatibility: Direct interface with all microprocessors without additional glue logic
• True Differential Inputs: Supports differential analog voltage inputs for improved noise rejection
• Wide Voltage Range: 0V to 5V analog input range with single 5V supply operation
• TTL/MOS Compatible I/O: Seamless integration with both TTL and MOS logic families
• Low Power Consumption: Maximum power dissipation of 25mW for energy-efficient designs
• Standard Package Options: Available in 24-pin or 28-pin Dual-In-Line (DIP) packages
• TRI-STATE Outputs: Allows for bus sharing in multi-device systems

Applications

The ADC1205 and ADC1225 are ideal for applications requiring precise analog-to-digital conversion. Common use cases include:

• Industrial process control systems
• Data acquisition systems
• Medical instrumentation
• Automotive sensing and control
• Precision measurement equipment
• Embedded control systems
• Audio signal processing

Electrical Characteristics

Absolute Maximum Ratings

Note: Exceeding these ratings may cause permanent device damage.

• Supply Voltage (V_CC): -0.3V to +7V
• Analog Input Voltage: -0.3V to V_CC + 0.3V
• Digital Input Voltage: -0.3V to V_CC + 0.3V
• Operating Temperature Range:
  • Commercial: 0°C to +70°C
  • Industrial: -40°C to +85°C
  • Military: -55°C to +125°C (when specified)
• Storage Temperature Range: -65°C to +150°C
• Lead Soldering Temperature: 260°C for 10 seconds

Recommended Operating Conditions

• Supply Voltage (V_CC): 4.75V to 5.25V
• Analog Input Voltage Range: 0V to 5V
• Clock Frequency: 100kHz to 800kHz
• Reference Voltage: 2.5V nominal

DC Characteristics (V_CC = 5V ±5%, T_A = 25°C)

• Resolution: 12 bits plus sign
• Integral Nonlinearity: ±1 LSB max
• Differential Nonlinearity: ±1/2 LSB max
• Zero Error: ±2 LSB max
• Full-Scale Error: ±2 LSB max
• Power Consumption: 25mW max
• Input Leakage Current: ±1μA max

AC Characteristics

• Conversion Time: 12μs typical
• Throughput Rate: 83k samples/second max
• Aperture Delay: 50ns max
• Signal-to-Noise Ratio: 72dB min

Package Information

24-Pin Dual-In-Line Package (DIP)

• Package Code: N24A
• Dimensions: 0.600" x 1.275" (15.24mm x 32.39mm)
• Pin Pitch: 0.100" (2.54mm)
• Lead Material: Alloy 42 or copper alloy
• Lead Finish: Solder plate or gold plate

28-Pin Dual-In-Line Package (DIP)

• Package Code: N28A
• Dimensions: 0.600" x 1.400" (15.24mm x 35.56mm)
• Pin Pitch: 0.100" (2.54mm)
• Lead Material: Alloy 42 or copper alloy
• Lead Finish: Solder plate or gold plate

Functional Description

The ADC1205/ADC1225 employs a successive approximation conversion technique to achieve 12-bit plus sign resolution. The device features a built-in sample-and-hold circuit that acquires the analog input signal during the conversion process. The true differential input architecture provides excellent common-mode rejection, making these converters suitable for noisy environments.

The digital interface includes TRI-STATE outputs for easy bus connection in microprocessor-based systems. A conversion start input initiates the conversion cycle, and a busy output signal indicates when the conversion is in progress. The end-of-conversion signal can be used to interrupt the host processor or trigger data transfer.

Ordering Information

Conclusion

The ADC1205 and ADC1225 provide a cost-effective solution for high-precision analog-to-digital conversion in a variety of applications. With their combination of high accuracy, low power consumption, and microprocessor compatibility, these converters offer excellent performance for demanding measurement and control systems. The availability in standard DIP packages facilitates easy prototyping and system integration.