ALD500RAU-20SEL

Analog To Digital Converters (ADC) Overview

The ALD500RAU-20SEL is a precision integrating dual-slope analog processor manufactured by Advanced Linear Devices Inc. It supports up to 18-bit resolution plus sign and over-range bits, operating on ±5V supplies with typical power dissipation of 6mW. The device features a differential analog input range of ±3.5V, high input impedance of 10^12 Ω, and low input current of 2pA. It includes an accurate on-chip voltage reference with temperature coefficients as low as 10 ppm/°C. The component utilizes a 20-pin SOIC package and operates within a commercial temperature range of 0°C to 70°C.

Analog To Digital Converters (ADC) Feature Summary

• Dual-slope integrating architecture providing inherent noise immunity and accuracy independent of source impedances
• On-chip precision voltage reference with guaranteed temperature coefficient as low as 10 ppm/°C
• Automatic zero offset compensation and internal polarity detection for bipolar signal acquisition
• Chip select power-down mode and flexible conversion speed versus resolution trade-off capabilities

Analog To Digital Converters (ADC) Applications

• 4 1/2 to 5 1/2 digits plus sign measurements
• Precision analog signal processing
• High accuracy DC measurement functions
• Portable battery operated instruments
• PCMCIA computer peripherals

Analog To Digital Converters (ADC) Procurement Notes

Verify the specific suffix 'SEL' against official manufacturer documentation to confirm packaging or tape-and-reel specifications, as standard datasheets list 'SE' for SOIC packages. Confirm that the 'RAU' designation corresponds to the 18-bit resolution variant with 0.005% linearity error. Ensure the required operating temperature range aligns with the 0°C to 70°C specification for this package type.

Analog To Digital Converters (ADC) Selection Notes

Select the ALD500RAU-20SEL when 18-bit resolution and ultra-low temperature coefficient (10 ppm/°C) are required. This variant offers better linearity (0.005%) compared to the RA (0.01%) and R (0.015%) series. Ensure the external digital controller can manage the four-phase conversion cycle including auto-zero and integrator zero phases. Verify that the application requires differential inputs and can accommodate the necessary external capacitors for integration and reference buffering.

Analog To Digital Converters (ADC) Part Context

The ALD500RAU-20SEL belongs to the ALD500R family of precision integrating analog processors. It is the highest performance variant in the series, offering 18-bit resolution. Other family members include the ALD500RA (17-bit) and ALD500R (16-bit), which offer lower resolution but potentially different cost structures. All variants share the same functional block diagram and basic interface requirements.

Analog To Digital Converters (ADC) Replacement Considerations

Direct replacements must match the 18-bit resolution, 20-pin SOIC package, and ±5V supply requirement. Variants like ALD500RAU-20SE differ only in packaging suffixes if verified; otherwise, cross-model substitution requires careful verification of pin compatibility and electrical characteristics against the original design constraints.

Analog To Digital Converters (ADC) FAQ

How does the ALD500RAU handle input noise?

The device uses a dual-slope integrating technique that inherently filters and integrates external noise spikes. It provides at least 20dB/decade attenuation and can reject interference signals at integral multiples of the integration period.

What is the function of the Integrator Zero Phase?

The Integrator Zero Phase ensures the integrator output returns to 0V after deintegration, removing any charge buildup caused by comparator delay or overshoot. This prevents degradation of performance in subsequent conversions.

Can the ALD500RAU operate with single-supply voltages?

The datasheet specifies operation on ±5V supplies. Contact the factory for other power supply operating voltage ranges, such as ±3V or ±2.5V, as these are not standard configurations listed in the primary specifications.