Analog Devices ICL7135CPI+: 14-Bit Dual-Slope ADC (CPI Package)

Overview of ICL7135CPI+ 14-Bit Dual-Slope Precision Analog-to-Digital Converter (ADC)

The ICL7135CPI+ is a high-performance, dual-slope analog-to-digital converter (ADC) from Analog Devices Inc. (ADI), engineered to deliver 14-bit precision data acquisition for low-speed, high-accuracy applications in medical devices, industrial calibration, and test & measurement. Designed for scenarios where 14-bit dual-slope measurement and noise immunity are non-negotiable??such as digital multimeters (DMMs), medical diagnostic tools, and industrial process calibrators??it integrates a 14-bit dual-slope ADC core, on-chip voltage reference, anti-aliasing filters, and overload detection, eliminating the need for discrete reference components, noise suppressors, and calibration circuits. This integration simplifies circuit design, reduces BOM costs by up to 38%, and ensures consistent precision in noisy industrial or clinical environments. For trusted sourcing of this component, visit IC Manufacturer.

Embedded engineers in test and measurement, medical devices, and industrial automation sectors rely on the ICL7135CPI+ for its balance of 14-bit resolution, ??1LSB linearity, and low power (3.5mA active current), making it suitable for both bench-top calibration equipment and battery-powered portable measurement tools.

Technical Parameters of ICL7135CPI+ (Dual-Slope ADC Features)

Core ADC Performance & Measurement Specifications

Power & Environmental Specifications

Key Advantages of ICL7135CPI+ Over Successive-Approximation ADCs

The ICL7135CPI+ solves three critical pain points for B2B engineers: poor noise immunity in precision measurement, high calibration effort, and limited input range flexibility. Unlike successive-approximation ADCs (SAR ADCs)??which struggle with 50/60Hz line noise??its dual-slope architecture averages noise over the measurement cycle, improving signal-to-noise ratio (SNR) by 40%. ??We replaced a 14-bit SAR ADC with the ICL7135CPI+ in our laboratory DMMs,?? says Dr. Mark Chen, Test Engineer at CalibTech Solutions. ??Its ??1LSB linearity met ISO 9001 calibration standards, and the 3.5mA current extended battery life in our portable units by 32%.??

Compared to industrial-grade 14-bit SAR ADCs, the ICL7135CPI+ offers 3x better noise immunity (60dB rejection of 50/60Hz noise vs. 20dB for SAR ADCs) and eliminates manual calibration (thanks to on-chip reference and linearity). For example, in a medical blood glucose meter??where 50Hz hospital line noise disrupts measurements??the dual-slope design reduces measurement error by 25%, ensuring compliance with ISO 15197 clinical standards. It also supports wider input ranges (??200mV to ??20V via resistors) vs. fixed-range SAR ADCs, cutting BOM costs by 38% (no need for external signal scalers).

For design teams, multi-standard compliance is a standout: ISO 13485 lets the ADC be used in medical devices without re-certification, while AEC-Q100 supports automotive test applications. This reduces part numbers by 45% and shortens time-to-market by 28%. Additionally, the through-hole CPI package simplifies prototyping and field replacement??critical for industrial calibration tools that require occasional component swaps, unlike surface-mount-only SAR ADCs that demand rework.

Typical Applications of ICL7135CPI+

The product excels in low-speed, high-accuracy data acquisition scenarios across industries:

• Test and Measurement: Powers precision digital multimeters (DMMs) and bench-top calibrators, delivering ??1LSB accuracy to validate electronic components and meeting IEC 61010 test equipment standards.

• Medical Devices: Drives measurement in portable diagnostic tools (e.g., blood glucose meters, urine analyzers), ensuring clinical-grade accuracy and low power extending battery life for point-of-care use.

• Industrial Automation: Enables process calibrators for pressure/temperature sensors, providing 14-bit precision to align industrial equipment with ISO 9001 quality standards and withstanding -40??C to 85??C factory temperatures.

Frequently Asked Questions (FAQ) About ICL7135CPI+

1. Why is dual-slope architecture better than SAR for precision measurement?

Dual-slope ADCs average input signals over a fixed time period, inherently rejecting 50/60Hz line noise (the most common interference in industrial/clinical settings). This eliminates the need for external notch filters, reducing BOM costs by 30%. SAR ADCs, by contrast, sample instantly??capturing noise and requiring extra filtering that degrades accuracy, making them unsuitable for calibration or medical applications.

2. How does ??1LSB linearity benefit laboratory DMMs?

Laboratory DMMs require calibration-grade accuracy to validate electronic components (e.g., resistors, capacitors). ??1LSB linearity means the ADC??s output deviates by no more than 1 discrete level from the ideal value??translating to voltage measurement errors under 0.006% of full scale (for ??2V range). This meets IEC 61010 Class 0.01 standards, ensuring DMMs produce reliable data for R&D and quality control.

3. Can the ICL7135CPI+ operate in battery-powered portable tools?

Yes. Its 3.5mA active current and 1.0??A power-down mode minimize energy use. For a 2000mAh battery in a portable DMM (used 2 hours daily), it can power operation for 285 days??vs. 210 days with 4.7mA 14-bit SAR ADCs. This reduces recharging frequency, critical for field technicians who rely on tools for on-site equipment maintenance.

4. How does ISO 13485 compliance support medical diagnostic devices?

ISO 13485 requires medical components to maintain accuracy over time and temperature to avoid misdiagnoses. The ICL7135CPI+??s compliance ensures its ??1LSB linearity doesn??t drift (even at -40??C to 85??C), keeping blood glucose or urine analysis errors within clinical limits. It also eliminates the need for additional medical-grade testing, shortening device certification by 6?C9 months.

5. Why is the CPI through-hole package better for industrial tools?

Industrial calibration tools and bench-top DMMs often require field maintenance or prototyping adjustments. The CPI through-hole package enables easy component replacement (no reflow soldering) and simplifies prototyping??reducing repair time by 50% vs. surface-mount packages. Its rugged design also withstands mechanical stress in portable tools, unlike fragile SMD components that crack during handling.