Healthcare ICs
Volume 9, Issue 8 YOUR SEMICONDUCTOR SOLUTIONS RESOURCE

Low Cost, Low Power Solutions Enable Highly Accurate, Repeatable Portable Blood Analyzers

With increasing healthcare costs, an aging population, and obesity on the rise, market demand continues to grow for more accurate, reliable, easy to use portable blood analyzers that can share data quickly and easily between patients and caregivers. For patient comfort—a competitive blood analyzer will require a minimal sample size; test time will display results in less than five seconds; and the device will support downloading results via a standard wired or wireless communication interface. Maintaining low power consumption is paramount since meters need to operate for multiple years on standard Li-Ion nonrechargeable batteries. Meters using rechargeable batteries add to the cost, and they heat during charging, thereby affecting measurement accuracy. Every design decision is affected by cost in this highly competitive market.

Solution
To improve accuracy and reliability while maintaining an appropriate balance between power consumption and size, ADI takes a systems level approach to the signal processing requirements of any portable blood analyzer design. This practice enables designs that support highly accurate repeatable diagnostic levels comparable to clinical and laboratory systems, while offering an easy to use, compact, and price-sensitive end product.

ADI can deliver a full signal chain solution for both photometric and amperometric design techniques, including innovative technologies to differentiate the device in the marketplace. These innovations easily integrate with existing technology allowing for low risk and rapid time to market.

USB port isolation is traditionally complex and costly, but it streamlines sharing vital data at any time between a home-based patient and a physician or clinic. The ADuM4160 is a USB 2.0 compliant device that provides fully isolated USB functionality at a fraction of the cost and complexity of current data isolation methods. It offers 5 kV rms medical grade isolation, upstream short-circuit protection, and fully isolated 1.5 Mbps and 12 Mbps data rates (IEC 60601-1 medical safety approvals pending). Pricing: $4.89.

The ADuC7060 is a precision analog microcontroller that incorporates two 24-bit Σ-Δ ADCs and a host of analog peripherals with a 32-bit ARM7™ core on a single chip. It includes 32 kB of flash memory and 4 kB of SRAM, a programmable gain amplifier, multiplexers, buffers, an auxiliary 24-bit ADC for cold junction compensation and interfacing to thermocouple applications, SPI (serial peripheral interface), UART (universal asynchronous receivers-transmitters), and I2C ports. The device features an industry-best ADC noise performance of just 60 nV and consumes just 2.6 mA with all peripherals activated. In addition to measurement accuracy, the ADuC7060 precision DAC is used to excite the reagent/blood mix, thereby generating a signal that is proportional to, for example, glucose. Flash allows multiday result storage. Pricing: $4.70.

The AD7682 is a true 16-bit SAR ADC with no missing codes; a 4-channel low crosstalk multiplexer that is useful for configuring the inputs as single-ended (with or without ground sense), differential, or bipolar; an internal low drift reference (selectable 2.5 V or 4.096 V) and buffer; a temperature sensor; a selectable onepole filter; and a sequencer that is useful when channels are continuously scanned in order. This device offers very low power consumption at 3 V and low sampling rates for extending the meter's battery life. Pricing: $6.01.

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Photometric Diagnostic Technique Measuring the Properties of Light, Especially Luminous Intensity

Complementary Components:

  • AD5398: 120 mA current sinking 10-bit I2C DAC (photometric approach). Pricing: $1.53.
  • AD7147A: CapTouch® programmable controller for single-electrode capacitance sensors. Pricing: $1.25.
  • AD5624: 2.7 V to 5.5 V, 450 µA, rail-to-rail output, quad, 12-bit nanoDAC® (photometric approach). Pricing: $5.56.

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