Electronic Design

Low-Power DAS Integrates Data Converters For Signal Conditioning

The MAX1329 data-acquisition system (DAS) from Maxim Integrated Products integrates precision data converters for signal conditioning and sensor excitation. It features a 12/16-bit analog-to-digital converter (ADC), dual 12-bit force-sense digital-to-analog converters (DACs), and voltage references.

The 12-bit ADC’s fast 300-ksample/s conversion rate is ideal for profiling fast-decaying transient signals such as those from a blood glucose sensor, according to the company. For greater resolution, internal dithering and digital signal processing extend the ADC’s natural 12-bit resolution to 16 bits. High-accuracy, internal 12-bit digital-to-analog converters (DACs) (±2 LSB INL, ±1 DNL) with fast 10-µs (max) settling times also are included for sensor excitation.

These features support the intelligent microcontroller interface’s seamless connection to a low-cost microcontroller, which completes the high-performance, closed-loop system used in applications such as battery-powered and portable devices and DASs. The device’s high integration also simplifies the design process, saves board space, and gives designers much greater flexibility in their selection of microcontrollers, according to Maxim.

Furthermore, the MAX1329 integrates analog support blocks that are ideal for portable DASs, Maxim says. These analog blocks include operational amplifiers, a 16:1 input multiplexer, a programmable-gain amplifier (PGA), and low-leakage single-poll double-throw (SPDT) and single-pole single-throw (SPST) solid-state switches. The 1-V/V to 8-V/V PGA provides a wide, dynamic measurement range to measure low-level signals.

An integrated oscillator offers a 32-kHz clock for timekeeping. A configurable frequency-locked loop (FLL) generates the high-speed clock necessary for driving a host microcontroller. Other support features include dual voltage monitors, temperature measurement (internal and external temperature sensors), user-programmable general-purpose I/Os that can be used to output system interrupts, control switches, and drive shutdown.

Optimized for battery-powered applications, the MAX1329 operates from a 1.8- to 3.6-V digital supply and a 2.7- to 5.5-V analog supply. An on-chip charge pump provides a 5-V supply up to 25 mA to power other circuitry. With all of the analog blocks enabled, the MAX1329 has a quiescent supply current of 3.75 mA (typical) that drops to 0.5 µA (typical) in shutdown mode.

The MAX1329 is specified for the extended temperature range of –40°C to 85°C. It’s available in a 6- by 6-m, 40-pin, thin quad flat no-lead (TQFP) package. Prices start at $7.49 in quantities of 1000 and up.

Maxim Integrated Products


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