General Description

The MAX11161 is a 16-bit, 250ksps, SAR ADC offering excellent AC and DC performance with true unipolar input range, internal reference, and small size. The MAX11161 measures a +5V (0 to 5V) input range and can operate with a single 5V supply. The MAX11161 integrates a low drift reference with internal buffer, saving the cost and space of an external reference.

This ADC achieves 92.2dB SNR at 10kHz and -106.5dB THD. The MAX11161 guarantees 16-bit no-missing codes and ±0.8 LSB INL (typ).

The MAX11161 communicates using an SPI-compatible serial interface at 2.3V, 3V, 3.3V, or 5V logic. The serial interface can be used to daisy-chain multiple ADCs for multichannel applications and provides a busy indicator option for simplified system synchronization and timing.

The MAX11161 is offered in a 10-pin, 3mm x 5mm, µMAXM package and is specified over the -40°C to +85°C temperature range.

 

 Applications

  • Contrôle des processus industriels
  • Data Acquisition Systems
  • Medical Instrumentation
  • Équipement d'essai automatique

 

Benefits and Features

  • High DC/AC Accuracy Provides Better Measurement Quality
  • 16-Bit Resolution with No Missing Codes
  • 250ksps Throughput Rates Without Pipeline Delay/Latency
  • 92.2dB SNR and -106.5dB THD at 10kHz
  • 0.5 LSBRMS Transition Noise
  • ±0.8 LSB INL (typ) and ±0.3 LSB DNL (typ)
  • Highly Integrated ADC Saves Cost and Space
  • ±7ppm/°C Internal Reference
  • Internal Reference Buffer
  • Flexible and Low Power Supply Saves Space and Cost
  • +5V Analog and +2.3V to +5V Digital Supply
  • 31mW Power Consumption at 250ksps
  • 10µA in Shutdown Mode
  • Multi-Industry Standard Serial Interface and Small Package Reduces Size
  • SPI/QSPI™/MICROWIRE®/DSP-Compatible
  • 3mm x 5mm, Tiny 10-Pin µMAX Package

 

Description détaillée

The MAX11161 is a 16-bit single-channel, pseudo-differential ADC with maximum throughput rates of 250ksps. Both inputs (AIN+ and AIN-) are sampled with a pseudo differential on-chip track-and-hold.

This ADC includes a precision internal reference.

The MAX11161 allows for measuring an input voltage interval from 0 to 5V inputs that are protected for up to Q20mA of overrange current. This ADC is powered from a 4.75V to 5.25V analog supply (VDD) and a separate 2.3V to 5.25V digital supply (OVDD). The MAX11161 requires 1µs to acquire the input sample on an internal track-and hold and then converts the sampled signal to 16 bits of resolution using an internally clocked converter.

Analog Inputs

The MAX11161 ADC consists of a true sampling pseudo differential input stage with high-impedance, capacitive inputs. The internal T/H circuitry features a small-signal bandwidth of about 6MHz to provide 16-bit accurate sampling in 1µs. This allows for accurate sampling of a number of scanned channels through an external multiplexer.

The MAX11161 accurately converts input signals on the AIN+ input in the interval from AIN- to (+5V + AIN-). AIN+ has a max input interval from -0.1V to +5.1V. AIN- has a max input interval from -0.1V to +0.1V. The MAX11161 performs a true differential sampling on inputs between AIN+ and AIN- with good common-mode rejection.This allows for improved sampling of remote transducer inputs.

The MAX11161 includes a patented input switch architecture that allows direct sampling of high-impedance sources.

Référence

The MAX11161 includes a precision internal reference source as well as an internal reference buffer circuit to drive the converter. The internal reference buffer requires a low inductance and ESR external decoupling capacitor of at least 10µF to be placed as close as possible to the reference pin.

Input Amplifier

The conversion results are accurate when the ADC acquires the input signal for an interval longer than the input signal’s worst-case settling time. The ADC input sampling capacitor charges during the acquisition period. During this acquisition period, the settling of the sampled voltage is affected by the source resistance and the input sampling capacitance. Sampling error can be estimated by modeling the time constant of the total input capacitance and the driving source impedance.