Analog Devices Inc./Maxim Integrated MAX189BEWE

Overview

MAX189BEWE from Maxim Integrated is a 12-bit successive-approximation analog-to-digital converter (ADC) operating from a single +5V supply, accepting 0–5V unipolar analog input, featuring internal track/hold, 75ksps throughput, and SPI/QSPI/MICROWIRE-compatible 3-wire serial interface. It requires an external reference voltage (2.5V to VDD), supports industrial temperature range (–40°C to +85°C), and targets low-power sensor and remote data acquisition systems.

For engineers reviewing the MAX189BEWE datasheet, MAX189BEWE pinout, MAX189BEWE application, or MAX189BEWE equivalent, this page delivers verified electrical parameters, package mapping, functional pin roles, real-world use scenarios, and two confirmed alternative parts - all grounded in Maxim's official documentation for the MAX189BEWE variant.

Technical Context

The MAX189BEWE implements a 12-bit SAR architecture with integrated track/hold, acquiring signals in ≤1.5µs and completing conversion in 5.5–8.5 clock cycles (t_CONV). Its serial interface operates with SCLK up to 5MHz, uses CS falling edge to initiate conversion, and outputs MSB-first unipolar data preceded by an EOC high bit.

It relies on an externally supplied reference (2.5V to VDD), draws 1.0–2.0mA during operation and ≤10µA in shutdown, and features separate AGND/DGND pins in its 16-pin wide SO package - enabling noise-sensitive mixed-signal layouts without internal reference buffering.

Key Specifications

Pinout & Package

MAX189BEWE is housed in a 16-pin wide SO (SOIC-W) package with exposed pad (not thermally enhanced per datasheet), pin-compatible with MAX187 variants but omitting internal reference circuitry. Pin functions are electrically validated per Maxim's Pin Description table and functional diagrams.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 12-bit serial ADC applications.

Compared with ADS7822U and AD7490BRUZ, the MAX189BEWE uniquely balances external reference adaptability, 3-wire protocol versatility (SPI/QSPI/MICROWIRE), industrial temperature rating, and ultra-low shutdown current - making it optimal for isolated, battery-constrained, or reference-flexible precision acquisition.

Availability

MAX189BEWE is available at Aetrix Electronics and suitable for portable data logging, remote DSP, isolated data acquisition, and high-accuracy process control requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for MAX189BEWE includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Maxim Integrated (now part of Analog Devices) designs precision analog, mixed-signal, and power management ICs for industrial, medical, and communications applications.

The MAX189BEWE belongs to Maxim's legacy low-power serial ADC product line, engineered specifically for space-constrained, low-quiescent-current systems needing flexible reference architecture and robust serial interfacing without external timing components.

FAQ

What reference voltage range does the MAX189BEWE support?

The MAX189BEWE accepts an external reference voltage from +2.5V to VDD (up to +5.25V). For guaranteed DC accuracy, the reference must deliver ≤350µA load current and exhibit ≤10Ω output impedance. A 0.1µF bypass capacitor is required at the REF pin; a 4.7µF capacitor is recommended if the reference is noisy or has higher output impedance. The MAX189BEWE does not include an internal reference.

Does the MAX189BEWE require an external track/hold amplifier?

No, the MAX189BEWE integrates a track/hold circuit with ≤1.5µs acquisition time. Its 16pF input capacitance and internal sampling capacitor eliminate the need for an external track/hold amplifier in most applications. However, source impedance driving AIN must remain below 5kΩ to maintain full 75ksps throughput and AC performance - op amps like the MAX427 or OP27 are recommended for high-frequency or high-Z sources.

How does the MAX189BEWE interface with an SPI master controller?

The MAX189BEWE supports SPI mode 0,0 (CPOL = 0, CPHA = 0). A CS falling edge initiates conversion; DOUT goes low during conversion and rises to signal end-of-conversion (EOC). After EOC, 13 SCLK falling edges shift out 12 data bits (MSB first), preceded by a leading high bit. Data is valid on SCLK's falling edge and can be latched on the rising edge. No external pull-ups or level shifters are needed for 5V-tolerant controllers.

What is the maximum sampling frequency supported by the MAX189BEWE?

The MAX189BEWE achieves a maximum throughput rate of 75ksps, corresponding to a Nyquist frequency of 37.5kHz. While its small-signal bandwidth is 4.5MHz, input signals above 37.5kHz will alias unless undersampling techniques and appropriate anti-alias filtering are applied. For baseband applications, the practical maximum sinusoidal input frequency is 37.5kHz to avoid aliasing artifacts in the digitized output.

Can the MAX189BEWE operate in shutdown mode between conversions to save power?

Yes, pulling the SHDN pin low places the MAX189BEWE in shutdown mode, reducing supply current to ≤10µA. Conversion resumes within <1µs after SHDN is deasserted (since no internal reference must stabilize). This feature is ideal for duty-cycled systems such as wireless sensor nodes, where average current consumption scales linearly with sampling interval - enabling multi-year battery life in low-duty-cycle deployments.