Analog Devices Inc./Maxim Integrated MAX189AEWE

Overview

MAX189AEWE from Maxim Integrated is a 12-bit successive-approximation analog-to-digital converter (ADC) operating from a single +5V supply, accepting 0 to 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 MAX189AEWE datasheet, MAX189AEWE pinout, MAX189AEWE application, or MAX189AEWE equivalent, this page delivers verified electrical specs, validated package mapping (16-pin wide SO), confirmed pin functions, real-world timing behavior (tACQ = 1.5µs, tCONV = 5.5–8.5µs), and two field-tested alternative ADCs with documented functional trade-offs.

Technical Context

The MAX189AEWE implements a capacitor-based SAR architecture with integrated track/hold, eliminating need for external hold capacitors. Its conversion cycle begins on CS falling edge, completes in 5.5–8.5µs, and outputs 12-bit unipolar data plus leading EOC bit via DOUT on SCLK falling edges.

It uses an external reference applied to the REF pin (2.5V to VDD), with input impedance ≥12kΩ and max DC load current of 350µA during conversion. Shutdown mode reduces supply current to ≤10µA, with wake-up time dependent on external REF bypass capacitor discharge.

Key Specifications

Pinout & Package

MAX189AEWE is supplied in a 16-pin wide SO (SOIC-W) package with exposed pad (not electrically connected). Pin functions are validated per Maxim's official pin description table and functional diagram.

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 MAX189AEWE uniquely balances external reference support, QSPI/MICROWIRE compatibility, industrial temperature rating, and ultra-low shutdown current-making it optimal for isolated, battery-backed, or reference-critical 12-bit acquisition where interface flexibility and power efficiency are primary constraints.

Availability

MAX189AEWE is available at Aetrix Electronics and suitable for portable data logging, remote digital signal processing, and isolated data acquisition requiring stable component supply, long-term lifecycle assurance, and traceable sourcing.

Supply support for MAX189AEWE 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 MAX189AEWE belongs to Maxim's low-power serial ADC product line, engineered specifically for space-constrained, battery-operated, and electrically isolated measurement systems demanding high DC accuracy and robust serial interfacing.

FAQ

What is the reference voltage requirement for MAX189AEWE?

The MAX189AEWE requires an external reference voltage applied to the REF pin, ranging from +2.5V to VDD (+5V). It does not include an internal reference. The reference must supply up to 350µA DC load current during conversion and exhibit ≤10Ω output impedance for specified accuracy. A 0.1µF bypass capacitor is mandatory at the REF pin; a 4.7µF capacitor is recommended if the reference is noisy or has higher output impedance. This design allows precise system-level reference selection independent of the MAX189AEWE's internal circuitry.

Does MAX189AEWE support SPI, QSPI, and MICROWIRE interfaces simultaneously?

Yes, the MAX189AEWE's 3-wire serial interface is electrically and logically compatible with SPI, QSPI, and MICROWIRE standards without hardware modification. It operates with CPOL = 0 and CPHA = 0 for all three protocols. For SPI/QSPI, 13 clock cycles are required to read the full 12-bit result plus leading EOC bit. MICROWIRE compatibility is confirmed by its unidirectional DOUT, active-low CS, and SCLK-driven timing - enabling direct connection to microcontrollers supporting any of these industry-standard serial interfaces.

What is the maximum analog input frequency supported by MAX189AEWE?

The MAX189AEWE has a 4.5MHz small-signal bandwidth and a 75ksps sampling rate, limiting its fundamental Nyquist frequency to 37.5kHz. While it can accurately digitize sinusoidal inputs up to ~37.5kHz, higher frequencies may be captured using undersampling techniques - provided anti-alias filtering removes out-of-band energy. The device's 0.8MHz full-power bandwidth and 8V/µs slew rate further constrain large-signal fidelity. For reliable full-scale accuracy, input signals should remain below 37.5kHz unless undersampling methodology and appropriate filtering are implemented.

How does shutdown mode affect conversion timing in MAX189AEWE?

In shutdown mode, the MAX189AEWE draws ≤10µA supply current and halts internal clocking and conversion circuitry. Wake-up time depends on the external reference bypass capacitor's discharge state: since the MAX189AEWE uses an external reference (not internal bandgap), tWAKE is effectively zero - conversion can begin immediately after SHDN is deasserted and CS is pulsed, unlike the MAX187 which requires ~2µs for internal reference stabilization. This makes the MAX189AEWE especially suitable for burst-mode acquisition where rapid on-demand sampling is required after extended sleep periods.

What are the absolute maximum ratings for the AIN pin of MAX189AEWE?

The MAX189AEWE AIN pin has an absolute maximum rating of –0.3V to (VDD + 0.3V), meaning it tolerates –0.3V to +5.3V with VDD = +5V. However, for accurate conversion near full scale, the input must stay within GND – 0.05V to VDD + 0.05V (i.e., –50mV to +5.05V). Exceeding these limits risks degraded linearity or damage. If the input swings beyond ±50mV of the supply rails, input current must be limited to ≤2mA using series resistance to prevent accuracy loss - a requirement confirmed in the device's Absolute Maximum Ratings and Applications Information sections.