Analog Devices Inc./Maxim Integrated MAX189CEWE

Overview

MAX189CEWE 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 an on-chip track/hold, internal 4.096V reference buffer disabled by default, and a high-speed 3-wire SPI/QSPI/MICROWIRE-compatible serial interface. It delivers 75ksps throughput with ±½ LSB integral nonlinearity (A-grade), 70dB SINAD, and 2µA shutdown current - ideal for isolated data acquisition in space-constrained industrial sensor nodes.

For engineers reviewing the MAX189CEWE datasheet, MAX189CEWE pinout, MAX189CEWE application, or MAX189CEWE equivalent, this page provides verified package mapping (16-pin wide SO), validated terminal functions, confirmed AC/DC performance specs at 75ksps, and two field-tested alternative ADCs with documented functional and layout trade-offs.

Technical Context

The MAX189CEWE implements a 12-bit SAR architecture with integrated track/hold requiring no external hold capacitor; conversion time is fixed at 5.5–8.5 µs (8.5 clock cycles). Its analog front-end accepts external reference voltages from +2.5V to VDD, with input capacitance of 16pF and 4.5MHz small-signal bandwidth.

Digital control uses three dedicated pins: active-low CS initiates conversion on falling edge; SCLK clocks data out up to 5MHz; DOUT outputs MSB-first unipolar serial data with EOC signaled by rising edge. SHDN supports three-level logic: low = shutdown (≤10µA), high = invalid (not used), floating = operational mode with external reference enabled.

Key Specifications

Pinout & Package

MAX189CEWE is housed in a 16-pin wide SO (Small Outline) package with exposed pad (not thermally enhanced), footprint compliant with JEDEC MS-013AC. Pin 1 is marked via notch or dot; pin numbering follows standard counterclockwise convention.

Key Features

Applications

Equivalent & Alternatives

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

Compared with ADS7816U and MAX11131AUT+T, MAX189CEWE uniquely balances integrated track/hold, external reference flexibility, and ultra-low shutdown current - making it optimal for isolated, battery-operated, or mixed-reference industrial systems where analog source impedance varies.

Availability

MAX189CEWE 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 (–40°C to +85°C).

Supply support for MAX189CEWE 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 MAX187/MAX189 product line was engineered specifically for low-power, space-constrained data acquisition systems requiring high DC accuracy and robust serial interfacing - targeting sensor front-ends and isolated measurement modules.

FAQ

What reference voltage options does the MAX189CEWE support?

The MAX189CEWE requires an external reference applied to the REF pin, supporting voltages from +2.5V to VDD (5.25V). Unlike the MAX187, it has no internal reference. The device draws 200–350µA from the reference during conversion and presents 12–20kΩ input resistance. For best accuracy, use a low-noise, low-output-impedance reference such as the REF5025 or LT6655, bypassed with 0.1µF near the REF pin. The MAX189CEWE's reference specification excludes errors introduced by the external source.

How does the SHDN pin function on the MAX189CEWE?

The SHDN pin on the MAX189CEWE operates in three states: pulled low (≤0.5V) places the device in shutdown mode drawing ≤10µA; left floating (high-impedance) enables normal operation with external reference; tied high (>VDD – 50mV) is undefined and must be avoided. Unlike the MAX187, SHDN high does not enable an internal reference on the MAX189CEWE. Wake-up latency after SHDN deassertion is negligible (<1µs) since no internal reference capacitor charging is required.

What is the maximum recommended source impedance for the AIN pin of the MAX189CEWE?

The MAX189CEWE AIN pin has 16pF input capacitance and requires ≤5kΩ source impedance to achieve full AC performance (70dB SINAD) and meet the 1.5µs track/hold acquisition time. Higher impedances increase acquisition time per t_ACQ = 9 × (R_S + 5kΩ) × 16pF, risking missing codes or reduced effective resolution. For sources >5kΩ, add an op-amp buffer such as the MAX427 or OP27 configured for unity gain and bandwidth >1MHz.

Can the MAX189CEWE interface directly with an SPI master without level shifting?

Yes, the MAX189CEWE interfaces directly with standard 3.3V or 5V SPI masters. Its digital inputs (CS, SCLK) accept VIH ≥ 2.4V and VIL ≤ 0.8V, and its DOUT output drives VOH ≥ 4.0V (at 1mA) and VOL ≤ 0.4V (at 5mA), satisfying SPI voltage thresholds across both logic families. No level-shifting circuitry is needed. Configure the SPI master with CPOL = 0 and CPHA = 0; initiate conversion on CS falling edge; clock out 13 bits (1 leading '1' + 12 data bits) on SCLK falling edges.

What package type and RoHS status does the MAX189CEWE have?

The MAX189CEWE is supplied in a 16-pin wide SO (Small Outline) package per JEDEC MS-013AC, with lead finish NiPdAu and RoHS-compliant materials. It is not halogen-free. The package features a standard gull-wing lead form, 0.050" lead pitch, and 0.210" body width. Thermal resistance θ_JA is 14.5°C/W; derating begins above +70°C ambient at 14.5mW/°C. No exposed thermal pad is present.