Analog Devices Inc./Maxim Integrated MAX189BCWE+

Overview

MAX189BCWE+ from Maxim Integrated is a 12-bit successive-approximation analog-to-digital converter (ADC) designed for low-power, single-supply +5V operation with external reference support. It delivers 75ksps throughput, ±½ LSB integral nonlinearity (A-grade), 70dB SINAD, and features an integrated track/hold, 3-wire SPI/QSPI/MICROWIRE-compatible serial interface - deployed in isolated data acquisition and remote sensor monitoring where precision, space, and power are constrained.

For engineers reviewing the MAX189BCWE+ datasheet, MAX189BCWE+ pinout, MAX189BCWE+ application, or MAX189BCWE+ equivalent, this page provides verified functional identity, package mapping to 16-pin wide SO, confirmed 12-bit unipolar transfer function, real-world timing constraints (tACQ = 1.5µs, tCONV = 5.5–8.5µs), and validated alternative options for external-reference ADC replacement in industrial embedded systems.

Technical Context

The MAX189BCWE+ implements a capacitor-based SAR architecture with internal track/hold circuitry that acquires input signals within 1.5µs and completes conversion in 5.5–8.5µs. Its analog front-end accepts 0V to VREF inputs (VREF = 2.5V to +5.25V), with input capacitance of 16pF and small-signal bandwidth of 4.5MHz.

Digital control uses three dedicated pins - CS (active-low chip select), SCLK (up to 5MHz clock input), and DOUT (MSB-first serial output synchronized to SCLK falling edge). The device operates in two states: normal mode (1.0–2.0mA supply current) and shutdown mode (≤10µA), with wake-up time dependent on external reference capacitor discharge.

Key Specifications

Pinout & Package

MAX189BCWE+ is housed in a 16-pin wide SO (SOIC-W) package with exposed pad (not electrically connected), compliant with JEDEC MS-013AC. Pin 1 is marked by notch or dot; pin numbering follows standard counterclockwise layout.

Key Features

Applications

Equivalent & Alternatives

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

Compared with ADS7816U and AD7490BRUZ, the MAX189BCWE+ uniquely balances 75ksps throughput, integrated track/hold, ultra-low shutdown current, and compact 16-pin SO packaging - making it optimal for space-constrained, battery-aware industrial sensing where external reference control is already implemented.

Availability

MAX189BCWE+ is available at Aetrix Electronics and suitable for portable data logging, isolated data acquisition, and high-accuracy process control requiring stable component supply across extended temperature ranges (−40°C to +85°C).

Supply support for MAX189BCWE+ 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) is a fabless semiconductor company specializing in high-performance analog, mixed-signal, and power-management ICs for industrial, communications, and computing applications.

The MAX187/MAX189 family was engineered for low-power, single-supply 12-bit digitization in space- and energy-constrained systems - emphasizing ease of interface, robustness in noisy environments, and compatibility with legacy microcontroller serial peripherals.

FAQ

What is the reference voltage requirement for MAX189BCWE+?

The MAX189BCWE+ requires an external reference voltage applied to the REF pin, ranging from +2.50V to VDD + 50mV (i.e., up to +5.30V at VDD = +5.25V). For full 12-bit accuracy, the reference must provide ≤10Ω output impedance and sustain ≤350µA DC load during conversion. A 0.1µF ceramic bypass capacitor is mandatory at the REF pin; a 4.7µF capacitor is recommended if noise or long traces are present. The MAX189BCWE+ does not include an internal reference - unlike the MAX187 variant.

Does MAX189BCWE+ support SPI mode with CPOL = 0 and CPHA = 0?

Yes, the MAX189BCWE+ is fully compatible with SPI mode 0 (CPOL = 0, CPHA = 0). In this configuration, CS falling edge initiates conversion, DOUT goes low during conversion, and data becomes valid on SCLK's falling edge starting with the MSB. The device outputs a leading end-of-conversion (EOC) bit followed by 12 data bits - requiring exactly 13 SCLK cycles for complete readout. No additional framing or polarity inversion is needed.

What is the maximum analog input frequency supported by MAX189BCWE+?

The MAX189BCWE+ has a 4.5MHz small-signal bandwidth and 75ksps sampling rate, so its Nyquist limit is 37.5kHz. While it can accurately digitize sinusoidal inputs up to that frequency, higher frequencies may be undersampled for spectral analysis - provided anti-alias filtering is applied. The 1.5µs track/hold acquisition time and 16pF input capacitance impose practical limits: source impedance should remain below 5kΩ to avoid degradation of AC performance or increased acquisition delay.

How does shutdown mode affect wake-up timing for MAX189BCWE+?

In shutdown mode, the MAX189BCWE+ draws ≤10µA and disables internal circuitry except for SHDN input detection. Wake-up time depends on external REF capacitor discharge: with a standard 4.7µF capacitor, tWAKE increases with shutdown duration (per Figure 7 in datasheet), reaching ~2.5ms after 10 seconds shutdown. Unlike the MAX187, the MAX189BCWE+ does not require internal reference re-stabilization, so conversion can begin immediately after tWAKE expires - no additional delay is needed before asserting CS.

Can MAX189BCWE+ operate from a 3.3V supply?

No, the MAX189BCWE+ is specified only for +4.75V to +5.25V operation (VDD range). Absolute maximum rating is +6V, and operation below 4.75V violates electrical specifications including INL, SINAD, and timing parameters. It is not 3.3V-tolerant: digital inputs require VIH ≥ 2.4V and VIL ≤ 0.8V, which are incompatible with 3.3V logic thresholds unless level-shifted. For 3.3V systems, consider pin-compatible alternatives like the ADS7816 or AD7476A.