Analog Devices Inc./Maxim Integrated MAX156BEWI+

Overview

MAX156BEWI+ from Maxim Integrated is a high-speed, 4-channel, 8-bit analog-to-digital converter (ADC) with simultaneous track-and-hold (T/H) inputs, 3.6µs per-channel conversion time, internal 2.5V reference, and support for unipolar/bipolar and single-ended/differential input configurations - used in vibration analysis, AC power metering, and DSP front-ends.

For engineers reviewing the MAX156BEWI+ datasheet, MAX156BEWI+ pinout, MAX156BEWI+ application, or MAX156BEWI+ equivalent, this page delivers verified electrical parameters, hard-wired and I/O mode interface behavior, timing-critical control logic (WR/RD/CS/BUSY), and real-world acquisition constraints including aperture delay matching (±4ns) and channel-to-channel gain error (±1 LSB).

Technical Context

The MAX156BEWI+ integrates four independent track-and-hold amplifiers that sample all enabled analog inputs simultaneously on the falling edge of WR, eliminating inter-channel timing skew. Its successive-approximation ADC core operates at up to 5MHz clock frequency and stores results in an internal 8×8 RAM buffer.

Configuration is supported in two modes: hard-wired (MODE tied high/low with VSS grounded or at –5V) for fixed 4-channel differential or single-ended conversions, and I/O mode (MODE open) where D0–D7 double as address/data/control lines to program channel selection, polarity, input type, power-down, and read/write sequencing via the configuration register.

Key Specifications

Pinout & Package

MAX156BEWI+ is housed in a 24-pin narrow-body plastic DIP (PDIP) package with 0.3-inch width, RoHS-compliant lead finish, and through-hole mounting. Pin 1 is marked with a notch or dot; pin numbering follows standard counter-clockwise convention from top view.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 4-channel, 8-bit ADC applications.

Compared with ADS7822U and MAX1166BCAP+, the MAX156BEWI+ uniquely delivers guaranteed simultaneous sampling across 4 channels with sub-5 ns aperture matching - making it irreplaceable in phase-sensitive applications where inter-channel timing integrity is non-negotiable.

Availability

MAX156BEWI+ is available at Aetrix Electronics and suitable for vibration analysis systems, AC power metering platforms, and portable data loggers requiring stable component supply, long-term lifecycle support, and traceable sourcing from authorized channels.

Supply support for MAX156BEWI+ 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, automotive, and communications applications - emphasizing high accuracy, low power, and robust operation.

The MAX155/MAX156 product line was engineered specifically for high-fidelity, multi-channel data acquisition in noise-sensitive environments - delivering simultaneous sampling, integrated reference, and flexible input configuration without external support components.

FAQ

What is the maximum clock frequency supported by MAX156BEWI+?

The MAX156BEWI+ accepts an external clock input from 0.5 MHz to 5.0 MHz. At 5 MHz, the device achieves its specified 3.6 µs per-channel conversion time. Operating below 0.5 MHz increases conversion latency and may affect timing margins for WR/RD strobes - always verify tWR, tRDL, and tWRD against actual clock period in design validation. The MAX156BEWI+ does not include an internal oscillator.

Does MAX156BEWI+ support true bipolar input ranges?

Yes, the MAX156BEWI+ supports true bipolar operation from –2.5V to +2.5V when VSS is connected to –5V and the BIP bit is set to 1 in the configuration register. This requires the internal 2.5V reference (REFOUT) to remain active and properly bypassed. With VSS = AGND, only unipolar 0V to 2.5V operation is possible - the MAX156BEWI+ does not support rail-to-rail input beyond VSS/VDD limits.

How does the hard-wired mode work on MAX156BEWI+?

In hard-wired mode, MODE and VSS pins are strapped to fixed logic levels to select predefined 4-channel configurations: MODE = 1 + VSS = AGND enables 4-channel differential unipolar conversion; MODE = 1 + VSS = –5V enables 4-channel differential bipolar. No configuration register writes are needed - WR directly initiates conversion. This mode bypasses D0–D7 control functionality and simplifies firmware for deterministic acquisition tasks.

Can MAX156BEWI+ perform single-channel conversions only?

Yes, the MAX156BEWI+ supports single-channel conversion via the ALL bit in the configuration register: setting ALL = 1 converts only the channel selected by A2–A0, and a single RD pulse retrieves that result. This avoids reading unused RAM locations and reduces bus activity - useful in systems where only one sensor is active per acquisition cycle. The MAX156BEWI+ still samples all four AINs simultaneously, but stores only the selected channel's result.

What is the recommended bypassing for MAX156BEWI+ REFOUT pin?

The MAX156BEWI+ REFOUT pin requires a 4.7 µF electrolytic capacitor in parallel with a 0.1 µF ceramic capacitor, both connected directly between REFOUT and AGND. This dual-capacitor network suppresses low-frequency drift and high-frequency noise to maintain reference stability. If using an external reference at REFIN, REFOUT must still be bypassed or tied to VDD - leaving it floating causes oscillation and conversion errors in the MAX156BEWI+.