Analog Devices Inc./Maxim Integrated MAX155BCWI+

Overview

MAX155BCWI+ from Maxim Integrated is an 8-channel, 8-bit simultaneous-sampling analog-to-digital converter (ADC) with integrated track-and-hold amplifiers, 2.5V internal reference, and 3.6µs per-channel conversion time. It supports unipolar/bipolar and single-ended/differential input configurations, operates from +5V or ±5V supplies, and stores results in an internal 8×8 RAM - ideal for phase-sensitive data acquisition and vibration analysis systems.

For engineers reviewing the MAX155BCWI+ datasheet, MAX155BCWI+ pinout, MAX155BCWI+ application, or MAX155BCWI+ equivalent, this page delivers verified technical context, real-world interface timing constraints, channel-matching accuracy (±½ LSB), aperture delay matching (4 ns), and design-meaningful alternatives for multichannel synchronized sampling systems.

Technical Context

The MAX155BCWI+ implements a successive-approximation ADC core with eight independent track-and-hold circuits that sample all analog inputs simultaneously on the falling edge of WR. Its configuration register-accessed via bidirectional D0–D7 pins-controls channel selection, input mode (single-ended/differential), polarity (unipolar/bipolar), power-down, and sequential vs. specific-address readout.

It supports two operational modes: Input/Output (MODE = open circuit) for full software-configurable conversions, and Hard-Wired Mode (MODE tied high/low with VSS) for fixed 4- or 8-channel conversions without register programming. Internal 2.5V reference output (REFOUT) requires 4.7µF + 0.1µF bypassing; external reference use mandates REFOUT disable or bypass to prevent noise coupling.

Key Specifications

Pinout & Package

MAX155BCWI+ is packaged in a 28-pin wide SO (SOIC) surface-mount package with 0.3-inch body width and standard 1.27 mm pitch. Pin 1 is marked with a beveled corner; pin numbering follows counter-clockwise convention from top-left when viewed from component side.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar multichannel simultaneous-sampling ADC applications.

Compared with AD7864ASTZ-1 and ADS8556IPM, the MAX155BCWI+ uniquely combines 8-channel simultaneous sampling, internal reference, parallel 8-bit interface, and mixed-mode configurability in a single SOIC package - making it optimal for cost-sensitive, space-constrained industrial DAQ systems requiring deterministic timing and minimal support components.

Availability

MAX155BCWI+ is available at Aetrix Electronics and suitable for phase-sensitive data acquisition, vibration analysis, AC power metering, and portable data logging applications requiring stable component supply and long-term industrial availability.

Supply support for MAX155BCWI+ 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 markets - emphasizing integration, reliability, and application-specific optimization.

The MAX155BCWI+ belongs to Maxim's high-speed data-acquisition product line, engineered specifically for systems demanding synchronized multichannel sampling, on-chip reference stability, and flexible analog input configuration without external support components.

FAQ

What is the maximum clock frequency supported by the MAX155BCWI+?

The MAX155BCWI+ operates with an external clock frequency ranging from 0.5 MHz to 5.0 MHz. At 5 MHz, the device achieves its specified 3.6 µs per-channel conversion time. Clock frequencies below 5 MHz increase conversion time linearly - e.g., at 2.5 MHz, conversion time extends to ~7.2 µs. The MAX155BCWI+ does not include an internal oscillator and relies entirely on the externally applied CLK signal for timing control.

Does the MAX155BCWI+ require external track-and-hold amplifiers?

No, the MAX155BCWI+ integrates eight independent track-and-hold amplifiers - one per analog input channel - enabling true simultaneous sampling without external components. Each T/H captures its respective AIN signal at the exact same instant on the falling edge of the WR signal. This eliminates timing skew between channels, a critical requirement for coherent multichannel measurements in the MAX155BCWI+.

Can the MAX155BCWI+ operate with only a +5V supply?

Yes, the MAX155BCWI+ functions fully with a single +5V supply (VDD = +4.75V to +5.25V) and ground (VSS = 0V), supporting unipolar input ranges (0 V to +2.5 V). For bipolar operation (±2.5 V) or extended dynamic range, VSS must be connected to -5V. The device's dual-supply capability is built-in and requires no modification - only appropriate biasing of VSS and analog input references.

How is channel configuration performed on the MAX155BCWI+?

Channel configuration on the MAX155BCWI+ is performed via its bidirectional D0–D7 pins acting as a shared address/data bus. Configuration bits - including DIFF (differential/single-ended), BIP (bipolar/unipolar), ALL (multichannel/single-channel), and PD (power-down) - are loaded into an internal register on the rising edge of WR. In Input/Output mode (MODE = open), this register defines per-channel behavior; in Hard-Wired mode (MODE tied high/low), configuration is fixed and the register is ignored.

What is the purpose of the INH (Inhibit) bit in the MAX155BCWI+ configuration register?

The INH (Inhibit) bit in the MAX155BCWI+ configuration register prevents conversion initiation when set to logic 1 during a WR pulse. This allows safe loading of new configuration data (e.g., updated DIFF or BIP settings) or arbitrary RAM address selection (via A0–A2) without triggering unintended sampling. Only when INH = 0 on a WR pulse does the MAX155BCWI+ execute sampling and conversion - ensuring deterministic control over timing-critical sequences.