Analog Devices Inc./Maxim Integrated MAX155BEWI+T

Overview

The MAX155BEWI+T from Maxim Integrated is an 8-channel, 8-bit analog-to-digital converter with simultaneous track-and-hold inputs, 3.6µs per-channel conversion time, internal 2.5V reference, and ±5V dual-supply or +5V single-supply operation-designed for phase-sensitive data acquisition in vibration analysis systems.

For engineers reviewing the MAX155BEWI+T datasheet, MAX155BEWI+T pinout, MAX155BEWI+T application, or MAX155BEWI+T equivalent, this page delivers verified electrical parameters, hard-wired and I/O mode interface behavior, unipolar/bipolar differential/single-ended input flexibility, and real-world timing constraints for embedded DSP analog front-ends.

Technical Context

The MAX155BEWI+T integrates eight independent track-and-hold amplifiers sampling all channels simultaneously on WR falling edge, feeding a successive-approximation ADC core. Conversion results are stored in an internal 8×8 RAM with addressable readout via D0–D7 bus and A0–A2 address lines.

It supports two operational modes: hard-wired (MODE pin tied high/low/VSS) for fixed 4- or 8-channel configurations, and I/O mode (MODE open) enabling dynamic configuration of input type (single-ended/differential), polarity (unipolar/bipolar), power-down, and channel selection via shared data/address pins.

Key Specifications

Pinout & Package

MAX155BEWI+T is packaged in a 28-pin wide SO (SOIC-W) surface-mount package with 0.3-inch body width and standard 1.27 mm pitch.

Key Features

Applications

Equivalent & Alternatives

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

Compared with ADS8556IPM and AD7656ASTZ, the MAX155BEWI+T uniquely delivers true 8-channel simultaneous sampling at 8-bit resolution with integrated reference and minimal external components-making it optimal for cost-sensitive, space-constrained phase-coherent acquisition where 10–12 bit ENOB suffices.

Availability

MAX155BEWI+T is available at Aetrix Electronics and suitable for vibration monitoring systems, portable power analyzers, and DSP-based motor control requiring stable component supply across extended temperature ranges (–40°C to +85°C).

Supply support for MAX155BEWI+T 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.

The MAX155BEWI+T belongs to Maxim's high-speed data acquisition product line, engineered specifically for applications demanding deterministic multi-channel sampling without inter-channel timing skew.

FAQ

What is the maximum clock frequency supported by the MAX155BEWI+T?

The MAX155BEWI+T 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. Lower clock frequencies increase conversion time linearly-e.g., at 2.5 MHz, conversion time extends to approximately 7.2 µs. The MAX155BEWI+T does not include an internal oscillator; all timing is derived from the externally applied CLK signal.

Does the MAX155BEWI+T require external decoupling capacitors, and if so, what values?

Yes, the MAX155BEWI+T requires specific decoupling: VDD must be bypassed to AGND with a 47 µF electrolytic capacitor and a 0.1 µF ceramic capacitor; the internal 2.5 V reference (REFOUT) requires a 4.7 µF electrolytic and 0.1 µF ceramic capacitor to AGND; and if using an external reference at REFIN, it must be bypassed with a 4.7 µF capacitor. These values are specified in the Maxim datasheet to ensure stable operation and meet dynamic performance specifications for the MAX155BEWI+T.

Can the MAX155BEWI+T perform differential conversions on all eight channels simultaneously?

No-the MAX155BEWI+T supports differential input pairs (e.g., AIN0–AIN1, AIN2–AIN3), but only four differential channels can be acquired per conversion cycle due to internal multiplexer architecture. In differential mode, each pair shares one T/H amplifier, limiting total concurrent differential inputs to four. The MAX155BEWI+T datasheet confirms that differential operation is implemented as four independent AIN_n–AIN_n+1 pairs, not eight fully independent differential inputs.

How does power-down mode affect the configuration register and RAM contents in the MAX155BEWI+T?

In power-down mode (PD = 1), the MAX155BEWI+T retains all contents of the configuration register and internal RAM. The device draws ≤100 µA, and the internal reference is disabled. Configuration updates remain possible via WR pulses while powered down, allowing pre-load of new settings before wake-up. However, no conversions may be initiated and no RAM data can be read until PD is cleared (PD = 0). The MAX155BEWI+T requires up to 5 ms for internal reference stabilization after exiting power-down if using the internal reference.

Is the MAX155BEWI+T pin-compatible with the MAX156 series?

No-the MAX155BEWI+T is not pin-compatible with any MAX156 variant. Although both share functional similarity and some overlapping pin names, the MAX155BEWI+T uses a 28-pin wide SO package with dedicated AIN4–AIN7 pins (pins 25–28), whereas MAX156 variants use either 24-pin narrow PDIP or 28-pin wide SO packages with N.C. (no-connect) pins in those positions. Pin mapping differs for A2, D2/A2, and channel input assignments-direct substitution would cause incorrect analog input routing and bus conflicts.