Analog Devices Inc./Maxim Integrated MAX155ACWI+T

Overview

The MAX155ACWI+T 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, 3.6µs per-channel conversion time, and ±5V dual-supply or +5V single-supply operation - used in phase-sensitive data acquisition and vibration analysis systems.

For engineers reviewing the MAX155ACWI+T datasheet, MAX155ACWI+T pinout, MAX155ACWI+T application, or MAX155ACWI+T equivalent, this page delivers verified electrical specs, hard-wired and I/O mode interface timing, unipolar/bipolar differential/single-ended input flexibility, and real-world design constraints for DSP analog front-ends and portable data loggers.

Technical Context

The MAX155ACWI+T implements a successive-approximation ADC core with eight independent track-and-hold circuits sampling all channels simultaneously on WR falling edge. Conversion sequencing and RAM storage are controlled via a shared bidirectional configuration/data bus using MODE-pin-selectable I/O or hard-wired modes.

It supports mixed-input configurations (e.g., some channels single-ended, others differential) through programmable D0–D7 pins acting as address/control bits (A0–A2, PD, INH, BIP, DIFF, ALL), with latency-critical behavior: BIP/DIFF changes take effect only on the subsequent WR cycle unless INH = 1 is used during register update.

Key Specifications

Pinout & Package

MAX155ACWI+T is housed in a 28-pin wide SOIC (SO) package with 0.3-inch body width and standard gull-wing leads. Pin 1 is marked by a beveled corner or dot; pin numbering follows counterclockwise convention from top-left when viewed from component side.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 8-bit simultaneous-sampling ADC applications.

Compared with AD7828LNZ and ADS8325IPW, the MAX155ACWI+T uniquely combines on-chip simultaneous T/Hs, internal reference, and parallel interface - reducing component count and inter-channel timing uncertainty in multi-signal acquisition systems.

Availability

MAX155ACWI+T is available at Aetrix Electronics and suitable for phase-sensitive data acquisition, vibration analysis, and AC power metering requiring stable component supply across industrial temperature ranges (0°C to +70°C).

Supply support for MAX155ACWI+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, medical, and communications applications.

The MAX155 family targets high-fidelity, multi-channel data acquisition systems where timing coherence, low power, and integration density are critical - especially in portable test equipment and predictive maintenance sensors.

FAQ

What is the operating temperature range for the MAX155ACWI+T?

The MAX155ACWI+T is rated for commercial temperature operation from 0°C to +70°C. This grade is designated by the "C" suffix in the part number and is validated per Maxim's datasheet specifications under those conditions. It is not rated for extended industrial (–40°C to +85°C) operation - that variant would be MAX155AEWI+T. Thermal derating applies above +70°C per the 12.5mW/°C SOIC power dissipation curve.

Does the MAX155ACWI+T require an external crystal or clock source?

Yes, the MAX155ACWI+T requires an external clock signal applied to the CLK pin. It accepts a TTL/CMOS-compatible square wave from 0.5 MHz to 5.0 MHz. The clock frequency directly sets conversion timing: at 5 MHz, conversion completes in 3.6 µs; lower frequencies increase conversion time proportionally. No internal oscillator is present - all timing is externally driven.

Can the MAX155ACWI+T perform differential conversions on all eight channels simultaneously?

No. While the MAX155ACWI+T supports differential input mode per channel, its architecture samples eight analog inputs simultaneously but converts them sequentially. In differential mode, each pair (e.g., AIN0–AIN1) occupies one channel slot, limiting practical differential configurations to four pairs. True simultaneous 8-channel differential conversion is not supported - the device provides eight single-ended or four differential inputs per conversion cycle.

How does power-down mode affect the configuration register in the MAX155ACWI+T?

In power-down mode (PD = 1), the MAX155ACWI+T retains all contents of its configuration register, including channel selections, BIP/DIFF settings, and address pointers. The register remains fully writable via WR pulses even while powered down, allowing pre-configuration before wake-up. However, no conversions execute and no data can be read from RAM until PD is cleared to 0 and the internal reference stabilizes (up to 5 ms with internal REFOUT).

Is the MAX155ACWI+T pin-compatible with the MAX156 series?

No, the MAX155ACWI+T is not pin-compatible with any MAX156 variant. The MAX155ACWI+T uses a 28-pin wide SO package with AIN4–AIN7 exposed on pins 25–28, while the MAX156 occupies either 24-pin narrow PDIP or 28-pin wide SO packages with different pinouts - notably omitting AIN4–AIN7 and relocating several control pins. Board-level substitution requires layout revision.