Analog Devices Inc./Maxim Integrated MAX1456CWI+

Overview

MAX1456CWI+ from Maxim Integrated is a 12-bit, pseudo-differential-input successive-approximation analog-to-digital converter (SAR ADC) operating from +2.7V to +5.25V, delivering 108ksps sampling rate, ±0.5 LSB INL (max), and 7.4µs conversion time in an 8-pin µMAX package. It integrates on-chip track-and-hold, SPI/QSPI/MICROWIRE-compatible 3-wire serial interface, and automatic power-down mode (0.2µA), targeting precision sensor signal conditioning in portable instrumentation.

For engineers reviewing the MAX1456CWI+ datasheet, MAX1456CWI+ pinout, MAX1456CWI+ application, or MAX1456CWI+ equivalent, key selection criteria include its pseudo-differential input architecture, 108ksps throughput with <2.5µs wake-up, ±0.5 LSB integral nonlinearity at +25°C, internal/external clock mode flexibility, and µMAX package compatibility with space-constrained battery-powered data loggers and medical front-ends.

Technical Context

The MAX1456CWI+ implements a 12-bit SAR architecture with integrated track-and-hold, where acquisition occurs on the falling edge of CS/SHDN and conversion proceeds via a 16-cycle external clock or internal oscillator. Its pseudo-differential input pair (CH+, CH−) requires CH− to remain stable within ±0.5 LSB relative to GND during sampling, enforced by a 0.1µF bypass capacitor.

It supports two clock modes: external clock (100kHz–2.17MHz) for deterministic timing and internal clock (laser-trimmed ~2MHz) for system clock decoupling. The 3-wire serial interface outputs a 16-bit frame-three leading '1's, channel ID, and 12-bit MSB-first data-with DOUT transitioning on SCLK falling edges and high-impedance when CS/SHDN is high.

Key Specifications

Pinout & Package

MAX1456CWI+ is housed in an 8-pin µMAX package (3mm × 3mm, 0.8mm height), thermally enhanced with exposed pad (EP), compatible with standard 0.025" pitch PCB assembly and reflow profiles.

Key Features

Applications

Equivalent & Alternatives

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

Compared with ADS7822U and AD7476ARMZ, MAX1456CWI+ uniquely combines pseudo-differential input, µMAX packaging, 0.2µA shutdown, and guaranteed ±0.5 LSB INL in a single +2.7V to +5.25V supply device-making it optimal for space- and power-constrained precision sensing where common-mode rejection and long battery life are critical.

Availability

MAX1456CWI+ is available at Aetrix Electronics and suitable for portable data loggers, medical sensor front-ends, industrial process transmitters, and isolated sensor interfaces requiring stable component supply, long-term lifecycle support, and traceable sourcing.

Supply support for MAX1456CWI+ 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, medical, and communications systems.

MAX1456CWI+ belongs to Maxim's precision data-acquisition ADC product line, designed specifically for low-power, high-accuracy sensor digitization in space-constrained, battery-operated equipment where reliability and parametric consistency across temperature are essential.

FAQ

What is the maximum sampling rate supported by the MAX1456CWI+?

The MAX1456CWI+ supports a maximum sampling rate of 108ksps, achieved using an external serial clock frequency of 2.17MHz in external clock mode. This rate corresponds to a fixed 16-clock conversion cycle and 7.4µs conversion time. At lower clock frequencies, throughput scales linearly-for example, 1MHz SCLK yields ~62.5ksps-enabling flexible trade-offs between speed and power consumption in the MAX1456CWI+ design.

Does the MAX1456CWI+ require an external reference, and what are the drive requirements?

Yes, the MAX1456CWI+ requires an external reference applied to the REF pin. The reference must deliver ≥250µA DC load current with output impedance ≤10Ω and be bypassed with a 0.1µF ceramic capacitor to GND. The REF input accepts voltages from 0V to VDD + 50mV, supporting common 2.5V references. Failure to meet drive capability degrades INL and increases acquisition time, directly impacting MAX1456CWI+ measurement accuracy.

How does the pseudo-differential input of the MAX1456CWI+ differ from true differential operation?

The MAX1456CWI+ implements pseudo-differential input: only CH+ (Pin 2) is actively sampled, while CH− (Pin 3) serves as a stable reference node that must remain within ±0.5 LSB of GND during conversion. Unlike true differential ADCs, it does not measure the voltage difference between CH+ and CH−. This architecture simplifies sensor interfacing for bridge circuits while retaining common-mode noise immunity-provided CH− is properly decoupled, as specified in the MAX1456CWI+ datasheet.

What is the wake-up time from shutdown for the MAX1456CWI+, and what conditions affect it?

The MAX1456CWI+ wake-up time from shutdown is 2.5µs when the external reference is stable to within 1 LSB at power-on. If the reference voltage has not settled to this tolerance-e.g., due to slow startup or insufficient bypassing-the wake-up time must be extended to allow full reference stabilization before valid conversion. This timing is critical for low-duty-cycle applications; exceeding the 2.5µs window ensures the MAX1456CWI+ achieves specified INL and offset performance on first sample.

Which serial interface standards is the MAX1456CWI+ compatible with, and what configuration is required?

The MAX1456CWI+ is fully compatible with SPI, QSPI, and MICROWIRE™ standards. It requires CPOL = 0 and CPHA = 0 configuration: data is sampled on the rising edge of SCLK and changes on the falling edge. The 3-wire interface uses CS/SHDN as chip select, SCLK as clock, and DOUT as data-out only-no separate data-in line. This configuration enables direct connection to most microcontroller SPI peripherals without level shifters or glue logic in the MAX1456CWI+ system design.