Analog Devices Inc./Maxim Integrated MAX144BCUA

Overview

MAX144BCUA from Maxim Integrated is a low-power, 12-bit successive-approximation analog-to-digital converter (SAR ADC) with two single-ended input channels, 108ksps sampling rate, ±1 LSB integral nonlinearity, and SPI/QSPI/MICROWIRE-compatible 3-wire serial interface - designed for battery-powered data acquisition in portable instrumentation and system supervision.

For engineers reviewing the MAX144BCUA datasheet, MAX144BCUA pinout, MAX144BCUA application, or MAX144BCUA equivalent, key selection criteria include its 8-pin µMAX package, 2.7V–5.25V single-supply operation, automatic power-down (0.2µA), 7.4µs conversion time, and channel-switching control via CS/SHDN pin toggling.

Technical Context

The MAX144BCUA implements a SAR architecture with integrated track-and-hold, internal laser-trimmed oscillator (for internal clock mode), and analog multiplexer for alternating CH0/CH1 conversions. It supports both internal clock mode (SCLK high at CS/SHDN fall) and external clock mode (SCLK low at CS/SHDN fall), with conversion initiated on the second SCLK falling edge in external mode.

Its analog input structure features 9kΩ input resistance, 16pF input capacitance, and ±0.5LSB channel-to-channel offset matching. The device accepts 0–VREF single-ended inputs, requires an external reference (0–VDD+50mV), and delivers 70dB SINAD and –85dB channel-to-channel crosstalk at 10kHz.

Key Specifications

Pinout & Package

MAX144BCUA is housed in an 8-pin µMAX package (U8-1), measuring 3mm × 3mm × 0.8mm with exposed pad for thermal enhancement and fine-pitch gull-wing leads.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX144ACUA, MAX144BCUA trades 0.5 LSB INL tolerance for broader production yield and lower unit cost, while retaining identical timing, power, and interface behavior; versus ADS7822U, it integrates track-and-hold and supports simpler reference design at the expense of maximum speed.

Availability

MAX144BCUA is available at Aetrix Electronics and suitable for battery-powered data loggers, portable medical sensors, and industrial process monitors requiring stable component supply across extended production lifecycles.

Supply support for MAX144BCUA 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 demanding industrial, medical, and communications applications.

The MAX144 family targets low-power, space-constrained data acquisition systems requiring high-resolution digitization without external support components - emphasizing ease of use, minimal external BOM, and robust serial interfacing.

FAQ

What is the guaranteed integral nonlinearity (INL) specification for MAX144BCUA?

The MAX144BCUA has a guaranteed ±1 LSB integral nonlinearity over its operating temperature range of 0°C to +70°C. This specification ensures monotonic operation and limits full-scale linearity error to ≤0.024%, supporting accurate measurements in precision sensing applications without per-unit calibration.

How does the MAX144BCUA handle channel selection between CH0 and CH1?

The MAX144BCUA alternates automatically between CH0 and CH1 on successive conversions after power-on reset. Channel selection is controlled by toggling the CS/SHDN pin: one toggle advances to the next channel, and two rapid toggles allow repeated sampling of the same channel. No configuration register access is required.

Can the MAX144BCUA operate with an external reference voltage lower than 2.5V?

Yes, the MAX144BCUA accepts any external reference voltage from 1.0V to VDD+50mV. Lower reference voltages reduce full-scale input range and effective resolution due to increased quantization noise relative to signal, but are fully supported electrically - e.g., a 1.25V reference yields 0.3mV/LSB step size.

What is the minimum acquisition time required before starting a conversion on MAX144BCUA?

The MAX144BCUA specifies a maximum acquisition time (tACQ) of 7µs under typical conditions (RS < 1kΩ). For higher source impedances, tACQ increases per tACQ = 9(RS + 9kΩ) × 16pF. To ensure accuracy, allow ≥7µs between CS/SHDN falling edge and first SCLK falling edge in external clock mode.

Does MAX144BCUA support both internal and external clock modes, and how are they selected?

Yes, MAX144BCUA supports both modes. Internal clock mode is selected when SCLK is high at the falling edge of CS/SHDN - enabling SCLK frequencies from 0 to 5MHz. External clock mode activates when SCLK is low at that edge - requiring 100kHz–2.17MHz SCLK to drive conversion timing directly.