Analog Devices Inc./Maxim Integrated MAX1275AETC+

Overview

MAX1275AETC+ from Maxim Integrated is a 12-bit, true-differential, single-supply analog-to-digital converter (ADC) with 1.8Msps throughput, ±1 LSB INL DC accuracy, and bipolar input range (–VREF/2 to +VREF/2). It operates from +4.75V to +5.25V analog supply and supports 1.8V–VDD digital logic via dedicated VL pin. Used in motor control feedback loops requiring high dynamic range and noise immunity.

For engineers reviewing the MAX1275AETC+ datasheet, MAX1275AETC+ pinout, MAX1275AETC+ application, or MAX1275AETC+ equivalent, key selection criteria include bipolar differential input architecture, 70dB SINAD at 525kHz, 1µA full power-down current, SPI/QSPI/MICROWIRE 3-wire interface timing, and TQFN-12 package thermal performance for industrial embedded signal acquisition.

Technical Context

The MAX1275AETC+ employs a successive-approximation register (SAR) architecture with an internal true-differential track-and-hold (T/H), enabling accurate sampling of bipolar signals without external level-shifting circuitry. Its 20MHz small-signal bandwidth supports undersampling of RF and transient waveforms.

Conversion is initiated by a CNVST falling edge, synchronized to SCLK; 16 clock cycles output 12 data bits plus 3 leading zeros in MSB-first format. The device supports partial (1mA IDD) and full (1µA IDD) power-down modes controlled solely by CNVST/SCLK sequencing-no register writes required.

Key Specifications

Pinout & Package

MAX1275AETC+ is housed in a 12-pin 3mm × 3mm TQFN package with exposed paddle (EP) internally connected to GND. Thermal resistance θJA = 59.3°C/W enables operation up to +85°C ambient without forced airflow.

Key Features

Applications

Equivalent & Alternatives

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

Compared with ADS8326IPW and AD7457BRMZ, the MAX1275AETC+ uniquely combines true-differential bipolar input, 1.8Msps throughput, and hardware-only power-down sequencing-enabling lower system BOM cost, higher signal fidelity, and deterministic low-power behavior in real-time embedded systems.

Availability

MAX1275AETC+ is available at Aetrix Electronics and suitable for motor control feedback, industrial data acquisition, communications base station signal processing, and portable test equipment requiring stable component supply across extended temperature ranges.

Supply support for MAX1275AETC+ 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 with emphasis on integration and reliability.

The MAX1275AETC+ belongs to Maxim's high-speed precision ADC product line, engineered specifically for applications demanding true-differential input, low power, and seamless microcontroller/DSP interfacing in harsh electromagnetic environments.

FAQ

What is the input voltage range for MAX1275AETC+?

The MAX1275AETC+ features a bipolar true-differential analog input with a range of –VREF/2 to +VREF/2. With a typical 4.096V reference, this yields ±2.048V differential input swing. Absolute input voltage on AIN+ and AIN– must remain between GND and VDD, and internal clamping diodes protect against transients beyond those limits. This range enables direct digitization of AC-coupled sensor outputs without external level-shifting circuitry.

Does MAX1275AETC+ require an external reference voltage?

Yes, the MAX1275AETC+ requires an external reference voltage applied to the REF pin. The reference voltage sets the full-scale differential input range and must be stable and low-noise. The datasheet specifies a usable range of +1.0V to VDD + 50mV, with 4.096V being the most common choice for 12-bit resolution. Bypassing REF with both 0.01µF and 4.7µF capacitors to RGND is mandatory for achieving specified AC performance including 70dB SINAD.

How does the power-down functionality work on MAX1275AETC+?

The MAX1275AETC+ implements two hardware-controlled power-down modes: partial (1mA IDD) and full (1µA IDD). Both are entered and exited using precise timing sequences between CNVST and SCLK-no register writes or configuration commands are needed. Partial power-down is activated by pulling CNVST high between the 3rd and 14th SCLK rising edges; full power-down requires executing the partial sequence twice. This simplifies firmware and guarantees deterministic wake-up latency.

What digital interfaces is MAX1275AETC+ compatible with?

The MAX1275AETC+ supports SPI, QSPI, and MICROWIRE 3-wire serial interfaces natively. It operates in all four SPI modes (CPOL/CPHA combinations) and requires only SCLK, CNVST, and DOUT connections-no chip-select line is needed. The device outputs 12 data bits preceded by three leading zeros in MSB-first format, making it compatible with standard microcontroller and DSP synchronous serial ports including TI TMS320C54x without glue logic.

What is the significance of the separate VL supply pin on MAX1275AETC+?

The VL pin on MAX1275AETC+ provides an independent digital logic supply (1.8V to VDD), decoupling the interface voltage from the analog supply (VDD). This allows direct connection to 1.8V, 2.5V, 3.3V, or 5V controllers without level shifters, reduces digital switching noise coupling into the analog section, and improves overall SNR. Bypassing VL with 0.01µF and 10µF capacitors to GND is essential to maintain timing integrity and minimize jitter on DOUT transitions.