Analog Devices Inc./Maxim Integrated MAX1276ETC+T

Overview

MAX1276ETC+T from Maxim Integrated is a 12-bit, true-differential, serial-output analog-to-digital converter (ADC) with internal 4.096V reference, 1.8Msps sampling rate, ±1.25 LSB INL, and unipolar input range (0 to V_REF). It operates from a single +4.75V to +5.25V analog supply and supports 1.8V–V_DD digital logic via dedicated VL pin, enabling direct interfacing with low-voltage microcontrollers in industrial motor control systems.

For engineers reviewing the MAX1276ETC+T datasheet, MAX1276ETC+T pinout, MAX1276ETC+T application, or MAX1276ETC+T equivalent, key selection criteria include its unipolar differential input architecture, SPI/QSPI/MICROWIRE-compatible 3-wire interface, 55mW typical power dissipation at full speed, and guaranteed -40°C to +85°C operation in a 12-pin TQFN package.

Technical Context

The MAX1276ETC+T employs a successive-approximation register (SAR) architecture with an integrated true-differential track-and-hold (T/H), delivering no pipeline delay and 70dB SINAD at 525kHz input frequency. Its internal 4.096V reference remains active in normal and partial power-down modes but is disabled in full power-down mode, requiring ≥2ms recovery time after wake-up.

Conversion is initiated by a falling edge on CNVST, synchronized to SCLK (up to 28.8MHz); data appears MSB-first on DOUT starting at the 4th SCLK rising edge, with 16 clock cycles required for full 12-bit output plus 3 leading zeros. The device supports three power states: normal (13mA IDD), partial power-down (2mA), and full power-down (1µA max).

Key Specifications

Pinout & Package

MAX1276ETC+T is housed in a 12-pin 3mm × 3mm TQFN package with exposed paddle (EP), rated for -40°C to +85°C operation. Pin 1 is AIN−; pin 12 is AIN+; pins 5 and 11 are no-connect; EP is internally tied to GND.

Key Features

Applications

Equivalent & Alternatives

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

Compared with ADS8326IPW and AD7476AARMZ, the MAX1276ETC+T uniquely combines unipolar differential input, internal 4.096V reference, 1.8Msps throughput, and 12-pin TQFN packaging - making it optimal for space-constrained, noise-sensitive industrial control where speed and integration outweigh raw resolution or minimal footprint.

Availability

MAX1276ETC+T is available at Aetrix Electronics and suitable for industrial motor control, portable instrumentation, and communications baseband processing requiring stable component supply, RoHS-compliant lead-free packaging, and extended temperature support.

Supply support for MAX1276ETC+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 markets.

The MAX1276ETC+T belongs to Maxim's high-speed, low-power SAR ADC product line, engineered specifically for demanding real-time control and data acquisition applications where differential signaling, internal reference integration, and multi-mode power management are critical.

FAQ

What is the analog input configuration of the MAX1276ETC+T?

The MAX1276ETC+T features a true-differential unipolar analog input (AIN+ and AIN−), supporting a 0V to 4.096V differential input range. This architecture provides superior noise rejection and dynamic range compared to single-ended inputs, and is distinct from the bipolar input of the pin-compatible MAX1278ETC+T. The MAX1276ETC+T does not accept negative input voltages.

Does the MAX1276ETC+T require an external reference voltage?

No, the MAX1276ETC+T includes a factory-trimmed internal 4.096V reference connected to the REF pin. This reference drives the internal capacitive DAC and can also serve as a precision voltage source for external circuitry, eliminating the need for an external reference IC. The REF output must be bypassed with 0.01µF and 4.7µF capacitors to RGND.

How does the MAX1276ETC+T enter and exit full power-down mode?

The MAX1276ETC+T enters full power-down mode by executing the partial power-down sequence twice - pulling CNVST high after the 3rd but before the 14th SCLK rising edge, then repeating. To exit, drive CNVST low, wait ≥14 SCLK cycles, then pull CNVST high. After exit, allow ≥2ms for the internal reference to settle before initiating conversions.

What digital interface protocols does the MAX1276ETC+T support?

The MAX1276ETC+T supports SPI, QSPI, and MICROWIRE protocols via its 3-wire serial interface (SCLK, CNVST, DOUT). It is compatible with all four SPI modes (CPOL/CPHA combinations) and requires no mode configuration. Data is output MSB-first with three leading zeros, and 16 SCLK cycles are needed per conversion - matching standard µP/DSP synchronous serial ports without modification.

What is the minimum acquisition time for the MAX1276ETC+T, and how is it affected by source impedance?

The MAX1276ETC+T has a guaranteed minimum acquisition time (t_ACQ) of 104ns. For source impedances above 12Ω, t_ACQ increases per t_ACQ ≥ 9 × (R_S + 200Ω) × 16pF. Accurate conversions require the analog input to settle within this window; exceeding it degrades AC performance, especially THD and SFDR. Layout best practice is to minimize series resistance before AIN+ and AIN−.