Analog Devices Inc./Maxim Integrated MAX1246ACEE

Overview

MAX1246ACEE from Maxim Integrated is a 12-bit, 4-channel serial analog-to-digital converter (ADC) with integrated track/hold, software-configurable unipolar/bipolar and single-ended/differential inputs, internal 2.5V reference, and SPI/QSPI/MICROWIRE-compatible 4-wire serial interface. It operates from a single +2.7V to +3.6V supply, consumes 1.2mA at 133ksps, and supports shutdown current as low as 1µA - ideal for portable data loggers and battery-powered medical instruments.

For engineers reviewing the MAX1246ACEE datasheet, MAX1246ACEE pinout, MAX1246ACEE application, or MAX1246ACEE equivalent, key selection criteria include its QSOP-16 package, internal reference accuracy (±0.5 LSB INL), 1.5µs acquisition time, and compatibility with TMS320-family DSPs via SSTRB strobe output.

Technical Context

The MAX1246ACEE uses successive-approximation register (SAR) architecture with an integrated track/hold circuit that acquires input signals in ≤1.5µs and achieves ±0.5 LSB integral nonlinearity (INL) over 0°C to +70°C. Its analog front-end supports four single-ended or two differential input channels, with COM pin serving as zero-code reference in single-ended mode and common-mode reference in differential mode.

It features dual clock operation: internal clock (7.5 MHz typical) for autonomous conversion control, or external serial clock (up to 2 MHz) for precise timing synchronization. The 4-wire serial interface operates in MSB-first format, with DOUT valid on SCLK falling edge and SSTRB providing conversion status strobe - enabling direct interfacing with SPI masters and TI TMS320 DSPs without glue logic.

Key Specifications

Pinout & Package

MAX1246ACEE is housed in a 16-pin QSOP package (5.3 mm × 10.0 mm), occupying the same PCB footprint as an 8-pin SOIC - enabling compact, high-density layouts in portable electronics.

Key Features

Applications

Equivalent & Alternatives

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

Compared with ADS7822U and MAX11131ETE+, the MAX1246ACEE uniquely combines internal 2.5V reference, TMS320-compatible SSTRB output, and three-level SHDN control - making it optimal for low-power, DSP-coupled portable instrumentation where reference stability and deterministic timing are critical.

Availability

MAX1246ACEE is available at Aetrix Electronics and suitable for portable data logging, medical instrumentation, and battery-powered test equipment requiring stable component supply and long-term manufacturability.

Supply support for MAX1246ACEE 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 leader in precision analog, mixed-signal, and power management ICs for industrial, medical, and communications applications.

The MAX1246ACEE belongs to Maxim's low-power serial ADC product line, designed specifically for battery-operated and space-constrained data acquisition systems requiring high accuracy, flexible input configuration, and minimal external components.

FAQ

What is the maximum sampling rate supported by the MAX1246ACEE?

The MAX1246ACEE achieves a maximum sampling rate of 133 ksps when using a 2 MHz external serial clock and operating in external clock mode. This rate is determined by the 15-clock conversion cycle (12 bits + 3 overhead clocks) and is specified under conditions of VDD = 3V, fSCLK = 2 MHz, and TA = 25°C. At lower clock frequencies or in internal clock mode, the rate decreases accordingly - for example, internal clock mode yields ~7.5 ksps typical.

Does the MAX1246ACEE require an external reference voltage?

No, the MAX1246ACEE does not require an external reference voltage because it integrates a precision 2.500 V reference buffer. This internal reference is factory-trimmed to ±0.5% initial accuracy and exhibits ±30 ppm/°C temperature coefficient over 0°C to +70°C. The REFADJ pin allows ±1.5% adjustment, and a 4.7 µF capacitor at VREF is mandatory for stability. In contrast, the MAX1247 variant requires an external reference.

How does the SHDN pin function on the MAX1246ACEE?

The SHDN pin on the MAX1246ACEE provides three distinct operating states: pulling it low enables full power-down (1 µA supply current); letting it float configures the reference buffer for external compensation (requiring 4.7 µF at VREF); and pulling it high selects internal compensation mode. This three-level control allows dynamic optimization of reference stability versus power consumption - a feature not found in most competing 12-bit ADCs.

Can the MAX1246ACEE interface directly with a TMS320 DSP?

Yes, the MAX1246ACEE interfaces directly with TMS320-family digital signal processors using its dedicated SSTRB (serial strobe) output. In internal clock mode, SSTRB goes low at conversion start and high at completion; in external clock mode, it pulses high for one clock period before the MSB decision. This deterministic strobe eliminates software polling and enables hardware-triggered DSP interrupts - confirmed in Maxim's application note AN1071 and supported across TMS320C2xx/C5x/C6x generations.

What are the analog input protection limits for the MAX1246ACEE?

The MAX1246ACEE includes internal ESD protection diodes that clamp analog inputs (CH0–CH3, COM) to AGND and VDD, allowing safe operation from AGND −0.3 V to VDD +0.3 V. However, for accurate conversions near full scale, inputs must remain within AGND +50 mV to VDD −50 mV. Exceeding these bounds risks forward-biasing protection diodes on inactive channels, potentially injecting >4 mA leakage current and corrupting adjacent channel readings.