Analog Devices Inc./Maxim Integrated MAX1261ACEI+

Overview

MAX1261ACEI+ from Maxim Integrated is a 12-bit, 250ksps successive-approximation ADC with integrated +2.5V reference, byte-wide parallel (8+4) interface, and software-configurable 8-channel single-ended or 4-channel pseudo-differential analog input multiplexer. It operates from a single +3V analog supply and supports digital logic levels from +1.8V to +3.6V via VLOGIC, enabling direct interfacing with low-voltage microcontrollers in portable data-acquisition systems.

For engineers reviewing the MAX1261ACEI+ datasheet, MAX1261ACEI+ pinout, MAX1261ACEI+ application, or MAX1261ACEI+ equivalent, key selection criteria include its ±0.5 LSB INL at 0°C to +70°C, 2µs wake-up from shutdown, internal 3MHz full-power bandwidth track/hold, and QSOP-28 package compatibility with industrial sensor front-ends and battery-powered medical monitors.

Technical Context

The MAX1261ACEI+ implements a charge-redistribution SAR architecture with an on-chip track/hold stage, supporting both internal and external clock modes (4.8MHz max) and internal/external acquisition control via ACQMOD bit. Its analog input structure enables unipolar/bipolar and single-ended/pseudo-differential operation through configurable control-byte bits SGL/DIF and UNI/BIP.

Conversion timing is deterministic: 13 clock cycles per conversion, with tCONV = 3.6µs in internal clock mode. The device uses a 12-bit capacitive DAC and features HBEN-controlled 12-bit output multiplexing (D0–D7 for LSBs, D0/D8–D3/D11 for MSBs), ensuring seamless integration with 8-bit microprocessor buses.

Key Specifications

Pinout & Package

MAX1261ACEI+ is housed in a 28-pin QSOP (Quad Small Outline Package) with 300 mil body width and standard 0.65mm lead pitch, optimized for high-density PCB layouts in space-constrained instrumentation.

Key Features

Applications

Equivalent & Alternatives

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

Compared with ADS7822U and MAX11607EEE+, the MAX1261ACEI+ uniquely combines 12-bit accuracy, 250ksps parallel throughput, on-chip +2.5V reference, and software-configurable pseudo-differential operation - making it optimal for space- and power-constrained industrial and medical data-acquisition designs where timing determinism and interface simplicity are critical.

Availability

MAX1261ACEI+ is available at Aetrix Electronics and suitable for industrial process monitoring, patient vital sign acquisition, and energy meter data logging requiring stable component supply across extended production lifecycles.

Supply support for MAX1261ACEI+ 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 high-reliability semiconductor solutions for industrial, medical, and communications markets.

The MAX1261ACEI+ belongs to Maxim's low-power, high-accuracy SAR ADC product line, designed specifically for battery-operated and space-constrained data-acquisition systems demanding integrated references and flexible analog input architectures.

FAQ

What is the operating temperature range for the MAX1261ACEI+?

The MAX1261ACEI+ is rated for commercial operation from 0°C to +70°C, as indicated by the 'C' suffix in its ordering code. This range is validated per the Absolute Maximum Ratings and Electrical Characteristics tables in the official datasheet, with all key parameters-including ±0.5 LSB INL and 250ksps sampling rate-guaranteed across this interval.

Does the MAX1261ACEI+ require an external clock source?

No, the MAX1261ACEI+ supports both internal and external clock modes. In internal clock mode (D7=1, D6=0), it generates its own 4.8MHz clock, eliminating external timing components. The CLK pin must be tied high or low to prevent floating, and conversion time is fixed at 3.6µs.

How does the HBEN pin function on the MAX1261ACEI+?

The HBEN (High Byte Enable) pin on the MAX1261ACEI+ controls multiplexing of the 12-bit conversion result onto the 8-bit data bus: when HBEN = 0, D0–D7 carry the 8 LSBs; when HBEN = 1, D0/D8–D3/D11 carry the 4 MSBs. This enables full 12-bit reads using two consecutive 8-bit µP accesses.

Can the MAX1261ACEI+ operate with a 1.8V digital supply?

Yes, the MAX1261ACEI+ supports digital logic voltages from +1.8V to +3.6V via the VLOGIC pin. When VLOGIC = 1.8V, input thresholds (VIH/VIL) and output drive (VOH/VOL) are guaranteed per datasheet specs, enabling direct interfacing with modern ultra-low-voltage microcontrollers without level translation.

What is the purpose of the COM pin on the MAX1261ACEI+?

The COM pin on the MAX1261ACEI+ serves as the analog common reference for single-ended mode, setting the zero-code voltage. In pseudo-differential mode, it is not used. For accurate conversions, COM must remain stable to ±0.5 LSB during acquisition and conversion, typically achieved with a low-impedance ground path and local decoupling.