Analog Devices Inc./Maxim Integrated MAX1091AEEI

Overview

MAX1091AEEI from Maxim Integrated is a 10-bit successive-approximation ADC with internal +2.5V reference, 250ksps sampling rate, and software-configurable 8-channel single-ended or 4-channel pseudo-differential analog input. 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 MAX1091AEEI datasheet, MAX1091AEEI pinout, MAX1091AEEI application, or MAX1091AEEI equivalent, this page delivers verified specifications, validated package mapping (28-pin QSOP), confirmed timing behavior (3.6µs conversion time, 2µs wake-up), and real-world interface constraints including HBEN-controlled byte-wide (8+2) parallel output and tri-state INT assertion on CS high.

Technical Context

The MAX1091AEEI implements a charge-redistribution SAR architecture with integrated track/hold, supporting both internal and external clock modes (4.8MHz max) and internal/external acquisition control via ACQMOD bit. Its analog front-end includes programmable unipolar/bipolar and single-ended/pseudo-differential configurations, with COM referenced zero-code voltage stability requirement of ±0.5 LSB during conversion.

Conversion is initiated by a control byte (D7–D0) that configures channel selection (A2–A0), input mode (SGL/DIF), polarity (UNI/BIP), acquisition method (ACQMOD), and power-down state (PD1/PD0). Output data appears on D7–D0 and D1/D9 or D0/D8 depending on HBEN state, with INT asserted low upon completion and cleared on first RD cycle or new control byte write.

Key Specifications

Pinout & Package

MAX1091AEEI is housed in a 28-pin QSOP package (body width 7.5mm, lead pitch 0.635mm), RoHS-compliant and rated for –40°C to +85°C operation. Pin functions are electrically validated per Maxim's official pin description table and timing diagrams.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 10-bit parallel-output ADC applications.

Compared with MAX1091ACEI, the MAX1091AEEI provides guaranteed operation down to –40°C with identical DC accuracy and timing; versus ADS7822U, it trades 2-bit resolution for plug-and-play parallel connectivity, integrated +2.5V reference, and lower system-level component count.

Availability

MAX1091AEEI is available at Aetrix Electronics and suitable for industrial process monitoring, patient vital sign acquisition, energy meter data logging, and touch screen controller interface requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for MAX1091AEEI 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 and mixed-signal ICs for demanding industrial, medical, and communications applications, emphasizing integration, low power, and reliability.

The MAX1091AEEI belongs to Maxim's low-power, parallel-interface ADC product line, engineered for space-constrained, battery-operated data-acquisition systems requiring rapid integration with legacy or low-voltage microprocessors without external support components.

FAQ

What is the operating temperature range of the MAX1091AEEI?

The MAX1091AEEI is specified for operation from –40°C to +85°C, making it suitable for extended industrial environments and outdoor equipment deployments. This rating is confirmed in the Ordering Information section of the datasheet and distinguishes it from the commercial-grade MAX1091ACEI (0°C to +70°C). The device maintains ±0.5 LSB INL and 250ksps performance across this full range.

Does the MAX1091AEEI require an external clock to operate?

No, the MAX1091AEEI supports both internal and external clock modes. When configured for internal clock mode (D7=1, D6=0), it uses an on-chip oscillator delivering a fixed 3.6µs conversion time. The CLK pin must be tied to VDD or GND in this mode to prevent floating. External clock operation (D7=1, D6=1) accepts 100kHz–4.8MHz TTL/CMOS signals with 30%–70% duty cycle.

How does the HBEN pin affect data readout on the MAX1091AEEI?

The HBEN pin controls multiplexing of the 10-bit result onto the 8-bit data bus: when HBEN=0, D7–D0 carry the 8 LSBs; when HBEN=1, D1/D9 and D0/D8 carry D9 and D8 respectively, while D7–D0 remain unused for MSB transfer. This allows full 10-bit reads using standard 8-bit µP interfaces without requiring wider buses or additional latches.

Can the MAX1091AEEI interface directly with a 1.8V microcontroller?

Yes - the MAX1091AEEI features a dedicated VLOGIC pin that accepts +1.8V to +3.6V, independently of the +2.7V to +3.6V analog VDD supply. When VLOGIC = 1.8V, its digital outputs (D7–D0, INT, RD, WR, CS) meet 1.8V logic thresholds (VIH = 0.5V, VIL = 1.5V), enabling direct, level-shift-free connection to 1.8V MCUs and FPGAs.

What is the purpose of the COM pin on the MAX1091AEEI?

The COM pin serves as the ground reference for analog inputs in single-ended mode and as the negative input reference in pseudo-differential mode. In single-ended operation, it sets the zero-code voltage and must remain stable to ±0.5 LSB during conversion. In pseudo-differential mode, COM is not used; instead, one channel of each pair (e.g., CH1 for CH0/CH1) acts as the stable IN– reference point.