Analog Devices Inc./Maxim Integrated MAX1109EUB+

Overview

MAX1109EUB+ from Maxim Integrated is a low-power, 8-bit, dual-channel successive-approximation ADC with internal track/hold, +4.096V reference, SPI/QSPI/MICROWIRE-compatible 4-wire serial interface, and software-configurable unipolar/bipolar input modes. It operates from +4.5V to +5.5V, consumes 130µA at 50ksps, and supports battery monitoring in portable data loggers and hand-held measurement devices.

For engineers reviewing the MAX1109EUB+ datasheet, MAX1109EUB+ pinout, MAX1109EUB+ application, or MAX1109EUB+ equivalent, this page delivers verified electrical specs, µMAX package footprint details, real-world timing behavior (20µs conversion time), VDD monitoring capability, and validated alternative parts for industrial sensor interfaces requiring low quiescent current and ±0.5LSB INL over –40°C to +85°C.

Technical Context

The MAX1109EUB+ uses a charge-redistribution SAR architecture with integrated track/hold and auto-zero rail, enabling accurate single-supply operation without external hold capacitors. Its analog front-end supports pseudo-differential sampling where only the sampled input (SI) is stored on CHOLD, while the reference input (RI) must remain stable within ±0.5LSB relative to GND during conversion.

Conversion is controlled via an 8-bit software-configurable control byte that selects clock source (internal or external), reference (internal +4.096V or external 1V–VDD), input mode (unipolar/bipolar), and channel (CH0/CH1/COM). The 4-wire serial interface operates up to 2MHz for data transfer, with conversion synchronized to SCLK edges in external-clock mode (50–500kHz).

Key Specifications

Pinout & Package

The MAX1109EUB+ is housed in a 10-pin µMAX package (3mm × 3mm, 0.5mm pitch), occupying only 20% of an 8-pin plastic DIP footprint. This thermally enhanced, lead-free RoHS-compliant package supports high-density PCB layouts in space-constrained portable instruments.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 8-bit dual-channel ADC applications.

Compared with ADS7822U and MAX1110EUB+, the MAX1109EUB+ uniquely combines VDD monitoring, software-selectable bipolar operation, and guaranteed ±0.5 LSB INL over –40°C to +85°C in a single 10-pin µMAX package - making it optimal for battery-aware, dual-sensor industrial diagnostics.

Availability

MAX1109EUB+ is available at Aetrix Electronics and suitable for portable data logging, hand-held measurement devices, and solar-powered remote systems requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for MAX1109EUB+ 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, medical, and communications applications - emphasizing low power, small size, and high reliability.

The MAX1108/MAX1109 product line targets ultra-low-power, dual-channel data acquisition in space- and energy-constrained environments - delivering integrated reference, track/hold, and serial interface in minimal footprint.

FAQ

What is the operating temperature range for the MAX1109EUB+?

The MAX1109EUB+ is specified for operation from –40°C to +85°C, as confirmed in the Ordering Information table and Absolute Maximum Ratings section. This extended industrial temperature range supports deployment in outdoor remote monitoring systems, automotive diagnostics tools, and medical field equipment where ambient conditions vary widely. The device maintains ±0.5 LSB INL and 130µA supply current across this full range.

Does the MAX1109EUB+ support bipolar input configurations?

Yes, the MAX1109EUB+ supports bipolar input operation through software configuration of its control byte. In bipolar mode, full scale is achieved when |(SI – RI)| = VREF / 2, allowing input signals to span above and below the reference point (e.g., COM or CH1) while staying within the 0V to VDD common-mode range. This is explicitly documented in the "Input Voltage Range" and "Modes of Operation" sections of the datasheet.

What is the minimum acquisition time required for accurate sampling with the MAX1109EUB+?

The MAX1109EUB+ requires a minimum acquisition time (t_ACQ) of 1µs at maximum SCLK frequency (2MHz), as specified in the Electrical Characteristics tables. This value assumes source impedance ≤3kΩ; for higher impedances, t_ACQ increases per the formula t_ACQ = 6(R_S + 6.5kΩ) × 18pF. Accurate sampling also requires COM stability to ±0.5LSB during conversion.

Can the MAX1109EUB+ use an external reference voltage?

Yes, the MAX1109EUB+ accepts an external reference voltage applied to the REF pin, ranging from 1V to VDD. When using an external reference, the internal +4.096V reference is disabled. The REF pin must be bypassed with a 1µF capacitor to GND, and the external reference must remain stable to ±0.5LSB during conversion to maintain accuracy - as detailed in the "External Reference" subsection of the datasheet.

How does the VDD monitoring mode function in the MAX1109EUB+?

The MAX1109EUB+ includes a dedicated VDD monitoring mode activated via bit selection in the control byte. In this mode, the device measures its own supply voltage relative to the internal +4.096V reference and outputs a corresponding 8-bit code. This enables autonomous battery health checks or brown-out detection without external resistive dividers or comparators - a feature explicitly listed under "Features" and described in the "Detailed Description" section.