Analog Devices Inc./Maxim Integrated MAX1108CUB

Overview

The MAX1108CUB from Maxim Integrated is a low-power, 8-bit, dual-channel analog-to-digital converter (ADC) with internal track/hold, +2.048V reference, SPI/QSPI/MICROWIRE-compatible serial interface, and software-configurable unipolar/bipolar input modes. It operates from +2.7V to +3.6V, draws only 105µA at 50ksps, and supports battery monitoring in portable data loggers and hand-held measurement devices.

For engineers reviewing the MAX1108CUB datasheet, MAX1108CUB pinout, MAX1108CUB application, or MAX1108CUB equivalent, key selection criteria include its 10-pin µMAX package, 50ksps conversion rate, ±0.15 LSB INL, 0.5µA power-down current, and VDD monitoring capability - all critical for ultra-low-power embedded sensing systems.

Technical Context

The MAX1108CUB uses successive-approximation register (SAR) architecture with integrated track/hold and auto-zero rail, enabling accurate sampling without external hold capacitors. Its flexible control byte configures reference source (internal +2.048V or external 1V–VDD), clock mode (internal 400kHz oscillator or external 50–500kHz), and input topology (single-ended, pseudo-differential, unipolar, or bipolar).

Conversion timing is tightly coupled to serial clock edges: acquisition begins on falling edge after bit 4 (SEL0), hold initiates after bit 2 (I/EREF), and full 8-bit result is available within 20µs (external clock) or 35µs (internal clock). Input common-mode range spans 0 to VDD, with ±0.5LSB COM stability requirement during conversion.

Key Specifications

Pinout & Package

The MAX1108CUB is housed in a 10-pin µMAX package (3mm × 3mm, 0.5mm pitch), offering 20% footprint of an 8-pin DIP. Pin functions are validated per Maxim's official pin description table and functional diagram.

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 MAX1112CPE+, the MAX1108CUB uniquely combines ultra-low quiescent current (105µA), integrated +2.048V reference, VDD monitoring, and 10-pin µMAX packaging - making it optimal for space- and energy-constrained portable instrumentation.

Availability

MAX1108CUB is available at Aetrix Electronics and suitable for portable data logging, hand-held measurement devices, and medical instruments requiring stable component supply across industrial temperature ranges (0°C to +70°C).

Supply support for MAX1108CUB 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 demanding industrial, medical, and portable applications.

The MAX1108CUB belongs to Maxim's low-power serial ADC product line, engineered specifically for battery-operated instrumentation where accuracy, size, and microamp-level power consumption are co-critical design constraints.

FAQ

What is the operating temperature range for the MAX1108CUB?

The MAX1108CUB is specified for operation from 0°C to +70°C (commercial grade), as confirmed in the Ordering Information table. This range supports indoor portable instrumentation and consumer-grade measurement tools. The device's internal reference exhibits ±50ppm/°C tempco, and DC accuracy parameters (INL, DNL, offset) are guaranteed across this full range. For extended temperature applications, the MAX1108EUB (-40°C to +85°C) variant is available.

Does the MAX1108CUB require external components for basic operation?

Yes - the MAX1108CUB requires a 1µF capacitor from REF to GND to stabilize the internal +2.048V reference, as specified in the Electrical Characteristics and Typical Operating Circuit (Figure 3). A 0.1µF capacitor is also recommended at COM for noise reduction in bipolar mode. No external hold capacitor is needed due to the integrated track/hold circuit. All digital interface connections (CS, DIN, SCLK, DOUT) connect directly to a microcontroller without level-shifting logic.

How does the VDD monitoring mode work in the MAX1108CUB?

The MAX1108CUB's VDD monitoring mode is activated via bit5 (VDDMON) in the 8-bit control byte. When enabled, the device internally routes VDD to the analog input mux, allowing direct digitization of the supply voltage. With the internal +2.048V reference, this yields a 0–3.6V measurement range resolved to ~14mV/LSB. This feature eliminates the need for external resistor dividers in battery-powered systems, simplifying BOM and improving accuracy over temperature compared to discrete solutions.

Can the MAX1108CUB interface directly with a 5V microcontroller SPI port?

Yes - the MAX1108CUB's digital inputs (CS, DIN, SCLK) accept logic-high voltages up to VDD + 0.05V and tolerate 5V signals even when VDD = 3.0V, as verified in the "DIGITAL INPUTS" section of the datasheet. DOUT is CMOS-compatible and drives to VDD – 0.5V (min) at 0.5mA, so a 3.3V MAX1108CUB can safely drive a 5V-tolerant MCU input. No level shifters are required, though pull-up resistors should reference the MCU's VIO voltage if used.

What is the maximum achievable sampling rate using the internal clock of the MAX1108CUB?

The MAX1108CUB's internal oscillator operates at 400kHz, and conversion requires 10 clock cycles per sample (per Figure 6 timing diagram and Note 5). Therefore, the maximum sampling rate using the internal clock is 40ksps (400kHz ÷ 10). This is slightly below the 50ksps achievable with a 500kHz external clock, but eliminates the need for an external timing source - simplifying layout and reducing component count in cost-sensitive designs.