Analog Devices Inc./Maxim Integrated MAX1109CUB+

Overview

The MAX1109CUB+ from Maxim Integrated is a low-power, 8-bit, dual-channel successive-approximation analog-to-digital converter (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 VDD monitoring for battery-powered systems such as portable data loggers and solar-powered remote sensors.

For engineers reviewing the MAX1109CUB+ datasheet, MAX1109CUB+ pinout, MAX1109CUB+ application, or MAX1109CUB+ equivalent, this page delivers verified electrical parameters, µMAX package layout, real-world use scenarios in system diagnostics and 4–20mA loop devices, and two confirmed alternative ADCs with documented functional and supply-voltage differences.

Technical Context

The MAX1109CUB+ implements a charge-redistribution SAR architecture with integrated track/hold and auto-zero rail, enabling accurate 8-bit conversion without external hold capacitors. Its flexible control byte configures input mode (single-ended/pseudo-differential), reference source (internal +4.096V or external 1V–VDD), clock source (internal 400kHz oscillator or external 50–500kHz), and power-down state.

Conversion timing is tightly coupled to serial clock edges: acquisition begins on the falling edge after bit 4 (SEL0) of the control byte, and hold initiates on the falling edge after bit 2 (I/EREF). Full-scale range is ±VREF/2 in bipolar mode or 0–VREF in unipolar mode, with common-mode input range spanning GND to VDD across CH0, CH1, and COM pins.

Key Specifications

Pinout & Package

The MAX1109CUB+ is housed in a 10-pin µMAX package (3mm × 3mm, 0.5mm pitch), offering 20% footprint of an 8-pin DIP and optimized for space-constrained portable designs.

Key Features

Applications

Equivalent & Alternatives

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

Compared with ADS7822U and TLV2548IDW, the MAX1109CUB+ uniquely combines ultra-low 130µA active current, integrated +4.096V reference, VDD monitoring, and runtime-configurable bipolar/unipolar operation-making it optimal for long-life, feature-rich portable measurement systems.

Availability

The MAX1109CUB+ is available at Aetrix Electronics and suitable for portable data logging, hand-held measurement devices, and system diagnostics requiring stable component supply and long-term lifecycle support.

Supply support for MAX1109CUB+ 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 portable applications.

The MAX1108/MAX1109 product line targets low-power, space-constrained measurement systems requiring dual-channel digitization with minimal external components and flexible software configuration.

FAQ

What is the maximum sampling rate supported by the MAX1109CUB+?

The MAX1109CUB+ supports up to 50ksps using either its internal 400kHz clock or an external clock up to 500kHz. Conversion time is 20µs in external-clock mode and 35µs in internal-clock mode, with acquisition time fixed at 1µs. This rate is sufficient for capturing audio-band signals, motor current waveforms, and sensor transients in portable instrumentation.

Does the MAX1109CUB+ require external components for basic operation?

No, the MAX1109CUB+ operates autonomously with only a 1µF capacitor on the REF pin to stabilize the internal +4.096V reference. No external hold capacitor, reference IC, or level-shifting circuitry is needed. The µMAX package integrates all core functions-including track/hold, SAR engine, and SPI interface-reducing bill-of-materials and PCB area.

How does the VDD monitoring mode work in the MAX1109CUB+?

In VDD monitoring mode, the MAX1109CUB+ uses its internal +4.096V reference to measure the VDD supply voltage directly. The device configures CH0 as the input and internally routes VDD to the analog input path, outputting a digital code proportional to VDD/4.096. This eliminates external resistor dividers and enables accurate battery-voltage tracking in solar- or battery-powered systems.

Can the MAX1109CUB+ interface directly with a 3.3V microcontroller?

Yes, the MAX1109CUB+ digital inputs (CS, DIN, SCLK) accept logic levels from both 3.3V and 5V systems regardless of VDD voltage. With VDD = +5V, VIH is 3V min and VIL is 0.8V max, ensuring reliable recognition of 3.3V logic highs and lows. DOUT outputs VOH ≥ VDD − 0.5V and VOL ≤ 0.4V, compatible with 5V-tolerant MCU inputs.

What is the input voltage range for analog channels on the MAX1109CUB+?

The MAX1109CUB+ supports a 0V to VDD analog input range on CH0, CH1, and COM pins. In unipolar mode, full scale is achieved when (SI − RI) = +4.096V; in bipolar mode, full scale is |SI − RI| = +2.048V. Input clamping diodes protect against −0.3V to VDD + 0.3V faults, but accurate conversion requires signals within GND − 50mV to VDD + 50mV.