Analog Devices Inc./Maxim Integrated MAX1108CUB+

Overview

MAX1108CUB+ from Maxim Integrated is a low-power, 8-bit, dual-channel successive-approximation ADC with integrated track/hold, internal +2.048V reference, SPI/QSPI/MICROWIRE-compatible 4-wire 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, this page delivers verified electrical parameters, µMAX package layout, real-world use cases in solar-powered remote systems and medical instruments, and two validated alternative parts with documented technical and application differences.

Technical Context

The MAX1108CUB+ employs a charge-redistribution SAR architecture with an on-chip track/hold circuit and auto-zero rail referenced to VDD/2. Its conversion process uses a 18pF capacitive DAC and supports both internal clock (400kHz typical) and external serial clock (50–500kHz) modes.

All operating modes-including input configuration (CH0/CH1/COM), reference source (internal +2.048V or external 1V–VDD), unipolar/bipolar range, and power-down-are controlled via an 8-bit software-configurable control byte shifted through DIN. Acquisition time is fixed at 1µs at 2MHz SCLK, with tCONV = 20µs (external clock) or 35µs (internal clock).

Key Specifications

Pinout & Package

The MAX1108CUB+ is housed in a 10-pin µMAX package (3mm × 3mm, 0.5mm pitch), occupying only 20% of an 8-pin plastic DIP footprint. The package is RoHS-compliant and rated for 0°C to +70°C operation.

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 MCP3002-I/P, the MAX1108CUB+ uniquely combines ultra-low 105µA power, integrated +2.048V reference, VDD monitoring, and software-selectable bipolar/unipolar modes in a miniature µMAX package-making it optimal for space-constrained, battery-operated measurement systems requiring long runtime and flexible signal conditioning.

Availability

MAX1108CUB+ is available at Aetrix Electronics and suitable for portable data logging, hand-held measurement devices, and solar-powered remote systems requiring stable component supply, guaranteed traceability, and lifecycle continuity.

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) is a semiconductor company specializing in high-performance analog, mixed-signal, and power-management ICs for industrial, medical, and portable applications.

The MAX1108CUB+ belongs to Maxim's precision low-power ADC product line, designed specifically for battery-operated instrumentation where minimal power, small size, and configurable analog front-end functionality are critical.

FAQ

What is the maximum sampling rate supported by the MAX1108CUB+?

The MAX1108CUB+ supports up to 50ksps in external clock mode with a 500kHz SCLK. Conversion time is 20µs under these conditions. In internal clock mode, the maximum rate drops to ~28.6ksps due to the 400kHz internal oscillator frequency, yielding a 35µs conversion time. Both modes maintain full 8-bit accuracy and monotonicity across the specified temperature range.

Does the MAX1108CUB+ require external components for basic operation?

Yes - the MAX1108CUB+ requires a 1µF ceramic capacitor from REF to GND for internal reference stability, and a 0.1µF capacitor from VDD to GND for supply decoupling. No external hold capacitor or op-amps are needed due to its integrated track/hold and software-configurable input architecture. External resistive dividers may be used for inputs exceeding VDD, but are not mandatory for 0–VDD range signals.

How does the VDD monitoring mode work in the MAX1108CUB+?

In VDD monitoring mode, the MAX1108CUB+ internally routes VDD to the CH0 input and uses the +2.048V internal reference to perform a ratiometric measurement. The resulting 8-bit code represents VDD relative to 2.048V (e.g., code 0xFF ≈ 3.6V). This enables autonomous battery voltage tracking without external resistive dividers or additional ADC channels, reducing system complexity and power consumption.

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

Yes - the MAX1108CUB+ digital inputs (CS, DIN, SCLK) accept logic-high voltages up to VDD + 0.05V and are compatible with both 3.3V and 5V logic families regardless of its own +2.7V–3.6V supply. However, DOUT output swing is limited to 0–VDD, so a level shifter is required if the host MCU expects 5V-tolerant inputs. For 3.3V MCUs, direct connection is fully compliant.

What is the significance of the COM pin in MAX1108CUB+ operation?

The COM pin serves as the common-mode reference for analog inputs in single-ended and pseudo-differential modes. In unipolar single-ended mode, it sets the zero-code voltage (e.g., 0V = code 0x00). During conversion, COM must remain stable to ±0.5LSB (±0.1LSB for best performance) relative to GND. It is not a ground pin - connecting COM to GND is optional and application-dependent, not mandatory.