Analog Devices Inc./Maxim Integrated MAX1118EKA

Overview

MAX1118EKA from Maxim Integrated is an 8-bit, dual-channel, serial-output analog-to-digital converter (ADC) with internal track/hold, programmable external reference input (1V to VDD), and SPI/QSPI/MICROWIRE-compatible 3-wire interface. It operates from +2.7V to +5.5V, consumes only 135µA at 100ksps, and delivers ±1 LSB INL/DNL over –40°C to +85°C - ideal for low-power battery-operated sensor monitoring in portable instrumentation.

For engineers reviewing the MAX1118EKA datasheet, MAX1118EKA pinout, MAX1118EKA application, or MAX1118EKA equivalent, this page provides verified electrical specs, SOT23-8 pin mapping, real-world use cases in solar-powered remote systems and 4–20mA data acquisition, and two validated alternative ADCs with documented functional and supply-range differences.

Technical Context

The MAX1118EKA uses successive-approximation register (SAR) architecture with integrated track-and-hold, enabling accurate sampling up to 100ksps without external timing components. Its analog input range is fully determined by an externally applied reference (1V to VDD), decoupling full-scale scaling from supply voltage.

Digital communication follows SPI-mode 0 or mode 3 protocols (CPOL/CPHA = 0/0 or 1/1), with conversion results clocked out on SCLK falling edges. The device enters AutoShutdown mode (<1µA) automatically after conversion completion, eliminating need for software-controlled power gating.

Key Specifications

Pinout & Package

MAX1118EKA is housed in an 8-pin SOT23 package (footprint 11% of 8-pin DIP), optimized for space-constrained PCB layouts in handheld and remote devices.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX1117EKA and ADS7822U, the MAX1118EKA uniquely supports external reference scaling (1V–VDD) across the widest supply range (+2.7V to +5.5V), enabling adaptive full-scale configuration in mixed-voltage systems without sacrificing dual-channel capability or AutoShutdown efficiency.

Availability

MAX1118EKA is available at Aetrix Electronics and suitable for portable instrumentation, solar-powered remote sensing, and 4–20mA loop diagnostics requiring stable component supply across extended temperature ranges.

Supply support for MAX1118EKA 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 communications applications.

The MAX1117/MAX1118/MAX1119 family was engineered for ultra-low-power, space-constrained data acquisition - delivering dual-channel 8-bit conversion with integrated T/H and flexible reference architecture in SOT23-8.

FAQ

What is the maximum sampling rate supported by the MAX1118EKA?

The MAX1118EKA supports up to 100ksps (100,000 samples per second) with full 8-bit resolution and guaranteed ±1 LSB INL/DNL performance. This rate is achieved using the internal clock; no external timing components are required. At lower rates like 10ksps, supply current drops to 18µA typical, and in AutoShutdown mode between conversions, it falls below 1µA - making the MAX1118EKA especially efficient for duty-cycled sensing applications.

Does the MAX1118EKA require an external reference voltage?

Yes - the MAX1118EKA is specifically designed to accept an external reference voltage applied to the I.C.(REF) pin, ranging from +1V to VDD. Unlike the MAX1117EKA (fixed +2.048V) or MAX1119EKA (fixed +4.096V), the MAX1118EKA has no internal reference and relies entirely on this external input to define its full-scale analog input range (0 to VREF). The reference must deliver ≤100Ω output impedance and sustain up to 20µA load during conversion.

How does channel selection work on the MAX1118EKA?

Channel selection on the MAX1118EKA is controlled solely by the CNVST pin. A single falling edge on CNVST initiates conversion on CH0. To convert CH1, CNVST must be brought high (for ≥50ns), then brought low again - the second falling edge triggers CH1 sampling. Both channels share the same DOUT pin and serial interface; the conversion result reflects whichever channel was last selected. No additional control lines or register writes are needed.

What is the purpose of the I.C.(REF) pin on the MAX1118EKA?

The I.C.(REF) pin on the MAX1118EKA is the dedicated external reference input terminal. It must be connected to a stable voltage source between +1V and VDD to set the full-scale range (0 to VREF) for both CH0 and CH1 analog inputs. This pin exhibits extremely high DC input impedance (10nA typical leakage), but during conversion it draws up to 20µA average current. For optimal accuracy, the reference source should have ≤100Ω output impedance and be bypassed with ≥10nF capacitance close to the I.C.(REF) pin.

Can the MAX1118EKA operate from a 3.3V supply while using a 2.5V external reference?

Yes - the MAX1118EKA supports independent supply and reference voltages. With VDD = +3.3V, the I.C.(REF) pin can be driven by a precision 2.5V reference, establishing a 0–2.5V input range for CH0 and CH1. This configuration is valid because the MAX1118EKA's supply range (+2.7V to +5.5V) and reference range (+1V to VDD) overlap at 2.5V–3.3V. The device maintains ±1 LSB INL/DNL and 135µA typical supply current at 100ksps under these conditions.