Analog Devices Inc./Maxim Integrated MAX1112EPP+

Overview

The MAX1112EPP+ from Maxim Integrated is an 8-bit, 8-channel successive-approximation analog-to-digital converter (ADC) with integrated track/hold, 4.096V internal reference, SPI/QSPI/MICROWIRE-compatible serial interface, and software-configurable unipolar/bipolar and single-ended/differential input modes. It operates from a single 4.5V–5.5V supply, draws only 135µA at 50ksps, and targets portable data loggers, handheld test equipment, and solar-powered remote sensing systems.

For engineers reviewing the MAX1112EPP+ datasheet, MAX1112EPP+ pinout, MAX1112EPP+ application, or MAX1112EPP+ equivalent, this page delivers verified technical context, real-world timing behavior, confirmed power-down performance (13µA at 1ksps), exact channel configuration logic, and validated alternative options for low-power, multi-channel 8-bit ADC selection in battery-constrained embedded designs.

Technical Context

The MAX1112EPP+ uses a capacitive DAC-based successive-approximation architecture with an internal track/hold circuit that acquires input signals in ≤1µs (typical) and completes conversion in 25µs (internal clock mode) or 10 SCLK cycles (external clock mode). Its analog front-end supports pseudo-differential sampling via configurable IN+/IN− pairs (CH0/CH1, CH2/CH3, CH4/CH5, CH6/CH7) with COM-referenced common-mode stability requirements (±0.5 LSB).

Serial communication follows a strict 8-bit control byte format (START–SEL2–SEL1–SEL0–UNI/BIP–SGL/DIF–PD1–PD0) that defines channel, polarity, input mode, and power state before each conversion. The device supports two clock modes: external clock (50kHz–500kHz, 50% duty cycle) for synchronous µP control, and internal clock (400kHz typ) enabling asynchronous readout at up to 2MHz SCLK without conversion interruption.

Key Specifications

Pinout & Package

The MAX1112EPP+ is housed in a 20-pin SSOP (Shrink Small Outline Package) with 0.65mm lead pitch, JEDEC MO-153 compliant, and thermal pad omitted. Pin functions are electrically validated per Maxim's official datasheet Rev 2 (April 2011).

Key Features

Applications

Equivalent & Alternatives

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

Compared with ADS7822U and MAX1110EAP+, the MAX1112EPP+ uniquely combines 8-channel flexibility, internal T/H, bipolar support, and ultra-low 13µA power-down current - making it optimal for compact, battery-operated systems requiring full analog signal chain integration without external support components.

Availability

The MAX1112EPP+ is available at Aetrix Electronics and suitable for portable instrumentation, remote condition monitoring, and medical diagnostics requiring stable component supply across extended temperature ranges (–40°C to +85°C) and long production lifecycles.

Supply support for MAX1112EPP+ 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 fabless semiconductor company specializing in high-performance analog, mixed-signal, and power management ICs for industrial, medical, and communications applications.

The MAX1112EPP+ belongs to Maxim's legacy low-power serial ADC product line, designed specifically for space- and energy-constrained embedded systems requiring integrated signal conditioning, minimal external components, and robust serial interfacing.

FAQ

What is the maximum sampling rate of the MAX1112EPP+ and under what conditions is it achieved?

The MAX1112EPP+ achieves a maximum sampling rate of 50ksps when using an external 500kHz serial clock with 10 clock cycles per conversion and unipolar input mode. This rate assumes VDD = 4.5V–5.5V, TA = –40°C to +85°C, and proper 1µF REFOUT bypassing. At lower clock frequencies or in internal clock mode, the effective rate decreases due to fixed 25µs conversion time.

Does the MAX1112EPP+ support differential input measurements, and how are they configured?

Yes, the MAX1112EPP+ supports pseudo-differential measurements across four channel pairs: CH0/CH1, CH2/CH3, CH4/CH5, and CH6/CH7. Configuration is done via the SGL/DIF bit (bit 2) and SEL2–SEL0 bits (bits 4–6) in the 8-bit control byte. In differential mode, IN+ and IN– are internally switched to the selected pair, with COM serving as the reference for common-mode stability.

How does the power-down mode operate on the MAX1112EPP+, and what are the current savings?

The MAX1112EPP+ offers two power-down methods: software-controlled (PD1/PD0 bits in control byte) and pin-driven (SHDN pulled to DGND). Software power-down reduces supply current to 13µA at 1ksps sampling, while SHDN-driven mode achieves ≤10µA. Both retain register state and allow wake-up in <1µs, enabling rapid resumption of acquisition without reconfiguration.

What is the role of the SSTRB pin on the MAX1112EPP+, and how does its behavior differ between clock modes?

The SSTRB pin on the MAX1112EPP+ provides hardware end-of-conversion signaling. In external clock mode, it pulses high for two SCLK periods before MSB output. In internal clock mode, it asserts low for 25µs (typ) starting at conversion initiation and returns high upon completion. This allows µPs to use SSTRB as an interrupt source in both modes, eliminating polling overhead.

Can the MAX1112EPP+ operate with an external reference voltage, and what is the acceptable range?

Yes, the MAX1112EPP+ accepts an external reference voltage applied to the REFIN pin. The valid range is 1V to VDD (4.5V–5.5V), allowing full-scale input spans from 1V to 5.5V. When using an external reference, the internal 4.096V reference is disabled, and REFOUT becomes high-impedance. Accuracy remains within ±1 LSB TUE as long as the external reference meets required stability and noise specs.