Analog Devices Inc./Maxim Integrated MAX1112CAP+

Overview

MAX1112CAP+ 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 logging and hand-held measurement systems.

For engineers reviewing the MAX1112CAP+ datasheet, MAX1112CAP+ pinout, MAX1112CAP+ application, or MAX1112CAP+ equivalent, key selection considerations include its 8-channel single-ended input capability, 1µs minimum acquisition time, ±1 LSB total unadjusted error, internal clock option for interrupt-driven operation, and SSOP-20 package compatibility with space-constrained embedded sensor interfaces.

Technical Context

The MAX1112CAP+ implements a capacitive DAC-based successive-approximation architecture with an internal track/hold circuit that acquires signals in ≤1µs 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 channel pairs (CH0/CH1, CH2/CH3, etc.) and accepts input ranges from AGND to VDD with ±0.5 LSB COM stability requirement.

Digital control is executed via an 8-bit command byte (START, SEL2–SEL0, UNI/BIP, SGL/DIF, PD1, PD0) shifted in on DIN with CS active low; conversion results are output MSB-first on DOUT synchronized to SCLK falling edges. The SSTRB pin provides end-of-conversion strobe-low-active in internal clock mode, pulse-high in external clock mode-and enables direct interrupt handling without polling.

Key Specifications

Pinout & Package

The MAX1112CAP+ is housed in a 20-pin SSOP (Shrink Small Outline Package) with 0.65mm pitch, optimized for high-density PCB layouts in portable instrumentation.

Key Features

Applications

Equivalent & Alternatives

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

Compared with ADS7822U, MAX1112CAP+ trades 150ksps headroom for integrated reference and double the input channels; versus MAX1113CEE+, it delivers 100% more analog inputs in a slightly larger package-making it optimal for space-tolerant, multi-sensor edge nodes requiring self-contained accuracy.

Availability

MAX1112CAP+ is available at Aetrix Electronics and suitable for portable data logging, hand-held measurement devices, and medical instruments requiring stable component supply, long-term lifecycle support, and guaranteed traceable sourcing.

Supply support for MAX1112CAP+ 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 communications applications.

The MAX1112/MAX1113 product line was designed for ultra-low-power, multi-channel data acquisition in battery-operated and space-constrained systems-emphasizing integration of reference, track/hold, and serial interface to reduce system-level complexity.

FAQ

What is the maximum sampling rate supported by the MAX1112CAP+?

The MAX1112CAP+ achieves up to 50ksps when using the external serial clock at 500kHz with 10 clocks per conversion cycle. In internal clock mode, conversion time is fixed at 25µs (typ), enabling sustained 40ksps operation independent of host processor timing. This rate supports accurate digitization of signals up to 25kHz under Nyquist criteria, making MAX1112CAP+ suitable for audio-band and sensor signal conditioning tasks.

Does the MAX1112CAP+ require an external voltage reference?

No, the MAX1112CAP+ includes a precision 4.096V internal reference with ±0.8ppm/°C temperature coefficient, eliminating the need for an external reference in most applications. REFOUT is provided for bypassing with a 1µF capacitor to AGND. An external reference (1V to VDD) may be applied to REFIN if tighter tolerance or different full-scale range is required-but doing so disables the internal reference and increases component count.

How does the SHDN pin function on the MAX1112CAP+?

The SHDN pin on the MAX1112CAP+ operates in three states: high-impedance (normal operation), pulled low (10µA shutdown mode), or pulled high (internal reference disabled while analog core remains active). This three-level control allows selective power gating-e.g., disabling the reference during sleep while retaining fast wake-up capability. Unlike simple enable pins, SHDN provides granular control over power domains without requiring firmware reconfiguration.

Can the MAX1112CAP+ perform differential measurements?

Yes, the MAX1112CAP+ supports true pseudo-differential measurements using four configurable channel pairs: CH0/CH1, CH2/CH3, CH4/CH5, and CH6/CH7. In differential mode, the device samples the voltage difference between the selected pair while rejecting common-mode noise. The COM pin serves as the reference point, and input stability within ±0.5 LSB is required on the negative input to maintain accuracy-achievable with a 0.1µF capacitor to AGND.

What serial interface protocols is the MAX1112CAP+ compatible with?

The MAX1112CAP+ is fully compatible with SPI, QSPI, and MICROWIRE serial protocols through its 4-wire interface (CS, SCLK, DIN, DOUT). It requires CPOL = 0 and CPHA = 0 for SPI mode. All protocols use MSB-first, 8-bit command and data framing. The SSTRB pin provides hardware-ready signaling, allowing interrupt-driven transfers without polling-making MAX1112CAP+ interoperable with virtually all modern microcontrollers' hardware serial peripherals.