Analog Devices Inc./Maxim Integrated MAX199ACWI

Overview

MAX199ACWI from Maxim Integrated is a 12-bit, multi-range data-acquisition system (DAS) with eight software-programmable analog input channels, single +5V supply operation, ±4V input range capability, and 100ksps throughput rate. It integrates fault-protected multiplexing (±16.5V), internal/external clock support, and an 8+4 parallel bus interface for microprocessor systems in industrial data logging and sensor interfacing applications.

For engineers reviewing the MAX199ACWI datasheet, MAX199ACWI pinout, MAX199ACWI application, or MAX199ACWI equivalent, this page delivers verified technical context, real-world timing behavior, confirmed power-down modes (STBYPD/FULLPD), reference configuration options (internal 4.096V or external), and precise analog input range selection logic (±VREF, ±VREF/2, 0–VREF, 0–VREF/2).

Technical Context

The MAX199ACWI employs successive-approximation architecture with integrated track-and-hold (5MHz small-signal bandwidth) and programmable acquisition control-either internally timed (6-clock-cycle hold) or externally triggered via dual WR pulses. Its 12-bit conversion result is delivered via an 8+4 multiplexed parallel bus, where HBEN selects between LSBs (HBEN = low) or MSBs (HBEN = high), preserving compatibility with 8-bit µP data buses.

Input channel selection, polarity (bipolar/unipolar), full-scale range, and power-down mode are all configured via an 8-bit control byte written to D7–D0 during CS/WR assertion. The device supports both internal reference (4.096V buffered output at REF, adjustable via REFADJ) and external reference modes, with REFADJ gain trimmed to 1.6384 for precise scaling.

Key Specifications

Pinout & Package

MAX199ACWI is packaged in a 28-pin Wide SO (Small Outline) package, compatible with surface-mount assembly and offering thermal and mechanical stability for industrial environments.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar data-acquisition system applications.

Compared with MAX197BCWI and ADS7816U, the MAX199ACWI uniquely combines software-configurable sub-ranges, integrated ±16.5V fault protection, and internal 4.096V reference - reducing external component count by ≥7 parts and enabling direct connection to 4–20mA sensors without signal conditioning.

Availability

MAX199ACWI is available at Aetrix Electronics and suitable for industrial-control systems, automated test equipment, medical instrumentation, and robotics requiring stable component supply, long-term lifecycle support, and consistent parametric performance across temperature.

Supply support for MAX199ACWI 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 MAX199ACWI belongs to Maxim's high-accuracy data-acquisition system family, engineered specifically for single-supply, multi-sensor industrial monitoring where fault resilience, range flexibility, and µP compatibility are critical.

FAQ

What input voltage ranges does the MAX199ACWI support, and how are they selected?

The MAX199ACWI supports four software-selectable input ranges: ±VREF, ±VREF/2, 0V to VREF, and 0V to VREF/2 - corresponding to ±4.096V, ±2.048V, 0–4.096V, and 0–2.048V when using the internal reference. These are configured via the RNG and BIP bits (D4, D3) in the 8-bit control byte written during a WR cycle. This flexibility allows direct interfacing with 4–20mA transmitters, ±12V sensors, and unipolar industrial signals without external op-amp scaling networks.

Does the MAX199ACWI require an external reference, or can it operate with its internal reference?

The MAX199ACWI operates with either its internal 4.096V bandgap reference (available at the REF pin, adjustable via REFADJ) or an external reference applied to REF or REFADJ. In internal mode, a 4.7µF capacitor is required at REF and 0.01µF at REFADJ. In external mode, REFADJ must be tied to VDD to disable the internal buffer. The internal reference provides ±10ppm/°C drift and eliminates the need for external reference ICs in most industrial applications.

How does the 8+4 parallel bus interface of the MAX199ACWI work with standard 8-bit microprocessors?

The MAX199ACWI uses an 8+4 multiplexed parallel interface: when HBEN = low, D0–D7 carry the 8 LSBs of the 12-bit result; when HBEN = high, D4–D7 carry the 4 MSBs (with sign extension in bipolar mode). This allows seamless connection to 8-bit µPs like the 8051 or Z80 without data bus widening. CS, RD, and WR provide standard I/O strobe timing, and INT signals conversion completion - enabling efficient polled or interrupt-driven data reads in the MAX199ACWI.

What are the two power-down modes of the MAX199ACWI, and when should each be used?

The MAX199ACWI offers STBYPD (standby power-down) and FULLPD (full power-down), selected via PD0/PD1 bits in the control byte. STBYPD keeps the internal reference buffer active - eliminating start-up delay when resuming conversion. FULLPD shuts down all analog circuitry, drawing ≤5µA. Use STBYPD in burst-sampling applications (e.g., portable data loggers); use FULLPD in always-off standby states (e.g., remote sensor nodes powered by coin cells) to maximize battery life.

Is the MAX199ACWI pin-compatible with other members of the MAX19x family, such as the MAX197 or MAX196?

No, the MAX199ACWI is not pin-compatible with the MAX197 or MAX196. While functionally related, these devices differ in pin assignment (e.g., MAX197 uses different control bit mapping and lacks HBEN), package pinouts, and reference architecture. The MAX199ACWI's 28-pin Wide SO layout and 8+4 bus structure are unique to its multi-range, fault-protected DAS architecture. Direct replacement requires PCB redesign and firmware updates to match control byte definitions and timing sequences.