Analog Devices Inc./Maxim Integrated MAX199AEWI

Overview

MAX199AEWI 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, fault protection to ±16.5V, and 100ksps throughput - used in industrial control systems for interfacing 4mA-to-20mA and ±12V sensors to low-voltage microprocessor-based systems.

For engineers reviewing the MAX199AEWI datasheet, MAX199AEWI pinout, MAX199AEWI application, or MAX199AEWI equivalent, this page delivers verified specifications, package mapping to 28-pin wide SO, confirmed 8+4 parallel bus interface timing, internal/external clock and acquisition control modes, and real-world design implications of its ±VREF/±VREF/2/0–VREF/0–VREF/2 range selection.

Technical Context

The MAX199AEWI implements a successive-approximation ADC with integrated track/hold circuitry, supporting both internal (6-clock-cycle) and external (dual-WR edge-triggered) acquisition control. Its input multiplexer is fault-protected to ±16.5V independent of power state, and conversion completes in 6µs with 12 clock cycles.

It features dual reference options: internal 4.096V buffer (trimmable via REFADJ) or external reference applied at REF or REFADJ pins; the 8+4 parallel interface uses HBEN to multiplex LSBs (HBEN = low) or MSBs (HBEN = high), with TTL/CMOS-compatible digital I/O and three-state outputs.

Key Specifications

Pinout & Package

MAX199AEWI is packaged in a 28-pin wide SO (Small Outline) surface-mount package, pin-compatible with other MAX199 variants in DIP, SSOP, and ceramic SB packages.

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 MAX199AEWI uniquely combines software-configurable input scaling, ±16.5V fault tolerance, and 8+4 bus architecture - making it irreplaceable in mixed-signal industrial systems requiring field-reconfigurable sensor interfacing without hardware changes.

Availability

MAX199AEWI is available at Aetrix Electronics and suitable for industrial process monitoring, automated test equipment, medical patient monitoring, and telecom line card diagnostics requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for MAX199AEWI 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 and mixed-signal ICs for industrial, medical, and communications applications, emphasizing high integration, robustness, and low-power operation.

The MAX199AEWI belongs to Maxim's high-accuracy data-acquisition system family, engineered specifically for single-supply industrial systems needing flexible sensor interfacing, fault resilience, and µP-friendly parallel connectivity.

FAQ

What is the operating temperature range for the MAX199AEWI?

The MAX199AEWI is specified for operation from 0°C to +70°C. This commercial-grade temperature range aligns with its intended use in controlled-environment industrial and test equipment applications. The 'E' grade (MAX199EEWI) extends to -40°C to +85°C, while the 'M' grade covers -55°C to +125°C - but the MAX199AEWI itself is validated only across the 0°C to +70°C span per its ordering code suffix 'A' and packaging documentation.

Does the MAX199AEWI require an external reference, or does it have an internal one?

The MAX199AEWI includes an internal 4.096V reference buffer, adjustable via the REFADJ pin over ±1.5%. It can operate fully autonomously using this internal reference, bypassed with a 4.7µF capacitor at REF and 0.01µF at REFADJ. Alternatively, an external reference may be applied at either REF (with REFADJ tied to VDD to disable the buffer) or REFADJ (to leverage the 1.6384× gain for generating 4.096V from a 2.5V source). No external reference is required for basic operation of the MAX199AEWI.

How does the 8+4 bus interface of the MAX199AEWI work in practice?

The MAX199AEWI uses an 8+4 parallel interface to fit 12-bit data onto an 8-bit microprocessor bus. When HBEN is low, D0–D7 carry the 8 LSBs of the conversion result; when HBEN is high, D0–D3 carry the 4 MSBs, and D4–D7 replicate the MSB (in bipolar mode) or are zero (in unipolar mode). This eliminates the need for external latches or wider data buses, enabling direct connection to standard 8-bit µPs like the 8051 or Z80 - a core design advantage of the MAX199AEWI.

What are the key differences between STBYPD and FULLPD power-down modes in the MAX199AEWI?

In STBYPD (standby power-down), the internal reference buffer remains active, allowing immediate conversion restart without reference settling delay - ideal for periodic sampling. In FULLPD (full power-down), all circuitry except the digital interface shuts down, reducing supply current to <10µA. Both modes preserve input fault protection and allow register reads. The MAX199AEWI exits either mode on the first WR pulse, but STBYPD avoids the 8ms reference settling time required after FULLPD - a critical distinction for low-latency wake-up scenarios.

Can the MAX199AEWI interface directly with ±12V or ±15V powered sensors?

Yes - the MAX199AEWI supports this directly via its software-programmable input ranges. When configured for ±VREF (±4.096V) or ±VREF/2 (±2.048V) ranges, and paired with appropriate external signal conditioning (e.g., resistive scaling networks), it safely acquires signals from ±12V or ±15V sensors. Its ±16.5V fault tolerance protects inputs during transients or miswiring. The MAX199AEWI's ability to handle these rails without external op-amps or isolated supplies is a defining feature for industrial sensor fusion systems.