Analog Devices Inc./Maxim Integrated MAX158AEAI

Overview

MAX158AEAI from Maxim Integrated is an 8-channel, 8-bit CMOS analog-to-digital converter with integrated track/hold, 2.5V on-chip reference, and 2.5µs per-channel conversion time. It operates from a single +5V supply, accepts 0V to +5V analog inputs, and interfaces directly to microprocessor data buses via latched three-state outputs. It is used in high-speed data acquisition systems requiring multi-channel sampling without external support circuitry.

For engineers reviewing the MAX158AEAI datasheet, MAX158AEAI pinout, MAX158AEAI application, or MAX158AEAI equivalent, key selection criteria include its 8-channel multiplexed architecture, ±1/2 LSB total unadjusted error, SSOP-28 package, Mode 0/Mode 1 digital interface flexibility, and built-in reference stability over –40°C to +85°C.

Technical Context

The MAX158AEAI employs a half-flash conversion architecture with two 4-bit flash ADC sections and an internal DAC to generate the full 8-bit result in 2.5µs. Its analog input stage uses sampled-data comparators with 45pF input capacitance and requires ≤100Ω source impedance for full-spec settling within the 1µs tracking window.

Digital control relies solely on CS and RD signals, supporting two modes: Mode 0 (WAIT-state compatible, INT-driven read) and Mode 1 (non-WAIT, pipelined read of prior result). Status is indicated via open-drain RDY (for READY/WAIT input) and active-low INT outputs.

Key Specifications

Pinout & Package

MAX158AEAI is housed in a 28-pin Shrink Small-Outline Package (SSOP) with 0.65 mm lead pitch, measuring 10.33 mm × 5.38 mm × 1.99 mm (max), optimized for high-density PCB layouts.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX158BCAI, the MAX158AEAI offers superior accuracy (±1/2 LSB vs. ±1 LSB) at identical temperature rating and package; versus ADS7822U, it provides integrated MUX, reference, and higher throughput-but in a larger 28-pin footprint.

Availability

MAX158AEAI is available at Aetrix Electronics and suitable for high-speed data acquisition, telecommunications infrastructure, and audio instrumentation requiring stable component supply across industrial temperature ranges.

Supply support for MAX158AEAI 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, communications, and computing markets.

The MAX154/MAX158 product line was designed for compact, high-speed data acquisition systems needing integrated signal conditioning-replacing discrete ADC + MUX + reference combinations with a single 8-bit solution.

FAQ

What is the maximum sampling rate achievable with the MAX158AEAI?

The MAX158AEAI achieves a maximum aggregate sampling rate of 400 kHz, calculated as 1/(tCRD + tp) = 1/(2.5 µs + 0.5 µs). This allows up to 50 kHz per channel across all eight inputs. The rate is constrained by the fixed 2.5 µs conversion time and minimum 500 ns delay between conversions, as specified in the electrical characteristics table. MAX158AEAI maintains this performance across its full –40°C to +85°C operating range.

Does the MAX158AEAI require an external clock signal?

No, the MAX158AEAI does not require an external clock. All timing is generated internally and controlled exclusively by the CS and RD digital inputs. Conversion initiation, tracking duration, and data latching are fully synchronous to these control signals-enabling simple interface with microprocessors lacking dedicated ADC clocks. This self-timed operation is confirmed in the Digital Interface section and timing diagrams for both Mode 0 and Mode 1.

What is the purpose of the REF OUT pin on the MAX158AEAI?

The REF OUT pin on the MAX158AEAI provides a buffered 2.50 V ±3 mV reference voltage derived from the internal bandgap circuit. It serves dual purposes: (1) as the stable reference for the ADC's conversion process, and (2) as a precision voltage source for external circuitry such as sensor excitation or comparator thresholds. Datasheet Figure 8a specifies mandatory 0.01 µF bypassing to GND to maintain stability-larger capacitors degrade reference buffer performance.

Can the MAX158AEAI operate with bipolar analog inputs?

Yes, the MAX158AEAI can digitize bipolar inputs using external signal conditioning. As shown in Figure 10a of the datasheet, an op-amp stage scales and offsets ±4V inputs into the 0V–5V unipolar range accepted by the ADC. The resulting output code follows complementary offset binary format. This configuration preserves the MAX158AEAI's ±1/2 LSB accuracy and 2.5 µs conversion time, provided the op-amp maintains sufficient loop gain at ~1 MHz to drive the 45 pF input capacitance.

What digital interface modes does the MAX158AEAI support?

The MAX158AEAI supports two hardware-configurable interface modes determined by RD pulse width: Mode 0 (WAIT-state compatible) and Mode 1 (pipelined, non-WAIT). In Mode 0, RD remains low until conversion completes, and data is read after INT asserts. In Mode 1, RD is pulsed narrow enough to read the previous result while initiating the next conversion-requiring ≥2.5 µs between RD edges. Both modes use only CS and RD, with no additional control lines needed.