Analog Devices Inc./Maxim Integrated MAX158ACPI

Overview

MAX158ACPI from Maxim Integrated is an 8-bit, 8-channel high-speed analog-to-digital converter (ADC) with integrated track/hold, on-chip 2.5V reference, and single +5V supply operation. It delivers 2.5µs per-channel conversion time, supports 0V to +5V analog input range, and interfaces directly to microprocessor data buses via latched three-state outputs - used in real-time speech analysis and high-speed servo control systems.

For engineers reviewing the MAX158ACPI datasheet, MAX158ACPI pinout, MAX158ACPI application, or MAX158ACPI equivalent, this page provides verified technical context, exact pin functions, confirmed accuracy specs (±1/2 LSB), interface timing behavior (Mode 0/1), and validated alternative options for multi-channel data acquisition designs.

Technical Context

The MAX158ACPI employs a half-flash architecture with two 4-bit flash ADC sections and an internal DAC to generate 8-bit results using 31 comparators. Its built-in track/hold eliminates external sample-and-hold circuitry, and the 2.5V reference output (REF OUT) is internally buffered and specified at 2.47–2.53V with ±100ppm/°C drift.

Digital interface relies solely on CS and RD control lines, supporting two modes: Mode 0 (WAIT-state compatible, conversion starts on CS+RD low, data valid after INT assertion) and Mode 1 (no WAIT required, RD low reads prior result while initiating new conversion). Conversion timing is fixed at 2.5µs (typ), with minimum inter-conversion delay of 500ns.

Key Specifications

Pinout & Package

MAX158ACPI is housed in a 28-pin plastic DIP package (0.600" wide), compliant with JEDEC MS-001. Pin spacing is 0.100", body width 0.600", and lead finish is matte tin.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX158ACPI, ADS7822U trades parallel simplicity for higher resolution and serial flexibility, while MAX1113ECPP offers identical performance in a smaller footprint at half the channel count - both require revalidation of timing margins and bus interface logic.

Availability

MAX158ACPI is available at Aetrix Electronics and suitable for high-speed data acquisition, telecommunications infrastructure monitoring, and real-time servo control applications requiring stable component supply across extended production lifecycles.

Supply support for MAX158ACPI 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 and mixed-signal ICs for industrial, communications, and computing markets.

The MAX154/MAX158 product line was designed specifically for cost-sensitive, high-throughput data acquisition systems where integration of multiplexer, track/hold, reference, and parallel interface reduces system-level component count and layout complexity - exemplified by the MAX158ACPI variant.

FAQ

What is the operating temperature range for MAX158ACPI?

The MAX158ACPI is rated for 0°C to +70°C ambient operation, as indicated by the 'C' suffix in the part number. This commercial-grade temperature range is validated across all electrical specifications including ±1/2 LSB total unadjusted error, 2.5µs conversion time, and 2.50V reference output stability. The device uses silicon process and packaging qualified for this range, and derating is not required within these limits.

Does MAX158ACPI require an external clock signal?

No, MAX158ACPI does not require an external clock. It contains an internal timing generator that controls the half-flash conversion sequence, track/hold sampling, and output latching autonomously. All timing is derived from the +5V supply and internal RC networks - confirmed by the "No External Clock" feature in the official datasheet and absence of CLK or XTAL pins in the pinout.

Can MAX158ACPI operate with a 0V to +2.5V input range using its internal reference?

Yes, MAX158ACPI can operate with a 0V to +2.5V input range by connecting VREF+ to REF OUT (2.5V) and VREF- to GND. This configuration scales the full-scale code to 2.5V instead of 5V, maintaining 8-bit resolution and ±1/2 LSB accuracy. The transfer function remains linear, and no hardware modification beyond reference wiring is needed - verified in the Analog Considerations section of the datasheet.

What is the maximum recommended source impedance for analog inputs on MAX158ACPI?

The maximum recommended source impedance for MAX158ACPI analog inputs is 100Ω. This limit ensures full settling of the 45pF input capacitance within the 1µs internal acquisition window, preventing gain and linearity errors. Exceeding 100Ω introduces measurable settling error, as modeled in the RC network analysis (Figure 9b) and confirmed by the "large source resistances (>100Ω) will cause settling errors" statement in the datasheet.

How does the RDY pin function in Mode 0 versus Mode 1 operation of MAX158ACPI?

In Mode 0, RDY goes low on the falling edge of CS and returns to high-impedance at conversion completion - directly driving a microprocessor's WAIT input. In Mode 1, RDY goes low on CS fall and returns to high-impedance on CS rise, decoupling it from conversion status. Both modes use open-drain RDY requiring an external pull-up; the functional difference lies in timing alignment with CS rather than conversion state - per Figures 5 and 6 in the datasheet.