Analog Devices Inc./Maxim Integrated MAX158AEAI+

Overview

The MAX158AEAI+ 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, ±1/2 LSB total unadjusted error, and supports microprocessor interface via CS/RD control without external logic. It is used in real-time speech analysis, high-speed servo control, and telecom data acquisition systems.

For engineers reviewing the MAX158AEAI+ datasheet, MAX158AEAI+ pinout, MAX158AEAI+ application, or MAX158AEAI+ equivalent, this page provides verified technical context, package-validated pin functions, real-world timing behavior in Mode 0/1, accuracy vs. VREF dependency, and design-critical analog input settling constraints for source impedances ≤100Ω.

Technical Context

The MAX158AEAI+ uses a half-flash architecture with two 4-bit flash ADC sections and an internal DAC to generate the lower 4 bits from the residue voltage. Its 31 comparator array (16 MSB + 15 LSB) enables full 8-bit resolution within 2.5µs while maintaining ±1/2 LSB linearity error across –40°C to +85°C.

Digital interface operates in Mode 0 (WAIT-state compatible) or Mode 1 (non-WAIT), both using only CS and RD signals. INT asserts low at conversion completion; RDY is open-drain and synchronizes to CS falling edge. The device requires no external clock and latches multiplexer address (A0–A2) on CS/RD assertion.

Key Specifications

Pinout & Package

MAX158AEAI+ is housed in a 28-pin Shrink Small-Outline Package (SSOP) with 0.65mm lead pitch, body dimensions 5.3mm × 10.2mm, and moisture sensitivity level (MSL) 3 per JEDEC J-STD-020.

Key Features

Applications

Equivalent & Alternatives

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

Compared with ADS7822U and MAX1113ECM+, the MAX158AEAI+ uniquely integrates reference, track/hold, and parallel microprocessor interface in a single +5V 28-pin SSOP package-enabling faster system integration, lower component count, and guaranteed timing behavior without external timing dependencies.

Availability

MAX158AEAI+ is available at Aetrix Electronics and suitable for high-speed data acquisition, telecom line monitoring, and real-time speech analysis requiring stable component supply across extended 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) designs precision analog, mixed-signal, and power management ICs for industrial, communications, and computing applications.

The MAX158AEAI+ belongs to Maxim's high-speed data acquisition product line, engineered specifically for systems demanding fast, accurate, and self-contained analog digitization without external support components.

FAQ

What is the operating temperature range for MAX158AEAI+?

The MAX158AEAI+ is rated for operation from –40°C to +85°C, matching the 'E' grade designation in its ordering code. This extended industrial temperature range ensures reliable performance in harsh environments such as factory automation controllers and outdoor telecom equipment where ambient temperatures fluctuate widely. All electrical specifications-including ±1/2 LSB error and 2.5µs conversion time-are guaranteed across this full range.

Does MAX158AEAI+ require an external clock signal?

No, the MAX158AEAI+ does not require an external clock. Its conversion timing is fully self-timed and initiated by the falling edge of CS and RD signals. Internal timing generators handle track/hold, flash comparison, and data latching-eliminating clock distribution, jitter concerns, and external oscillator components. This simplifies PCB layout and improves system-level timing predictability compared to clock-dependent ADCs.

How does the MAX158AEAI+ handle analog input settling for high-impedance sources?

The MAX158AEAI+ requires analog source impedance ≤100Ω to achieve full accuracy. Its 45pF input capacitance and fixed 1µs acquisition window mean higher source impedances cause incomplete settling and increased differential nonlinearity. For sources >100Ω, an external op-amp buffer with ≥1MHz loop gain is mandatory. The datasheet specifies this constraint explicitly in the Analog Considerations section and validates it via RC network modeling in Figure 9b.

Can MAX158AEAI+ operate with VREF+ tied to +5V and VREF− grounded?

Yes, the MAX158AEAI+ supports this configuration: tying VREF+ to VDD (+5V) and VREF− to GND establishes a 0V to +5V full-scale input range, aligning with standard op-amp output rails. In this mode, the internal 2.5V reference (REF OUT) remains active and usable for external circuitry. This setup is explicitly validated in Figure 8b ("Power Supply as Reference") and confirmed in the Electrical Characteristics table under "Analog Input Voltage Range".

What is the function of the RDY pin on MAX158AEAI+ and how should it be connected?

The RDY pin on MAX158AEAI+ is an open-drain status output that goes low when CS falls and returns to high-impedance at conversion completion. It is designed to connect directly to a microprocessor's READY or WAIT input. Since it lacks an internal pull-up, an external 4.7kΩ–10kΩ resistor to +5V is required. Omitting the pull-up disables WAIT-state synchronization but does not prevent basic Mode 1 operation, as confirmed in the Digital Interface section.