Analog Devices Inc./Maxim Integrated MX7576JN+

Overview

MX7576JN+ from Maxim Integrated is an 8-bit, microprocessor-compatible analog-to-digital converter (ADC) with 10µs conversion time, single +5V supply operation, 0V to 2VREF input range, and external 1.23V reference requirement - designed for high-speed data acquisition in embedded signal processing systems.

For engineers reviewing the MX7576JN+ datasheet, MX7576JN+ pinout, MX7576JN+ application, or MX7576JN+ equivalent, key selection considerations include its asynchronous conversion mode (via MODE pin), 100ns data-access time, 8-bit µP interface timing compatibility, and absence of on-chip track/hold - distinguishing it from the MX7575JN+.

Technical Context

The MX7576JN+ uses successive-approximation architecture with internal DAC and comparator, sampling the analog input eight times during conversion - once before each bit decision - enabling stable digitization without integrated track/hold. It supports both synchronous (MODE = high) and asynchronous (MODE = low) conversion modes, with BUSY signaling start/end of conversion.

Timing is governed by external clock (2MHz typical) or internal RC oscillator; all digital I/O (CS, RD, D0–D7, BUSY, MODE) are CMOS-compatible with 0.8V/2.4V logic thresholds, and output latches are three-state buffered for direct µP bus connection. Analog inputs require low-impedance drive (<2kΩ) and quiet digital environment during sampling.

Key Specifications

Pinout & Package

MX7576JN+ is housed in an 18-pin plastic DIP package (0.3-inch width), with 16 functional pins and 2 unused (N.C.) positions. Pin 1 is CS; pin 18 is DGND. All digital I/O are CMOS-level compatible; analog and digital grounds (AGND/DGND) must be separated and joined at single point.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MX7575JN+, MX7576JN+ trades track/hold capability for asynchronous operation and simplified control logic; versus MAX166, it lacks differential input and internal reference but offers DIP packaging and lower system BOM cost where external reference is already present.

Availability

MX7576JN+ is available at Aetrix Electronics and suitable for high-speed data acquisition, telecommunications monitoring, and embedded audio systems requiring stable component supply across industrial temperature ranges.

Supply support for MX7576JN+ 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, mixed-signal, and power management ICs for industrial, communications, and computing markets.

The MX7575/MX7576 product line was engineered for µP-centric data acquisition systems demanding fast, low-power, easy-to-interface 8-bit conversion - targeting cost-sensitive, space-constrained embedded applications circa 1990s design era.

FAQ

What is the maximum recommended source impedance for the AIN input of the MX7576JN+?

The MX7576JN+ analog input requires a driving source impedance of ≤2kΩ to ensure accurate settling within the 10µs conversion window and preserve its specified ±1 LSB total unadjusted error. Higher impedances degrade effective resolution due to incomplete capacitor charging in the sampling circuit, especially at higher input frequencies. This specification is confirmed in the "Analog Input" section of the MX7576JN+ datasheet under "DC Input Impedance" and "Slew Rate" parameters.

Does the MX7576JN+ include an on-chip track/hold function?

No, the MX7576JN+ does not include an on-chip track/hold function. Unlike the MX7575JN+, which integrates a track/hold circuit capable of acquiring 50kHz full-power signals, the MX7576JN+ samples the analog input eight times during conversion without dedicated hold capacitance. This architectural difference means external signal conditioning or careful timing control is required for high-frequency or high-slew-rate inputs. The MX7576JN+ datasheet explicitly states this distinction in the "General Description" and "MX7576 Analog Input" sections.

How does the MODE pin affect the operation of the MX7576JN+?

The MODE pin on the MX7576JN+ selects between two fundamental interface modes: when MODE = high, the device operates in synchronous or ROM interface mode, where RD and CS control both data access and conversion initiation; when MODE = low, it enters asynchronous conversion mode, performing continuous conversions independent of µP timing - with RD and CS used only for data readback. This behavior is documented in the "Pin Description", "Asynchronous Conversion Mode", and timing diagrams of the MX7576JN+ datasheet.

What external components are required for stable operation of the MX7576JN+ reference input?

The MX7576JN+ REF pin requires a stable 1.23V source with low AC and DC impedance. Maxim recommends using the ICL8069 shunt reference with 0.1µF ceramic and 47µF electrolytic decoupling capacitors placed directly at the REF pin. This configuration suppresses transient currents drawn during DAC code changes and maintains reference stability across temperature and conversion cycles - as specified in Figure 15 and the "Reference Input" section of the MX7576JN+ datasheet.

Can the MX7576JN+ be interfaced directly to a Z-80 microprocessor without additional logic?

Yes, the MX7576JN+ can be interfaced directly to a Z-80 microprocessor using its ROM interface mode. In this configuration, the Z-80's MREQ and RD signals connect to MX7576JN+ CS and RD respectively, with D0–D7 tied to the data bus. No wait-state generation or additional glue logic is needed, as BUSY is not used for handshaking in ROM mode. This interface is validated in Figure 7 of the MX7576JN+ datasheet and supports full 8-bit data transfer at Z-80 bus speeds.