Analog Devices Inc./Maxim Integrated MX7828LCWI+T

Overview

MX7828LCWI+T from Maxim Integrated is an 8-bit, 8-channel high-speed analog-to-digital converter (ADC) with 2.5 µs conversion time, single +5V supply operation, built-in track/hold, and 0V to +5V analog input range. It serves as a core data acquisition front-end in real-time signal capture systems requiring fast channel multiplexing and direct microprocessor bus interfacing.

For engineers reviewing the MX7828LCWI+T datasheet, MX7828LCWI+T pinout, MX7828LCWI+T application, or MX7828LCWI+T equivalent, key selection considerations include its 8-channel CMOS successive-approximation architecture, open-drain RDY/INT timing interface for Mode 0/1 microprocessor synchronization, ±1/2 LSB total unadjusted error, and compatibility with AD7828-based legacy designs.

Technical Context

The MX7828LCWI+T employs a half-flash conversion architecture with two 4-bit flash ADC sections and an internal DAC to generate the lower 4 bits from the residue voltage. Its analog input stage includes 31 comparator inputs with total input capacitance of 45 pF and requires ≤100 Ω source impedance for full-spec settling within 1 µs acquisition window.

Digital interface supports two modes: Mode 0 uses RDY to extend microprocessor WAIT states, while Mode 1 enables pipelined conversions with overlapping read cycles and 2.5 µs minimum inter-conversion delay. The device accepts multiplexer address inputs A0–A2 to select among eight analog channels and outputs latched 8-bit data via three-state DB0–DB7 lines.

Key Specifications

Pinout & Package

MX7828LCWI+T is housed in a 28-pin plastic DIP package with 0.6-inch width and 0.3-inch row spacing. Pin functions are electrically identical to AD7828 and support direct PCB replacement in legacy layouts.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AD7828BQ, MX7828LCWI+T offers tighter ±1/2 LSB error for precision measurement; compared with MAX158CNG+, it retains external reference flexibility and drop-in compatibility with AD7828 layouts-critical for cost-sensitive industrial retrofits.

Availability

MX7828LCWI+T is available at Aetrix Electronics and suitable for telecommunications signal monitoring, industrial servo control feedback, and audio instrumentation digitization requiring stable component supply and long-term obsolescence management.

Supply support for MX7828LCWI+T 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 applications.

The MX7824/MX7828 family was designed specifically for high-speed, multi-channel data acquisition in space-constrained embedded systems where low power, single-supply operation, and microprocessor bus compatibility are essential.

FAQ

What is the maximum sampling rate achievable with MX7828LCWI+T?

The MX7828LCWI+T achieves a maximum aggregate sampling rate of 400 kHz, calculated from its 2.5 µs conversion time (tCRD) plus 500 ns minimum inter-conversion delay (tp). This yields 50 kHz per channel across all eight inputs, exceeding the 20 kHz Nyquist rate required for 10 kHz bandwidth signals without aliasing.

Does MX7828LCWI+T require an external reference voltage?

Yes, MX7828LCWI+T requires external reference connections at VREF+ and VREF− to define its full-scale and zero-code points. Unlike the MAX158, it does not include an internal reference. Valid configurations include using the +5 V supply as VREF+ with GND as VREF−, or applying precision external references between 0 V and +5 V.

Can MX7828LCWI+T be used with microcontrollers lacking WAIT-state capability?

Yes, MX7828LCWI+T supports Mode 1 operation for microcontrollers without WAIT-state support. In this mode, a READ cycle simultaneously initiates a new conversion and outputs the previous result, enabling pipelined data flow with 2.5 µs minimum inter-conversion delay-ideal for Z80, 8051, and ARM7 derivatives.

What is the input impedance requirement for MX7828LCWI+T analog channels?

MX7828LCWI+T analog inputs exhibit 45 pF capacitance and require source impedances ≤100 Ω to achieve full 2.5 µs conversion accuracy. Higher impedances cause incomplete settling during the 1 µs internal acquisition window, resulting in gain and linearity errors. Op-amp drivers must maintain >1 MHz loop gain to ensure low output impedance at the sampling frequency.

Is MX7828LCWI+T pin-compatible with AD7828?

Yes, MX7828LCWI+T is fully pin-compatible with AD7828 in 28-pin DIP packaging. Electrical characteristics-including timing parameters, input/output voltage levels, and control signal behavior-are matched to enable direct replacement in existing AD7828 designs without PCB or firmware modifications.