Analog Devices Inc. AD7824LNZ

Overview

AD7824LNZ from Analog Devices is a 4-channel, 8-bit LC2MOS successive-approximation analog-to-digital converter with built-in track-and-hold, single 5 V supply operation, ±1/2 LSB total unadjusted error, and 2.5 µs per-channel conversion time. It digitizes 0 V to 5 V analog inputs across four multiplexed channels and is used in real-time data acquisition systems requiring multichannel sampling without external sample-and-hold circuitry.

For engineers reviewing the AD7824LNZ datasheet, AD7824LNZ pinout, AD7824LNZ application, or AD7824LNZ equivalent, this page delivers verified technical context, package-specific pin functions, confirmed timing behavior in Mode 0 and Mode 1, exact accuracy specs at 0°C to 70°C, and validated alternative parts for industrial multichannel ADC replacement scenarios.

Technical Context

The AD7824LNZ employs a half-flash architecture using two 4-bit flash ADCs-one for MSBs and one for LSBs-combined with an internal 4-bit DAC to reconstruct and subtract the MSB approximation, enabling full 8-bit resolution without external clocking. Its analog input structure inherently performs track-and-hold over ~1 µs, supporting 10 kHz full-scale sinusoidal signals (157 mV/µs slew rate) on all four channels.

Digital interface uses standard CS and RD control lines with dual operational modes: Mode 0 synchronizes conversion start and data read via RDY/INT status outputs for WAIT-state microprocessors; Mode 1 decouples conversion trigger from data read, allowing non-WAIT operation with back-to-back reads spaced by ≥2.5 µs. Address inputs A0/A1 select among AIN1–AIN4.

Key Specifications

Pinout & Package

AD7824LNZ is supplied in a 24-lead plastic DIP (N-24) package, 0.3" wide, with 0.1" lead pitch and through-hole mounting. Pin 1 identifier is a notch or dot; pins are numbered counter-clockwise from top-left corner when viewed from top.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 4-channel, 8-bit ADC applications.

Compared with AD7824KNZ, AD7824LNZ provides tighter accuracy without layout or firmware changes; compared with MAX1136CPI+, AD7824LNZ reduces system-level timing design effort and component count despite lower channel density.

Availability

AD7824LNZ is available at Aetrix Electronics and suitable for industrial data acquisition, motor control feedback, and medical instrumentation requiring stable component supply, long-term lifecycle support, and traceable sourcing from authorized channels.

Supply support for AD7824LNZ 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

Analog Devices is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, founded in 1965 and headquartered in Wilmington, MA.

The AD7824 series belongs to Analog Devices' legacy precision data acquisition portfolio, designed specifically for cost-effective, multichannel, real-time analog-to-digital conversion in industrial and instrumentation systems operating from single 5 V supplies.

FAQ

What is the operating temperature range for AD7824LNZ?

The AD7824LNZ is rated for commercial operation from 0°C to +70°C. This is defined by its "L" grade suffix and confirmed in the Ordering Guide table, where AD7824LN corresponds to the L version with 0°C to 70°C range and ±1/2 LSB total unadjusted error. Operation outside this range may degrade accuracy or cause functional failure.

Does AD7824LNZ require an external clock signal?

No, AD7824LNZ does not require an external clock signal. Its half-flash conversion architecture uses internal timing control driven solely by CS and RD transitions. The datasheet explicitly states "No clock signal is required for the ADC," and timing diagrams confirm conversion initiation and completion are fully controlled by digital strobes.

Can AD7824LNZ perform bipolar input measurements?

Yes, AD7824LNZ supports bipolar operation via external op-amp conditioning, as shown in Figure 12 of the datasheet. Using an AD544 amplifier, it accepts ±4 V inputs with complementary offset binary output coding. The device itself is unipolar (0 V to 5 V), but the differential reference inputs (VREF(+) and VREF(–)) enable flexible input range translation.

What is the maximum analog input source impedance supported by AD7824LNZ?

The AD7824LNZ analog input requires a source impedance ≤100 Ω to ensure accurate 1/2 LSB settling within the 1 µs tracking window. This is specified in the "INPUT CURRENT" section, which models the input as an RC network and recommends low-impedance drivers like the AD544 or AD644 to maintain full accuracy at 10 kHz signal bandwidth.

How does AD7824LNZ handle channel selection in Mode 1 operation?

In Mode 1, AD7824LNZ latches the A0/A1 address on the rising edge of RD, starts conversion of the selected channel, and simultaneously outputs the previous conversion result on DB0–DB7. A second RD pulse is required to read the new result. This decouples address update from data read, enabling use with microprocessors lacking WAIT-state capability, as documented in Figure 15 and the "MODE 1" section.