Analog Devices Inc. AD7828LPZ

Overview

AD7828LPZ from Analog Devices is an 8-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 eight multiplexed channels and is used in real-time speech analysis, multichannel data acquisition, and industrial sensor monitoring systems.

For engineers reviewing the AD7828LPZ datasheet, AD7828LPZ pinout, AD7828LPZ application, or AD7828LPZ equivalent, this page delivers verified technical context, package-specific pin functions, confirmed timing behavior in Mode 0 and Mode 1, and validated alternative options for multichannel 8-bit ADC selection in embedded control and signal conditioning designs.

Technical Context

The AD7828LPZ uses a half-flash architecture with two 4-bit flash ADCs - one for MSBs and one for LSBs - eliminating external clock requirements and enabling deterministic 2.5 µs conversion per channel. Its internal DAC reconstructs the MSB-derived analog value for subtraction and LSB quantization.

It supports dual interface modes: Mode 0 (WAIT-state microprocessor sync via RDY/INT) and Mode 1 (non-WAIT, pipelined read of prior result). Address latching occurs on RD rising edge in Mode 1, while A0–A2 select among eight analog inputs (AIN1–AIN8) with no missing codes guaranteed over full temperature range.

Key Specifications

Pinout & Package

AD7828LPZ is supplied in a 28-pin plastic DIP (N-28) package with 0.6" width, 0.1" lead pitch, and through-hole mounting. Pin 1 identifier is located at top-left corner when notch faces upward.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AD7828LPZ, AD7828LN offers identical electrical performance in a standard PDIP package ideal for prototyping, while MAX1138ACPP+ trades parallel simplicity for serial compactness - making AD7828LPZ optimal for deterministic, low-latency, microprocessor-native multichannel acquisition.

Availability

AD7828LPZ is available at Aetrix Electronics and suitable for industrial sensor data loggers, automated test equipment, motor control feedback loops, and speech analysis systems requiring stable component supply and long-term obsolescence management.

Supply support for AD7828LPZ 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, serving industrial, automotive, communications, and healthcare markets since 1965.

The AD7828LPZ belongs to Analog Devices' legacy LC2MOS precision data acquisition family, designed specifically for cost-sensitive, multichannel embedded systems needing fast, self-contained 8-bit conversion without external clocks or S/H circuits.

FAQ

What is the operating temperature range for AD7828LPZ?

The AD7828LPZ is rated for commercial temperature operation from 0°C to +70°C. This range is specified for the L-grade version and applies to all electrical parameters in the datasheet unless otherwise noted. The device maintains ±1/2 LSB total unadjusted error across this full range, supporting reliable deployment in office environments, laboratory instruments, and non-extreme industrial enclosures. Thermal derating begins above +75°C per the absolute maximum ratings table.

Does AD7828LPZ require an external clock signal?

No, the AD7828LPZ does not require an external clock signal. Its half-flash conversion architecture uses two internal 4-bit flash ADCs and an integrated DAC to generate the 8-bit result deterministically in 2.5 µs per channel. This eliminates clock distribution, jitter sensitivity, and associated layout complexity - a key differentiator versus SAR or sigma-delta ADCs. All timing is controlled solely by CS and RD strobes.

How does the AD7828LPZ handle analog input slew rate?

The AD7828LPZ supports analog input slew rates up to 157 mV/µs, enabling accurate digitization of 10 kHz full-scale sine waves without external sample-and-hold circuitry. This capability stems from its inherent track-and-hold behavior: the input is sampled for ~1 µs after conversion start, and the value at that instant determines the final 8-bit code. Input source impedance must be ≤100 Ω to ensure proper settling within this window.

Can AD7828LPZ operate with a reference voltage less than 5 V?

Yes, the AD7828LPZ supports fully differential reference inputs (VREF(+) and VREF(–)), allowing operation with any reference span from 1 V to 5 V. Reducing VREF increases resolution - e.g., with 2 V reference, 1 LSB = 7.8 mV - and enables ratiometric measurements where reference and signal share the same supply. The analog input range always tracks VREF(–) to VREF(+), permitting offset operation such as –2 V to +2 V bipolar configurations.

What is the difference between Mode 0 and Mode 1 operation for AD7828LPZ?

Mode 0 uses RDY/INT to synchronize with microprocessors having WAIT-state capability (e.g., Z80, MC68000): CS+RD low starts conversion, and data appears only after RDY releases WAIT. Mode 1 targets non-WAIT processors (e.g., TMS32010): CS+RD low initiates conversion *and* reads the previous result simultaneously; a second read retrieves the new data. Mode 1 requires ≥2.5 µs delay between reads and disables RDY status use.