Analog Devices Inc. AD7828KP

Overview

AD7828KP from Analog Devices is an 8-channel, 8-bit LC2MOS analog-to-digital converter with built-in track-and-hold, single 5 V supply operation, ±1 LSB total unadjusted error, 2.5 µs per-channel conversion time, and 0 V to 5 V analog input range. It serves as a multichannel data acquisition front-end in industrial monitoring systems requiring simultaneous sampling of sensor signals up to 10 kHz bandwidth.

For engineers reviewing the AD7828KP datasheet, AD7828KP pinout, AD7828KP application, or AD7828KP equivalent, this page delivers verified specifications, validated package mapping (P-28A 28-pin PDIP), confirmed microprocessor interface timing (Mode 0/1), and real-world design implications for channel selection, reference configuration, and slew-rate-limited signal acquisition.

Technical Context

The AD7828KP implements a half-flash architecture using two 4-bit flash ADCs - one for MSBs and one for LSBs - with an internal 4-bit DAC bridging them. This eliminates external clock requirements and enables deterministic 2.5 µs conversion per selected channel.

It features an 8-channel analog multiplexer with address inputs A0–A2, open-drain RDY and active-low INT outputs, three-state 8-bit parallel data bus (DB0–DB7), and fully differential reference inputs (VREF(+) and VREF(–)) enabling ratiometric or offset-adjusted unipolar/bipolar operation.

Key Specifications

Pinout & Package

AD7828KP is packaged in a 28-pin plastic DIP (P-28A), 0.6" wide, compliant with JEDEC MS-011AB. Pin spacing is 0.1" (2.54 mm), with 0.3" row-to-row distance. The package includes 2 ground pins (pins 14 and 28) for noise isolation and thermal relief.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AD7828LN, AD7828KP trades 0.5 LSB accuracy for lower unit cost and broader commercial temperature tolerance (0°C to 70°C). Versus MAX195BCPP, AD7828KP provides integrated 8-channel MUX and track-and-hold at 8-bit resolution - reducing BOM count and PCB area in multi-sensor systems.

Availability

AD7828KP is available at Aetrix Electronics and suitable for industrial data acquisition, motor control feedback, and test & measurement equipment requiring stable component supply across extended production lifecycles.

Supply support for AD7828KP 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, Inc. 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/AD7828 family was engineered for cost-sensitive, space-constrained multichannel data acquisition in industrial and instrumentation systems - prioritizing integration (MUX + T/H), single-supply operation, and microprocessor compatibility over ultra-high resolution.

FAQ

What is the maximum analog input frequency supported by the AD7828KP without external sample-and-hold?

The AD7828KP supports analog input frequencies up to 10 kHz while maintaining ±1 LSB total unadjusted error, enabled by its inherent track-and-hold function with 157 mV/µs slew rate capability. This allows direct digitization of full-scale sinusoidal signals across all eight channels without external circuitry - verified under VDD = 5 V, VREF(+) = 5 V, and VREF(–) = GND conditions per the AD7828KP datasheet Rev. F.

Does the AD7828KP require an external clock signal to operate?

No, the AD7828KP does not require an external clock. Its half-flash conversion architecture uses two internal 4-bit flash ADCs and an integrated 4-bit DAC to autonomously complete each 8-bit conversion in 2.5 µs. Timing is controlled solely by the CS and RD digital inputs - eliminating clock distribution, jitter concerns, and associated layout constraints common in SAR or sigma-delta ADCs.

How is channel selection implemented on the AD7828KP?

Channel selection on the AD7828KP is performed via three address inputs: A0, A1, and A2. These pins decode binary values 000–111 to select AIN1 through AIN8 respectively. In Mode 0, addresses must remain stable during CS and RD assertion; in Mode 1, the address is latched on the rising edge of RD. Pin A2 is unused (NC) on AD7824 variants but essential for accessing AIN5–AIN8 on the AD7828KP.

What are the reference input configuration options for the AD7828KP?

The AD7828KP supports flexible reference configurations via fully differential VREF(+) and VREF(–) inputs. Standard unipolar operation uses VREF(+) = 5 V and VREF(–) = GND for 0–5 V input range. Bipolar mode sets VREF(–) to 2.5 V and applies level-shifted input, yielding ±4 V range. Ratiometric operation ties VREF(+) and VREF(–) to sensor excitation rails - preserving measurement accuracy against supply drift. All configurations retain the AD7828KP's ±1 LSB error specification.

Can the AD7828KP interface directly with a Z80 microprocessor?

Yes, the AD7828KP interfaces directly with the Z80 microprocessor in Mode 0. When assigned a memory-mapped address (e.g., C000h), a LD instruction triggers CS and RD assertion, initiating conversion and halting the Z80 via WAIT until RDY deasserts. The 8-bit result appears on DB0–DB7 and loads into the target register - requiring no glue logic, clock generators, or external timing components beyond a 5 kΩ pull-up on RDY as specified in the AD7828KP application diagram.