Analog Devices Inc. AD7888ACHIPS

Overview

AD7888ACHIPS from Analog Devices is a micropower, 12-bit, 8-channel successive-approximation ADC operating from a single 2.7 V to 5.25 V supply, delivering 125 kSPS throughput with 500 ns track/hold acquisition time and on-chip 2.5 V reference. It features SPI/QSPI/MICROWIRE/DSP-compatible serial interface and supports battery-powered medical instruments and portable instrumentation.

For engineers reviewing the AD7888ACHIPS datasheet, AD7888ACHIPS pinout, AD7888ACHIPS application, or AD7888ACHIPS equivalent, key selection considerations include its 12-bit resolution with ±1 LSB DNL (B-grade), 71 dB SNR at 10 kHz, channel-to-channel isolation of –80 dB, flexible power management (shutdown current ≤1 µA at 2.7–3.6 V), and TSSOP-16 package compatibility with space-constrained embedded systems.

Technical Context

The AD7888ACHIPS implements a charge redistribution SAR architecture with integrated track-and-hold, 8:1 analog multiplexer, and programmable power modes (normal, autoshutdown, autostandby, full shutdown). Its control register configures channel selection (ADD0–ADD2), reference source (internal 2.5 V or external 1.2–VDD), and power state via PM1/PM0 bits.

It uses a 16-clock serial frame (4 leading zeros + 12-bit result, MSB first) synchronized to SCLK rising/falling edges, with CS framing both conversion initiation and data transfer. The analog input structure includes 38 pF capacitance in track mode and 4 pF in hold mode, requiring low-impedance drive for optimal THD performance.

Key Specifications

Pinout & Package

AD7888ACHIPS is housed in a 16-lead thin shrink small outline package (TSSOP), pin-compatible with the SOIC-16 variant and optimized for high-density PCB layouts.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 12-bit, 8-channel, serial-interface ADC applications.

Compared with ADS7822U and MAX11131ETE+, AD7888ACHIPS uniquely balances 8-channel count, internal 2.5 V reference, sub-µA shutdown, and dual-voltage (3 V/5 V) operation-making it optimal for battery-powered multi-sensor platforms where layout area, supply flexibility, and power budget are co-constrained.

Availability

AD7888ACHIPS is available at Aetrix Electronics and suitable for battery-powered medical instruments, industrial sensor hubs, and portable data loggers requiring stable component supply, long-lifecycle availability, and consistent parametric performance across production batches.

Supply support for AD7888ACHIPS 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 precision instrumentation, industrial automation, and communications markets.

The AD7888ACHIPS belongs to Analog Devices' precision data acquisition product line, engineered specifically for low-power, multi-channel, high-SNR applications in portable and energy-conscious embedded systems.

FAQ

What is the maximum sampling frequency supported by the AD7888ACHIPS?

The AD7888ACHIPS supports a maximum throughput rate of 125 kSPS when operated with a 2 MHz SCLK across its full 2.7 V to 5.25 V supply range. This corresponds to a minimum conversion time of 7.25 µs (14.5 SCLK cycles) plus 1.5 SCLK cycles for track/hold acquisition, totaling 16 SCLK cycles per complete conversion cycle. Performance remains stable across temperature and supply voltage variations per the Rev. C datasheet specifications.

Does the AD7888ACHIPS include an internal voltage reference, and can it be disabled?

Yes, the AD7888ACHIPS integrates a 2.5 V on-chip reference with ±50 ppm/°C tempco and 2.45–2.55 V output range. It can be disabled via the REF bit (Bit 2) in the 8-bit control register: setting REF = 1 disables the internal reference, enabling use of an external 1.2 V to VDD reference. Disabling the internal reference reduces input impedance at REF IN/REF OUT from ~5 kΩ to >1 GΩ, improving noise immunity when driving from a low-noise external source.

What are the power consumption characteristics of the AD7888ACHIPS in shutdown mode?

In full shutdown mode (PM1=0, PM0=1), the AD7888ACHIPS draws ≤1 µA at 2.7–3.6 V and ≤2 µA at 4.75–5.25 V, with typical values of 0.5 µA and 1 µA respectively. Wake-up time from shutdown is 5 µs, and the device retains control register contents during shutdown. Shutdown power dissipation is ≤3 µW at 3 V and ≤10 µW at 5 V, making it suitable for ultra-low-duty-cycle battery applications.

How does the AD7888ACHIPS handle channel selection and sequencing?

Channel selection on the AD7888ACHIPS is controlled by the ADD2, ADD1, and ADD0 bits (Bits 5–3) in the write-only 8-bit control register. These three bits decode to select one of eight single-ended analog inputs (AIN1–AIN8) per conversion cycle, as defined in Table II of the datasheet. The selected channel persists across conversions unless reprogrammed; on power-up, default selection is AIN1. Sequencing across channels requires host MCU software to update the control register before each CS assertion.

Is the AD7888ACHIPS pin-compatible with other packages or variants in the AD7888 family?

Yes, the AD7888ACHIPS (TSSOP-16) shares identical pinout and electrical functionality with the AD7888ARUZ (also TSSOP-16) and AD7888ARZ (SOIC-16). All variants use the same 16-pin configuration, signal mapping, and control register structure. Mechanical differences are limited to package dimensions and thermal characteristics (θJA = 150.4°C/W for TSSOP vs. 124.9°C/W for SOIC); no PCB redesign is needed when migrating between these packages.