Analog Devices Inc. AD570JD/+

Overview

AD570JD/+ from Analog Devices is an 8-bit monolithic successive-approximation analog-to-digital converter (ADC) with integrated DAC, comparator, SAR register, and temperature-compensated buried Zener reference. It operates from +5 V and –15 V supplies, delivers ±1/2 LSB relative accuracy over 0°C to +70°C, supports unipolar (0 V to +10 V) and bipolar (–5 V to +5 V) input ranges, and achieves 25 µs typical conversion time - used in precision data acquisition systems interfacing with microprocessors or multiplexed sensor arrays.

For engineers reviewing the AD570JD/+ datasheet, AD570JD/+ pinout, AD570JD/+ application, or AD570JD/+ equivalent, key selection considerations include its self-contained architecture requiring no external timing or trimming components, TTL-compatible digital interface with open-collector DATA READY, dual-supply operation, and ceramic DIP-18 packaging for industrial stability.

Technical Context

The AD570JD/+ implements a complete successive-approximation ADC using I²L logic and an internal 8-bit current-output DAC. Conversion is initiated by a low pulse on the BLANK & CONVERT (B&C) line, and completion is signaled by the open-collector DATA READY output going low after ≤40 µs. The SAR sequenced from MSB to LSB balances input current through a laser-trimmed 5 kΩ thin-film resistor against DAC output current.

It features separate analog and digital common terminals with ±200 mV allowable common-mode range, bipolar offset control via dedicated pin (open = ±5 V range, grounded = 0 V to +10 V), and zero-offset adjustment via analog common current modulation. Power supply rejection is specified at ±62 LSB for both +5 V and –15 V rails.

Key Specifications

Pinout & Package

AD570JD/+ is housed in an 18-lead side-brazed ceramic dual-in-line package (SBDIP, package option D-18), measuring 0.960" × 0.290" × 0.220" (24.38 mm × 7.37 mm × 5.59 mm), with 0.100" lead pitch and hermetic sealing for long-term reliability in harsh environments.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AD570JD/+, AD571KD/+ offers two extra bits but demands external clocking and higher power, while MAX160BCPP simplifies design at the expense of guaranteed linearity, bipolar support, and system-level noise immunity from split commons.

Availability

AD570JD/+ is available at Aetrix Electronics and suitable for industrial data acquisition, microprocessor-based instrumentation, multiplexed sensor systems, and calibration-grade test equipment requiring stable component supply across extended production lifecycles.

Supply support for AD570JD/+ 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 AD570JD/+ belongs to Analog Devices' legacy precision converter family, designed specifically for self-contained, low-glue-data-acquisition in industrial and instrumentation applications where reliability, temperature stability, and minimal external components are critical.

FAQ

What is the function of the BIPOLAR OFFSET pin on the AD570JD/+?

The BIPOLAR OFFSET pin on the AD570JD/+ selects input range mode: grounding it configures the device for unipolar 0 V to +10 V operation with true binary coding; leaving it open enables bipolar –5 V to +5 V operation with positive true offset binary coding. This pin controls an internal switch that injects a precise offset current into the comparator summing node, and it is not TTL-compatible - logic-level interfacing requires an external gate as shown in Figure 5 of the datasheet. The AD570JD/+ does not require external resistors or references to implement either mode.

Does the AD570JD/+ require an external clock or sample-hold amplifier?

No, the AD570JD/+ does not require an external clock or sample-hold amplifier. It contains a fully integrated successive-approximation register, DAC, comparator, and temperature-compensated buried Zener reference, enabling autonomous conversion triggered solely by the BLANK & CONVERT input pulse. While a sample-hold (e.g., AD582) can be added for high-speed or noisy signal acquisition, the AD570JD/+ itself performs accurate conversions directly from DC to ~25 kHz input bandwidth without auxiliary components.

What is the purpose of having separate ANALOG COMMON and DIGITAL COMMON pins on the AD570JD/+?

The separate ANALOG COMMON and DIGITAL COMMON pins on the AD570JD/+ enable physical isolation of analog and digital return paths to suppress noise coupling - a critical feature for achieving ±6½ LSB relative accuracy. The device tolerates up to ±200 mV common-mode voltage between these pins, allowing flexible PCB grounding schemes. ANALOG COMMON carries transient currents up to 2 mA during conversion and a static 2 mA in unipolar mode, while DIGITAL COMMON serves only TTL logic interfaces. This separation is essential in mixed-signal systems where microprocessor noise would otherwise degrade ADC performance.

Can the AD570JD/+ be used with modern microcontrollers like ARM Cortex-M or ESP32?

Yes, the AD570JD/+ can interface with modern microcontrollers such as ARM Cortex-M or ESP32, but requires level translation and timing adaptation. Its TTL-compatible outputs (3.2 mA sink) and open-collector DATA READY need 5 V-tolerant GPIO or buffer ICs (e.g., 74LVC244) when connecting to 3.3 V logic. The BLANK & CONVERT pulse must meet ≥2 µs width and proper setup/hold timing relative to DATA READY assertion. While not SPI/I²C-native, the AD570JD/+'s parallel 8-bit output and simple control protocol make it viable for legacy-compatible or high-accuracy edge-node designs where software-driven conversion timing is acceptable.

How is full-scale calibration performed for the AD570JD/+?

Full-scale calibration for the AD570JD/+ leverages its laser-trimmed 5 kΩ input resistor, which is set to produce DAC-matching current at 9.961 V input (10 V – 1 LSB). For basic use, inserting a 15 Ω series resistor yields ±2 LSB (±0.8%) error. For higher precision, a 200 Ω trimmer is adjusted while applying 9.961 V until the output transitions from 11111110 to 11111111 - establishing exact 39.06 mV/LSB weight. Calibration affects both zero and full-scale points, so zero offset adjustment (via analog common resistor) must precede full-scale trim. The AD570JD/+ does not require external reference voltage sources.