Analog Devices Inc. AD670JN

Overview

AD670JN from Analog Devices is a complete 8-bit signal conditioning analog-to-digital converter integrating an instrumentation amplifier front end, precision voltage reference, successive approximation register (SAR), DAC, comparator, and three-state digital output buffer on a single monolithic IC. It operates from a single +5 V supply, delivers 10 µs conversion time, supports differential inputs with ±128 mV or ±1.28 V bipolar ranges (or 0–255 mV / 0–2.55 V unipolar), and requires no user trims for full 8-bit accuracy - enabling direct interface to transducer-based industrial sensor systems.

For engineers reviewing the AD670JN datasheet, AD670JN pinout, AD670JN application, or AD670JN equivalent, this page provides verified technical context, confirmed pin functions, real-world transducer interface use cases, and validated alternative options for embedded data acquisition designs requiring integrated signal conditioning and microprocessor bus compatibility.

Technical Context

The AD670JN implements a dynamic SAR architecture using a tapped inverter delay line instead of a clocked DAC, eliminating external timing dependencies while achieving guaranteed no-missing-codes performance over 0°C to +70°C. Its instrumentation amplifier front end provides high-impedance differential inputs with 1 LSB common-mode rejection across both 255 mV and 2.55 V input ranges.

Control logic accepts standard microprocessor signals (R/W, CS, CE) to initiate conversion or read data; STATUS pin indicates active conversion; FORMAT and BPO/UPO pins configure output coding (straight binary or 2's complement) and input format (unipolar/bipolar) prior to each conversion cycle - enabling per-conversion flexibility without reconfiguration hardware.

Key Specifications

Pinout & Package

AD670JN is housed in a 20-pin plastic DIP (N-20) package with 0.3-inch body width and through-hole mounting. Pin spacing follows standard 0.1-inch grid; leads are tin-lead plated for solderability.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AD7823AN and MAX1241ACPP, the AD670JN uniquely combines instrumentation amp front end, precision reference, and microprocessor bus interface in a single +5 V–compatible 8-bit ADC - making it the only option that eliminates external gain, reference, and interface logic for transducer-to-bus digitization.

Availability

AD670JN is available at Aetrix Electronics and suitable for industrial sensor interfaces, embedded data loggers, and transducer-based process control systems requiring stable component supply and long-term obsolescence management.

Supply support for AD670JN 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 AD670JN belongs to Analog Devices' legacy signal conditioning ADC product line, designed specifically for cost-sensitive industrial and instrumentation applications requiring integrated transducer interface capability without external support components.

FAQ

What is the operating temperature range specified for the AD670JN?

The AD670JN is rated for operation from 0°C to +70°C. This commercial-grade temperature specification is defined in the Ordering Guide and confirmed in the Absolute Maximum Ratings table. The J-grade designation explicitly denotes this range, distinguishing it from A/B/S grades with extended industrial or military temperature coverage. All electrical specifications - including conversion time, accuracy, and common-mode rejection - are guaranteed across this full range.

Does the AD670JN require external components to achieve full 8-bit accuracy?

No, the AD670JN requires no external components to achieve full 8-bit accuracy. Its monolithic construction integrates an instrumentation amplifier, precision 2.5 V reference, DAC, SAR logic, comparator, and three-state output buffer. Laser wafer trimming of thin-film SiCr resistors ensures gain and offset errors remain within ±1.5 LSB over temperature, eliminating the need for user trims, external references, or calibration circuitry - as explicitly stated in the FEATURES and GENERAL DESCRIPTION sections.

How does the AD670JN support both unipolar and bipolar input configurations?

The AD670JN supports both unipolar and bipolar inputs via the BPO/UPO pin (Pin 11). When grounded (logic low), the device operates in unipolar mode with input ranges of 0–255 mV or 0–2.55 V. When tied to VCC (logic high), it injects a bipolar offset current equal to MSB – ½ LSB into the comparator summing node, enabling ±128 mV or ±1.28 V differential input ranges - all without external resistors or switches.

What digital interface standards does the AD670JN support?

The AD670JN supports standard microprocessor bus timing with TTL-compatible digital I/O. Its R/W, CS, and CE control lines accept 0.8 V low / 2.0 V high logic thresholds, and its three-state outputs drive 1.6 mA sink / 0.5 mA source into TTL loads. Timing parameters - including 300 ns minimum write pulse width and 250 ns bus access time - align with Z80, 8085, and 6800 family bus cycles, enabling direct connection without level shifters or interface logic.

Can the AD670JN be used in stand-alone mode without a microprocessor?

Yes, the AD670JN supports stand-alone operation. By tying CS and CE together and using R/W as the sole control signal, a simple pulse generator can initiate conversions: a low-going R/W pulse starts conversion, and STATUS going low signals completion. Data becomes valid within 250 ns after STATUS falls, allowing direct connection to latches or FIFOs - as detailed in the STAND-ALONE OPERATION section with timing diagrams for single and continuous conversion modes.