Analog Devices Inc. AD573KN

Overview

AD573KN from Analog Devices is a complete monolithic 10-bit successive approximation analog-to-digital converter (ADC) with integrated buried Zener reference, comparator, clock, DAC, and SAR logic. It delivers ±1/2 LSB relative accuracy, 20 µs typical conversion time, and supports unipolar (0 V to +10 V) or bipolar (–5 V to +5 V) input ranges using a single pin configuration. It is used in precision data acquisition systems requiring stable, self-contained A/D conversion without external trimming components.

For engineers reviewing the AD573KN datasheet, AD573KN pinout, AD573KN application, or AD573KN equivalent, key selection considerations include its dual-supply operation (+5 V / –12 V to –15 V), 20-pin PDIP package, 10-bit left-justified output format, and compatibility with 8-bit microprocessor buses via HBE/LBE byte-enable control.

Technical Context

The AD573KN implements successive approximation using integrated injection logic (I2L) and a laser-trimmed SiCr thin-film resistor ladder for high linearity. Its temperature-compensated subsurface Zener reference ensures stable full-scale calibration across temperature.

Conversion is initiated by a 500 ns minimum positive CONVERT pulse; DATA READY (DR) asserts within 1.5 µs after the rising edge and goes low upon completion. Output data is latched into three-state buffers controlled independently by HIGH BYTE ENABLE (HBE) and LOW BYTE ENABLE (LBE), supporting both 8+2-bit and full 10-bit read modes.

Key Specifications

Pinout & Package

The AD573KN is supplied in a 20-pin plastic dual in-line package (PDIP), narrow body (N-20), with 0.300-inch width and 0.100-inch lead pitch. Pin 1 identifier is located at top-left corner when viewed from top with notch facing up.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 10-bit ADC applications.

Compared with AD573KN, AD7819BRZ and MAX1112CCPP+ offer modern serial interfaces but lack native dual-supply operation, built-in Zener reference, and parallel bus compatibility-making AD573KN uniquely suited for retrofitting and industrial systems requiring deterministic timing and legacy voltage rails.

Availability

AD573KN is available at Aetrix Electronics and suitable for industrial process monitoring, test equipment manufacturing, avionics sensor interfaces, and legacy control system upgrades requiring stable component supply and long-lifecycle support.

Supply support for AD573KN 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 AD573KN belongs to Analog Devices' legacy precision ADC product line, designed specifically for industrial and aerospace applications demanding guaranteed no-missing-codes performance, dual-supply operation, and monolithic integration of reference and timing resources.

FAQ

What is the operating temperature range for the AD573KN?

The AD573KN is specified for operation from 0°C to +70°C. This commercial-grade temperature range is validated across all electrical parameters in the datasheet, including relative accuracy (±1/2 LSB), conversion time (10–30 µs), and power supply rejection. The "K" grade designation explicitly denotes this temperature range, distinguishing it from the military-grade AD573S (–55°C to +125°C) and industrial-grade AD573J (0°C to +70°C, ceramic DIP). For designs requiring extended temperature coverage, the AD573KN should not be substituted without requalification.

Does the AD573KN require external components to achieve full 10-bit accuracy?

No, the AD573KN requires no external components to achieve full 10-bit accuracy. It integrates a buried Zener voltage reference, comparator, clock generator, 10-bit current-output DAC, successive approximation register (SAR), and three-state output buffers on a single die. The only required external connections are the +5 V and –12 V to –15 V power supplies, analog input signal, and CONVERT trigger pulse. Full-scale calibration can be performed with a simple 15 Ω series resistor, but even this is optional for applications tolerating ±2 LSB error.

How does the AD573KN support both unipolar and bipolar input ranges?

Unipolar (0 V to +10 V) and bipolar (–5 V to +5 V) input ranges are selected via Pin 16 (BIPOLAR OFFSET CONTROL). Grounding Pin 16 to DIGITAL COMMON enables unipolar mode; leaving Pin 16 open enables bipolar mode. Internally, this controls a switch that injects a precise offset current-equal to the MSB value minus 1/2 LSB-into the comparator's summing node. This shifts the transfer function by exactly 5 V, converting the nominal 0 V–10 V range into a centered –5 V–+5 V range with offset binary coding.

What is the purpose of the HBE and LBE pins on the AD573KN?

HBE (HIGH BYTE ENABLE) and LBE (LOW BYTE ENABLE) are active-low control signals that independently enable the AD573KN's three-state output buffers. HBE enables DB2–DB9 (the 8 MSBs), while LBE enables DB0–DB1 (the 2 LSBs). This allows the AD573KN to interface directly with 8-bit microprocessor buses: the high byte is read from one memory-mapped address, and the low byte from the next. Both pins must be held high during conversion to prevent bus contention from intermediate SAR results.

Can the AD573KN be used with modern microcontrollers lacking dedicated WR/RD signals?

Yes, the AD573KN can interface with modern microcontrollers using GPIO-controlled timing. The CONVERT pulse can be generated by any GPIO pin with ≥500 ns pulse width; DATA READY (DR) can be polled or used to trigger an interrupt. HBE and LBE may be tied together and driven by a single GPIO to read all 10 bits simultaneously, or controlled separately for byte-wise reads. While originally designed for 6502/8085 buses, its asynchronous timing and three-state outputs make it adaptable to ARM Cortex-M, PIC, and RISC-V systems with careful software timing management.