Analog Devices Inc. AD7575KN

Overview

AD7575KN from Analog Devices is an 8-bit successive approximation analog-to-digital converter (ADC) with integrated track-and-hold, single +5 V supply operation, 5 µs conversion time, ±1/2 LSB total unadjusted error, and 0 to +70°C temperature range. It digitizes full-scale signals up to 50 kHz in microprocessor-based data acquisition systems.

For engineers reviewing the AD7575KN datasheet, AD7575KN pinout, AD7575KN application, or AD7575KN equivalent, key selection considerations include its LC2MOS process, 18-lead plastic DIP package, unipolar 0–2.46 V input range, 100 ns data access time, and compatibility with Z80H, 8085A-2, 6502B, 68B09, and TMS32010 microprocessors.

Technical Context

The AD7575KN implements a SAR architecture with on-chip track-and-hold, using a 4 MHz external clock or internal RCLK/CCLK oscillator to achieve 5 µs conversion. Its analog input stage features 10 MΩ DC impedance and supports 386 mV/µs slew rate for full-accuracy sampling of 50 kHz sine waves.

Digital interface logic uses CS and RD control lines to support both Slow Memory (WAIT-state) and ROM-style (non-blocking) read protocols. All eight data outputs (DB0–DB7) are latched and three-state buffered, enabling direct connection to 8-bit microprocessor data buses without external latch logic.

Key Specifications

Pinout & Package

AD7575KN is supplied in an 18-lead plastic dual in-line package (N-18), with 0.3" body width and through-hole mounting. Pin 1 identifier is marked on top surface; TP must be hard-wired HIGH for normal operation.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX160BCNG+ and ADC0804LCN, the AD7575KN delivers 5× faster conversion and integrated track-and-hold-critical for dynamic signal fidelity-while maintaining ±1/2 LSB accuracy and direct 8-bit bus compatibility without external timing components.

Availability

AD7575KN is available at Aetrix Electronics and suitable for industrial sensor interfaces, embedded test equipment, audio signal sampling, and data acquisition systems requiring stable component supply across extended production lifecycles.

Supply support for AD7575KN 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, headquartered in Norwood, MA.

The AD7575KN belongs to Analog Devices' legacy LC2MOS precision ADC family, designed specifically for microprocessor-centric data acquisition where speed, low power, and simple interface are prioritized over ultra-high resolution.

FAQ

What is the maximum analog input frequency supported by the AD7575KN with full accuracy?

The AD7575KN supports full-accuracy digitization of analog signals up to 50 kHz, corresponding to a 2.46 V_PP sine wave with 386 mV/µs slew rate. This is enabled by its integrated track-and-hold circuit. At higher frequencies, amplitude accuracy degrades due to slew-rate limiting, not sampling theory alone. The AD7575KN's 45 dB SNR at 10 kHz confirms its suitability for audio-band applications.

Does the AD7575KN require external calibration for typical industrial use?

No, the AD7575KN does not require external calibration in most industrial applications due to its ±1/2 LSB total unadjusted error specification across 0–70°C. Offset and full-scale errors are sufficiently low that system-level accuracy is maintained without trimming. Calibration circuits (e.g., op-amp offset null, reference adjustment) are provided in the datasheet only for metrology-grade requirements exceeding ±1/2 LSB.

Can the AD7575KN operate with an internal clock, and what are the trade-offs?

Yes, the AD7575KN can operate with an internal clock using external RCLK (100 kΩ) and CCLK (100 pF). However, unit-to-unit frequency variation is up to ±50%, resulting in conversion times ranging from ~3.5 µs to ~7.5 µs. For deterministic timing-especially in real-time systems or when interfacing to fast microprocessors like the TMS32010-an external 4 MHz clock is recommended to guarantee 5 µs conversion.

How should the TP pin be handled in a production AD7575KN design?

The TP (Test Pin) on the AD7575KN must be hard-wired to a logic HIGH level (e.g., +5 V via 10 kΩ pull-up) in all production designs. It is not functional in normal operation and serves only for factory testing. Leaving TP floating or connecting it to a signal trace-especially on double-sided PCBs where it could act as a feedthrough-may cause undefined behavior or conversion errors. The AD7575KN will not operate correctly if TP is not held HIGH.

What is the correct grounding scheme for optimal AD7575KN performance?

Optimal AD7575KN performance requires separation of AGND (analog ground) and DGND (digital ground), joined at a single point near the device or power supply entry. AIN and VREF return paths must route exclusively to AGND; DB0–DB7, CS, RD, and BUSY return to DGND. A dedicated ground plane is preferred. Source impedance at AIN must remain below 2 kΩ to prevent full-scale errors from charging current through the 2 pF input capacitance.