Analog Devices Inc. AD7575KP

Overview

AD7575KP from Analog Devices is an 8-bit successive approximation ADC with integrated track-and-hold, single +5 V supply operation, ±1/2 LSB total unadjusted error (max), 5 µs conversion time (with 4 MHz external clock), and 0 to +70°C operating range. It digitizes full-scale signals up to 50 kHz in microprocessor systems such as Z80H, 8085A-2, and TMS32010.

For engineers reviewing the AD7575KP datasheet, AD7575KP pinout, AD7575KP application, or AD7575KP equivalent, this page delivers verified technical context, interface timing constraints, unipolar/bipolar configuration details, real-world SNR performance at 10 kHz, and validated alternative options for embedded data acquisition designs requiring low-power, easy-microprocessor integration.

Technical Context

The AD7575KP implements a SAR architecture with on-chip track-and-hold that samples on the third falling edge of CLK after CS and RD go low, enabling accurate digitization of 386 mV/µs slew-rate signals. Its LC2MOS process ensures compatibility with TTL/CMOS logic levels and supports both internal RC clocking (100 kΩ/100 pF) and external 4 MHz clock input.

It features latched, three-state digital outputs (DB0–DB7) and dual interface modes: Slow Memory (WAIT-state driven via BUSY) and ROM-style (non-blocking, two-read sequence). The TP pin must be hard-wired HIGH; it is test-only and not functional in system operation.

Key Specifications

Pinout & Package

AD7575KP is packaged in a 20-terminal plastic leaded chip carrier (PLCC, P-20A), with 18 active terminals and 2 NC pins (pins 15 and 19). Pin 1 identifier corner is marked by a notch or dot; pin numbering follows standard PLCC counterclockwise convention.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AD7575KP, AD7574KN lacks integrated track-and-hold and is slower, making it unsuitable for 50 kHz full-scale signals; MAX160BCNG+ offers higher speed but demands dual supplies and consumes significantly more power - neither is pin-compatible, and both require PCB redesign and firmware adaptation.

Availability

AD7575KP is available at Aetrix Electronics and suitable for industrial data logging, medical sensor interface, audio test equipment, and motor control feedback applications requiring stable component supply across extended production lifecycles.

Supply support for AD7575KP 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 AD7575KP belongs to Analog Devices' legacy LC2MOS precision ADC product line, designed specifically for microprocessor-centric embedded systems requiring low-power, single-supply, easy-to-interface 8-bit data conversion with integrated signal conditioning.

FAQ

What is the maximum input signal frequency the AD7575KP can accurately digitize?

The AD7575KP supports full-power signal bandwidth up to 50 kHz, meaning it can accurately digitize 2.46 V_PP sine waves at that frequency without slewing-induced error. This capability stems from its on-chip track-and-hold with 386 mV/µs slew rate. For higher-frequency signals, amplitude accuracy degrades due to input settling limitations - the AD7575KP datasheet confirms 45 dB SNR at 10 kHz but does not specify performance beyond 50 kHz full-power bandwidth.

Does the AD7575KP require external calibration for typical unipolar applications?

No, the AD7575KP does not require external calibration in most unipolar applications because its total unadjusted error is specified at ±1/2 LSB max across temperature, covering zero-scale, full-scale, and linearity errors. The datasheet explicitly states offset and gain adjustments are "not required" for many uses. However, if system-level accuracy tighter than ±1/2 LSB is needed, calibration procedures using op-amp nulling (for offset) and VREF adjustment (for full-scale) are documented in the AD7575KP datasheet Rev. B, pages 9–10.

Can the AD7575KP operate with an internal clock, and what are the trade-offs?

Yes, the AD7575KP supports internal clocking using an external 100 kΩ resistor and 100 pF capacitor (RCLK/CCLK), yielding typical conversion times of ~5–13 µs depending on temperature. However, internal clock frequency varies ±50% unit-to-unit and with temperature, so it is recommended only for non-critical timing applications. For guaranteed 5 µs conversion and deterministic software timing, Analog Devices specifies use of a 4 MHz external clock applied to the CLK pin - this is the only condition under which full accuracy is assured.

How should the TP pin be handled in an AD7575KP circuit design?

The TP (Test Pin) of the AD7575KP must be hard-wired to a logic HIGH level (e.g., tied to VDD via a 10 kΩ pull-up resistor) in all operational circuits. It serves no functional purpose during normal operation and is reserved exclusively for factory testing. Leaving TP floating or connecting it to logic LOW may cause undefined behavior or failure to acquire valid conversions. The AD7575KP datasheet Rev. B explicitly warns: "This pin is used in testing the device and should not be used as a feedthrough pin."

What are the grounding requirements for optimal AD7575KP performance?

The AD7575KP requires separate AGND and DGND connections, joined at a single point near the device (star ground) to prevent digital switching noise from modulating the analog input path. The datasheet mandates short, low-impedance traces for AIN and AGND - source resistance should remain below 2 kΩ to avoid full-scale errors from input charging current. Additionally, a 0.1 µF ceramic decoupling capacitor must be placed between VDD and DGND, and a second 47 µF bulk capacitor is recommended on the +5 V rail near the AD7575KP.