Analog Devices Inc. AD7575JN

Overview

AD7575JN 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 LSB total unadjusted error, and 0 to +70°C operating range in 18-lead plastic DIP package. It digitizes full-scale signals up to 50 kHz for embedded data acquisition in microprocessor-based instrumentation.

For engineers reviewing the AD7575JN datasheet, AD7575JN pinout, AD7575JN application, or AD7575JN equivalent, key selection criteria include unipolar/bipolar input configuration, internal vs. external clock timing control, BUSY-driven wait-state interface compatibility with 8085A-2/Z80/6502/TMS32010, and 1.23 V reference voltage sourcing.

Technical Context

The AD7575JN implements a SAR architecture with on-chip track-and-hold that samples the analog input on the third falling edge of CLK after CS and RD assertion. Its LC2MOS process enables single-supply operation and low power (15 mW typ), while internal clock generation (RCLK/CCLK) or 4 MHz external clock support provides flexible timing control.

Interface logic supports two modes: Slow Memory (BUSY forces processor WAIT state) and ROM (two-read sequence with interrupt-ready BUSY signaling). The TP pin must be hard-wired HIGH; DB0–DB7 outputs are latched and three-state buffered for direct microprocessor bus connection without external drivers.

Key Specifications

Pinout & Package

AD7575JN is housed in an 18-lead plastic dual in-line package (N-18), 0.3" wide, with through-hole mounting and standard DIP footprint.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX113CCNG and ADS7822U, the AD7575JN uniquely combines parallel 8-bit output, integrated track/hold, 5 µs speed, and single-supply operation in an industry-standard 18-pin DIP-making it optimal for legacy microprocessor systems requiring minimal external components and deterministic timing.

Availability

AD7575JN is available at Aetrix Electronics and suitable for industrial data acquisition, medical instrumentation, automated test equipment, and audio signal processing requiring stable component supply across extended production lifecycles.

Supply support for AD7575JN 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 AD7575 belongs to Analog Devices' precision data acquisition IC family, designed specifically for microprocessor-interfaced, medium-speed digitization in industrial, instrumentation, and embedded control applications.

FAQ

What is the maximum analog input frequency supported by the AD7575JN without accuracy degradation?

The AD7575JN 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 bandwidth is enabled by its integrated track-and-hold circuit. Input signals exceeding this frequency may exhibit reduced SNR or increased total unadjusted error beyond the specified ±1 LSB limit. For reliable operation, the AD7575JN should be used within this 50 kHz full-power bandwidth, especially when sampling at the rated 200 kSPS rate.

Does the AD7575JN require external calibration for typical unipolar applications?

No, the AD7575JN does not require external calibration in most unipolar applications due to its ±1 LSB total unadjusted error specification across 0°C to +70°C. The device's low offset error (±0.5 LSB max) and full-scale error (±1 LSB max) ensure monotonic transfer characteristics and no missing codes without trimming. Calibration is only needed if system-level accuracy demands exceed ±1 LSB or when operating in bipolar mode with external resistor networks.

How is the AD7575JN interfaced to an 8085A-2 microprocessor in Slow Memory mode?

In Slow Memory mode, the AD7575JN connects to the 8085A-2 via CS and RD tied to the decoded address and READ lines, with BUSY driving the READY input. A memory READ instruction asserts CS and RD, initiating conversion and forcing the processor into WAIT until BUSY goes HIGH. The AD7575JN then places converted data on DB0–DB7. This single-instruction interface relies on the AD7575JN's 5 µs conversion time and requires TP pin hard-wired HIGH for correct operation.

Can the AD7575JN operate with an internal clock, and what are the trade-offs?

Yes, the AD7575JN can operate with an internal clock using external RCLK (100 kΩ) and CCLK (100 pF), yielding nominal 5 µs conversion at +25°C. However, unit-to-unit variation (±50%) and temperature drift (e.g., 13 µs at –55°C) make it unsuitable for time-critical applications. External 4 MHz clocking is recommended when guaranteed 5 µs timing, deterministic software delays, or synchronization across multiple converters is required.

What is the function of the TP pin on the AD7575JN, and how should it be connected?

TP (Test Pin) on the AD7575JN is reserved for factory testing and must be hard-wired HIGH (e.g., pulled to VDD via 10 kΩ) in all applications. It is not a functional signal pin and must never be left floating, driven low, or used as a feedthrough on double-sided PCBs. Incorrect TP connection causes undefined behavior, including failure to sample or invalid BUSY signaling, because the AD7575JN's internal logic depends on TP being asserted HIGH for normal operation.