Analog Devices Inc. AD7575KNZ

Overview

AD7575KNZ 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 0–2.46 V input range using a +1.23 V reference. It interfaces directly to 8-bit microprocessors including Z80H, 8085A-2, and TMS32010 via CS/RD control logic and is used in real-time data acquisition systems requiring high-speed digitization of audio-frequency signals.

For engineers reviewing the AD7575KNZ datasheet, AD7575KNZ pinout, AD7575KNZ application, or AD7575KNZ equivalent, key selection considerations include its 5 µs conversion time with internal/external clock flexibility, on-chip track-and-hold supporting 50 kHz full-power bandwidth, 100 ns data access time, 15 mW typical power dissipation, and compatibility with memory-mapped or ROM-style microprocessor interfaces.

Technical Context

The AD7575KNZ implements a SAR architecture with internal clock division (÷2) and samples on the third falling edge of CLK after CS and RD assertion. Its LC2MOS process enables single-supply operation while maintaining low leakage for hold capacitor stability.

Conversion timing is deterministic: 20 external clock cycles (10 internal) per conversion, with sampling synchronized to control inputs. The track-and-hold function operates continuously between conversions and captures input at a precise, repeatable clock phase-critical for jitter-sensitive sampling in instrumentation and DSP front-ends.

Key Specifications

Pinout & Package

AD7575KNZ is packaged in an 18-lead plastic DIP (N-18), with 0°C to +70°C operating temperature range and lead finish per MIL-STD-202, Method 208.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX160BCNG+ and ADS7822U, the AD7575KNZ uniquely integrates track-and-hold with 5 µs conversion and parallel microprocessor interface-making it optimal for deterministic, low-overhead digitization of wideband analog signals in legacy 8-bit systems.

Availability

AD7575KNZ is available at Aetrix Electronics and suitable for industrial sensor interfaces, audio sampling circuits, data acquisition systems, and DSP front-ends requiring stable component supply and long-term obsolescence management.

Supply support for AD7575KNZ 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 AD7575KNZ belongs to Analog Devices' legacy precision ADC product line, designed specifically for cost-sensitive, high-speed 8-bit data acquisition in 5 V microprocessor-based instrumentation and control systems.

FAQ

What is the maximum input signal frequency the AD7575KNZ can accurately digitize?

The AD7575KNZ supports a full-power signal bandwidth of 50 kHz, meaning it can accurately digitize a 2.46 V_PP sine wave at 50 kHz (slew rate ≤386 mV/µs) without missing codes or distortion. This is enabled by its on-chip track-and-hold circuit. For higher frequencies, amplitude must be reduced to stay within the slew rate limit. The AD7575KNZ datasheet confirms this specification under "Full Power Signal Bandwidth" with test conditions at f_IN = 10 kHz and SNR ≥45 dB.

Does the AD7575KNZ require external calibration for typical use?

No, the AD7575KNZ does not require external calibration in most applications due to its ±1/2 LSB total unadjusted error-covering zero, full-scale, and linearity errors across the entire transfer function. The datasheet explicitly states offset and gain adjustments are "not required" for many implementations. Calibration circuits (e.g., op-amp offset null, reference trimming) are provided only for applications demanding highest accuracy, such as metrology-grade instruments.

Can the AD7575KNZ operate with an external clock, and what frequency is recommended?

Yes, the AD7575KNZ accepts an external clock at its CLK pin. A 4 MHz input clock is recommended to achieve the specified 5 µs conversion time and full accuracy. The internal logic divides this by two, resulting in a 2 MHz internal clock driving the SAR. Slower clocks increase conversion time and may degrade accuracy due to hold capacitor leakage, as shown in Figure 14 of the AD7575KNZ datasheet.

How is the AD7575KNZ interfaced to an 8085A-2 microprocessor?

The AD7575KNZ connects to the 8085A-2 using the Slow Memory Interface: CS and RD are tied to the processor's IO/M̅ and RD̅ lines (or decoded address), BUSY drives the READY input, and DB0–DB7 connect directly to the data bus. When CS and RD go low, BUSY asserts to halt the processor until conversion completes. This method uses one memory READ instruction to start and retrieve data. Figure 4 in the AD7575KNZ datasheet shows the exact wiring, including S0 status signal use for early READY assertion.

What is the purpose of the TP pin on the AD7575KNZ, and how should it be connected?

TP (Test Pin) on the AD7575KNZ is reserved exclusively for factory testing and must be hard-wired to +5 V (logic HIGH) in all application circuits. It is not a functional I/O pin and must never be left floating, used as a feedthrough, or connected to any signal net. The AD7575KNZ datasheet warns that incorrect TP connection may cause improper operation or failure to acquire valid conversions.