Analog Devices Inc. AD7875KNZ

Overview

AD7875KNZ from Analog Devices is a complete monolithic 12-bit successive approximation ADC with integrated track-and-hold amplifier, laser-trimmed internal clock, and on-chip 3 V buried Zener reference. It supports unipolar 0 V to +5 V analog input range, delivers 72 dB SNR at 10 kHz, achieves 8 μs conversion time with external 2.5 MHz clock, and features 57 ns data access time for direct interfacing with 8-/16-bit microprocessors and DSPs in data acquisition systems.

For engineers reviewing the AD7875KNZ datasheet, AD7875KNZ pinout, AD7875KNZ application, or AD7875KNZ equivalent, this page provides verified technical context, real-world interface timing constraints, confirmed dynamic and dc accuracy specs, package-specific pin functions, and validated alternative options for industrial sensor signal conditioning and embedded measurement designs.

Technical Context

The AD7875KNZ implements a SAR architecture with a fast-settling DAC, high-speed comparator, and internal 3 V temperature-compensated Zener reference trimmed to ±10 mV. Its track-and-hold acquires signals to 12-bit accuracy in ≤2 μs, enabling full-power conversion up to 50 kHz while maintaining 70–72 dB SNR across 0–50 kHz input bandwidth.

Digital interface flexibility includes three modes: 12-bit parallel (DB11–DB0), two-byte parallel (HBEN-controlled DB7–DB0 and DB11–DB8), and serial (SCLK/SSTRB/SDATA) - all supported by production-tested timing parameters including t6 = 57 ns (J/K/L versions) and guaranteed bus relinquish times. Control logic responds asynchronously to CONVST rising edge or CS falling edge for standalone or processor-synchronized operation.

Key Specifications

Pinout & Package

AD7875KNZ is supplied in a 24-pin, 0.3 inch-wide plastic DIP package (N-24). Pin functions are electrically identical to the SOIC variant but differ mechanically in lead pitch and thermal mass.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 12-bit sampling ADC applications.

Compared with AD7875KNZ, AD7870KNZ offers identical speed and accuracy but targets bipolar signal chains, while ADS7822U trades integration and dual-supply operation for size and single-supply compatibility - making AD7875KNZ optimal for fixed 0–5 V industrial measurement where board area and component count are critical.

Availability

AD7875KNZ is available at Aetrix Electronics and suitable for industrial data acquisition, embedded sensor interfaces, test equipment front-ends, and DSP-based signal analysis requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for AD7875KNZ 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 AD7870/AD7875/AD7876 family was designed specifically for high-accuracy, medium-speed data acquisition in industrial automation and instrumentation - integrating precision analog front-end functions with robust digital interfacing to reduce system complexity.

FAQ

What is the maximum analog input frequency the AD7875KNZ can accurately digitize?

The AD7875KNZ supports full-power input signals up to 50 kHz while maintaining 12-bit accuracy and 72 dB SNR at 10 kHz. Its track-and-hold amplifier has a 0.1 dB cutoff typically at 500 kHz, ensuring minimal aperture jitter and faithful reconstruction of signals within the Nyquist band of its 100 kSPS maximum sampling rate. For anti-aliasing, a 50 kHz cutoff filter is recommended before VIN.

Does the AD7875KNZ require external components to operate?

No, the AD7875KNZ is a complete ADC subsystem requiring only decoupling capacitors on VDD, VSS, and REF OUT. It integrates a 3 V buried Zener reference, laser-trimmed clock oscillator, and track-and-hold amplifier - eliminating external op amps, references, clock crystals, or timing resistors. External pull-up resistors (4.7 kΩ on SSTRB/SDATA, 2 kΩ on SCLK) are needed only for serial interface operation.

How does the AD7875KNZ handle unipolar offset error?

The AD7875KNZ specifies unipolar offset error ≤±5 LSB at +25°C and provides dedicated adjustment circuitry per Figure 13 in Rev. C datasheet. Offset must be trimmed before full-scale calibration using external 10-turn trimpots connected to designated pins. This adjustment compensates for input-stage DC errors and ensures code zero aligns precisely with 0 V input under production conditions.

Can the AD7875KNZ interface directly with a 3.3 V microcontroller?

Yes, but with level translation on digital I/O lines. The AD7875KNZ operates from ±5 V supplies and produces TTL-compatible outputs (VOH ≥ 4.0 V, VOL ≤ 0.4 V), which exceed 3.3 V logic thresholds. However, its inputs (RD, CS, CONVST) require VINH ≥ 2.4 V and VINL ≤ 0.8 V - compatible with 3.3 V CMOS outputs. No level shifters are needed for control signals, but 3.3 V MCU outputs driving AD7875KNZ inputs must meet these voltage thresholds.

What is the purpose of the 12/8/CLK pin on the AD7875KNZ?

The 12/8/CLK pin configures both data format and serial clock behavior: at +5 V it enables 12-bit parallel output only; at 0 V it enables byte or serial mode with gated SCLK; at −5 V it enables byte or serial mode with continuous SCLK. This single pin eliminates external mode-select logic, allowing flexible interface selection without redesigning PCB traces or firmware register maps for different host processors.