Analog Devices Inc. AD7875KN

Overview

AD7875KN from Analog Devices is a complete monolithic 12-bit sampling analog-to-digital converter (ADC) with integrated track-and-hold amplifier, laser-trimmed internal clock, on-chip 3 V buried Zener reference, and parallel/byte/serial digital interface. It supports unipolar 0 V to +5 V analog input range, achieves 72 dB SNR at 10 kHz, and delivers 57 ns data access time. It is used in precision data acquisition systems requiring high dynamic performance and microprocessor compatibility.

For engineers reviewing the AD7875KN datasheet, AD7875KN pinout, AD7875KN application, or AD7875KN equivalent, this page provides verified technical context, real-world interface timing constraints, confirmed unipolar input behavior, validated package mapping to 28-pin PLCC, and documented alternative options for industrial signal conditioning and DSP front-end designs.

Technical Context

The AD7875KN implements a successive approximation register (SAR) architecture with a dedicated 2 μs track-and-hold amplifier and internal 3 V reference, enabling full-scale conversion of 0 V to +5 V signals without external components. Its laser-trimmed internal clock guarantees 6.5–9 μs conversion time and eliminates need for external timing circuitry.

It supports three output formats-12-bit parallel, two 8-bit bytes, or serial-with mode selection controlled by the 12/8/CLK pin. BUSY/INT and RD signals provide synchronous handshaking for microprocessor interfacing, while HBEN enables byte-mode data alignment on DB7–DB0 or DB11–DB8 depending on control state.

Key Specifications

Pinout & Package

AD7875KN is packaged in a 28-pin plastic leaded chip carrier (PLCC), compliant with JEDEC MO-047AB, with 1.27 mm pitch and body size 11.5 mm × 11.5 mm. Pin 1 is identified by a notch or dot; all pins are gold-plated for reliable solderability and long-term contact integrity.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AD7870KN, AD7875KN provides optimized unipolar interface and straight-binary coding for sensor signal chains, while MAX195BCPP trades simplicity and speed for higher resolution and serial-only connectivity - making AD7875KN the preferred choice for cost-sensitive, microprocessor-based industrial DAQ.

Availability

AD7875KN is available at Aetrix Electronics and suitable for industrial data acquisition, test equipment design, and medical instrumentation requiring stable component supply, long-lifecycle availability, and traceable sourcing from authorized channels.

Supply support for AD7875KN 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, Inc. is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, headquartered in Wilmington, MA, with design centers worldwide.

The AD7875KN belongs to the LC2MOS 12-bit sampling ADC family, engineered for precision data acquisition in industrial, instrumentation, and DSP applications where integration, dynamic performance, and ease of microprocessor interfacing are essential.

FAQ

What is the analog input voltage range supported by the AD7875KN?

The AD7875KN supports a unipolar analog input range of 0 V to +5 V, referenced to AGND. This range is fixed and not software-configurable. The device uses straight-binary coding, where 000…000 corresponds to 0 V and 111…111 corresponds to +5 V. Input impedance is typically 25 kΩ, and the track-and-hold amplifier acquires full-scale steps within 2 μs.

Does the AD7875KN require an external clock to operate?

No, the AD7875KN does not require an external clock. It features a built-in laser-trimmed oscillator that guarantees conversion times between 6.5 μs (minimum) and 9 μs (maximum). An external TTL-compatible clock may be applied to the CLK pin if tighter timing control is needed, but tying CLK to VSS enables the internal clock - eliminating external timing components entirely.

What digital interface modes does the AD7875KN support?

The AD7875KN supports three hardware-selectable interface modes via the 12/8/CLK pin: 12-bit parallel (12/8/CLK = +5 V), two-byte parallel (12/8/CLK = 0 V or −5 V, with HBEN control), and serial (using SDATA, SCLK, and SSTRB outputs). All modes share the same BUSY/INT and RD handshaking protocol, ensuring consistent timing behavior across configurations.

Can the internal 3 V reference of the AD7875KN be used externally?

Yes, the REF OUT pin provides the internal 3 V buried Zener reference, specified at 3.00 V ±10 mV and capable of sourcing up to 500 μA. For external use, Analog Devices recommends series decoupling with a 200 Ω resistor and parallel filtering using a 10 μF tantalum capacitor plus a 0.1 μF ceramic capacitor to suppress switching noise from internal ADC operation.

What package type is the AD7875KN supplied in?

The AD7875KN is supplied in a 28-pin plastic leaded chip carrier (PLCC) package per JEDEC MO-047AB. It features a 1.27 mm pitch, 11.5 mm × 11.5 mm body, and pin 1 identification via notch or dot. This package is distinct from the 24-pin DIP version used for AD7870/AD7876 and supports surface-mount assembly with standard reflow profiles.