Asahi Kasei Microdevices/AKM AK9255NK

Overview

AK9255NK from Asahi Kasei Microdevices is a 16-bit, 0.54 MSPS ZDS-NS (Zero latency Delta Sigma with Noise Suppression) analog-to-digital converter featuring simultaneous dual-channel sampling, differential/pseudo-differential input, and integrated digital noise suppression filtering. It delivers ±3.0 LSB typical INL and 86 dBFS typical SNR (NS Setting1), targeting high-accuracy position measurement in SinCos encoder-based motor control systems.

For engineers reviewing the AK9255NK datasheet, AK9255NK pinout, AK9255NK application, or AK9255NK equivalent, this page provides verified technical context, package mapping to 3×3 mm QFN-16, real-world use value in industrial automation signal chains, and validated alternative options for noise-sensitive, real-time sampling applications.

Technical Context

The AK9255NK implements a proprietary ZDS-NS architecture that combines SAR-like zero-latency response with delta-sigma–level accuracy and built-in oversampling + digital averaging. Its internal noise suppression function operates via configurable digital filter settings (NS Setting1–4), directly improving system-level SNR without external hardware averaging.

It supports true simultaneous sampling across two channels with independent differential inputs (AIN0P/N, AIN1P/N), referenced to dedicated VREF0P/N and VREF1P/N pairs. Power is split between analog (VDD = 3.0–3.6 V, 26 mA typ.) and digital driver (DRVDD = 3.0–3.6 V, 0.3 mA typ.) domains to minimize coupling noise.

Key Specifications

Pinout & Package

AK9255NK is housed in a 3 mm × 3 mm, 0.5 mm pitch, 16-pin QFN package with exposed thermal pad (must be connected to ground per AKM recommendation). The package supports high-density PCB layouts and efficient heat dissipation in compact motor drive modules.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar high-speed, noise-suppressed ADC applications.

Compared with AD7380BCPZ-RL7 and ADS131M04IPBSR, the AK9255NK uniquely balances 0.54 MSPS simultaneous sampling, 16-bit no-missing-code linearity, and on-chip noise suppression - making it optimal for real-time motor control where latency, channel alignment, and encoder interface simplicity are critical.

Availability

AK9255NK is available at Aetrix Electronics and suitable for motor control systems, industrial PLC analog input modules, and power quality analyzers requiring stable component supply, long-term lifecycle support, and guaranteed traceable sourcing.

Supply support for AK9255NK 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

Asahi Kasei Microdevices (AKM) is a Japanese semiconductor company specializing in high-precision analog and mixed-signal ICs, particularly for industrial, automotive, and audio applications.

The AK9255NK belongs to AKM's ZDS-NS ADC product line, engineered specifically for real-time industrial motion control systems demanding simultaneous sampling, ultra-low latency, and deterministic noise suppression without external processing overhead.

FAQ

What is the ZDS-NS architecture used in the AK9255NK?

The AK9255NK employs AKM's proprietary Zero latency Delta Sigma with Noise Suppression (ZDS-NS) architecture. Unlike conventional delta-sigma converters, it achieves zero-cycle latency while maintaining 16-bit accuracy and integrating on-chip oversampling + digital filtering. This architecture directly addresses the need for fast, precise sampling in motor control - the AK9255NK delivers simultaneous 0.54 MSPS conversion without sacrificing SNR or linearity, unlike SAR or pipeline alternatives.

Does the AK9255NK support true simultaneous sampling across both channels?

Yes, the AK9255NK performs true simultaneous sampling on both AIN0 and AIN1 channels. Its internal timing circuitry captures both inputs at the exact same instant, ensuring phase coherence critical for SinCos encoder angle computation and three-phase current reconstruction. This eliminates inter-channel skew found in multiplexed ADCs - a key differentiator confirmed in AKM's block diagram and timing specifications for the AK9255NK.

What are the recommended layout practices for the AK9255NK's exposed thermal pad?

Per AKM's official package documentation, the exposed thermal pad on the AK9255NK's QFN-16 must be connected to ground. When PCB wiring density exceeds 200%, AKM explicitly recommends grounding the pad to ensure thermal stability and noise immunity. A minimum of four thermal vias (0.3 mm diameter) connecting the pad to an internal ground plane is advised to maintain junction temperature within −40 °C to +105 °C operating limits during continuous 26 mA VDD operation.

How does the noise suppression function of the AK9255NK improve system-level performance?

The AK9255NK's noise suppression function applies configurable digital filtering (NS Settings 1–4) to averaged oversampled data, improving effective SNR by up to 4 dB versus baseline - e.g., from 86 dBFS to 90 dBFS. This replaces external RC filters and firmware averaging, reducing signal chain latency and component count. In practice, this allows the AK9255NK to resolve sub-millivolt encoder signals in electrically noisy motor drive environments without degrading real-time loop bandwidth.

Is the AK9255NK pin-compatible with the AK9256A?

No, the AK9255NK and AK9256A are not pin-compatible. Although both share the same QFN-16 package outline and pin configuration (confirmed in AKM's Pin Configurations diagram), they differ in resolution (16-bit vs. 14-bit), sampling rate (0.54 MSPS vs. 0.62 MSPS), and INL/SNR specifications. Interchanging them requires firmware recalibration and validation - the AK9255NK is optimized for higher accuracy at slightly lower speed, while the AK9256A trades resolution for throughput.