Asahi Kasei Microdevices/AKM AK9234NK

Overview

AK9234NK from Asahi Kasei Microdevices is a 16-bit, dual-channel, simultaneous-sampling analog-to-digital converter (ADC) with serial interface, 0.93 MSPS maximum conversion rate in serial output mode, internal reference buffer, and support for reduced-pin-count digital wiring via CONVSTN/CSN shorting, SDATI/SDATO multiplexing, and SDO0/SDO1 time-multiplexed output. It targets high-precision current/voltage sensing in motor control inverters.

For engineers reviewing the AK9234NK datasheet, AK9234NK pinout, AK9234NK application, or AK9234NK equivalent, key selection considerations include simultaneous dual-channel sampling integrity, serial interface flexibility (3-wire vs. 4-wire), guaranteed tDD timing compliance, HVDD/DRVDD power domain separation, and layout-sensitive decoupling capacitor placement per application note Rev 1.0.

Technical Context

The AK9234NK implements a successive approximation register (SAR) ADC architecture with two independent sample-and-hold circuits enabling true simultaneous sampling of AIN0 and AIN1. It supports both parallel-output (dual SDOx) and serial-output (time-multiplexed SDO0/SDO1) data modes, with CONT bit configuration determining output sequencing.

Digital interface flexibility includes four wiring reduction methods: (1) CONVSTN/CSN shorting for shared command strobe, (2) SDATI/SDATO shorting for bidirectional 3-wire SPI, (3) SDO0/SDO1 time-division multiplexing under CONT=1, and (4) optional CALC pin omission when CSN timing satisfies tDD constraint after CONVSTN.

Key Specifications

Pinout & Package

AK9234NK is housed in a 32-pin QFN package (5 mm × 5 mm, 0.5 mm pitch) with exposed thermal pad. Pin assignment follows AKM's standard AK923x family layout, verified against Rev 1.0 Application Note Figures 6–7 and functional descriptions.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar dual-channel simultaneous-sampling ADC applications.

Compared with AD7656ASTZ and ADS8684IPWR, the AK9234NK uniquely balances minimal GPIO count (via 4 wiring-reduction modes), integrated reference buffering, and simultaneous dual-channel fidelity - making it optimal for cost- and space-constrained inverter and servo drive designs requiring exactly two synchronized inputs.

Availability

AK9234NK is available at Aetrix Electronics and suitable for motor control inverters, industrial PLC analog input modules, energy metering reference designs, and servo drive position feedback systems requiring stable component supply and verified layout compatibility.

Supply support for AK9234NK 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 mixed-signal ICs, magnetic sensors, and audio solutions, with core expertise in precision analog front-ends and low-noise signal conditioning.

The AK923x family, including AK9234NK, was designed specifically for high-fidelity current and voltage sensing in power electronics - emphasizing simultaneous sampling integrity, layout robustness, and digital interface flexibility in noisy inverter environments.

FAQ

What is the maximum conversion rate of the AK9234NK in serial output mode?

The AK9234NK achieves a maximum conversion rate of 0.93 MSPS in serial output mode, delivering 465 kSPS per channel via time-multiplexed SDO0/SDO1 output. This rate is sustained under continuous 39-cycle SCLK input while CSN is low, as specified in Figure 10 of the Rev 1.0 Application Note. The AK9234NK maintains full 16-bit resolution and simultaneity at this rate.

Can the AK9234NK operate without an external reference voltage?

Yes, the AK9234NK can operate without an external reference voltage because it integrates a buffered internal reference (VREFP/VREFN). Decoupling capacitors C11 and C12 must be placed per the Rev 1.0 Application Note layout guidelines to ensure stability. This eliminates the need for external reference ICs in most motor control and PLC applications, reducing BOM cost and layout complexity for the AK9234NK.

How does the AK9234NK support reduced-pin-count digital interfacing?

The AK9234NK supports four distinct wiring reduction methods: (1) shorting CONVSTN/CSN, (2) shorting SDATI/SDATO for 3-wire SPI, (3) time-multiplexing SDO0/SDO1 under CONT=1, and (4) omitting the CALC pin when tDD timing is met. These are all validated in the Rev 1.0 Application Note and enable AK9234NK integration using as few as three digital lines - a key advantage over conventional dual-channel ADCs.

What PCB layout recommendations apply to the AK9234NK?

The AK9234NK requires a 4-layer PCB per Rev 1.0 Application Note: Layer 1 and 4 are signal/GND planes, Layer 2 is solid ground, and Layer 3 is split HVDD/DRVDD power planes. All decoupling capacitors (C7–C16) must use 1005-size chip components placed adjacent to respective power pins. This layout minimizes noise coupling and ensures stable operation of the AK9234NK in high-dv/dt inverter environments.

Is the AK9234NK pin-compatible with other members of the AK923x family?

Yes, the AK9234NK is pin-compatible with AK9232NK and AK9233NK within the same 32-pin QFN package. Differences lie in internal configuration (e.g., gain settings, default register values) and maximum sampling rate - AK9232NK supports 0.5 MSPS, AK9233NK 0.75 MSPS, and AK9234NK 0.93 MSPS. Layouts designed for one variant can be reused for another with firmware register updates, preserving AK9234NK hardware compatibility.