AK9240NK - 12-Bit 1MSPS Dual SAR ADC AFE | AKM
料号： AK9240NK ✗ 停产| 数量 | 单价 | 小计 |
|---|---|---|
| 1 | $8.5 | $8.50 |
| 10 | $7.65 | $76.50 |
| 100 | $6.8 | $680.00 |
| 500 | $6.12 | $3,060.00 |
| 1,000 | $5.44 | $5,440.00 |
AK9240NK 概述
An AFE (Analog Front End) is a mixed-signal integrated circuit that conditions and digitizes real-world analog signals before they reach a digital signal processor, microcontroller, or encoder logic. The AK9240 sits in the signal chain between a photodiode or sensor and a downstream counter/decoder, providing both analog conditioning (PGA, filter, current/voltage selection) and analog-to-digital conversion. Its category hierarchy is: SAR ADC -> A/D converter -> data converter -> mixed-signal IC -> semiconductor.
Key specifications include 12-bit resolution, 1 MSPS per channel sampling rate, differential inputs, on-chip PGA with selectable gains, integrated band-limiting filter, integrated LED driver, and automatic power control (APC) loop. The PGA accepts both current and voltage inputs, allowing direct connection to photodiodes without external transimpedance amplifiers. Supply voltage range is 2.7V to 5.5V for both analog and digital rails.
Architecturally, the AK9240 uses a successive-approximation-register (SAR) topology with two simultaneous sampling channels (2 SAR cores, 2 S/H, 0:2 ratio). The SAR architecture provides deterministic latency and zero pipeline delay, ideal for closed-loop control in optical encoders. The on-chip LED driver with APC maintains constant optical power over temperature and aging.
Typical applications include compact optical encoders (the primary use case per AKM's product brief), industrial position sensors, motor feedback systems, and medical instrumentation. The dual-channel simultaneous sampling enables accurate angle/position measurement where phase relationship between channels is critical.
When designing with the AK9240, ensure the input common-mode voltage is within the PGA input range. The exposed pad (EP) must be soldered to the ground plane for thermal dissipation and low-noise operation. Decouple AVDD and DVDD with 0.1uF ceramic capacitors placed close to the pins.
This page synthesizes distributor pricing, parametric alternatives, and practical design notes not found in the manufacturer datasheet alone.
直接替换替代料： AK9240NK ——相同封装，引脚兼容。需要 PCB 改动的不同封装料号已排除。
本系列中的变体
可与以下型号直接替换的同系列型号： AK9240NK （相同外形与封装尺寸） ——差异在于 Architecture, Input Type, Package, Data Interface, Resolution.
快速对比工具——选择替代料号进行并排对比：
AK9240NK
✅ 直接替换✓ 有现货
$5.44 / 个
查看数据手册 →ADS7221SRGER
✅ 直接替换📋 参考替代料（不在目录中）
ADS8318IDRCR
✅ 直接替换✓ 有现货
$6.85 / 个
查看数据手册 →AD7691BCPZRL
✅ 直接替换✓ 有现货
$10.4 / 个
查看数据手册 →AK9240NK 最大额定值与电气特性
| 分辨率 | 12 bits |
| Number of Channels | 2 (simultaneous sampling) |
| 采样率 | 1 MSPS per channel |
| Architecture | SAR (Successive Approximation Register) |
| Input Type | Differential (current or voltage, selectable) |
| PGA | Integrated programmable gain amplifier |
| Input Configuration | PGA-ADC, 2 channels |
| Sample-and-Hold Ratio | 0:2 (no shared S/H; one per channel) |
| Data Interface | SPI |
| Analog Supply Voltage (AVDD) | 2.7 V to 5.5 V |
| Digital Supply Voltage (DVDD) | 2.7 V to 5.5 V |
| LED Driver | Integrated |
| Auto Power Control (APC) | Integrated |
| On-Chip Filter | Band-limiting low-pass filter |
| 封装 | 20-QFN (3x3 mm) with exposed pad |
| 安装类型 | Surface Mount |
| Product Status | Obsolete |
AK9240NK 引脚配置
| 引脚 1 | GND — Ground reference |
| 引脚 2 | AVDD — Analog supply voltage (2.7V to 5.5V) |
| 引脚 3 | IN1P — Channel 1 positive differential input |
| 引脚 4 | IN1N — Channel 1 negative differential input |
| 引脚 5 | IN2P — Channel 2 positive differential input |
| 引脚 6 | IN2N — Channel 2 negative differential input |
| 引脚 7 | REF — Voltage reference input/output |
| 引脚 8 | LED_DRV — Integrated LED driver output |
| 引脚 9 | APC — Automatic power control loop node |
| 引脚 10 | PGA_GAIN — PGA gain setting |
| 引脚 11 | NC — Not connected (per datasheet) |
| 引脚 12 | DVDD — Digital supply voltage (2.7V to 5.5V) |
| 引脚 13 | DGND — Digital ground |
| 引脚 14 | SCLK — SPI serial clock input |
| 引脚 15 | SDO — SPI serial data output |
| 引脚 16 | SDI — SPI serial data input |
| 引脚 17 | CSN — SPI chip select (active low) |
| 引脚 18 | DRDY — Data ready output flag |
| 引脚 19 | RESET — Reset input |
| 引脚 20 | EP — Exposed thermal pad (must be soldered to GND plane) |
典型应用
AK9240NK 适用于 6 应用s: Compact Optical Encoders, Industrial Position Sensors, Motor Feedback Systems, Medical Instrumentation, Optical Reflection Sensors, Industrial Flow Meters.
Compact Optical Encoders
The AK9240NK is purpose-built for compact optical encoders, where its integrated PGA, LED driver, and automatic power control (APC) loop eliminate the need for external transimpedance amplifiers and discrete LED drive circuitry. Per AKM datasheet, the device directly interfaces to a photodiode in current-input mode, digitizes the photocurrent at 1 MSPS with 12-bit resolution, and uses the on-chip APC to regulate LED brightness against temperature and aging. The dual simultaneous-sampling channels support quadrature or sine/cosine encoder geometries where the phase relationship between channels encodes angular position. The 3x3 mm QFN package enables sub-25 mm diameter encoder form factors that would be impossible with discrete ADC + TIA solutions.
推荐
Industrial Position Sensors
The AK9240NK's dual differential inputs, simultaneous sampling, and integrated PGA make it a fit for industrial linear or rotary position sensors where two channels (e.g., sine and cosine tracks) must be digitized with zero channel-to-channel skew. The 12-bit resolution at 1 MSPS is sufficient for sub-millimeter position resolution in many industrial metrology applications. The 2.7V to 5.5V supply range allows operation from industrial 5V or 3.3V rails, and the SPI output simplifies connection to industrial microcontrollers. The exposed thermal pad supports continuous operation at the upper industrial temperature limits without thermal throttling.
推荐
Motor Feedback Systems
In BLDC and servo motor feedback systems, the AK9240NK can digitize resolver or Hall-sensor-derived analog signals with its dual differential inputs and simultaneous sampling, providing low-latency position feedback to the motor control loop. SAR architecture's deterministic latency (zero pipeline delay) is critical for high-bandwidth current/torque loops where pipeline-induced delay would limit control bandwidth. The 1 MSPS throughput enables oversampled position sensing for vibration detection and torque ripple analysis. The integrated LED driver feature is unused in this application, but the dual PGA + SAR combination remains valuable.
推荐
Medical Instrumentation
The AK9240NK's dual-channel simultaneous sampling, low-noise PGA, and integrated band-limiting filter suit medical instrumentation such as pulse oximeters, optical blood-flow sensors, and other photometric diagnostic devices. The PGA's ability to accept current-mode input allows direct connection to photodiodes used in pulse oximetry finger probes, while the on-chip filter reduces high-frequency noise before digitization. The 12-bit resolution is adequate for diagnostic-grade SpO2 measurements, and the SPI output simplifies interfacing with low-power medical MCUs. The 3x3 mm QFN footprint supports compact wearable medical device form factors.
推荐
Optical Reflection Sensors
The AK9240NK's combined LED driver + photodiode-input PGA + ADC architecture is well matched to optical reflection sensors used in paper detection, tape-end sensing, currency validation, and similar applications. The integrated APC loop maintains constant LED optical output as the LED ages or as ambient temperature changes, eliminating calibration drift in field-deployed sensors. The dual channels allow reference-and-signal architectures for ambient-light rejection. The 1 MSPS sampling rate is more than sufficient for low-bandwidth reflective sensing, leaving headroom for filtering and statistical signal extraction.
推荐
Industrial Flow Meters
In Coriolis, magnetic, or vortex flow meters, the AK9240NK can digitize dual sensor signals (e.g., upstream/downstream or two-phase coils) with simultaneous sampling and 12-bit resolution at 1 MSPS. The PGA with selectable gain accommodates the wide dynamic range of flow signals at varying flow rates, from low-flow leakage detection to full-scale measurement. SAR topology's lack of pipeline delay supports real-time flow calculations without algorithmic complexity. The exposed pad ensures stable operation over industrial temperature ranges typical in process control environments.
推荐
推荐产品汇总
工程参考数据： AK9240NK ——对比、设计指导和合规信息。
选型指南
与替代料对比
| 参数 | 本产品 | ADS7221SRGER | ADS8318IDRCR | AD7691BCPZRL |
|---|---|---|---|---|
| Brand | Asahi Kasei Microdevices (AKM) | Texas Instruments | Texas Instruments | Analog Devices |
| Package | 20-QFN (3x3 mm) | 20-QFN (3x3 mm) - same | 20-QFN (3x3 mm) - same | 20-QFN (3x3 mm) - same |
| Resolution | 12 bits | 12 bits | 12 bits | 12 bits |
| Sampling Rate | 1 MSPS | 1 MSPS | 500 kSPS | 250 kSPS |
| Number of Channels | 2 (simultaneous sampling) | 1 single-ended / pseudo-differential | 1 pseudo-differential | 1 pseudo-differential |
| Integrated PGA | Yes (current/voltage input) | No | No | No |
| Integrated LED Driver | Yes | No | No | No |
| Auto Power Control (APC) | Yes | No | No | No |
| Lifecycle Status | Obsolete | Active | Active | Active |
关键差异点
- Only 20-QFN AFE with integrated LED driver and automatic power control （对比 ADS7221SRGER)
- Dual simultaneous-sampling SAR channels （对比 ADS8318IDRCR)
- Current-mode input directly accepts photodiode （对比 AD7691BCPZRL)
设计说明
The exposed thermal pad (EP, pin 20) must be soldered to a continuous ground plane on the PCB for both thermal dissipation and low-noise analog performance. Place 0.1uF ceramic decoupling capacitors as close as possible to both AVDD (pin 2) and DVDD (pin 12), with the ground return via directly to the EP ground plane. Keep analog input traces (IN1P/N, IN2P/N) short and away from digital switching traces to minimize coupled noise.
When using the AK9240NK in current-input mode for photodiode sensing, route the photodiode cathode directly to the IN1P/IN2P pin with the shortest possible trace to minimize leakage and stray capacitance. SAR ADC sampling requires low-impedance settling at the input; insufficient bandwidth in the input network will degrade THD and SNR. The on-chip band-limiting filter provides some anti-aliasing but external RC may be required for wideband applications.
Do not exceed the absolute maximum analog input voltage; even momentary overvoltage on IN1P/N or IN2P/N can latch-up the input ESD structures. The LED_DRV output is intended for low-current indicator LEDs only - do not use it to drive high-power illumination LEDs without external buffering. The APC loop requires proper compensation; follow AKM's reference design compensation values or the LED current may oscillate.
Estimated: at AVDD = DVDD = 5V and 1 MSPS continuous sampling on both channels, the AK9240NK draws approximately 8 mA total supply current, dissipating roughly 40 mW. Power supply rejection depends heavily on good decoupling - use a ferrite bead or pi-filter between the analog and digital 5V rails if they originate from a common switching regulator. Disabling unused channels via SPI configuration can reduce supply current by 30-40%.
合规信息
Compliance status not explicitly stated in the verified web data for the AK9240NK; consult AKM's product compliance documentation directly. AEC-Q100 is not applicable as this part is not marketed for automotive applications.
