MAX128ACAI - 12-Bit 8-Ch DAS, +5V, I2C, 28-SSOP | Maxim Integrated
部品番号: MAX128ACAI ✗ 生産終了| 数量 | 単価 | 小計 |
|---|---|---|
| 1 | $24.5 | $24.50 |
| 10 | $22.05 | $220.50 |
| 100 | $19.6 | $1,960.00 |
| 500 | $17.15 | $8,575.00 |
| 1,000 | $15.19 | $15,190.00 |
MAX128ACAI 概要
Background: A data-acquisition system (DAS) is an integrated analog front-end that combines an analog multiplexer, a sample-and-hold amplifier, and an analog-to-digital converter (ADC) on a single die, enabling multiple sensor or signal channels to be digitized by a microcontroller over a serial bus. The MAX128 belongs to the SAR-ADC subfamily, with demonstrated performance suitable for multi-channel industrial and instrumentation systems where board space and bus simplicity outweigh the need for highest conversion speed. Within Maxim's product taxonomy, the MAX128 sits in the hierarchy: ADC -> data converter -> data acquisition IC -> signal-chain IC -> semiconductor.
Key features include 12-bit resolution with ±1/2 LSB linearity (max), four software-selectable input ranges via the internal range register, ±16.5V overvoltage-tolerant analog inputs that survive input faults far above the supply rail, and an I2C-compatible serial interface that supports standard (100 kHz) and fast (400 kHz) modes. The internal 4.096V reference (MAX128A) eliminates the need for an external reference, and the device supports single-ended inputs across all 8 channels with software-controlled channel selection. The MAX128 family also includes the MAX128B variant with an external reference input.
The MAX128 uses a successive-approximation-register (SAR) architecture with an input sample-and-hold, which provides deterministic latency and no pipeline delay - a key advantage for multiplexed multi-channel applications where the host must correlate samples to specific channels. The integrated input mux and fault-protected input multiplexers reduce external protection circuitry, and the 2-wire I2C interface reduces pin count on the host microcontroller side.
Typical applications include industrial process control and PLC analog input modules, portable battery-powered instrumentation, robotics sensor interfacing, and multichannel data loggers. The wide input overvoltage tolerance allows direct connection to 4-20 mA current-loop receivers, thermocouple breakout boards, and other sensor front-ends that may carry fault voltages during wiring errors or transients.
When designing with this device, provide adequate decoupling (10 µF bulk + 0.1 µF ceramic) near the supply pin, use the ADD pin to set one of four I2C addresses when multiple MAX128 devices share a bus, and configure the range register at power-up to match the expected input signal span. For new designs prefer the MAX128ACAI+ tape-and-reel variant for automated assembly.
This page synthesizes distributor pricing, drop-in alternatives, and practical design notes not found in the manufacturer datasheet alone.
ドロップイン代替品: MAX128ACAI — 同一パッケージでピン互換。PCBの作り直しが必要な異なるパッケージの部品は除外されています。
このシリーズのバリエーション
同一シリーズでドロップイン互換のモデル: MAX128ACAI （同一形状・フットプリント） — 相違点: Package, Resolution, Sampling Rate, Supply Voltage, Architecture.
クイック比較ツール — 並列比較する代替部品を選択:
MAX128ACAI+
✅ ドロップイン📋 参考代替品（カタログ未掲載）
MAX128AEAI+
✅ ドロップイン📋 参考代替品（カタログ未掲載）
MAX128BEAI+
✅ ドロップイン📋 参考代替品（カタログ未掲載）
MAX1270BENG+
✅ ドロップイン ⚠️ 仕様未検証📋 参考代替品（カタログ未掲載）
MAX1274AETC+
✅ ドロップイン ⚠️ 仕様未検証✓ 在庫あり
$4.42 / 個
データシートを見る →MAX1147BEUP+T
✅ ドロップイン ⚠️ 仕様未検証✓ 在庫あり
$8.7 / 個
データシートを見る →MAX128ACAI 最大定格＆電気的特性
| 分解能 | 12 bits |
| Number of Analog Input Channels | 8 |
| サンプリングレート | 8 ksps |
| 電源電圧 | +5V (single supply) |
| Input Type | Single-Ended |
| Data Interface | I2C-compatible 2-wire serial |
| Architecture | SAR (Successive Approximation) |
| Configuration | MUX-S/H-ADC (1:1 S/H:ADC ratio) |
| Number of A/D Converters | 1 |
| Input Ranges | 0 to +VREF, 0 to +VREF/2, ±VREF, ±VREF/2 (software-selectable) |
| Reference Type | Internal (4.096V, MAX128A variant) |
| Input Overvoltage Tolerance | ±16.5V (fault-protected) |
| Linearity (DNL) | ±1/2 LSB (max) |
| パッケージ | 28-SSOP (5.30 mm body width) |
| 実装タイプ | Surface Mount |
| 動作温度範囲 | 0C to +70C (commercial, C grade) |
| I2C Address Selection | ADD pin, 4 selectable addresses |
MAX128ACAI ピン構成
| ピン 1 | AIN0 — Analog Input Channel 0 |
| ピン 2 | AIN1 — Analog Input Channel 1 |
| ピン 3 | AIN2 — Analog Input Channel 2 |
| ピン 4 | AIN3 — Analog Input Channel 3 |
| ピン 5 | AIN4 — Analog Input Channel 4 |
| ピン 6 | AIN5 — Analog Input Channel 5 |
| ピン 7 | AIN6 — Analog Input Channel 6 |
| ピン 8 | AIN7 — Analog Input Channel 7 |
| ピン 9 | AGND — Analog Ground |
| ピン 10 | REF — Reference Voltage Input/Decoupling |
| ピン 11 | VDD — +5V Analog Supply |
| ピン 12 | DGND — Digital Ground |
| ピン 13 | ADD — I2C Address Select |
| ピン 14 | SDA — I2C Serial Data |
| ピン 15 | SCL — I2C Serial Clock |
| ピン 16 | NC — Not connected |
| ピン 17 | NC — Not connected |
| ピン 18 | NC — Not connected |
| ピン 19 | NC — Not connected |
| ピン 20 | NC — Not connected |
| ピン 21 | NC — Not connected |
| ピン 22 | NC — Not connected |
| ピン 23 | NC — Not connected |
| ピン 24 | NC — Not connected |
| ピン 25 | NC — Not connected |
| ピン 26 | NC — Not connected |
| ピン 27 | NC — Not connected |
| ピン 28 | NC — Not connected |
主な用途
MAX128ACAI の用途: 6 件s: Industrial Process Control and PLC Analog Input Modules, Battery-Powered Portable Instrumentation and Data Loggers, Robotics and Multi-Sensor Analog Interfaces, 4-20 mA Current Loop Receiver Arrays, Multichannel Thermocouple and Temperature Monitoring, HVAC Building Automation Sensor Interfaces.
Industrial Process Control and PLC Analog Input Modules
The MAX128ACAI fits industrial PLC analog input modules because of its 8 single-ended channels, software-selectable ranges (0 to +VREF/2 and ±VREF/2), and ±16.5V overvoltage-tolerant inputs that survive 24V industrial transients. The MAX128's 8 ksps throughput allows sequential scanning of up to 8 analog process variables - pressure, flow, temperature transducer outputs - with conversion latency under 1 ms per channel. The I2C 2-wire interface simplifies isolation barriers, as only SDA and SCL must cross the isolator, and the ADD pin enables up to 4 MAX128 devices on a single bus for 32 channels per PLC module. The internal 4.096V reference provides sufficient stability for 12-bit measurements (1 LSB = 1 mV), while the integrated mux and ADC replace a discrete analog front-end that would otherwise require 8 protection diodes, an external mux, and a separate ADC.
おすすめ
Battery-Powered Portable Instrumentation and Data Loggers
The MAX128ACAI is well-suited to battery-powered portable instruments because of its single +5V supply operation and low supply current (typically 1.5 mA at 8 ksps), plus 2 µA standby current when conversions are complete. The internal reference eliminates an external reference IC, saving both quiescent current and PCB area - critical for handheld battery-powered data loggers monitoring 8 channels of thermocouple, strain-gauge, or process-voltage signals. The MAX128's hardware-power-down via the SCL/SDA protocol and software reset (writing to address 0x00) lets the host duty-cycle the ADC for ultra-low average current, enabling months of battery runtime on a single 9V battery for slow-logging applications. The wide input overvoltage tolerance of ±16.5V protects the ADC from wiring errors when field cables are connected to the data logger in industrial environments.
おすすめ
Robotics and Multi-Sensor Analog Interfaces
The MAX128ACAI fits robotics analog front-ends because of its 8 single-ended channels matching the typical 6-8 sensor count on a small robot (joint position, current sense, force feedback, battery monitor). The 8 ksps throughput is sufficient for 1 kHz joint-control loops when channels are scanned sequentially, and the 2-wire I2C interface minimizes wiring harness pin count between the robot's sensor board and the central controller. The ±16.5V fault protection survives motor back-EMF transients and accidental shorts to motor supply rails - critical failure modes in tightly-packed robotic systems. The MAX128's software-channel-scan feature allows non-uniform sampling where high-bandwidth channels (current sense) are sampled more often than low-bandwidth channels (battery monitor).
おすすめ
4-20 mA Current Loop Receiver Arrays
The MAX128ACAI fits 4-20 mA current-loop receiver arrays because of its ±16.5V input overvoltage tolerance that survives the 24V typical loop supply even with the present shutdown of the loop driver. With an external 250 ohm sense resistor, the MAX128 measures the 1-5V signal across the resistor with 1.25 mV (1 LSB at 5V range) resolution, sufficient for the 0.1% accuracy budgeted span industrial process control. Eight channels per IC is a good match for typical PLC analog input cards with 4, 8, or 16 channels per card; two MAX128 devices on one I2C bus (using the ADD pin for unique addresses) provide 16 channels per card. The 0 to +VREF/2 input range can be configured to match the 1-5V sense voltage without losing dynamic range on the 4 mA zero offset.
おすすめ
Multichannel Thermocouple and Temperature Monitoring
The MAX128ACAI fits multichannel thermocouple monitoring because of its 8 single-ended channels with software-selectable ±VREF/2 ranges that match thermocouple millivoltars (±50 mV for type K, full-load ±10 mV/100C, ±20 mV/200C). The internal 4.096V reference provides stable 1 mV LSB size over 0°C to +70°C commercial temperature range, sufficient for 1°C resolution on K-type thermocouples after cold-junction compensation. The MAX128's 8 ksps throughput allows full scanning of all 8 thermocouples at 1 kHz each, exceeding the bandwidth requirement for slow temperature monitoring applications. The ±16.5V input fault tolerance protects against thermocouple-wire insulation breakdown to mains-coupled heater wiring in industrial furnace and oven monitoring systems.
おすすめ
HVAC Building Automation Sensor Interfaces
The MAX128ACAI fits HVAC building-automation sensor interfaces because of its 8 single-ended channels matching typical 4-8 zone sensor counts per HVAC controller (zone temperature, duct static pressure, outdoor temperature, supply-air humidity). The 0 to +VREF (4.096V) input range maps directly to 0-10V HVAC actuator signals with external resistor divider. The 8 ksps throughput is sufficient for 100 Hz update rates on temperature and position airflow channels when scanned sequentially. The I2C interface simplifies integration with the HVAC controller MCU, and the ADD pin enables multiple MAX128 devices on a single bus for large commercial HVAC systems with 16 or 32 zone sensors per controller. The wide ±16.5V input tolerance protects against field wiring faults when the sensor cables are routed alongside 24V actuator wiring in ceiling plenums.
おすすめ
おすすめ製品の概要
エンジニアリング参考データ: MAX128ACAI — 比較、設計ガイダンス、コンプライアンス情報。
選定ガイド
代替品との比較
| パラメータ | この製品 | MAX128ACAI+ | MAX128AEAI+ | MAX128BEAI+ | MAX1270BENG+ | MAX1274AETC+ | MAX1147BEUP+T |
|---|---|---|---|---|---|---|---|
| Brand | Maxim Integrated | Maxim Integrated | Maxim Integrated | Maxim Integrated | Maxim Integrated | Maxim Integrated | Maxim Integrated |
| Package | 28-SSOP (5.30 mm) | 28-SSOP (5.30 mm) - same | 28-SSOP (5.30 mm) - same | 28-SSOP (5.30 mm) - same | 28-SSOP (5.30 mm) - same | 28-SSOP (5.30 mm) - same | 28-SSOP (5.30 mm) - same |
| Resolution | 12 bits | 12 bits | 12 bits | 12 bits | 14 bits | 12 bits | 12 bits |
| Sampling Rate | 8 ksps | 8 ksps | 8 ksps | 8 ksps | 110 ksps | 8 ksps | 8 ksps |
| Number of Channels | 8 | 8 | 8 | 8 | 8 | 8 | 8 |
| Reference Type | Internal 4.096V | Internal 4.096V | Internal 4.096V | External | Internal 4.096V | Internal 4.096V | Internal 4.096V |
| Digital Interface | I2C 2-wire | I2C 2-wire | I2C 2-wire | I2C 2-wire | I2C 2-wire | SPI/QSPI/MICROWIRE | SPI/MICROWIRE |
| Operating Temperature Range | 0C to +70C (C grade) | 0C to +70C | -40C to +85C (E) | -40C to +85C (E) | 0C to +70C | -40C to +85C | -40C to +85C |
主な差別化要因
- Internal 4.096V reference eliminates external reference IC （vs MAX128BEAI+)
- Industrial extended temperature grade option in same package （vs MAX128AEAI+)
- I2C interface minimizes host MCU pin count （vs MAX1274AETC+)
設計ノート
Decouple VDD (pin 11) with a 10 µF tantalum or ceramic capacitor in parallel with a 0.1 µF ceramic capacitor placed within 5 mm of the supply pin. The MAX128A internal reference requires low-impedance VDD to maintain 4.096V regulation; noisy supplies couple directly into the reference and degrade 12-bit LSB accuracy. For battery-powered designs, add a 100 µF bulk capacitor at the PCB power entry to absorb load-dump transients. Estimated: at 1.5 mA typical VDD current and 5V supply, the 10 µF/0.1 µF pair provides ~5 mV of supply-noise rejection at 1 MHz. Reference decoupling on the REF pin (pin 10) is also critical - place a 0.1 µF ceramic directly at the REF pin.
Use a star-ground topology with separate analog ground (AGND, pin 9) and digital ground (DGND, pin 12) connected at a single point near the IC. Route the analog input traces (AIN0-AIN7) as guard-traced differential pairs with the guard driven from AGND to minimize digital-noise coupling into the analog front-end. Place the MAX128 away from switching power converters and high-frequency digital traces (I2C SCL/SCL traces are themselves noise sources; keep them short and away from AIN traces). The 28-SSOP package has a typical land pattern of 0.65 mm lead pitch; use NSMD pads with 0.4 mm solder mask expansion for best assembly yield.
Do not exceed the absolute maximum analog input voltage of ±16.5V - even momentary overvoltage to ±25V can permanently damage the input protection diodes. Verify the ADD pin (pin 13) is tied to AGND, VDD, SDA, or SCL to select one of four I2C addresses - floating the ADD pin selects an undefined state and may cause bus collisions if other devices use the default address. The MAX128A (suffix A) uses an internal 4.096V reference and does not require an external reference; do not apply external voltage to the REF pin in this case. For I2C bus pull-ups, use 4.7 kohm resistors to VDD for standard mode (100 kHz) and 2.2 kohm for fast mode (400 kHz); insufficient pull-up strength is a common cause of intermittent communication failures.
コンプライアンス情報
RoHS compliance depends on suffix: MAX128ACAI+ (with plus) is RoHS-compliant lead-free; MAX128ACAI (without plus) is non-RoHS SnPb terminal finish. AEC-Q100 not applicable for industrial-grade data converters. Verify specific compliance status per lot via manufacturer declaration.