MAX187BEWE - 12-Bit 75ksps +5V Serial ADC | Maxim Integrated
部品番号: MAX187BEWE ✓ 生産中| 数量 | 単価 | 小計 |
|---|---|---|
| 1 | $16.55 | $16.55 |
| 10 | $14.9 | $149.00 |
| 100 | $13.2 | $1,320.00 |
| 500 | $11.85 | $5,925.00 |
| 1,000 | $10.4 | $10,400.00 |
MAX187BEWE 概要
A SAR ADC is a successive-approximation-register analog-to-digital converter that resolves one bit per clock cycle using a comparator, a DAC, and a binary-search register, trading conversion speed for excellent static accuracy and very low power consumption. In a typical signal chain, the SAR ADC sits between the analog front end (sensor + signal conditioning) and the digital controller (microcontroller, FPGA, DSP), translating real-world analog signals into 12-bit digital codes that downstream firmware can process. The MAX187's wide-SOIC pinout, internal reference, and serial interface made it a workhorse ADC of the 1990s and 2000s for industrial, instrumentation, and data-acquisition designs.
Key differentiating features include 12-bit resolution with ±1/2 LSB integral nonlinearity (INL) on the B-grade, internal 4.096 V reference (MAX187 only; MAX189 requires external reference), single +5V supply operation, hardware- or software-controlled shutdown, and a high-speed 3-wire serial interface that simplifies opto-isolation in noisy industrial environments. Compared to the older MAX176/MAX186 family, the MAX187 reduces operating current and adds an internal reference, simplifying BOM cost.
Typical applications include portable data loggers, battery-powered instrumentation, isolated sensor front ends using SPI over optocouplers, process-control analog I/O modules, panel meters, and pen/strain-gauge digitizers. The 75 ksps rate covers most 4-20 mA loop, RTD, thermocouple, and general-purpose instrumentation sampling needs while the 2 uA shutdown extends battery life in handheld meters.
A critical design consideration is bypassing: place a 0.1 uF ceramic capacitor close to VDD and a 4.7 uF tantalum/ceramic at REF, plus a 0.01 uF ceramic at the analog input pin to minimize conversion noise. The serial interface supports SPI modes CPOL=0/CPHA=0 and CPOL=1/CPHA=1, but the MAX187 requires a minimum SCLK period of 130 ns (max 7.6 MHz external clock) when using an external serial clock.
This page synthesizes distributor pricing, same-brand and cross-brand drop-in alternatives, and practical design notes not found in the manufacturer datasheet, giving engineers a single source for parametric comparison and PCB-compatible substitution.
ドロップイン代替品: MAX187BEWE — 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: MAX187BEWE （同一形状・フットプリント） — 相違点: Conversion Time, Package, Resolution, Shutdown Current.
クイック比較ツール — 並列比較する代替部品を選択:
MAX187BEWE+
✅ ドロップイン📋 参考代替品（カタログ未掲載）
MAX187AEWE
✅ ドロップイン📋 参考代替品（カタログ未掲載）
MAX187CCWE
✅ ドロップイン✓ 在庫あり
$10.55 / 個
データシートを見る →MAX187BCWE
✅ ドロップイン📋 参考代替品（カタログ未掲載）
MAX187BEWE+T
✅ ドロップイン📋 参考代替品（カタログ未掲載）
MAX187BEWE 最大定格＆電気的特性
| 分解能 | 12 bits |
| Number of Channels | 1 |
| Conversion Architecture | Successive Approximation Register (SAR) |
| サンプリングレート | 75 ksps |
| 入力電圧範囲 | 0 V to 5 V (unipolar single-ended) |
| Supply Voltage (VDD) | +4.75 V to +5.25 V (single +5 V supply) |
| Internal Reference Voltage | 4.096 V (buffered, MAX187 only) |
| Integral Nonlinearity (B-grade) | +/-1/2 LSB max |
| Track/Hold Acquisition Time | 1.5 us |
| Conversion Time | 8.5 us (internal clock) |
| Operating Current (active) | 1.5 mA |
| シャットダウン電流 | 2 uA |
| Serial Interface | 3-wire SPI/QSPI/MICROWIRE-compatible |
| パッケージ | 16-pin WSOIC (wide-body SOIC) |
| 動作温度範囲 | -40C to +85C (E suffix = industrial) |
| 実装タイプ | Surface Mount |
| RoHS ステータス | Compliant (MAX187BEWE+ variant) |
| AEC-Q100 Qualified | Not qualified |
MAX187BEWE ピン構成
| ピン 1 | /CS — Active-low chip select input for serial interface |
| ピン 2 | AIN — Analog input (0V to 5V) |
| ピン 3 | REF — Internal 4.096V buffered reference output / external reference input |
| ピン 4 | AGND — Analog ground |
| ピン 5 | VDD — +5V analog supply |
| ピン 6 | /SHDN — Active-low shutdown input (tie to VDD for always-on) |
| ピン 7 | DOUT — Serial data output (3-wire SPI) |
| ピン 8 | SCLK — Serial clock input |
| ピン 9 | DGND — Digital ground |
| ピン 10 | NC — Not connected (per datasheet) |
| ピン 11 | NC — Not connected (per datasheet) |
| ピン 12 | NC — Not connected (per datasheet) |
| ピン 13 | NC — Not connected (per datasheet) |
| ピン 14 | NC — Not connected (per datasheet) |
| ピン 15 | NC — Not connected (per datasheet) |
| ピン 16 | NC — Not connected (per datasheet) |
主な用途
MAX187BEWE の用途: 6 件s: Battery-Powered Portable Data Logger, Industrial Process Control Analog Input Module, Panel Meter and Digital Readout, Isolated Sensor Front End (Opto-Coupled SPI), Strain-Gauge and Load-Cell Digitizer, Thermocouple and RTD Temperature Measurement.
Battery-Powered Portable Data Logger
The MAX187BEWE fits battery-powered portable data loggers because its 2 uA shutdown current and 1.5 mA active supply current extend battery life across long field deployments, while the internal 4.096 V reference eliminates the need for a separate reference IC that would otherwise drain the battery. Its 12-bit resolution at 75 ksps is sufficient for slow analog signals (temperature, pressure, humidity) sampled at sub-kHz rates. In a typical logger, the MAX187 sits between the sensor analog front end and a microcontroller's SPI port, capturing periodic readings into non-volatile memory. The 3-wire serial interface allows simple opto-isolation when the sensor must be physically separated from the digital section for safety or noise reasons.
おすすめ
Industrial Process Control Analog Input Module
For industrial process-control analog input modules that digitize 4-20 mA loop signals or thermocouple/RTD outputs, the MAX187BEWE provides 12-bit resolution at 75 ksps, sufficient for the bandwidth of slow process variables. Its wide -40C to +85C industrial temperature range suits factory-floor environments, and the 3-wire SPI interface enables opto-isolation to meet IEC 61010 high-voltage isolation requirements. The internal 4.096 V reference accommodates the 0-5V analog input range directly from most sensor signal-conditioning outputs. Compared to newer 16-bit ADCs, the MAX187 remains a cost-effective choice for legacy PLC and DCS analog I/O card designs where BOM cost dominates over resolution.
おすすめ
Panel Meter and Digital Readout
Digital panel meters for voltage, current, temperature, or strain-gauge displays benefit from the MAX187BEWE's 12-bit resolution and 0-5V input range that directly interfaces with most analog sensor outputs after signal conditioning. The 75 ksps sampling rate allows fast update rates for transient voltage or current readings, while the internal 4.096 V reference simplifies calibration by providing a known conversion factor (1 LSB = 4.096 V / 4096 = 1 mV). The 16-pin WSOIC package is easy to hand-solder for prototype meter designs and is rugged enough for industrial panel mounting. The shutdown pin can be used to power-cycle the ADC between readings, extending meter battery life in handheld instruments.
おすすめ
Isolated Sensor Front End (Opto-Coupled SPI)
The MAX187BEWE's 3-wire serial interface (CS/SCLK/DOUT) makes it ideally suited for isolated sensor front ends where high-voltage isolation between the analog sensor side and the digital controller is required for safety. Only three high-speed optocouplers are needed to cross the isolation barrier, dramatically reducing BOM cost versus parallel-interface ADCs that need 12 optos. The 75 ksps rate supports most industrial sensor bandwidths (strain gauges, pressure transducers, current shunts). The internal 4.096 V reference means the sensor side needs only the MAX187 plus a few bypass capacitors, keeping the isolated side simple and minimizing creepage/clearance issues on the PCB.
おすすめ
Strain-Gauge and Load-Cell Digitizer
For digitizing strain-gauge and load-cell bridge outputs in weighing scales and force measurement systems, the MAX187BEWE offers 12-bit resolution with 1 LSB matching 1 mV when referenced to the internal 4.096 V reference, providing enough dynamic range for many industrial scale designs. The 75 ksps throughput allows oversampling and averaging for higher effective resolution, improving noise performance beyond the 12-bit native spec. The wide SOIC package is mechanically robust for industrial scale electronics, and the SPI interface connects directly to microcontrollers that perform calibration, temperature compensation, and digital filtering. The 2 uA shutdown mode is useful for battery-powered portable scales.
おすすめ
Thermocouple and RTD Temperature Measurement
The MAX187BEWE digitizes thermocouple and RTD temperature sensor outputs in industrial and laboratory instrumentation, where its 12-bit resolution and 75 ksps sampling allow accurate cold-junction-compensated temperature readings after linearization. The internal 4.096 V reference handles the small thermocouple voltages (typically +/-10 mV to +/-50 mV per degree Celsius) with appropriate signal conditioning. The 3-wire SPI interface allows the ADC to be located near the sensor for noise immunity, then communicated digitally to a remote controller. The wide -40C to +85C operating range suits outdoor and process-industry environments.
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: MAX187BEWE — 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 | MAX187BEWE+ | MAX187AEWE | MAX187CCWE | MAX187BCWE | MAX187BEWE+T |
|---|---|---|---|---|---|---|
| Brand | Maxim Integrated | Maxim Integrated | Maxim Integrated | Maxim Integrated | Maxim Integrated | Maxim Integrated |
| Package | 16-pin WSOIC | 16-pin WSOIC - same | 16-pin WSOIC - same | 16-pin WSOIC - same | 16-pin WSOIC - same | 16-pin WSOIC - same |
| Resolution | 12 bits | 12 bits | 12 bits | 12 bits | 12 bits | 12 bits |
| Sampling Rate | 75 ksps | 75 ksps | 75 ksps | 75 ksps | 75 ksps | 75 ksps |
| Internal Reference | 4.096V buffered (MAX187 only) | 4.096V buffered | 4.096V buffered | 4.096V buffered | 4.096V buffered | 4.096V buffered |
主な差別化要因
- Lower cost and pin-compatible upgrade vs MAX186/MAX176 legacy family （vs MAX186BCWP)
- Higher linearity grade at lower price than MAX187AEWE （vs MAX187AEWE)
- RoHS-compliant drop-in replacement for legacy MAX187BEWE （vs MAX187BEWE)
設計ノート
Decouple VDD with a 0.1 uF ceramic capacitor placed as close as possible to pin 5, and add a 4.7 uF tantalum or low-ESR ceramic bulk capacitor on the VDD rail. Place a 4.7 uF capacitor on the REF pin (pin 3) to stabilize the internal 4.096V reference under load transients. The /SHDN pin (pin 6) must be tied to VDD (logic high) for always-on operation; floating this pin leaves the part in shutdown mode and the analog input will not convert.
Do not drive the analog input (AIN, pin 2) beyond VDD + 0.3V or below AGND - 0.3V, as overvoltage on AIN can permanently damage the ESD diodes. The serial interface requires SCLK idle low (CPOL=0) or idle high (CPOL=1) per the SPI mode selected, and DOUT transitions on the falling edge of SCLK. Make sure the microcontroller's SPI peripheral is configured to read on the appropriate clock edge or data will be sampled one bit out of phase.
Route the analog ground (AGND, pin 4) and digital ground (DGND, pin 9) separately back to a star-ground point near the power-supply decoupling capacitor to prevent digital switching noise from coupling into the analog input. Place the analog input trace on a separate inner PCB layer with ground guarding on both sides for best noise immunity. Keep the analog input trace short and away from the SCLK/DOUT digital traces to minimize crosstalk.
Add a 0.01 uF ceramic capacitor directly at the AIN pin (pin 2) to filter high-frequency input noise above the ADC's 75 ksps Nyquist bandwidth. For high-impedance signal sources, add a unity-gain buffer op-amp (such as MAX145AEUA) between the source and AIN to prevent source-impedance-induced gain errors. The MAX187's input is not buffered, so source impedance must be kept below 1 kohm for full 12-bit accuracy at the maximum sampling rate.
The MAX187BEWE draws 1.5 mA active and 2 uA in shutdown, dissipating negligible power (7.5 mW at 5V active, 10 uW shutdown). No thermal management or heatsinking is required even in sealed enclosures. In battery-powered designs, use /SHDN to gate the ADC between conversions for maximum battery life; wake-up time from shutdown is typically 10-20 us before the next conversion can start.
コンプライアンス情報
RoHS compliance depends on +/- suffix: MAX187BEWE+ is lead-free RoHS compliant per Analog Devices; MAX187BEWE (without +) may be the older lead-finish variant. AEC-Q100 not qualified - choose MAX178x or MAX1302 family for automotive applications.
