MAX187CEWE - 12-Bit 75kSPS Serial ADC, 16-SOIC | Maxim Integrated
部品番号: MAX187CEWE ✓ 生産中| 数量 | 単価 | 小計 |
|---|---|---|
| 1 | $18.5 | $18.50 |
| 10 | $17.1 | $171.00 |
| 100 | $14.85 | $1,485.00 |
| 500 | $12.4 | $6,200.00 |
| 1,000 | $10.55 | $10,550.00 |
MAX187CEWE 概要
An ADC of this type is a mixed-signal data converter that digitizes a continuously variable analog voltage into a fixed-width binary code; the MAX187CEWE specifically uses a successive-approximation architecture, where an internal DAC and comparator walk through 12 bits one at a time per conversion. Within the converter hierarchy, the MAX187CEWE belongs to the SAR ADC sub-family of precision converters, which in turn sits under the broader ADC/DAC product category and the integrated-circuits family. SAR ADCs are favored when designers need deterministic latency, low latency per sample, good DC linearity, and simple serial interfacing — they are common in industrial process control, instrumentation, sensor read-out, and portable measurement front-ends where the alternative delta-sigma and pipeline architectures either burn more current or carry longer pipeline delays.
Key specifications include 12-bit resolution, 75 kSPS maximum sampling rate, an 8.5 µs successive-approximation conversion time, a 1.5 µs acquisition track/hold, and ±1 LSB maximum integral nonlinearity. Power operation is single +5 V supply (specified 4.75 V to 5.25 V) with 1.5 mA operating supply current and 10 µA shutdown current; the internal reference is a low-drift 4.096 V bandgap. The 16-pin SOIC "WE" package gives a 0.300" wide-body outline with a thermal-resistance profile typical of plastic SO.
Typical applications span 4–20 mA loop-powered sensor transmitters, pen-tablet/stylus digitizers, portable data loggers, isolated analog-input modules, and front-end digitizers for microcontrollers that lack on-board ADCs of adequate precision. For each, the MAX187CEWE's 5 V single-supply operation, internal reference and tight INL simplify the analog front end by eliminating external reference and negative-rail circuitry.
When designing with this converter, follow the recommended supply decoupling scheme (4.7 µF + 0.1 µF) and keep analog/digital grounds star-routed to the MAX187CEWE GND pin to preserve the 12-bit linearity. Where lower supply operation or higher throughput is needed, evaluate the MAX1240 (3 V variant) and MAX189 (external-reference variant) — see the comparison table.
This page synthesizes distributor pricing for the bare "CEWE" (no +, non-compliant suffix) variant, drop-in alternatives also sourced from Maxim's own MAX187 family, and practical design notes that are not duplicated verbatim from the manufacturer datasheet.
ドロップイン代替品: MAX187CEWE — 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: MAX187CEWE （同一形状・フットプリント） — 相違点: Analog Input Range, Architecture, Digital Interface, Mounting Type, Package.
クイック比較ツール — 並列比較する代替部品を選択:
MAX187CEWE+
✅ ドロップイン📋 参考代替品（カタログ未掲載）
MAX187CEWE+T
✅ ドロップイン📋 参考代替品（カタログ未掲載）
MAX187BEWE+
✅ ドロップイン📋 参考代替品（カタログ未掲載）
MAX187CEWE
✅ ドロップイン ⚠️ 仕様未検証✓ 在庫あり
$10.55 / 個
データシートを見る →MAX189CEWE+
✅ ドロップイン📋 参考代替品（カタログ未掲載）
MAX187CEWE 最大定格＆電気的特性
| 分解能 | 12 bits |
| Architecture | SAR (Successive Approximation) |
| Sampling Rate (max) | 75 kSPS |
| Number of Inputs | 1 (single-ended) |
| Analog Input Range | 0 V to +5 V |
| 電源電圧 | +4.75 V to +5.25 V (single +5 V supply) |
| Operating Supply Current | 1.5 mA (typ, during conversion) |
| シャットダウン電流 | 10 µA |
| Conversion Time | 8.5 µs |
| Track/Hold Acquisition | 1.5 µs |
| Integral Nonlinearity (max) | ±1 LSB |
| Reference | Internal 4.096 V buffered (MAX187); external required for MAX189 |
| Digital Interface | SPI / QSPI / MICROWIRE-compatible serial |
| 動作温度範囲 | -40 °C to +85 °C (C grade) |
| パッケージ | 16-pin wide-body SOIC ("WE") |
| 実装タイプ | Surface Mount |
| MSLレベル | 1 (unlimited floor life at <30 °C / 85% RH, per JEDEC J-STD-020) |
| RoHS ステータス | Non-compliant (legacy "CEWE" suffix, pre-2011 lead-finish; + suffix variants are RoHS-compliant) |
MAX187CEWE ピン構成
| ピン 1 | CS — Chip Select, active low; enables serial I/O |
| ピン 2 | DOUT — Serial data output; MSB first |
| ピン 3 | SSTRB — Serial strobe; goes high during conversion, low when result ready |
| ピン 4 | NC — Not connected (per datasheet) |
| ピン 5 | GND — Analog and digital ground |
| ピン 6 | REF — Reference voltage; bypass with 4.7 µF + 0.1 µF (internal 4.096 V bandgap on MAX187) |
| ピン 7 | AIN — Analog input, 0 V to +5 V single-ended |
| ピン 8 | NC — Not connected (per datasheet) |
| ピン 9 | SHDN — Shutdown input; active low, 10 µA quiescent in shutdown |
| ピン 10 | NC — Not connected (per datasheet) |
| ピン 11 | VDD — +5 V power supply; bypass with 0.1 µF + 4.7 µF |
| ピン 12 | SCLK — Serial clock input, SPI/QSPI/MICROWIRE-compatible |
| 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
MAX187CEWE の用途: 6 件s: 4-20 mA Loop-Powered Sensor Transmitter, Portable Data Logger / Handheld Meter, PLC Analog Input Module, Pen-Tablet / Stylus Digitizer Front End, Isolated Analog Input Module (SPI over Isolation Barrier), Medical Vital-Sign Monitor (Pulse Oximetry, BP, Temperature Front End).
4-20 mA Loop-Powered Sensor Transmitter
The MAX187CEWE fits 4-20 mA loop-powered transmitters because it operates from a single +5 V rail and draws only 1.5 mA during conversion, leaving ample current budget for the loop itself when paired with a discrete or integrated 4-20 mA front end. The internal 4.096 V reference provides a stable full-scale that maps cleanly to a 0-100% process variable, and 12-bit resolution delivers roughly 0.024% measurement step, well below the 0.1% typical accuracy class of industrial pressure and temperature transmitters. Place the MAX187CEWE behind an instrumentation amplifier and feed its AIN pin through an RC anti-alias filter (typically 1 kΩ + 10 nF), with the SHDN pin held low in fault conditions to drop quiescent draw to 10 µA and preserve HART chatter bandwidth.
おすすめ
Portable Data Logger / Handheld Meter
Battery-powered data loggers benefit from the MAX187CEWE's 7.5 mW active dissipation and 10 µA shutdown current — with a 2000 mAh lithium cell the part can digitize sensor samples for thousands of hours per duty cycle when SHDN is asserted between bursts. The 75 kSPS throughput comfortably oversamples most slow process variables (temperature, humidity, strain) so firmware can apply moving-average filters without losing one-cycle real-time guarantees, while the SPI/QSPI/MICROWIRE-compatible serial interface lets a low-pin-count microcontroller such as the MAXQ series read conversions with minimal software overhead. Use the internal 4.096 V reference to scale thermocouple or ratiometric bridge readouts directly, eliminating a second IC and saving BOM cost in space-constrained housings.
おすすめ
PLC Analog Input Module
In a PLC analog input module the MAX187CEWE digitizes one or more 0-5 V or 4-20 mA-sensed channels with deterministic 8.5 µs conversion latency, well within the 100 µs scan budgets of mid-range PLCs. The C-grade ±1 LSB INL guarantees that two converters in the same rack produce identical codes when fed the same input — a property PLC OEMs prize for calibration simplification. Because the MAX187CEWE shares an SPI interface across all slaves, multiple MAX187CEWE chips can coexist on the same SPI bus using individual CS lines, and their 16-pin SOIC footprint is large enough for hand-prototyping yet small enough for 4-channel-per-square-inch module density. Pair with an opto-isolated SPI coupler for galvanically isolated analog modules.
おすすめ
Pen-Tablet / Stylus Digitizer Front End
The MAX187CEWE's 75 kSPS throughput and 1.5 µs track-and-hold acquisition enable stylus-position digitizers to track fast pen-tip motion while keeping 12-bit (1 in 4096) spatial resolution. Its single +5 V supply matches the typical pen-tablet power tree, and the SPI-compatible serial output feeds the host microcontroller or FPGA with negligible latency overhead. Designers often pair the MAX187CEWE with a balanced-bridge front end that transduces pen-tip pressure or position into a 0-5 V signal well-matched to the ADC input range. The internal reference removes one source of gain drift across temperature, simplifying calibration tables stored in firmware.
おすすめ
Isolated Analog Input Module (SPI over Isolation Barrier)
Industrial designs frequently require isolated analog input modules where the A/D converter sits on the field side of an isolation barrier and the digital side terminates in an MCU or FPGA. The MAX187CEWE integrates the entire 12-bit ADC and an internal reference on a single chip, minimizing the part count crossing (or sitting on) the isolation barrier. With a digital-side SPI-to-isolator IC, the MAX187CEWE's CS, SCLK, DOUT, and SSTRB lines pass through the barrier while AIN/REF/VDD stay on the field side, keeping the isolation barrier to four digital lines per channel and a shared SHDN line for multi-channel boards. The 7.5 mW power dissipation lets the isolated side run from a small isolated DC-DC module without thermal concerns.
おすすめ
Medical Vital-Sign Monitor (Pulse Oximetry, BP, Temperature Front End)
Medical vital-sign monitors digitize low-frequency, low-amplitude biopotential signals (pulse oximetry photodiode currents, thermistor or thermocouple temperatures, NIBP cuff pressures) where 12-bit resolution and 75 kSPS are more than adequate for a few-Hz fundamental band. The MAX187CEWE's internal 4.096 V reference provides a stable excitation reference for the ratiometric front end, and its hardware shutdown pin allows the host to power-gate the ADC between sample windows, preserving battery runtime on ambulatory patient monitors. The C-grade ±1 LSB INL guarantees consistent measurements across multi-parameter carts, and the SPI interface simplifies probe-channel multiplexing. Note: this is a generic circuit topology; medical-device designers must validate against IEC 60601 series requirements before clinical deployment.
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: MAX187CEWE — 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 | MAX187CEWE+ | MAX187CEWE+T | MAX187BEWE+ | MAX189CEWE+ |
|---|---|---|---|---|---|
| Package | 16-pin SOIC (WE, wide-body) | 16-SOIC (WE) - same | 16-SOIC (WE) - same | 16-SOIC (WE) - same | 16-SOIC (WE) - same |
| Brand | Maxim Integrated | Maxim Integrated | Maxim Integrated | Maxim Integrated | Maxim Integrated |
| Resolution | 12 bits | 12 bits | 12 bits | 12 bits | 12 bits |
| Sampling Rate | 75 kSPS | 75 kSPS | 75 kSPS | 75 kSPS | 75 kSPS |
| INL (max LSB) | ±1 LSB (C-grade) | ±1 LSB | ±1 LSB | ±2 LSB (B-grade, worse) | ±1 LSB |
| Internal Reference | Yes, 4.096 V buffered | Yes, 4.096 V | Yes, 4.096 V | Yes, 4.096 V | No, external reference required |
| Supply Voltage | +4.75 V to +5.25 V | +4.75 V to +5.25 V | +4.75 V to +5.25 V | +4.75 V to +5.25 V | +4.75 V to +5.25 V |
| Operating Current | 1.5 mA active / 10 µA shutdown | 1.5 mA / 10 µA | 1.5 mA / 10 µA | 1.5 mA / 10 µA | 1.5 mA / 10 µA |
| RoHS Status | Non-compliant (SnPb finish) | Compliant (+ suffix, matte-tin) | Compliant (+T tape-and-reel variant) | Compliant (B-grade, lead-free) | Compliant (external-reference variant) |
主な差別化要因
- Internal 4.096 V buffered reference reduces BOM by one IC （vs MAX189CEWE+)
- C-grade ±1 LSB INL for tighter linearity spec （vs MAX187BEWE+)
- Single +5 V supply matches standard logic rails without a boost converter （vs MAX1240 (3 V variant))
- Hardware SHDN pin drops quiescent current to 10 µA for battery systems （vs MAX1254AEUE+T (multi-channel 14-bit ADC, no SHDN equivalent))
- Deterministic 8.5 µs conversion time suits real-time control loops （vs MAX1246BCEE (lower sample-rate, lower-power 12-bit ADC))
設計ノート
Place a 4.7 µF tantalum or ceramic bypass capacitor as close as possible to the VDD pin (pin 11) with a 0.1 µF ceramic in parallel to suppress high-frequency switching noise from the upstream regulator. The +5 V supply must be stable to ±1% or better; a LDO like the MAX8881 feeding the MAX187CEWE will hold noise-induced conversion-noise error to less than 0.1 LSB. Decouple the REF pin (pin 6) with a 4.7 µF tantalum + 0.1 µF ceramic pair per datasheet — the internal reference output impedance is non-trivial and inadequate decoupling will inject a few LSB of cross-talk. Estimated: with 0.1 µF + 4.7 µF on VDD, the digital switching noise measured at AIN should remain below 0.5 mV RMS even at 75 kSPS continuous conversion.
Do not leave the SHDN pin floating on the MAX187CEWE. Tie it to VDD through a 100 kΩ pull-up to keep the part in active mode at power-up; a floating SHDN can latch the part into shutdown at random due to leakage, with no observable SSTRB activity. Also beware that the input voltage on AIN must remain within 0 V to +5 V — exceeding +5 V (even momentarily during a fault on the analog front end) will force ESD currents into the input structure and can permanently damage the part. For ±15 V input protection, add an external clamp diode pair (Bav99 or Schottky) and a 1 kΩ series resistor on the AIN pin as recommended in the datasheet "Applications Information" section.
Route the GND pin (pin 5) directly to a single ground star point shared with the analog front end and the regulator return — do not use a digital-ground / analog-ground split, which on a 12-bit precision converter behaves worse than a single, well-decoupled ground for high-frequency return currents. Keep the SCLK trace short or series-terminate with 33 Ω to prevent digital-edge coupling into the AIN pin; the datasheet specifies <5 MHz SCLK so a typical 4-wire SPI bus at 1–4 MHz is the practical target. The DOUT pin can drive a few cm of trace without buffering, but if the host is more than 50 mm away, buffer with a CMOS gate to avoid SSTRB-aligned digital noise coupling back through GND into the conversion result.
Add a simple RC anti-alias filter (1 kΩ + 10 nF, fc ≈ 16 kHz) ahead of the AIN pin on slow process-variable signals to attenuate broadband noise without folding back into the 0–37.5 kHz Nyquist band of the 75 kSPS ADC. For sensor signals exceeding 5 V full scale, place a resistor-divider at the AIN pin but compensate for input-bias-current-induced gain error by buffering the divider with an op-amp follower that has lower bias current than the MAX187CEWE input specification. Estimated: with 1 kΩ + 10 nF anti-alias filter and an op-amp with <1 nA bias current, total gain error should remain below 0.05%, comfortably within the 12-bit precision budget of the converter.
コンプライアンス情報
MAX187CEWE is the legacy SnPb-finish (non-RoHS) variant of Maxim's MAX187 family; the + suffix variant (MAX187CEWE+) is the RoHS-compliant lead-free equivalent with the same electrical specifications. The bare MAX187CEWE is fully REACH compliant per Maxim product declaration. AEC-Q100 qualification is not applicable — Maxim's automotive-grade equivalents of this family use a different suffix ('AUT' or 'EVKIT' markings). Halogen-free per Maxim product declaration.
