MAX144BCUA - 12-Bit 108ksps 2-Ch SAR ADC | Maxim Integrated
料号： MAX144BCUA ✓ 量产中| 数量 | 单价 | 小计 |
|---|---|---|
| 1 | $12.82 | $12.82 |
| 10 | $11.5 | $115.00 |
| 100 | $9.95 | $995.00 |
| 500 | $8.85 | $4,425.00 |
| 1,000 | $7.91 | $7,910.00 |
MAX144BCUA 概述
A SAR ADC (Successive Approximation Register Analog-to-Digital Converter) is a type of ADC that converts an analog input to a digital output using a binary search algorithm against an internal DAC. SAR ADCs are prized for low latency (single-cycle conversion), deterministic behavior, and low power consumption, which makes them ideal for multiplexed data-acquisition systems, sensor readouts, and battery-powered instrumentation. The MAX144 sits in the precision-low-power tier of the SAR ADC hierarchy: SAR ADC → successive-approximation ADC → ADC → data converter → signal chain IC → semiconductor.
Key features include a 7.4 µs successive-approximation conversion time, automatic power-down between conversions reducing current to sub-µA, fast 2.5 µs wake-up, an internal 4.096 MHz oscillator, and a high-speed SPI/QSPI/MICROWIRE-compatible 3-wire serial interface. Two analog input channels are multiplexed to a single ADC core, and the device operates from a single 2.7V to 5.25V supply. The integrated input track-and-hold accepts full-scale inputs from 0 to VREF.
Architecturally, the MAX144BCUA combines a charge-redistribution DAC with a successive-approximation register and on-chip clock, eliminating the need for an external oscillator. The proprietary AutoShutdown® mode drops supply current to 0.3 µA (typical) between conversions, drawing active current only when conversions are in progress. This combination of high throughput and nanoamp-level standby current makes it well-suited for power-budgeted portable and loop-powered systems.
Typical applications include portable data logging, pen-tablet digitizers, battery-powered instrumentation, plus/minus instrumentation front ends, and process-control I/O modules. The part is also used in isolated sensor readouts where the low serial-interface pin count (4 signals: CS, SCLK, DOUT, DIN) simplifies optocoupler or digital-isolator bridges.
A single-decoupling 0.1 µF ceramic capacitor close to VDD and a 10 µF bulk cap are typically sufficient. Reference decoupling with 1 µF plus 0.1 µF at REF is critical for 12-bit performance; avoid running digital traces under the analog input pins on the PCB.
This page synthesizes distributor pricing, drop-in same-package alternatives, and practical design notes not found in the manufacturer datasheet.
直接替换替代料： MAX144BCUA ——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： MAX144BCUA （相同外形与封装尺寸） ——差异在于 Conversion Time, Package.
快速对比工具——选择替代料号进行并排对比：
MAX145ACUA+
✅ 直接替换📋 参考替代料（不在目录中）
MAX144ACUA+
✅ 直接替换📋 参考替代料（不在目录中）
MAX144AEUA+T
✅ 直接替换📋 参考替代料（不在目录中）
MAX145ACUA+T
✅ 直接替换📋 参考替代料（不在目录中）
MAX1242BUSA+
✅ 直接替换📋 参考替代料（不在目录中）
MAX144BCUA 最大额定值与电气特性
| 分辨率 | 12 bit |
| Number of Inputs | 2 (single-ended, multiplexed) |
| 采样率 | 108 ksps |
| Conversion Time | 7.4 µs (SAR successive approximation) |
| 输入电压范围 | 0 to VREF |
| 电源电压 | +2.7 V to +5.25 V (single) |
| Supply Current (AutoShutdown) | 0.3 µA typical (between conversions) |
| Wake-Up Time | 2.5 µs |
| Internal Clock Frequency | 4.096 MHz |
| 接口 | SPI/QSPI/MICROWIRE-compatible, 3-wire serial |
| 基准电压 | External (VREF applied to REF pin) |
| INL (max, B grade) | ±1 LSB |
| 工作温度 | 0 °C to +70 °C (commercial, B suffix CUA) |
| 封装 | 8-pin µMAX (8-MSOP, 3.00 mm width) |
| 安装类型 | Surface Mount |
| Compatible Pinout Part | MAX145 (14-bit upgrade, same 8-µMAX footprint) |
MAX144BCUA 引脚配置
| 引脚 1 | AIN1 — Analog Input 1 |
| 引脚 2 | AIN2 — Analog Input 2 |
| 引脚 3 | REF — Reference Voltage Input (external) |
| 引脚 4 | AGND — Analog Ground |
| 引脚 5 | SCLK — Serial Clock Input (SPI) |
| 引脚 6 | DOUT — Serial Data Output |
| 引脚 7 | DIN — Serial Data Input (CS active low via interface convention) |
| 引脚 8 | VDD — Positive Supply (+2.7V to +5.25V) |
典型应用
MAX144BCUA 适用于 6 应用s: Portable Battery Data Logging, Process Control Analog Input Module, Pen-Tablet and Touch Digitizer Readout, Isolated Sensor Readout Front End, Medical Patch Sensor Monitoring, Handheld Test and Measurement Instrument.
Portable Battery Data Logging
The MAX144BCUA's AutoShutdown® mode dropping supply current to 0.3 µA between conversions makes it ideal for battery-powered data loggers that wake briefly to sample, store, and return to sleep. With 12-bit resolution, ±1 LSB INL and a 108 ksps burst rate, the part can digitize a thermistor or load-cell channel in a single 7.4 µs conversion window before shutdown, achieving multi-year battery life on a single CR2032. Its 2.7V minimum supply lets it run directly from two AA alkaline cells, and the 3-wire SPI requires only three microcontroller pins, leaving the rest available for an SD card or BLE radio. Compared to a built-in MCU ADC, the dedicated MAX144BCUA provides a guaranteed 12-bit SAR with lower idle current.
推荐
Process Control Analog Input Module
Two single-ended channels in the 8-µMAX package allow the MAX144BCUA to read a 4-20 mA loop current (across a sense resistor) and a thermocouple temperature sensor in sequence, sharing a single ADC. The 12-bit resolution and ±1 LSB INL are sufficient for ±0.1 °C thermocouple cold-junction compensation with proper reference selection. The wide +2.7 V to +5.25 V supply tolerates 24 V industrial bus transients after external TVS clamping, and the 3-wire SPI simplifies optocoupler isolation since only four digital signals cross the isolation barrier. Designers commonly pair the MAX144BCUA with a MAX14850 isolated transceiver to meet IEC 61131-2 PLC module requirements.
推荐
Pen-Tablet and Touch Digitizer Readout
The MAX144BCUA's 108 ksps per-channel throughput and 7.4 µs conversion latency provide real-time pen-tip X/Y position tracking in graphics tablets. The 2-channel input multiplexes to the SAR core, allowing interleaved sampling of horizontal and vertical resistive-strip voltages without missing pen movement. The 0.3 µA shutdown current extends battery life in wireless stylus designs, while the 8-µMAX footprint fits inside the tight stylus barrel. The 12-bit resolution translates to 4096 pen-position levels, sufficient for sub-100 µm accuracy on a 12-inch tablet.
推荐
Isolated Sensor Readout Front End
With only four active digital pins (CS, SCLK, DOUT, DIN) the MAX144BCUA minimizes the number of optocouplers or digital isolators needed in a galvanically isolated sensor frontend. Placing the ADC on the field side, close to the transducer, eliminates ground-loop noise and converts the analog signal to a digital stream that crosses the isolation barrier in LVCMOS. The SAR architecture provides single-cycle conversion (no pipeline delay) so feedback loops such as motor-current sensing respond in microseconds. Used in 4-20 mA smart transmitters and isolated voltage probes, the MAX144BCUA delivers 12 bits over a 0-VREF range with 0.3 µA shutdown contributing negligibly to the total input current budget.
推荐
Medical Patch Sensor Monitoring
Wearables such as continuous-glucose-monitor (CGM) patches, ECG Holter recorders, and pulse-oximeter straps benefit from the MAX144BCUA's combination of 2-channel input, 0.3 µA shutdown, and 8-µMAX small footprint. With a 3 mm × 3 mm land pattern, the ADC fits alongside a low-power MCU and a BLE radio on a 25 mm diameter patch PCB. The 12-bit SAR provides adequate resolution for heart-rate and SpO2 waveforms at sub-µA average supply current when duty-cycled at 100 Hz. Reference grounding the ADC's AGND pin to the body's common-mode node further reduces 50/60 Hz mains pickup in clinical environments.
推荐
Handheld Test and Measurement Instrument
The MAX144BCUA's combination of 12-bit resolution, 108 ksps, and 2.7V operation makes it a fit for handheld multimeters and oscilloscope front-ends. The two input channels can be routed to two measurement ranges (e.g., 5V and 50V) selected by external resistive dividers, with the MAX144BCUA's low input capacitance preserving waveform fidelity at 100 ksps. Its 8-µMAX package fits in the cramped PCB of a probe body, and the 0.3 µA shutdown makes it ideal for battery-powered field instruments that must hold charge for weeks. Designers typically add a MAX6126 reference and front-end op-amp buffer to extend performance beyond ±1 LSB.
推荐
推荐产品汇总
工程参考数据： MAX144BCUA ——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 | MAX145ACUA+ | MAX144ACUA+ | MAX144AEUA+T | MAX145ACUA+T | MAX1242BUSA+ |
|---|---|---|---|---|---|---|
| Package | 8-µMAX (8-MSOP, 3.00 mm) | 8-µMAX (8-MSOP) - same | 8-µMAX (8-MSOP) - same | 8-µMAX (8-MSOP) - same | 8-µMAX (8-MSOP) - same | 8-µMAX (8-MSOP) - same |
| Brand | Maxim Integrated (Analog Devices) | Maxim Integrated | Maxim Integrated | Maxim Integrated | Maxim Integrated | Maxim Integrated |
| Resolution | 12 bit | 14 bit | 12 bit | 12 bit | 14 bit | 12 bit |
| Sampling Rate | 108 ksps | 108 ksps | 108 ksps | 108 ksps | 108 ksps | 73 ksps (-32%) |
| Number of Input Channels | 2 single-ended | 2 single-ended | 2 single-ended | 2 single-ended | 2 single-ended | 1 single-ended (-50%) |
| INL (max) | ±1 LSB (B grade) | ±2 LSB | ±0.5 LSB (A grade, improved) | ±0.5 LSB | ±2 LSB | ±2 LSB |
| Operating Temperature | 0 °C to +70 °C (commercial, CUA) | 0 °C to +70 °C | 0 °C to +70 °C | -40 °C to +85 °C (extended, EUA) | 0 °C to +70 °C | 0 °C to +70 °C |
| AutoShutdown Current | 0.3 µA | 0.3 µA | 0.3 µA | 0.3 µA | 0.3 µA | 2 µA |
| Supply Voltage Range | +2.7 V to +5.25 V | +2.7 V to +5.25 V | +2.7 V to +5.25 V | +2.7 V to +5.25 V | +2.7 V to +5.25 V | +2.7 V to +5.25 V |
关键差异点
- B-grade pin-compatible with MAX145 14-bit upgrade （对比 MAX145ACUA+)
- Lower-cost alternative to A-grade with the same package （对比 MAX144ACUA+)
- Two input channels in a smaller package than MAX1242 （对比 MAX1242BUSA+)
设计说明
Place a 0.1 µF X7R ceramic decoupling capacitor within 5 mm of the VDD pin (pin 8), plus a 10 µF bulk tantalum or ceramic cap. Reference decoupling - 4.7 µF plus 0.1 µF at the REF pin (pin 3) - is mandatory for the MAX144/MAX145 family to meet ±1 LSB INL at 108 ksps; without proper REF bypassing, INL can degrade to ±3 LSB or worse at high sample rates. Keep the digital ground return current separate from the analog ground by using a star-ground topology at the AGND pin.
Route the SPI signals (SCLK, DOUT, DIN) on a separate digital layer or in a digital-only zone at least 5 mm from AIN1, AIN2, REF and AGND. Place the MAX144BCUA away from switching regulators - 100 ksps SAR ADCs are particularly sensitive to high-frequency digital switching noise coupled into REF or AIN. Use a continuous analog ground pour under the IC, and avoid running digital traces under the analog input pins. A guard ring around AIN1 and AIN2 improves common-mode noise rejection when sampling low-level signals.
The MAX144BCUA's SPI interface accepts clock rates up to the internal oscillator frequency of 4.096 MHz. To prevent digital feedthrough into the analog input, terminate SCLK with a 33 Ω series resistor placed near the driver, and keep the SPI clock trace matched. The CS (active-low chip-select) falling edge should be sampled at the falling edge of SCLK; the part enters AutoShutdown when CS returns high for > 2.5 µs. For best AC performance, drive CS with a clean MCU GPIO rather than a slow RC network.
Do not leave REF floating - the MAX144BCUA requires an external reference; leaving REF open will produce saturated codes or erratic readings. Avoid using AIN above VREF - input voltages beyond VREF can forward-bias ESD diodes and corrupt conversion results. Note the B-grade ±1 LSB INL applies at 25 °C; for sub-LSB systems, choose the A-grade MAX144ACUA or extend averaging. Finally, do not exceed the 2.5 V absolute maximum on analog inputs relative to AGND, even momentarily during power sequencing.
合规信息
Lead-free and RoHS compliance for MAX144BCUA are not explicitly stated in the verified web results. The MAX144BCUA+ variant (with + suffix) follows Maxim/ADI standard lead-free packaging. AEC-Q100 not applicable - the MAX144BCUA is not automotive grade; the MAX144AEUA+T is the industrial-grade variant.
