MAX1237KEUA+ - 12-Bit 4-Ch 94.4kSPS 2-Wire ADC | Maxim
MPN： MAX1237KEUA+ ✓ 啟用中MAX1237KEUA+ 概覽
An ADC (Analog-to-Digital Converter) is a data-conversion integrated circuit that samples continuous analog voltages and produces a discrete digital code for processing by a microcontroller or DSP. Successive-approximation register (SAR) ADCs combine low power, deterministic latency, and high accuracy, making them the dominant choice for multiplexed multi-channel sensor acquisition. The MAX1237 belongs to the SAR ADC family, in the hierarchy ADC -> data converter -> signal chain IC -> mixed-signal semiconductor.
Key features include 12-bit resolution with ±1 LSB INL/DNL (max), an internal 4.096V reference (the K version), single-ended analog inputs from 0 to VREF, an I2C-compatible serial interface with up to 400 kHz clock, software-configurable unipolar/bipolar operation, and a low-power shutdown mode that drops supply current below 1 µA. The internal reference saves external circuitry and improves temperature stability versus an external RA-RA divider.
Architecturally, the MAX1237 uses a charge-redistribution SAR core with an input analog multiplexer, an integrated T/H, and an internal bandgap-based reference. The wide supply flexibility (2.7V-3.6V or 4.5V-5.5V) lets it ride directly on 3.3V digital rails or on 5V analog rails, while pin-selectable address bits support up to four devices on one I2C bus. Auto-shutdown between conversions minimizes average current in battery-powered, duty-cycled applications.
Typical applications include battery-powered temperature monitoring, 4-20 mA loop process instrumentation, handheld data loggers, PLC analog input modules, and HVAC sensor-front ends. The internal multiplexer (12 channels) eliminates an external analog switch, while the I2C interface reduces microcontroller pin count versus parallel-output ADCs.
When designing with the MAX1237, place the 0.1 µF VDD bypass capacitor within 5 mm of the supply pin, route SDA/SCL away from the analog inputs, and use the software-programmable setup register to enable auto-shutdown for standby power budgets below 10 µA.
This page synthesizes distributor pricing, drop-in equivalents from the MAX1236/MAX1136 families, and practical I2C layout guidance not consolidated in the manufacturer datasheet.
直接替換替代品，適用於 MAX1237KEUA+ — 相同封裝，腳位對腳位相容。需重新設計 PCB 的不同封裝零件不列入。
此系列的變體
與下列產品可直接替換的同系列型號： MAX1237KEUA+ （相同外形與佔位） — 差異在於 Package, Resolution, Architecture, Differential Nonlinearity (DNL), Integral Nonlinearity (INL).
MAX1236KEUA+
✅ 直接替換📋 參考替代品（不在目錄中）
MAX1237KEUA+T
✅ 直接替換聯絡詢價
查看資料表 →MAX1136KEUA+
✅ 直接替換📋 參考替代品（不在目錄中）
MAX1237MEUA+
✅ 直接替換📋 參考替代品（不在目錄中）
MAX1237KEUA+ 最大額定值與電氣特性
| 解析度 | 12 bit |
| Number of Inputs | 4 / 12 (input MUX, software configurable) |
| Conversion Rate | 94.4 ksps |
| Input Channels (MAX1237 K) | 12 single-ended / 6 differential |
| Supply Voltage - Single/Dual | 2.7 V to 3.6 V or 4.5 V to 5.5 V |
| Supply Current (typ at 94.4 ksps) | 133 µA |
| 關機電流 | < 1 µA |
| Internal Reference | 4.096 V (K-version) |
| INL (max) | ±1 LSB |
| DNL (max) | ±1 LSB (no missing codes) |
| 介面 | I2C-compatible 2-wire serial (up to 400 kHz) |
| Addressable Devices per Bus | Up to 4 (AD0, AD1 pins) |
| 封裝 | 8-pin µMAX (uSOP, 3 mm body) |
| 工作溫度 | -40 °C to +85 °C |
| 安裝類型 | Surface Mount |
| RoHS 狀態 | Compliant |
| Lead-Free Finish | Yes (NiPdAu) |
MAX1237KEUA+ 腳位配置
| 腳位 1 | AIN0 — Analog input channel 0 |
| 腳位 2 | AIN1 — Analog input channel 1 |
| 腳位 3 | AIN2/REF — Analog input channel 2 or external reference input |
| 腳位 4 | AIN3 — Analog input channel 3 |
| 腳位 5 | GND — Ground |
| 腳位 6 | SDA — I2C serial data |
| 腳位 7 | SCL — I2C serial clock |
| 腳位 8 | VDD — Positive supply (2.7V-3.6V or 4.5V-5.5V) |
典型應用
MAX1237KEUA+ 適用於 6 應用s: Battery-Powered Temperature Monitoring, 4-20 mA Loop Process Instrumentation, Handheld Data Loggers, PLC Analog Input Modules, HVAC Sensor Front Ends, Portable Medical Monitoring.
Battery-Powered Temperature Monitoring
The MAX1237KEUA+'s 133 µA supply current at 94.4 ksps, <1 µA shutdown, and 12-channel internal MUX make it ideal for battery-powered multi-thermocouple or thermistor monitoring in portable test gear or data loggers. The internal 4.096 V reference rails a full-scale input range suitable for amplified thermocouple outputs, while I2C communication to a host microcontroller saves board space versus a parallel-output ADC. Estimated battery life for a 2,000 mAh Li-ion cell sampling 12 channels at 1 Hz with auto-shutdown exceeds 8 months in a room-temperature cold-chain logger application.
推薦
4-20 mA Loop Process Instrumentation
Industrial 4-20 mA loop transmitters and PLC analog-input cards use the MAX1237KEUA+ to digitise sensor voltages with 12-bit accuracy and ±1 LSB INL. The 4.5V-5.5V supply capability rides directly on 24V-loop-derived 5V rails, while the I2C interface simplifies galvanic-isolator channel count versus parallel-output converters. With 94.4 ksps throughput the part is overspec for most loop rates, leaving substantial headroom for software filtering and 50/60 Hz rejection.
推薦
Handheld Data Loggers
Handheld multi-sensor data loggers benefit from the MAX1237KEUA+'s 12 single-ended channels, tiny 8-pin µMAX footprint (3 mm body), and I2C interface that shares two microcontroller pins with any other I2C sensors on the board. The auto-shutdown feature between conversions stretches battery life between charges, and the internal reference removes one external component per board. Sample rates of 1 kHz per channel are easily achievable for vibration or pressure logging where the 94.4 ksps throughput is sufficient.
推薦
PLC Analog Input Modules
Programmable logic controller analog input modules use the MAX1237KEUA+ to scan 12 channels per chip with deterministic SAR latency, simplifying firmware versus delta-sigma ADCs that have continuously-running modulators. Up to four devices can share a single 400 kHz I2C bus via the AD0/AD1 address pins, scaling a module to 48 channels with no extra digital isolation. The 5V supply option interfaces directly to legacy PLC backplanes without a level translator.
推薦
HVAC Sensor Front Ends
Commercial HVAC sensor-front-end boards place the MAX1237KEUA+ on the analog card to scan multiple temperature, humidity, and airflow sensor outputs through its 12-channel MUX. The internal 4.096 V reference is stable across the industrial -40 °C to +85 °C range, eliminating the need for a calibrated external reference. The 8-pin µMAX package fits beside larger TRIAC drivers without disturbing PCB routing.
推薦
Portable Medical Monitoring
Portable patient-monitoring devices - pulse oximeters, blood-pressure cuffs, wearable ECG patches - use the MAX1237KEUA+ to digitise multiple analog sensor channels while staying below 200 µA typical supply current. The 12-bit resolution is sufficient for derived parameters like heart-rate envelope and SpO2 waveform trending; the I2C interface allows a low-pin-count MCU to manage multiple ADCs in a small form-factor wearable. The internal reference reduces calibration steps in production.
推薦
推薦產品摘要
工程參考資料，適用於 MAX1237KEUA+ — 比較、設計指引及合規資訊。
選型指南
與替代品比較
| 參數 | 本產品 | MAX1236KEUA+ | MAX1237KEUA+T | MAX1136KEUA+ | MAX1237MEUA+ |
|---|---|---|---|---|---|
| Package | 8-pin µMAX | 8-pin µMAX (same) | 8-pin µMAX (same) | 8-pin µMAX (same) | 8-pin µMAX (same) |
| Brand | Analog Devices / Maxim Integrated | Analog Devices / Maxim Integrated | Analog Devices / Maxim Integrated | Analog Devices / Maxim Integrated | Analog Devices / Maxim Integrated |
| Resolution | 12 bit | 12 bit (same) | 12 bit (same) | 10 bit | 12 bit |
| Input Channels | 12 | 4 | 12 | 12 | 12 |
| Throughput | 94.4 ksps | 94.4 ksps | 94.4 ksps | 94.4 ksps | 94.4 ksps |
| Supply Voltage | 2.7-3.6 V or 4.5-5.5 V | 2.7-3.6 V or 4.5-5.5 V | 2.7-3.6 V or 4.5-5.5 V | 2.7-3.6 V or 4.5-5.5 V | 2.7-3.6 V or 4.5-5.5 V |
| Internal Reference | 4.096 V (K suffix) | 4.096 V (K) | 4.096 V (K) | 4.096 V (K) | 4.096 V (K) |
| Interface | I2C 2-wire (up to 400 kHz) | I2C 2-wire | I2C 2-wire | I2C 2-wire | I2C 2-wire |
| Packaging Type | Tube | Tube | Tape & Reel | Tube | Tube |
主要差異化特點
- 12 single-ended / 6 differential inputs without external mux (對比MAX1236KEUA+)
- Wide dual-range supply (對比Typical 3.3 V-only SAR ADCs)
- Internal 4.096 V reference with low-drift bandgap (對比External resistor-divider reference designs)
設計說明
Place a 0.1 µF X7R ceramic bypass capacitor directly between VDD (Pin 8) and GND (Pin 5), leads shorter than 5 mm. Add a 10 µF tantalum or polymer bulk cap on the same rail if the source is more than 50 mm away. The ADC reference ladder draws current spikes during conversion, so a stiff local supply reduces sampling-time noise coupling into the analog inputs.
Route the I2C SDA/SCL traces on an inner layer adjacent to a solid GND plane, with pull-up resistors placed within 20 mm of the ADC's SDA and SCL pins. Keep the analog-input traces (AIN0-AIN3) routed away from SDA/SCL by at least 3 mm or shielded by a GND fill to avoid clock coupling into the SAR comparator.
Do not float any unused analog input - tie to GND to prevent charge injection that can corrupt adjacent channel readings. Avoid driving the analog inputs above VDD + 0.3 V or below GND - 0.3 V; the ESD diodes clamp but can latch the part. When using the internal reference, leave AIN2/REF floating or bypass it with 10 µF X7R + 0.1 µF in parallel; the datasheet specifies the bypass.
合規資訊
RoHS compliant per Maxim/Analog Devices product page. Lead-free NiPdAu finish. Not AEC-Q100 qualified; automotive applications require separate vendor qualification. Halogen-free status not explicitly listed in the verified data - confirm with manufacturer before no-clean or no-halogen processes.
