MAX1138KEEE+ - 12-Channel 10-Bit SAR ADC, I2C, QSOP-16
MPN： MAX1138KEEE+ ✓ 啟用中MAX1138KEEE+ 概覽
A SAR ADC is a successive-approximation-register analog-to-digital converter that uses a binary search algorithm with an internal DAC and comparator to convert analog input voltages into digital codes within a single conversion cycle per bit. Within the broader hierarchy, the MAX1138KEEE+ is a multi-channel data converter -> ADC analog-to-digital converter -> data-acquisition IC -> mixed-signal semiconductor.
Key differentiating features include 12 single-ended analog input channels (vs. 4 channels on the MAX1136), an internal 2.5V reference, software-configurable unipolar/bipolar inputs, and an automatic channel-scanning state machine that cycles through selected channels sequentially. The part also integrates an internal oscillator and programmable acquisition time, eliminating the need for an external clock source.
Typical applications include portable data logging, patient monitoring, system supervision in embedded control, thermocouple/thermistor front-end digitisation, and battery-powered instrumentation where the small QSOP-16 footprint and low supply current (typically 200 µA at the lowest throughput) are decisive. The internal reference and track/hold simplify BOM cost and layout complexity.
When designing with this device, ensure the SCL/SDA pull-ups follow I2C bus specifications (typically 4.7 kΩ at 3.3V for Fast Mode) and that the AIN inputs respect the absolute-maximum input range to avoid latch-up. For best noise performance, place 0.1 µF bypass capacitors directly at VDD and use the internal reference rather than an external source.
This page synthesises distributor pricing, drop-in alternatives (including same-family Maxim parts and cross-brand ADI replacements), and practical design notes not found in the manufacturer datasheet alone.
直接替換替代品，適用於 MAX1138KEEE+ — 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： MAX1138KEEE+ （相同外形與佔位） — 差異在於 Input Type, Package, Resolution, Interface, Internal Reference Voltage.
MAX1138KEEE+T
✅ 直接替換聯絡詢價
查看資料表 →MAX1139EEE+
✅ 直接替換📋 參考替代品（不在目錄中）
MAX1238EEE+T
✅ 直接替換📋 參考替代品（不在目錄中）
MAX1137KEEE+
✅ 直接替換📋 參考替代品（不在目錄中）
MAX1067BCEE
✅ 直接替換聯絡詢價
查看資料表 →MAX1138KEEE+ 最大額定值與電氣特性
| 解析度 | 10 bit |
| Architecture | SAR (Successive Approximation) |
| Number of Input Channels | 6, 12 (single-ended, software-configurable) |
| Input Type | Single-Ended, Pseudo-Differential |
| 供應電壓 | 2.7 V to 3.6 V or 4.5 V to 5.5 V |
| Number of ADC Channels | 12 |
| 介面 | I2C-compatible 2-wire serial (400 kHz Fast Mode, 1.7 MHz High-Speed Mode) |
| Internal Reference Voltage | 2.5 V |
| Reference Type | Internal (external optional) |
| Track/Hold | Internal |
| 封裝 | 16-QSOP (QSOP-16, 0.154" / 3.90 mm width) |
| 工作溫度範圍 | -40 °C to +85 °C (industrial) |
| 安裝類型 | Surface Mount |
| RoHS 狀態 | Compliant |
MAX1138KEEE+ 腳位配置
| 腳位 1 | AIN0 — Analog input channel 0 |
| 腳位 2 | AIN1 — Analog input channel 1 |
| 腳位 3 | AIN2 — Analog input channel 2 |
| 腳位 4 | AIN3 — Analog input channel 3 |
| 腳位 5 | AIN4 — Analog input channel 4 |
| 腳位 6 | AIN5 — Analog input channel 5 |
| 腳位 7 | AIN6 — Analog input channel 6 |
| 腳位 8 | AIN7 — Analog input channel 7 |
| 腳位 9 | AIN8 — Analog input channel 8 |
| 腳位 10 | AIN9 — Analog input channel 9 |
| 腳位 11 | AIN10 — Analog input channel 10 |
| 腳位 12 | AIN11 — Analog input channel 11 |
| 腳位 13 | GND — Ground |
| 腳位 14 | VDD — Positive supply voltage |
| 腳位 15 | SDA — I2C serial data |
| 腳位 16 | SCL — I2C serial clock |
典型應用
MAX1138KEEE+ 適用於 6 應用s: Portable Data Logging, Patient Monitoring Systems, Industrial System Supervision, Battery-Powered Instrumentation, Embedded Control and PLCs, Thermocouple / Thermistor Front-End Digitisation.
Portable Data Logging
The MAX1138KEEE+ fits portable data-logging applications thanks to its 12 single-ended analog inputs, internal 2.5V reference, internal track/hold, and low 200 µA typical supply current in a compact QSOP-16 footprint. With up to 12 channels the part can digitise multiple thermocouples, RTDs, strain gauges, or 4-20 mA loop shunts through one IC, simplifying the BOM and shrinking PCB area for handheld instruments and field loggers.
推薦
Patient Monitoring Systems
In patient monitoring front-ends the MAX1138KEEE+ provides 12 channels of 10-bit digitisation for ECG leads, SpO2 sensor outputs, temperature probes, and respiration signals. The integrated 2.5V reference and internal clock remove the need for external precision components, while the I2C-compatible 2-wire interface (Fast Mode 400 kHz / High-Speed Mode 1.7 MHz) reduces microcontroller I/O pin count, critical for compact wearable designs.
推薦
Industrial System Supervision
The MAX1138KEEE+ is well-suited to industrial system supervision where multiple supply rails, temperature sensors, and current shunts must be monitored simultaneously. Its 12 single-ended input channels enable direct connection to voltage dividers and 4-20 mA loop receivers, while the internal reference ensures repeatable readings across the -40 °C to +85 °C industrial temperature range without external precision components.
推薦
Battery-Powered Instrumentation
For battery-powered instrumentation, the MAX1138KEEE+ integrates track/hold, voltage reference, and clock in a single QSOP-16 package, drawing only ~200 µA in active conversion mode and entering automatic shutdown between conversions. This minimises quiescent drain while still offering 10-bit resolution for temperature, battery voltage, and load-current measurements in handheld meters, portable test gear, and remote sensor nodes.
推薦
Embedded Control and PLCs
Embedded controllers and small PLCs benefit from the MAX1138KEEE+'s 12 single-ended input channels, which allow direct connection to potentiometers, thermistors, photo-diodes, and analogue output transducers without external muxing. The I2C-compatible 2-wire interface supports up to 1.7 MHz High-Speed Mode, ensuring fast updates of process-control loops, while the QSOP-16 footprint suits compact control boards where board area is constrained.
推薦
Thermocouple / Thermistor Front-End Digitisation
The MAX1138KEEE+ digitises thermocouple and thermistor bridge outputs directly with its 12 single-ended channels, internal 2.5V reference, and integrated track/hold. Software-configurable unipolar/bipolar input modes allow direct digitisation of thermocouple millivolt signals, and the small QSOP-16 footprint keeps the analogue front-end compact alongside the MCU in temperature-acquisition modules.
推薦
推薦產品摘要
工程參考資料，適用於 MAX1138KEEE+ — 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 | MAX1138KEEE+T | MAX1139EEE+ | MAX1238EEE+T | MAX1137KEEE+ | MAX1067BCEE |
|---|---|---|---|---|---|---|
| Brand | Analog Devices (Maxim Integrated) | Analog Devices | Analog Devices | Analog Devices | Analog Devices | Analog Devices |
| Package | QSOP-16 | QSOP-16 - same | QSOP-16 - same | QSOP-16 - same | QSOP-16 - same | QSOP-16 - same |
| Resolution | 10 bit | 10 bit | 10 bit | 12 bit | 10 bit | 12 bit |
| Number of Input Channels | 6, 12 (single-ended) | 6, 12 | 12 SE / 6 pseudo-diff | 12 | 8 | 8 |
| Interface | I2C (400 kHz / 1.7 MHz) | I2C | I2C | I2C | I2C | I2C |
| Supply Voltage | 2.7-3.6 V / 4.5-5.5 V | 2.7-3.6 V / 4.5-5.5 V | 2.7-3.6 V / 4.5-5.5 V | 2.7-3.6 V / 4.5-5.5 V | 2.7-3.6 V / 4.5-5.5 V | 2.7-3.6 V / 4.5-5.5 V |
| Internal Reference | 2.5 V | 2.5 V | 2.5 V | 2.5 V | 2.5 V | 2.5 V |
| Operating Temperature | -40 °C to +85 °C | -40 °C to +85 °C | -40 °C to +85 °C | -40 °C to +85 °C | -40 °C to +85 °C | -40 °C to +85 °C |
主要差異化特點
- Highest channel count in MAX1136-MAX1139 family with 12 channels (對比MAX1137KEEE+ (8 channels))
- Pin-compatible 12-bit upgrade path exists without PCB changes (對比MAX1136 (4 channels))
- Integrated reference, track/hold, and clock reduce BOM count (對比Discrete SAR ADC + external reference + external clock)
設計說明
Place a 0.1 µF ceramic bypass capacitor as close as possible to the VDD pin and a 10 µF bulk capacitor at the supply rail. The MAX1138KEEE+ operates from 2.7V-3.6V or 4.5V-5.5V; do not operate at intermediate voltages (3.7V-4.4V) where the internal reference regulation is undefined.
The SDA and SCL pins are open-drain and must be pulled high with external pull-up resistors (typically 4.7 kΩ at 3.3V for Fast Mode 400 kHz, lower values such as 2.2 kΩ for High-Speed Mode 1.7 MHz). Without pull-ups the I2C bus will not function. Do not exceed the absolute maximum analog input voltage (VDD + 0.3 V) on any AIN pin to avoid latch-up.
Route analog input traces away from digital switching lines (SDA, SCL, MCU traces). Use a ground plane under the QSOP-16 footprint and place the device's GND pin directly to the analog ground plane. For best noise performance, use the internal 2.5 V reference with a 0.1 µF + 10 µF decoupling network on REF, instead of an external reference, unless absolute precision is required.
合規資訊
RoHS compliant and lead-free per Maxim Integrated product page ('+' suffix denotes lead-free / RoHS-compliant packaging). REACH compliant per Maxim environmental documentation. Not AEC-Q100 qualified; for automotive-grade SAR ADCs consider MAX1138-MAX1139 automotive-grade variants if available.
