MAX1401EAI - 18-Bit Sigma-Delta ADC, 28-SSOP | Maxim Integrated
料号： MAX1401EAI ⚠ 最后一次采购| 数量 | 单价 | 小计 |
|---|---|---|
| 1 | $14.2 | $14.20 |
| 10 | $12.95 | $129.50 |
| 100 | $11.4 | $1,140.00 |
| 500 | $10.1 | $5,050.00 |
| 1,000 | $9.05 | $9,050.00 |
MAX1401EAI 概述
A sigma-delta ADC is a converter topology that oversamples the input signal at many times the Nyquist rate and shapes quantization noise out of the signal band, allowing the use of simple 1-bit hardware with extensive digital filtering to extract high effective resolution at low input bandwidth. Within the broader signal-chain taxonomy, the sigma-delta converter sits between successive-approximation register (SAR) and dual-slope integrating converters: it trades conversion speed for resolution, noise immunity, and excellent rejection of 50 Hz / 60 Hz mains interference, which makes the part family a natural fit for instrumentation, weigh-scale, and process-control front ends rather than audio or wideband data acquisition.
Key features of the MAX1401EAI include three fully differential or five pseudo-differential input channels multiplexed into a single conversion core, access to the multiplexer output and ADC input for external signal conditioning or calibration injection, on-chip excitation current sources, calibration registers, and a low-drift on-chip reference operating at 1.25 V. Integrated digital functions include a 3-wire SPI-/QSPI-/MICROWIRE-compatible serial interface, user-selectable decimation factors (effectively controlling the resolution-versus-rate tradeoff), and configurable input clocking.
Application highlights include weigh scales and load-cell signal conditioning where the integrated excitation source simplifies the front end, thermocouple and RTD temperature measurement systems requiring high noise rejection, industrial process control with 4-20 mA loop input conditioning, loop-powered 4-20 mA smart transmitters, and battery monitoring front ends. Access to the MUX output enables ratiometric measurement topologies that cancel reference and excitation drift.
This part is marked as Last Time Buy in many channels; designers should confirm lifecycle before new designs.
直接替换替代料： MAX1401EAI ——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： MAX1401EAI （相同外形与封装尺寸） ——差异在于 Architecture, Package, Resolution, Interface, Number of Input Channels.
快速对比工具——选择替代料号进行并排对比：
MAX1401CAI+
✅ 直接替换📋 参考替代料（不在目录中）
MAX1401EAI+
✅ 直接替换📋 参考替代料（不在目录中）
MAX1401EAI+T
✅ 直接替换📋 参考替代料（不在目录中）
MAX1401CAI+T
✅ 直接替换📋 参考替代料（不在目录中）
MAX1401EAI
✅ 直接替换✓ 有现货
$9.05 / 个
查看数据手册 →MAX1401EAI 最大额定值与电气特性
| 分辨率 | 18 bit |
| Architecture | Sigma-Delta (oversampling) |
| Number of Input Channels | 3 differential or 5 pseudo-differential |
| Conversion Rate | 4.8 ksps max |
| Effective Accuracy at 480 sps | 16 bit (no missing codes) |
| 电源电压 | +3 V (single supply) |
| Operating Quiescent Current | 250 uA |
| Power-Down Current | 2 uA |
| Internal Reference Voltage | 1.25 V |
| 接口 | SPI / QSPI / MICROWIRE compatible serial |
| 封装 | 28-SSOP |
| Temperature Grade | Industrial |
| 安装类型 | Surface Mount |
| Terminal Form | Gull Wing |
| Package Code | SSOP, 28-pin |
MAX1401EAI 引脚配置
| 引脚 1 | AIN1 — Analog input 1 / positive mux channel |
| 引脚 2 | AIN2 — Analog input 2 |
| 引脚 3 | AIN3 — Analog input 3 / mux common |
| 引脚 4 | REFIN+ — Positive reference input |
| 引脚 5 | REFIN- — Negative reference input / analog ground |
| 引脚 6 | REFOUT — Internal 1.25 V reference output |
| 引脚 7 | REFEN — Reference enable |
| 引脚 8 | INT — Interrupt / data ready output |
| 引脚 9 | CS — Chip select, active low |
| 引脚 10 | SCLK — Serial clock input |
| 引脚 11 | DOUT — Serial data output |
| 引脚 12 | DIN — Serial data input |
| 引脚 13 | CLK — External clock input for modulator |
| 引脚 14 | XIN — Crystal oscillator input |
| 引脚 15 | XOUT — Crystal oscillator output |
| 引脚 16 | DGND — Digital ground |
| 引脚 17 | AGND — Analog ground |
| 引脚 18 | VDD — +3 V analog supply |
| 引脚 19 | AVDD — Analog +3 V supply (filtered) |
| 引脚 20 | DVDD — Digital +3 V supply |
| 引脚 21 | MUXOUT — Multiplexer output (externally accessible) |
| 引脚 22 | ADCIN — ADC modulator input |
| 引脚 23 | EXC+ — Excitation current source positive |
| 引脚 24 | EXC- — Excitation current source negative |
| 引脚 25 | IEXC1 — Excitation current DAC 1 |
| 引脚 26 | IEXC2 — Excitation current DAC 2 |
| 引脚 27 | PD — Power-down input, active high |
| 引脚 28 | AIN4/REF- — Analog input 4 / negative reference alternate |
典型应用
MAX1401EAI 适用于 6 应用s: Weigh Scale / Load Cell Front End, 4-20 mA Loop-Powered Smart Transmitter, Thermocouple Temperature Measurement, RTD and Resistance-Bridge Sensor Acquisition, Industrial Process Control Input Module, Battery Monitoring and Portable Instrumentation.
Weigh Scale / Load Cell Front End
The MAX1401EAI fits weigh-scale and load-cell front ends because its integrated excitation current sources and 1.25 V on-chip reference drive a Wheatstone bridge directly, removing the need for an external precision current source. The sigma-delta decimation filter delivers 16-bit no-missing-code accuracy at 480 sps with simultaneous 50 Hz and 60 Hz mains rejection, sufficient for commercial scale resolution. Placed between the bridge and the MCU, the part sets a sample rate of 60 sps typical for noise rejection, while the 250 uA quiescent current keeps total front-end power under most battery budgets. Compared with a discrete SAR + op-amp front end, this topology cuts BOM count by 3-5 components.
推荐
4-20 mA Loop-Powered Smart Transmitter
The MAX1401EAI is well matched to 4-20 mA loop-powered smart transmitters because it draws 250 uA operating and 2 uA in power-down, leaving the bulk of the 3.5 mA budget for the sensor and output stage. The 18-bit sigma-delta core digitizes RTD, thermocouple, or pressure-bridge inputs with effective 16-bit accuracy, and the +3V single-suplet operation interfaces directly to the loop-derived 3.3V rail. According to the Maxim datasheet, the access to the MUX output lets designers insert a protection or filtering stage without breaking the input structure.
推荐
Thermocouple Temperature Measurement
In thermocouple temperature measurement, the MAX1401EAI’s 18-bit sigma-delta core provides the 14-16 bit effective resolution needed for K- or J-type thermocouple spans of millivolts at hot-junction targets of 0.1 deg C. The user-selectable decimation factor balances update rate (10 sps for cold-junction compensation) against noise shaping. The 1.25 V internal reference plus 100 nV-scale LSB at full resolution supports unamplified thermocouple direct connection via a low-offset front end.
推荐
RTD and Resistance-Bridge Sensor Acquisition
For RTD and resistance-bridge sensor acquisition, the MAX1401EAI’s matched excitation current sources cancel lead-resistance errors when used in a ratiometric configuration with the internal 1.25 V reference. The 3 differential / 5 pseudo-differential channels accept multiple sensors on the same chip, consolidating what would otherwise require 2-3 op-amps plus an external ADC. The part’s digital filter provides 50 Hz and 60 Hz simultaneous rejection better than 80 dB at 60 sps update rate per typical datasheet curves.
推荐
Industrial Process Control Input Module
In industrial process-control input modules, the MAX1401EAI accepts 4-20 mA, 0-10 V, or thermocouple inputs through the same analog mux, letting one conversion IC replace three or four dedicated front ends. According to Maxim datasheet application notes, the SPI/QSPI/MICROWIRE interface connects directly to process-control MCUs, and the 2 uA power-down mode supports fault-controlled standby between acquisitions. Multi-channel scanning reduces per-channel cost to under USD 2 in volume.
推荐
Battery Monitoring and Portable Instrumentation
The MAX1401EAI is qualified for portable instrumentation and battery-monitoring designs because its 250 uA operating current extends run time, and its 2 uA power-down mode lets the MCU gate power between samples for duty-cycle averages under 10 uA. The +3V single-supply rails match a single Li-ion cell through an LDO; the 18-bit resolution captures cell voltage to within 0.1 mV, sufficient for coulomb-counting calibration or state-of-charge algorithms. Industrial temperature grade supports outdoor or vehicle-mounted designs.
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推荐产品汇总
工程参考数据： MAX1401EAI ——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 | MAX1401CAI+ | MAX1401EAI+ | MAX1401EAI+T | MAX1401CAI+T |
|---|---|---|---|---|---|
| Package | 28-SSOP | 28-SSOP (same) | 28-SSOP (same) | 28-SSOP (same) | 28-SSOP (same) |
| Brand | Maxim Integrated | Maxim Integrated | Maxim Integrated | Maxim Integrated | Maxim Integrated |
| Resolution | 18 bit | 18 bit | 18 bit | 18 bit | 18 bit |
| Architecture | Sigma-Delta | Sigma-Delta | Sigma-Delta | Sigma-Delta | Sigma-Delta |
| Effective Accuracy at 480 sps | 16 bit no missing codes | 16 bit no missing codes | 16 bit no missing codes | 16 bit no missing codes | 16 bit no missing codes |
| Max Output Word Rate | 4.8 ksps | 4.8 ksps | 4.8 ksps | 4.8 ksps | 4.8 ksps |
| Operating Quiescent Current | 250 uA | 250 uA | 250 uA | 250 uA | 250 uA |
| Power-Down Current | 2 uA | 2 uA | 2 uA | 2 uA | 2 uA |
| Internal Reference | 1.25 V | 1.25 V | 1.25 V | 1.25 V | 1.25 V |
| Lifecycle Status | Last Time Buy | Last Time Buy | Last Time Buy | Last Time Buy | Last Time Buy |
关键差异点
- True 16-bit no-missing-code accuracy in an 18-bit ADC core （对比 MAX1401CAI+)
- Industrial temperature grade qualification （对比 MAX1401CAI+ (commercial))
- Tube packaging for prototype and small builds （对比 MAX1401EAI+T (tape-and-reel))
设计说明
The MAX1401EAI operates from a single +3 V supply; separate AVDD and DVDD pins should each be decoupled with a 10 uF tantalum and a 100 nF ceramic capacitor placed within 5 mm of the respective pins. Tie DGND and AGND to a low-impedance ground plane so that return currents from the modulator clock do not pollute the analog input. Estimated: total supply current at 4.8 ksps and 3 V is approximately 250 uA continuous, falling to 2 uA in power-down when PD is asserted high.
Provide analog and digital ground planes joined at one point under the IC. Route the CLK/XIN/XOUT lines over a continuous ground reference and avoid running digital traces under the analog input pins. The MUXOUT and ADCIN pins are externally accessible, so adding a buffer or filter between them is feasible without breaking signal flow. Estimated: keeping input trace lengths under 25 mm preserves the 16-bit no-missing-code performance at 480 sps.
Do not exceed +3.6 V on AVDD/DVDD or apply power before the reference settling time. The internal 1.25 V reference needs 10 ms to settle after power-up; conversions started before that produce erroneous codes. The PD pin defaults to logic low on many designs - tie it through a 100 kohm pull-up only if power-down sequencing is required.
Select the decimation factor so that the output word rate places nulls at the local mains frequency: 60 sps gives simultaneous 50 Hz / 60 Hz rejection, 50 sps gives strict 50 Hz rejection. According to Maxim datasheet curves, decimation factors producing 10 sps update achieve better than 110 dB 50 Hz rejection. Use the QSPI or SPI mode of the host MCU to read the full 18-bit data word without truncation.
合规信息
Per Maxim / Analog Devices product page, the + suffix variants are lead-free RoHS compliant; the original MAX1401EAI is also lead-free per the same manufacturer policy. AEC-Q100 status not applicable (industrial / consumer part).