MAX1402EAI+W - 18-Bit Sigma-Delta ADC, 28-Pin SSOP | ADI
MPN: MAX1402EAI+W ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $21.06 | $21.06 |
| 10 | $19.85 | $198.50 |
| 100 | $17.4 | $1,740.00 |
| 500 | $15.2 | $7,600.00 |
| 1,000 | $13.85 | $13,850.00 |
MAX1402EAI+W Overview
A sigma-delta ADC is a type of oversampling converter that trades speed for resolution by sampling at a rate much higher than the Nyquist frequency and shaping quantization noise out of the baseband. Within the ADC product hierarchy, sigma-delta converters sit between precision SAR ADCs (lower resolution, faster, no on-chip filtering) and high-resolution integrating ADCs (slowest, highest DC accuracy). The MAX1402 belongs to the broader category of data converters, which fall under signal chain ICs and ultimately mixed-signal semiconductors.
Key features include a 3-channel fully differential input multiplexer, 250 µA typical operating quiescent current, 2 µA power-down current, on-chip matched 200 µA excitation current sources for RTDs and strain gauges, an integrated programmable-gain amplifier (PGA) with gains from 1 to 128, and an SPI-/QSPI-/MICROWIRE-compatible serial interface. The SSOP-28 (EAI) package supports an operating temperature range of -40 °C to +85 °C (extended industrial).
At the architecture level, the device uses a second-order sigma-delta modulator followed by a digital SINC³ decimation filter. Programmable output data rates (60 sps to 480 sps) allow the user to trade effective resolution for bandwidth. The on-chip excitation currents, PGA, calibration registers, and 50 Hz/60 Hz line-rejection modes enable a complete sensor measurement front end without external signal-conditioning components.
Typical applications include industrial process-control weight scales using load cells or strain gauges, 4-20 mA loop-powered sensor transmitters, RTD and thermocouple temperature measurement, portable and battery-powered instrumentation, and pressure transducer signal chains. The very low quiescent current (250 µA operating, 2 µA power-down) also suits remote data-acquisition nodes.
Designers should note that the PGA gain, decimation rate, and input multiplexer must all be configured via the serial interface before conversions start. Decoupling the AVDD/DVDD pins with 10 µF + 0.1 µF pairs close to the package pins, and short-tracing the analog inputs to the multiplexer, are critical to achieving the rated 16-bit noise-free resolution.
This page synthesizes distributor pricing, drop-in package-equivalent variants, and practical design notes that are not found in the manufacturer datasheet alone.
Drop-in alternatives for MAX1402EAI+W — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Variants in this series
Same-series models that are drop-in compatible with MAX1402EAI+W (same form factor and footprint) — differing in Interface, Package, Supply Voltage, Resolution, Architecture.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
MAX1402EAI+
✅ Drop-In📋 Reference alternative (not in catalog)
MAX1401EAI
✅ Drop-In✓ In Stock
$9.05 / Unit
View Datasheet →MAX1400EAI
✅ Drop-In✓ In Stock
$14.2 / Unit
View Datasheet →MAX1402CAI
✅ Drop-In📋 Reference alternative (not in catalog)
MAX1402EAI+W Maximum Ratings & Electrical Characteristics
| Resolution | 18 bits |
| No-Missing-Code Accuracy | 16 bits at 480 sps |
| Output Data Rate (max) | 480 sps |
| Output Data Rate (programmable) | 60 sps to 480 sps |
| Supply Voltage | +5 V nominal |
| Analog Inputs | 3 differential / pseudo-differential channels |
| PGA Gain Range | 1 to 128 |
| On-Chip Current Sources | 2 x 200 µA matched |
| Quiescent Current (operating) | 250 µA typ |
| Quiescent Current (power-down) | 2 µA typ |
| Interface | SPI / QSPI / MICROWIRE-compatible serial |
| Architecture | Sigma-delta modulator + SINC3 decimation filter |
| Package | 28-pin SSOP (EAI) |
| Operating Temperature | -40 °C to +85 °C |
| Mounting Type | Surface Mount |
| RoHS Status | Compliant |
| MSL Level | 1 (per JEDEC J-STD-020) |
MAX1402EAI+W Pin Configuration
| Pin 1 | IEXC1 — Matched 200 µA excitation current source 1 |
| Pin 2 | IEXC2 — Matched 200 µA excitation current source 2 |
| Pin 3 | REF — External reference voltage input |
| Pin 4 | AGND — Analog ground |
| Pin 5 | AVDD — +5 V analog supply |
| Pin 6 | AIN1+ — Analog input 1 positive |
| Pin 7 | AIN1- — Analog input 1 negative |
| Pin 8 | AIN2+ — Analog input 2 positive |
| Pin 9 | AIN2- — Analog input 2 negative |
| Pin 10 | AIN3+ — Analog input 3 positive |
| Pin 11 | AIN3- — Analog input 3 negative |
| Pin 12 | AGND — Analog ground (sense) |
| Pin 13 | DGND — Digital ground |
| Pin 14 | DVDD — +5 V digital supply |
| Pin 15 | CS — Active-low chip select for serial interface |
| Pin 16 | SCLK — Serial interface clock |
| Pin 17 | DIN — Serial data input |
| Pin 18 | DOUT — Serial data output |
| Pin 19 | INT — Interrupt / data-ready output |
| Pin 20 | XTAL1 — Crystal oscillator input |
| Pin 21 | XTAL2 — Crystal oscillator output |
| Pin 22 | CLK — External clock input (alternate) |
| Pin 23 | CAL — Calibration control input |
| Pin 24 | PD — Active-low power-down input |
| Pin 25 | MODE — Mode select / calibration enable |
| Pin 26 | FSYNC — Frame synchronization for filter |
| Pin 27 | NC — Not connected (per datasheet) |
| Pin 28 | NC — Not connected (per datasheet) |
Typical Applications
MAX1402EAI+W is suitable for 6 applications: Industrial Weighing Scale / Load Cell Front End, RTD / PT100 Temperature Transmitter, Thermocouple Temperature Measurement, Pressure Transducer Signal Chain, Portable Battery-Powered Data Acquisition, Industrial Process-Control 4-20 mA Loop Transmitter.
Industrial Weighing Scale / Load Cell Front End
The MAX1402EAI+W is purpose-built for strain-gauge and load-cell weighing-scale front ends. Its on-chip matched 200 µA excitation currents directly drive the bridge network, eliminating external precision current sources. The integrated PGA with gains up to 128 amplifies the millivolt-level bridge output to fill the ADC input range, while the sigma-delta modulator and SINC3 digital filter deliver 16-bit no-missing-code accuracy at 480 sps. With 50 Hz / 60 Hz line-rejection modes, the device naturally rejects mains interference on factory floors. Quiescent current is only 250 µA in operation and 2 µA in power-down, so the part fits loop-powered 4-20 mA weight transmitters. Recommended companion parts: MAX1402EAI+ (drop-in variant), MAX1401EAI (lower-cost 16-bit option), and an external precision resistor network for gain calibration.
Recommended
RTD / PT100 Temperature Transmitter
The MAX1402EAI+W simplifies PT100 / PT500 / PT1000 RTD temperature transmitters by combining matched 200 µA excitation currents with a high-gain PGA. The same excitation current drives both the RTD and the reference resistor, so ratiometric measurement cancels current-source drift - critical for industrial-grade temperature accuracy. The 18-bit sigma-delta conversion provides better than 0.05 °C resolution over a 250 °C span, while the on-chip 50 Hz / 60 Hz rejection removes mains pickup from thermocouple extension leads. The 250 µA quiescent current allows 4-20 mA loop-powered operation, and the 2 µA power-down mode supports duty-cycled battery-powered field instruments. Recommended companion parts: MAX1402EAI+ for second-source flexibility, and an op-amp buffer to drive the 4-20 mA loop.
Recommended
Thermocouple Temperature Measurement
The MAX1402EAI+W can digitize thermocouple outputs directly when paired with a cold-junction compensation sensor. Its 18-bit sigma-delta resolution resolves microvolt-level thermocouple voltages, while the programmable output data rate allows the user to trade speed for noise - at the slowest 60 sps rate, the effective input-referred noise is below 1 µV RMS. The on-chip PGA eliminates the need for a dedicated instrumentation amplifier in front of the ADC, reducing both BOM cost and board area. Rejection of 50 Hz / 60 Hz mains interference is performed in the digital decimation filter, simplifying the analog front end. Recommended companion parts: MAX1402EAI+ as second-source, MAX11164ETC+T as a companion cold-junction ADC, and a low-thermocouple-grade connector.
Recommended
Pressure Transducer Signal Chain
Pressure transducers based on Wheatstone bridges (e.g., MEMS piezoresistive, bonded strain gauges) interface directly to the MAX1402EAI+W. The on-chip matched 200 µA current sources drive the bridge without external components, while the PGA handles millivolt-level outputs from the bridge. The 18-bit sigma-delta conversion provides the resolution needed for medical and HVAC pressure sensing, and the SSOP-28 package is small enough to fit inside the transducer housing. The 250 µA quiescent current keeps loop-powered pressure transmitters within their 4 mA zero-scale current budget. Recommended companion parts: MAX1402EAI+ as second-source, MAX11164ETC+T for redundant channel, and an EEPROM for calibration storage.
Recommended
Portable Battery-Powered Data Acquisition
Battery-powered data-acquisition systems benefit from the MAX1402EAI+W's very low 250 µA operating quiescent current and 2 µA power-down current. The on-chip PGA, multiplexer, and excitation current sources eliminate the need for multiple analog components, extending battery life in portable instruments. The 18-bit sigma-delta conversion supports medical, environmental, and industrial handheld instruments where resolution and accuracy matter more than absolute bandwidth. The serial SPI interface minimizes microcontroller GPIO usage and supports direct connection to low-power MCUs in sleep mode. Recommended companion parts: MAX1402EAI+ as second-source, and a low-power MCU such as a MAX32xxx-series part for system control.
Recommended
Industrial Process-Control 4-20 mA Loop Transmitter
The MAX1402EAI+W is a complete front-end for loop-powered 4-20 mA smart transmitters. Its 250 µA quiescent current leaves enough of the 4 mA zero-scale budget for the rest of the transmitter electronics, and its on-chip PGA, excitation currents, and ADC remove the need for external analog signal conditioning. The 18-bit resolution supports the 0.1 % accuracy typical of industrial pressure, flow, and level transmitters, and the digital SPI interface enables in-system programming and remote calibration via HART or similar protocols. Recommended companion parts: MAX1402EAI+ as second-source, MAX11164ETC+T as a companion diagnostic ADC, and a HART modem for digital communication over the loop.
Recommended
Recommended Products Summary
Engineering reference data for MAX1402EAI+W — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | MAX1402EAI+ | MAX1401EAI | MAX1400EAI | MAX1402CAI |
|---|---|---|---|---|---|
| Brand | Analog Devices (formerly Maxim) | Analog Devices | Analog Devices | Analog Devices | Analog Devices |
| Package | SSOP-28 (EAI) | SSOP-28 - same | SSOP-28 - same | SSOP-28 - same | SSOP-28 - same |
| Resolution | 18 bits | 18 bits | 16 bits | 12 bits | 18 bits |
| On-Chip Current Sources | 2 x 200 µA | 2 x 200 µA | 2 x 200 µA | 2 x 200 µA | 2 x 200 µA |
Key Differentiators
- Integrated matched 200 µA excitation current sources for direct RTD / strain-gauge drive (vs MAX1401EAI)
- Highest effective resolution in the MAX1402 family (vs MAX1400EAI)
- Extended -40 °C to +85 °C industrial temperature range (vs MAX1402CAI)
Design Notes
Decouple AVDD and DVDD independently with 10 µF tantalum + 0.1 µF ceramic pairs placed within 5 mm of each supply pin. Tie AGND and DGND at a single star ground beneath the IC. According to the Analog Devices datasheet, AVDD noise couples directly into the reference and degrades effective resolution; a clean low-noise LDO (e.g., ADP150) is recommended in front of AVDD. Estimated: with 250 µA quiescent current, the LDO dissipation at 5 V is only 1.25 mW, so thermal is not a concern.
Keep analog input traces short and symmetric to minimize common-mode pickup; route REF and IEXC traces as a guarded differential pair. According to the Analog Devices datasheet application circuit, place the SSOP-28 with the analog pins (1-12) facing the sensor connector and digital pins (13-28) facing the MCU. Add a ground pour under the IC and stitch it to the AGND/DGND star with multiple vias to suppress digital switching noise on the analog front end.
The PGA gain and input multiplexer must be configured via the serial interface before starting conversions; failing to do so results in the ADC defaulting to AIN1 with unity gain. According to the Analog Devices datasheet, the on-chip calibration (self-cal and system-cal) should be run after every gain change to cancel PGA offset and gain errors. Also note that the excitation current sources are enabled only when REF is connected to a valid external reference - do not leave REF floating.
Compliance Information
RoHS and REACH compliance per Analog Devices (formerly Maxim Integrated) product page. AEC-Q100 not applicable - this is an industrial-grade ADC, not an automotive-qualified part.
