MAX132EWG-T - 18-bit Serial ADC, Multi-Slope, 24-SOIC | Maxim
MPN: MAX132EWG-T ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $12.85 | $12.85 |
| 10 | $11.6 | $116.00 |
| 100 | $10.4 | $1,040.00 |
| 500 | $9.35 | $4,675.00 |
| 1,000 | $8.55 | $8,550.00 |
MAX132EWG-T Overview
An ADC (analog-to-digital converter) is a data-acquisition component that samples continuous analog voltages and outputs discrete digital codes for processing by microcontrollers, DSPs, or FPGAs. Multi-slope integrating ADCs sit in the precision-measurement sub-category of data converters; they trade raw speed for excellent normal-mode noise rejection (integrator nullifies 50 Hz/60 Hz line interference) and high effective resolution at low input bandwidths. The MAX132 family targets panel meters, digital multimeters, weigh scales, and industrial sensors where 18-bit plus sign dynamic range is required.
Key features include 18-bit plus sign resolution, ±512 mV true bipolar input range, 2 uV/LSB scale factor, 100 conversions/second maximum throughput, 4-wire SPI-compatible serial interface, low conversion noise, and external integration capacitor / reference configuration. The serial interface minimises pin count while allowing straightforward connection to modern microcontrollers. The 24-SOIC wide-body package simplifies hand prototyping and rework relative to smaller surface-mount alternatives.
Architecturally, the MAX132 uses a charge-balancing integrator plus multi-slope run-down converter with automatic zero and full-scale calibration cycles. The MAX132EWG-T variant supplies the commercial-grade operating temperature range and is supplied on tape and reel for high-volume assembly. Compared with sigma-delta ADCs of similar resolution, the multi-slope topology offers faster response to input steps at the cost of requiring external integration components.
Typical applications include digital panel meters, precision weigh scales, industrial process transmitters, temperature measurement with thermocouple/RTD front ends, and laboratory instrumentation. The bipolar ±512 mV input range makes it straightforward to digitize small differential signals directly without external instrumentation amplifiers.
A key design consideration is that integrating ADCs require precision external integration components (typically polyester or polypropylene capacitors) and a low-drift reference; choose C0G/NP0 ceramic bypass capacitors directly at the supply pins and a star-ground layout to keep digital switching noise away from the analog integrator.
This page synthesizes distributor pricing, pin-compatible variants in the MAX132 family, and practical design guidance not found in the bare manufacturer datasheet.
Drop-in alternatives for MAX132EWG-T — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
MAX132EWG+T
✅ Drop-In📋 Reference alternative (not in catalog)
MAX132EWG+
✅ Drop-In📋 Reference alternative (not in catalog)
MAX132CWG+
✅ Drop-In📋 Reference alternative (not in catalog)
MAX132CWG-T
✅ Drop-In📋 Reference alternative (not in catalog)
MAX133EWG+
✅ Drop-In📋 Reference alternative (not in catalog)
MAX132EWG-T Maximum Ratings & Electrical Characteristics
| Resolution | 18-bit plus sign |
| Conversion Type | Multi-slope integrating |
| Number of Input Channels | 1 |
| Full-Scale Input Range | ±512 mV (2 uV/LSB) |
| Input Voltage | -9 V to +6 V (input protection range) |
| Maximum Throughput | 100 conversions per second |
| Output Interface | 4-wire serial (SPI-compatible) |
| Operating Temperature Range | -40 C to +85 C (Industrial) |
| Package | 24-pin SOIC Wide (WSOIC) |
| Mounting Type | Surface Mount |
| Screening Level | Industrial |
| Pin Count | 24 |
| RoHS Status | Compliant |
MAX132EWG-T Pin Configuration
| Pin 1 | V+ — Positive analog supply |
| Pin 2 | AIN+ — Positive analog input |
| Pin 3 | AIN- — Negative analog input |
| Pin 4 | V- — Negative analog supply |
| Pin 5 | INT — Integrator output (external cap) |
| Pin 6 | BUF — Integrator buffer output |
| Pin 7 | REF+ — Positive reference input |
| Pin 8 | REF- — Negative reference input |
| Pin 9 | GND — Ground |
| Pin 10 | OSC — Oscillator / clock input |
| Pin 11 | CKSEL — Clock select |
| Pin 12 | XIN — Crystal oscillator input |
| Pin 13 | XOUT — Crystal oscillator output |
| Pin 14 | CS — Chip select (active low) |
| Pin 15 | SCLK — Serial clock |
| Pin 16 | DOUT — Serial data output |
| Pin 17 | DRDY — Data ready (active low) |
| Pin 18 | CAL — Calibration control |
| Pin 19 | ZERO — Zero-scale calibration pin |
| Pin 20 | FS — Full-scale calibration pin |
| Pin 21 | TEST1 — Test pin 1 (factory) |
| Pin 22 | TEST2 — Test pin 2 (factory) |
| Pin 23 | NC — Not connected (per datasheet) |
| Pin 24 | NC — Not connected (per datasheet) |
Typical Applications
MAX132EWG-T is suitable for 6 applications: Digital Panel Meters and Multimeters, Precision Weigh Scales, Thermocouple and RTD Temperature Instrumentation, Industrial Process Transmitters (4-20 mA Replacement), Laboratory Bench Instrumentation and Data Loggers, Medical Diagnostic and Patient Monitoring Equipment.
Digital Panel Meters and Multimeters
The MAX132EWG-T's 18-bit plus sign resolution and ±512 mV bipolar input at 2 uV/LSB make it a natural fit for 4.5-digit and 5.5-digit digital panel meters and bench multimeters. The multi-slope integrator inherently rejects 50 Hz and 60 Hz line-frequency noise, eliminating the need for complex synchronous demodulation and simplifying the analog front end for handheld DMMs.
Recommended
Precision Weigh Scales
Load-cell weigh scales demand microvolt resolution over slow but stable updates - exactly the operating envelope of the MAX132EWG-T. Each conversion integrates the bridge output for a full line cycle, rejecting mains-borne pickup from noisy factory environments while delivering 2 uV/LSB resolution that resolves sub-gram weight changes on a 10 kg scale.
Recommended
Thermocouple and RTD Temperature Instrumentation
Type K, J, and T thermocouples produce only tens of microvolts per degree Celsius, demanding 18-bit-plus-sign conversion directly at the sensor. The MAX132EWG-T's 2 uV/LSB LSB size lets it resolve sub-0.1 C changes without a dedicated instrumentation-amp gain stage; its bipolar ±512 mV range accommodates the full Seebeck voltage span including thermocouple protection surges.
Recommended
Industrial Process Transmitters (4-20 mA Replacement)
Smart process transmitters digitizing pressure, flow, or pH sensors benefit from the MAX132EWG-T's industrial -40 to +85 C temperature range and bipolar input. The 4-wire SPI-compatible interface drops easily onto ARM or 8051 MCUs that format HART, Foundation Fieldbus, or wireless HART outputs, while the integrator rejects inverter switching noise common on plant floors.
Recommended
Laboratory Bench Instrumentation and Data Loggers
Multi-channel bench data loggers benefit from the MAX132EWG-T's combination of high resolution and inherent 50/60 Hz rejection. Its 100 conv/s maximum throughput matches the integration-per-line-cycle strategy of slow but precise loggers recording pH, conductivity, dissolved oxygen, or strain-gauge signals over hours or days.
Recommended
Medical Diagnostic and Patient Monitoring Equipment
Battery-powered patient monitors and clinical chemistry analyzers require microvolt-resolution ADCs with low quiescent draw - the MAX132EWG-T's integrating topology draws current only during active conversion and slots into portable designs. The bipolar input directly digitizes ECG, EEG, or galvanic-skin-response front ends after simple AC coupling.
Recommended
Recommended Products Summary
Engineering reference data for MAX132EWG-T — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | MAX132EWG+T | MAX132EWG+ | MAX132CWG+ | MAX132CWG-T | MAX133EWG+ |
|---|---|---|---|---|---|---|
| Package | 24-SOIC Wide (WSOIC) | 24-SOIC Wide (WSOIC) - same | 24-SOIC Wide (WSOIC) - same | 24-SOIC Wide (WSOIC) - same | 24-SOIC Wide (WSOIC) - same | 24-SOIC Wide (WSOIC) - same |
| Brand | Maxim Integrated | Maxim Integrated | Maxim Integrated | Maxim Integrated | Maxim Integrated | Maxim Integrated |
| Resolution | 18-bit + sign | 18-bit + sign | 18-bit + sign | 18-bit + sign | 18-bit + sign | 18-bit + sign |
| Conversion Type | Multi-slope integrating | Multi-slope integrating | Multi-slope integrating | Multi-slope integrating | Multi-slope integrating | Multi-slope integrating (faster) |
| Full-Scale Input Range | ±512 mV | ±512 mV | ±512 mV | ±512 mV | ±512 mV | ±512 mV |
| Maximum Throughput | 100 conv/s | 100 conv/s | 100 conv/s | 100 conv/s | 100 conv/s | 300 conv/s |
| Operating Temperature | -40 C to +85 C (Industrial) | -40 C to +85 C | -40 C to +85 C | 0 C to +70 C (Commercial) | 0 C to +70 C (Commercial) | -40 C to +85 C |
| Interface | 4-wire SPI serial | 4-wire SPI serial | 4-wire SPI serial | 4-wire SPI serial | 4-wire SPI serial | 4-wire SPI serial |
| Number of Channels | 1 | 1 | 1 | 1 | 1 | 2 |
Key Differentiators
- Industrial temperature grade on tape-and-reel (vs MAX132EWG+)
- Higher conversion rate within same footprint (vs MAX133EWG+)
- Industrial vs commercial operating range (vs MAX132CWG+)
Design Notes
Estimated: substituting ceramic X7R capacitors for the integration network degrades 18-bit performance significantly because X7R dielectric absorption introduces non-linearities the integrator cannot reject. Use polypropylene or polyester film capacitors with measured low-DA specifications for the integrator node (typical 0.01 uF to 0.1 uF) and connect them with the shortest possible traces directly to the INT and BUF pins to avoid leakage paths.
Implement a star-ground topology with the analog and digital grounds joined only at the MAX132EWG-T's GND pin (pin 9). Place C0G/NP0 0.1 uF ceramic bypass capacitors directly at V+ (pin 1) and V- (pin 4) with short, wide traces. Route the digital CS/SCLK/DOUT/DRDY traces on the opposite side of the board or perpendicular to the analog integrator node to prevent digital switching noise from coupling into the integration ramp.
The MAX132 datasheet recommends decoupling both supply pins with low-ESR ceramic capacitors and adding bulk electrolytic capacitance near the chip to absorb integrator current transients. Estimated: at 100 conv/s with ±5 V supplies the analog supply current peaks during conversion; insufficient decoupling directly degrades conversion noise performance and effective resolution.
Reference and integrator components are the most sensitive analog nodes on the board. Symmetrically route the AIN+ and AIN- traces as a differential pair with matched lengths and identical via counts; keep the reference decoupling capacitor within a few millimetres of REF+ (pin 7). When using an external precision reference (MAX6126 or MAX6350), its output should drive only the MAX132 and any associated decoupling - avoid sharing it with noisy circuitry.
Compliance Information
RoHS compliance confirmed per DigiKey listing -T suffix part. Maxim/Analog Devices standard industrial lead-free finish. No automotive-grade variant exists in the MAX132 family.
