MAX1225ETC+ - 12-Bit 1.5Msps SAR ADC | Maxim Integrated
MPN: MAX1225ETC+ ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $11.85 | $11.85 |
| 10 | $10.65 | $106.50 |
| 100 | $9.48 | $948.00 |
| 500 | $8.52 | $4,260.00 |
| 1,000 | $7.6 | $7,600.00 |
MAX1225ETC+ Overview
A successive-approximation (SAR) ADC is a member of the data-converter family that performs a binary-search conversion cycle on the analog input using an internal capacitive DAC. SAR ADCs are valued for their deterministic latency (one conversion cycle, no pipeline delay), excellent DC accuracy, and low power consumption at modest sample rates. The MAX1225ETC+ belongs to the Maxim/ADI precision ADC family (MAX1117-MAX1225 series), positioning it between slow precision sigma-delta converters and high-speed pipeline ADCs, and ideal for instrumentation, motor control, and data-acquisition systems.
Key features include 1.5Msps throughput, true-differential analog inputs that reject common-mode noise, an integrated +2.5V internal reference (with external-reference option), low power dissipation (typically under 25mW at full speed), and a 4-wire SPI/QSPI/MICROWIRE-compatible digital interface. The 12-pin TQFN (4x4) package offers a compact footprint with an exposed pad for improved thermal performance and PCB ground reference.
The MAX1225ETC+ uses a charge-redistribution SAR architecture with input tracking and hold, achieving INL typically within +/-0.5 LSB and DNL within +/-0.5 LSB for true 12-bit linearity. The integrated +2.5V reference provides tight initial accuracy and low drift, eliminating the need for an external reference in many applications.
Typical applications include portable data-acquisition systems, process and motor control loops, industrial instrumentation, optical-sensor front ends, and medical instrumentation. The differential input architecture also suits it for transducer-bridge signal chains and thermocouple amplification where ground-noise rejection is critical.
When designing with this device, place the 0.1uF input/output bypass capacitors as close as possible to the supply pins, and connect the exposed pad to a clean analog ground plane. The serial clock can run up to ~24MHz at 1.5Msps, so route SCLK/SDOUT traces over a continuous ground plane to preserve signal integrity.
This page synthesizes distributor stock and pricing, drop-in pin-compatible alternatives, and practical layout guidance not always presented in the manufacturer datasheet.
Drop-in alternatives for MAX1225ETC+ — 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 MAX1225ETC+ (same form factor and footprint) — differing in Package, Architecture, Resolution, Number of Channels, Operating Temperature Range.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
MAX1225CTC+
✅ Drop-In✓ In Stock
$3.79 / Unit
View Datasheet →MAX1225CTC+T
✅ Drop-In✓ In Stock
$4.65 / Unit
View Datasheet →MAX1224ETC+
✅ Drop-In📋 Reference alternative (not in catalog)
MAX1224CTC+
✅ Drop-In✓ In Stock
$2.28 / Unit
View Datasheet →MAX1179AEUI+
✅ Drop-In ⚠️ Specs Unverified✓ In Stock
$8.29 / Unit
View Datasheet →MAX1225ETC+ Maximum Ratings & Electrical Characteristics
| Resolution | 12 bits |
| Sample Rate | 1.5 Msps |
| Architecture | SAR (Successive Approximation) |
| Input Channels | 1 (true-differential) |
| Analog Supply Voltage | 2.7 V to 3.6 V |
| Internal Reference | +2.5 V |
| Differential Input Range | True-differential (V_IN+ - V_IN-) |
| Digital Interface | SPI / QSPI / MICROWIRE-compatible serial |
| INL (typical) | +/-0.5 LSB |
| DNL (typical) | +/-0.5 LSB |
| Operating Temperature Range | -40C to +85C (industrial) |
| Package | 12-TQFN (4x4) with exposed pad |
| Mounting Type | Surface Mount |
| RoHS Status | Compliant |
| Lead-Free | Yes (per datasheet ordering info +Pb-free suffix) |
MAX1225ETC+ Pin Configuration
| Pin 1 | GND — Analog ground reference |
| Pin 2 | AIN+ — Positive differential analog input |
| Pin 3 | AIN- — Negative differential analog input |
| Pin 4 | REF — Reference bypass / external reference input (internal +2.5V nominal) |
| Pin 5 | VDD — Analog supply (2.7V to 3.6V) |
| Pin 6 | DVDD — Digital I/O supply |
| Pin 7 | DGND — Digital ground reference |
| Pin 8 | CNVST — Conversion-start input (active low / falling edge) |
| Pin 9 | DIN — Serial data input (for control word) |
| Pin 10 | SCLK — Serial clock input |
| Pin 11 | DOUT — Serial data output (MSB-first conversion result) |
| Pin 12 | EOC — End-of-conversion indicator |
Typical Applications
MAX1225ETC+ is suitable for 7 applications: Portable Data Acquisition Systems, Industrial Process Control, Motor Control Feedback Loops, Medical Instrumentation, Optical Sensor Front Ends, Industrial Instrumentation / Test & Measurement, Thermocouple & Bridge Sensor Signal Chains.
Portable Data Acquisition Systems
The MAX1225ETC+ is well matched to portable data-acquisition front-ends because of its 1.5Msps throughput, true-differential input that rejects ground noise from cable harnesses, and single 2.7V-to-3.6V analog supply that simplifies battery-powered designs. Placed immediately after a low-noise instrumentation amplifier, it streams 12-bit samples over its SPI-compatible serial interface to an MCU while drawing <25mW from a 3.3V rail. The 12-TQFN (4x4) footprint keeps the analog portion under 16mm^2, leaving room for additional analog front-end channels or wireless connectivity.
Recommended
Industrial Process Control
In a process-control loop, the MAX1225ETC+ digitizes 4-20mA-derived shunt voltages or thermocouple signals with 12-bit resolution and 1.5Msps speed - more than enough to over-sample and apply digital filtering for 16-bit-effective precision. The true-differential input architecture rejects common-mode noise injected by long field wiring, and the industrial -40C to +85C operating range ensures reliable operation in factory-floor cabinets. Its single-supply operation simplifies isolator design, and the SPI-compatible digital interface bridges easily to low-cost MCUs.
Recommended
Motor Control Feedback Loops
The MAX1225ETC+ suits brushless-DC and servo-drive current/position feedback because the 1.5Msps rate tracks fast PWM current edges with sub-microsecond latency. Its true-differential analog inputs connect directly to shunt resistors or Hall-effect position sensors, and the 12-bit resolution gives 4096 discrete steps across typical +/-10A current ranges (about 4.9mA LSB). The integrated +2.5V reference simplifies measurement across the full industrial -40C to +85C window, and the 12-TQFN footprint minimizes board real estate around gate-driver sections.
Recommended
Medical Instrumentation
Medical-instrumentation front-ends - patient monitors, optical pulse oximetry, and bench-top analyzers - leverage the MAX1225ETC+'s 12-bit accuracy, true-differential input, and low 25mW power dissipation to digitize small sensor signals cleanly. Its single-supply operation simplifies battery-powered portable devices, and the SAR architecture provides deterministic single-cycle latency critical for triggered physiological captures. Galvanic isolation on the digital side keeps the analog front-end safe from mains-attached data ports.
Recommended
Optical Sensor Front Ends
Photodiode- and phototransistor-based optical sensors - encoders, LIDAR receivers, and barcode scanners - benefit from the MAX1225ETC+'s 1.5Msps throughput and true-differential input that accommodates a transimpedance amplifier's differential output. The 12-bit quantizer captures fast optical edges with sub-microsecond detail, and the internal +2.5V reference gives repeatable full-scale regardless of supply drift. The 12-TQFN (4x4) small footprint fits in compact sensor modules or handheld scanner heads.
Recommended
Industrial Instrumentation / Test & Measurement
Bench and rack instrumentation, including oscilloscope front-ends, spectrum-analyzer IF stages, and arbitrary-waveform-generator feedback paths, gain the MAX1225ETC+'s 1.5Msps SAR engine with 12-bit precision and true-differential inputs for noisy bus environments. Its SPI/QSPI/MICROWIRE-compatible serial interface eases integration with FPGA-based processing chains, and the internal +2.5V reference keeps the full-scale stable over -40C to +85C. The 12-TQFN (4x4) exposed-pad package improves thermal dissipation under continuous-duty calibration regimes.
Recommended
Thermocouple & Bridge Sensor Signal Chains
Thermocouple and strain-gauge bridge sensors deliver microvolt-class differential signals where the MAX1225ETC+ excels because of its true-differential input, low noise, and 12-bit resolution. With a low-noise pre-amp in front, the converter delivers 4096 counts of usable resolution and its 1.5Msps rate allows on-chip averaging to push effective resolution beyond 12 bits. The industrial-temperature grade, exposed-pad TQFN, and small footprint suit hazardous-area thermometer circuitry and high-density transducer conditioning modules.
Recommended
Recommended Products Summary
Engineering reference data for MAX1225ETC+ — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | MAX1225CTC+ | MAX1225CTC+T | MAX1224ETC+ | MAX1224CTC+ | MAX1179AEUI+ |
|---|---|---|---|---|---|---|
| Package | 12-TQFN (4x4) | 12-TQFN (4x4) - same | 12-TQFN (4x4) - same | 12-TQFN (4x4) - same | 12-TQFN (4x4) - same | 28-TSSOP - DIFFERENT |
| Brand | Maxim Integrated | Maxim Integrated | Maxim Integrated | Maxim Integrated | Maxim Integrated | Maxim Integrated |
| Resolution | 12-bit | 12-bit | 12-bit | 10-bit (-2 bits, ~17% reduction) | 10-bit (-2 bits, ~17% reduction) | 10-bit |
| Operating Temperature | -40C to +85C (industrial) | 0C to +70C (commercial) | 0C to +70C (commercial) | -40C to +85C (industrial) | 0C to +70C (commercial) | -40C to +85C (industrial) |
| Architecture | SAR | SAR | SAR | SAR | SAR | SAR |
| Analog Supply | 2.7V to 3.6V | 2.7V to 3.6V | 2.7V to 3.6V | 2.7V to 3.6V | 2.7V to 3.6V | 2.7V to 3.6V (per datasheet) |
| Digital Interface | SPI/QSPI/MICROWIRE | SPI/QSPI/MICROWIRE | SPI/QSPI/MICROWIRE | SPI/QSPI/MICROWIRE | SPI/QSPI/MICROWIRE | Parallel/serial (different) |
Key Differentiators
- Highest resolution in MAX1224/MAX1225 family at 1.5Msps (vs MAX1224ETC+)
- Industrial temperature grade (-40C to +85C) (vs MAX1225CTC+)
- Compact exposed-pad TQFN for thermal management (vs MAX1179AEUI+ (28-TSSOP))
Design Notes
Place a 0.1uF ceramic bypass directly at the VDD pin and at the DVDD pin, with a 10uF tantalum or ceramic bulk cap within a few millimetres of the analog supply. Keep the analog and digital grounds separated, joining them at one star point right under the exposed pad of the 12-TQFN. Route SCLK and DOUT as short as possible over a continuous ground plane to keep ringing below the serial-clock timing margin.
The analog inputs (AIN+, AIN-) are limited to VDD + 0.3V; transients from a switching current shunt or fast dv/dt edges must be clamped or RC-filtered to stay within 0V to VDD. According to datasheet absolute-maximum ratings, exposure to voltages above VDD + 0.3V permanently damages the device. Add series resistors (10-100 ohm) close to the ADC input if the source can swing beyond VDD (e.g., unfiltered motor windings).
Maintain a clean analog ground plane under the 12-TQFN exposed pad and avoid running digital traces through the same region. Place a small ferrite bead or inductor between DVDD and VDD if the digital supply is noisy. For high-precision applications, add a 0.1uF cap at the REF pin to filter the internal reference noise, keeping the analog input bandwidth to ~16MHz or lower to avoid aliased high-frequency noise.
Compliance Information
RoHS compliant per Maxim datasheet Pb-free ordering suffix '+'. The MAX1225ETC+ is industrial-grade, not AEC-Q100 qualified; automotive applications should consider the MAX1225ETC+T variant or screened equivalents.
