MAX1279AETC+ - 12-Bit 1.5Msps Differential ADC | Analog Devices
MPN: MAX1279AETC+ ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $6.4 | $6.40 |
| 10 | $5.76 | $57.60 |
| 100 | $4.96 | $496.00 |
| 500 | $4.32 | $2,160.00 |
| 1,000 | $3.92 | $3,920.00 |
MAX1279AETC+ Overview
What is a successive-approximation ADC? An SAR (Successive Approximation Register) ADC is a sampled-data converter that uses an internal binary-search algorithm combined with an internal DAC to digitize an analog input. SAR ADCs typically offer an excellent balance of speed (hundreds of kSps to a few Msps), resolution (10-18 bits), latency (typically one conversion cycle), and power consumption (single-digit mA), placing them in the converter hierarchy between high-speed flash ADCs and high-resolution delta-sigma ADCs.
Key features of the MAX1279AETC+ include a true-differential analog input path that improves common-mode noise rejection, an internal 2.5V precision reference (eliminating an external component), a high-speed SPI/QSPI/MICROWIRE-compatible serial interface, and hardware- or software-controlled shutdown that reduces supply current to a few microamps between conversions. The MAX1277 (225 ksps) and MAX1279 (1.5 Msps) are pin-compatible family members sharing the same 12-pin TQFN footprint.
Internally, the MAX1279AETC+ uses a charge-distribution DAC and a high-bandwidth track-and-hold to digitize true-differential inputs in a single conversion cycle. The true-differential input structure rejects common-mode noise from the signal source and the PCB ground, which is critical in motor-control and industrial-sensor applications where ground loops and large common-mode transients are common.
Typical applications include data acquisition systems, motor control current sensing, industrial process control, weigh scales, and portable instrumentation. The combination of single-supply operation, internal reference, true-differential input, and low power dissipation makes the MAX1279AETC+ particularly attractive for battery-powered or loop-powered industrial sensor front-ends.
Design consideration: place the 0.1 µF and 10 µF bypass capacitors as close as possible to the AVDD pin with a short, wide trace, and route the differential input traces symmetrically with a solid ground plane beneath them. Decouple the digital DVDD from AVDD with a ferrite bead to prevent digital switching noise from coupling into the analog front-end.
This page synthesizes distributor pricing, drop-in compatible same-package alternatives from the MAX1277/MAX1279 family, and practical layout/design notes that complement (rather than duplicate) the manufacturer datasheet.
Drop-in alternatives for MAX1279AETC+ — 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 MAX1279AETC+ (same form factor and footprint) — differing in Analog Input Type, Digital Supply Voltage (DVDD), Internal Reference Voltage, Resolution.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
MAX1277AETC+
✅ Drop-In📋 Reference alternative (not in catalog)
MAX1279AETC+T
✅ Drop-In📋 Reference alternative (not in catalog)
MAX1279ACTC+
✅ Drop-In📋 Reference alternative (not in catalog)
MAX1275AETC+
✅ Drop-In📋 Reference alternative (not in catalog)
MAX1079CTC+
✅ Drop-In✓ In Stock
$4.78 / Unit
View Datasheet →MAX1279AETC+ Maximum Ratings & Electrical Characteristics
| Resolution | 12 bits |
| Sampling Rate | 1.5 Msps |
| Number of Channels | 1 (true-differential) |
| Supply Voltage (AVDD) | 3 V to 3.6 V |
| Digital Supply Voltage (DVDD) | 1.8 V to AVDD |
| Analog Input Type | True differential (unipolar) |
| Input Range (Unipolar, +VREF) | 0 V to +VREF (2.5 V typ.) |
| Internal Reference Voltage | 2.5 V |
| Interface | SPI/QSPI/MICROWIRE-compatible serial |
| Operating Temperature Range | -40 C to +85 C (industrial) |
| Package | 12-pin TQFN (HVQCCN), 4x4 mm |
| Mounting Type | Surface Mount |
| RoHS Status | Compliant |
MAX1279AETC+ Pin Configuration
| Pin 1 | AVDD — Analog supply voltage (+3.0V to +3.6V) |
| Pin 2 | AIN+ — Positive true-differential analog input |
| Pin 3 | AIN- — Negative true-differential analog input |
| Pin 4 | GND — Ground (analog and digital common) |
| Pin 5 | REF — Internal 2.5V reference output / external reference input (bypass with capacitor) |
| Pin 6 | SHDN — Shutdown input (active low, tie high for normal operation) |
| Pin 7 | CS — Active-low chip-select input for SPI interface |
| Pin 8 | SCLK — Serial clock input (SPI/QSPI/MICROWIRE-compatible) |
| Pin 9 | DOUT — Serial data output (ADC conversion result) |
| Pin 10 | DVDD — Digital supply voltage (1.8V to AVDD) |
| Pin 11 | DGND — Digital ground (tied to GND on PCB) |
| Pin 12 | EP — Exposed thermal pad (must be soldered to GND plane for thermal and electrical performance) |
Typical Applications
MAX1279AETC+ is suitable for 6 applications: Industrial Data Acquisition Systems, Motor Control Current Sensing, Portable Instrumentation and Handheld Test Equipment, Weigh Scales and Force Measurement, Medical Patient Monitoring Sensors, Communications Infrastructure (RF Power Amplifier Monitoring).
Industrial Data Acquisition Systems
The MAX1279AETC+ is well suited as the main ADC in a multi-channel industrial data-acquisition front-end. Its 1.5 Msps throughput digitizes fast-changing signals from strain gauges, RTDs, and 4-20 mA current-loop transmitters in process-control applications. The true-differential input rejects common-mode ground noise typical of long sensor cables, and the integrated 2.5V reference eliminates one external component, simplifying the BOM. Compared with an FPGA-integrated ADC, the MAX1279AETC+ offers better INL/DNL performance at this speed.
Recommended
Motor Control Current Sensing
In three-phase brushless DC (BLDC) and field-oriented control (FOC) motor drives, phase currents must be sampled at 10-20 kHz per channel. The MAX1279AETC+ supports simultaneous sampling of two phase currents through its true-differential inputs and 1.5 Msps throughput gives ample headroom for oversampling and digital filtering. The single-supply 3.3V operation matches typical MCU and DSP power rails, removing the need for a negative rail in the current-sense amplifier path.
Recommended
Portable Instrumentation and Handheld Test Equipment
For battery-powered oscilloscope probes, multimeters, and portable spectrum analyzers, the MAX1279AETC+ delivers 1.5 Msps conversion at moderate supply current, extending battery runtime. Its hardware shutdown pin reduces quiescent current to a few microamps in standby - essential for handheld equipment that spends most of its life in sleep mode. The 12-pin TQFN 4x4 mm footprint fits easily inside sealed probe housings.
Recommended
Weigh Scales and Force Measurement
Load-cell and weigh-scale applications need 12-16 bits of resolution with low-noise differential amplification of millivolt-level bridge signals. The MAX1279AETC+ pairs naturally with a low-noise instrumentation amplifier such as the MAX1165, digitizing the amplified differential bridge output with its true-differential input path and internal reference. This combination provides a compact, low-BOM solution for industrial weighing platforms.
Recommended
Medical Patient Monitoring Sensors
Patient-side vital-sign monitors (pulse oximetry, ECG, temperature) require low-power 12-bit ADCs that can digitize differential biosensor signals with high common-mode rejection. The MAX1279AETC+ true-differential inputs naturally reject DC offset from electrode half-cell potentials, and its single-supply +3.3V operation simplifies battery-powered medical device designs. Verify isolation and medical-grade (IEC 60601-1) certifications separately with the system integrator.
Recommended
Communications Infrastructure (RF Power Amplifier Monitoring)
In cellular base-station and small-cell RF power amplifiers, the PA forward/reflected power must be sampled at high speed for closed-loop gain control and VSWR protection. The MAX1279AETC+ digitizes the directional-coupler outputs with sufficient throughput for envelope tracking and DPD (digital pre-distortion) feedback loops. Its small 12-pin TQFN footprint fits beside the PA on densely populated RF modules.
Recommended
Recommended Products Summary
Engineering reference data for MAX1279AETC+ — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | MAX1277AETC+ | MAX1279AETC+T | MAX1279ACTC+ | MAX1275AETC+ | MAX1079CTC+ |
|---|---|---|---|---|---|---|
| Package | TQFN-12 (4x4 mm) | TQFN-12 (4x4 mm) - same | TQFN-12 (4x4 mm) - same | TQFN-12 (4x4 mm) - same | TQFN-12 (4x4 mm) - same | TQFN-12 (4x4 mm) - same |
| Brand | Analog Devices (formerly Maxim Integrated) | Analog Devices - same | Analog Devices - same | Analog Devices - same | Analog Devices - same | Analog Devices - same |
| Resolution | 12 bits | 12 bits | 12 bits | 12 bits | 12 bits | 12 bits |
| Supply Voltage | 3.0V to 3.6V | 3.0V to 3.6V | 3.0V to 3.6V | 3.0V to 3.6V | 3.0V to 3.6V | 2.7V to 3.6V |
| Input Type | True differential | True differential | True differential | True differential | True differential | Pseudo-differential |
| Internal Reference | 2.5V | 2.5V | 2.5V | 2.5V | 2.5V | External only |
| Operating Temperature | -40C to +85C (industrial) | -40C to +85C | -40C to +85C | 0C to +70C (commercial) | -40C to +85C | -40C to +85C |
Key Differentiators
- True-differential input vs pseudo-differential alternatives (vs MAX1079CTC+)
- Industrial -40C to +85C temperature range standard (vs MAX1279ACTC+)
- 5x faster throughput than the slowest family member (vs MAX1277AETC+)
Design Notes
Place the 0.1 µF high-frequency ceramic bypass and the 10 µF tantalum/ceramic bulk capacitor within 2-3 mm of the AVDD pin (pin 1), connected with short, wide traces to a low-impedance ground plane. Decouple DVDD (pin 10) with a separate 0.1 µF capacitor and connect DGND (pin 11) directly to the GND plane; do not daisy-chain digital and analog grounds. The exposed thermal pad (pin 12/EP) must be soldered to the GND plane for both thermal dissipation and electrical performance - skipping this reduces measurement integrity and risks overheating at full-speed conversion.
Route the AIN+ and AIN- differential analog traces symmetrically with matched length and width, keeping them parallel and on a continuous ground plane. Avoid routing digital SPI traces (SCLK, DOUT, CS) directly over or under the analog input traces to minimize capacitive coupling and noise pickup. If the input source is single-ended, drive AIN- through a bypass capacitor to ground near the IC while driving AIN+ with the active signal to preserve the common-mode rejection of the true-differential front-end.
Estimated: at maximum 1.5 Msps throughput and 3.6V AVDD, the MAX1279AETC+ typically draws a few mA. With a 3.3V supply and conservative 5 mA IDD, total dissipation is approximately 16.5 mW - well within the TQFN-12 thermal envelope. Ensure the reference bypass capacitor on the REF pin (typically 1 µF to GND) is placed within 2 mm of the pin to minimize reference noise and reference-bounce-induced conversion errors.
Do not leave the SHDN pin floating - tie it high via a 100 kohm pull-up resistor (or directly to AVDD) for normal operation; a floating SHDN pin can randomly latch the part into shutdown mode and produce no DOUT transitions. Verify that the SPI SCLK frequency does not exceed the MAX1279AETC+ maximum rating during MCU initialization - some bootloaders default to fast SPI modes that violate ADC timing. Confirm the REF capacitor is fully discharged before issuing a calibration or conversion-start command to avoid AVDD transient dip.
Compliance Information
RoHS and lead-free per Maxim/Analog Devices product page. Not AEC-Q100 qualified (this is a precision analog converter IC, not an automotive-grade MCU). Industrial -40C to +85C temperature range standard; AEC-Q100 qualified options from Maxim/ADI exist in higher-grade ADC families but not in this exact 12-pin TQFN form factor.
