MAX1274BETC+ - 1.8Msps 12-Bit Differential SAR ADC | Maxim
MPN: MAX1274BETC+ ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $7.2 | $7.20 |
| 10 | $6.48 | $64.80 |
| 100 | $5.76 | $576.00 |
| 500 | $5.12 | $2,560.00 |
| 1,000 | $4.55 | $4,550.00 |
MAX1274BETC+ Overview
A SAR ADC is a successive-approximation-register analog-to-digital converter: it uses a binary search across an internal capacitive DAC to digitize the input in N clock cycles, where N equals the resolution in bits. SAR ADCs occupy the middle ground between flash converters (very fast but power-hungry) and delta-sigma ADCs (very high resolution but slow). The MAX1274BETC+ fits the high-speed, moderate-resolution node of that taxonomy: SAR ADC -> data converter -> data acquisition IC -> mixed-signal semiconductor.
Key features include a 1.8Msps maximum sampling rate, true-differential analog inputs for superior common-mode noise rejection, single +5V analog supply operation, an external reference input, and low power consumption suitable for portable and industrial applications. The TQFN-12 4x4 mm package exposes the thermal pad on the underside for low thermal resistance, and SPI/QSPI/MICROWIRE compatibility simplifies connection to most microcontrollers and DSPs.
Architecturally, the device uses a BiCMOS process combining bipolar precision with CMOS logic, a track-and-hold front-end, a successive-approximation register with a binary-weighted capacitor array, and a serial output engine. The differential topology rejects common-mode noise from motors, switching regulators, and long cable harnesses - a meaningful advantage over single-ended ADCs in industrial environments.
Typical applications include data acquisition front-ends, industrial process control, motor control current sensing, portable instrumentation, and medical monitoring where true-differential inputs simplify sensor bridge readout. The exposed thermal pad also makes the part suitable for higher-temperature industrial environments.
When designing with this ADC, keep the analog input bandwidth below the Nyquist limit (Fs/2 = 900kHz) and place the external reference decoupling capacitor close to the REF pin. The exposed pad must be soldered to the board ground plane for thermal and electrical performance; failing to solder the pad increases thermal resistance and can degrade ADC accuracy.
This page synthesizes distributor pricing, drop-in and package-compatible alternatives, and practical design notes that the bare datasheet does not present side-by-side.
Drop-in alternatives for MAX1274BETC+ — 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 MAX1274BETC+ (same form factor and footprint) — differing in Package, Resolution, Sampling Rate, Architecture, Data Interface.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
MAX1274BETC+T
✅ Drop-In✓ In Stock
$4.45 / Unit
View Datasheet →MAX1274AETC+
✅ Drop-In✓ In Stock
$4.42 / Unit
View Datasheet →MAX1275BETC+
✅ Drop-In📋 Reference alternative (not in catalog)
MAX1209ETL+TG3U
✅ Drop-In ⚠️ Specs Unverified✓ In Stock
$9.95 / Unit
View Datasheet →MAX1139MEEE+
✅ Drop-In ⚠️ Specs Unverified✓ In Stock
$3.95 / Unit
View Datasheet →MAX1274BETC+ Maximum Ratings & Electrical Characteristics
| Resolution | 12 bit |
| Sampling Rate | 1.8 Msps |
| Number of Channels | 1 |
| Input Type | True Differential |
| Architecture | SAR (Successive Approximation) |
| Data Interface | SPI / QSPI / MICROWIRE-compatible serial |
| Reference Type | External |
| Analog Supply Voltage | 5 V |
| Operating Temperature | -40C to +85C (industrial) |
| Package | 12-TQFN (4x4 mm) with exposed pad |
| Package Code | TQFN-12 (HVQCCN) |
| Mounting Type | Surface Mount |
| Process Technology | BiCMOS |
| RoHS Status | Compliant (lead-free, marked +) |
MAX1274BETC+ Pin Configuration
| Pin 1 | AIN+ — Positive differential analog input |
| Pin 2 | AIN- — Negative differential analog input |
| Pin 3 | REF — External voltage reference input |
| Pin 4 | GND — Analog ground |
| Pin 5 | AVDD — Analog +5V supply |
| Pin 6 | DVDD — Digital supply for SPI I/O |
| Pin 7 | CS — Active-low chip select (SPI) |
| Pin 8 | SCLK — Serial clock input (SPI) |
| Pin 9 | DOUT — Serial data output (SPI MISO) |
| Pin 10 | DIN — Serial data input (SPI MOSI) |
| Pin 11 | SHDN — Active-low shutdown (per datasheet convention) |
| Pin 12 | EP — Exposed pad - solder to PCB ground for thermal/electrical performance |
Typical Applications
MAX1274BETC+ is suitable for 6 applications: Data Acquisition Front-End, Motor Control Current Sensing, Industrial Process Control Instrumentation, Portable Instrumentation and Handheld Meters, Medical Monitoring Front-End, Sensor Signal Conditioning Modules.
Data Acquisition Front-End
The MAX1274BETC+ provides a 1.8 Msps true-differential 12-bit conversion channel that fits data-acquisition front-ends where a single high-speed analog input drives an FPGA or DSP through SPI. The differential topology rejects common-mode noise from switching power rails, while the small 4x4 mm TQFN footprint frees board space for analog signal conditioning. In a typical 4-layer PCB the ADC sits next to a low-noise LDO (e.g. MAX8887) feeding its 5V AVDD, with REF decoupled by 10 uF + 100 nF ceramics. Compared with a delta-sigma alternative of equivalent speed, the MAX1274BETC+ offers lower latency because SAR conversion is one cycle rather than oversampled.
Recommended
Motor Control Current Sensing
The MAX1274BETC+ is well-suited for digitizing shunt-resistor current in brushless DC and stepper motor drives. Its true-differential inputs reject the high dV/dt common-mode swings on the switching node, and 1.8 Msps is sufficient for current-loop sampling at 20-50 kHz PWM frequencies. The exposed thermal pad keeps the junction temperature low when sampling at full rate in an enclosed motor-drive enclosure. Designers typically pair it with an op-amp current amplifier (e.g. MAX4475) in front of the shunt and read conversion results through SPI from the motor-control MCU. Compared with onboard MCU ADCs the MAX1274BETC+ delivers 12 bits at 1.8 Msps with much lower sampling jitter.
Recommended
Industrial Process Control Instrumentation
In industrial 4-20 mA loop and process-control instrumentation the MAX1274BETC+ converts differential sensor signals (strain gauges, pressure transducers) at high speed into SPI words for an isolated MCU. Its industrial -40C to +85C temperature range matches process-control cabinet environments, and the external reference input allows ratiometric measurements against bridge excitation. The 12-bit resolution is sufficient for 0.1% full-scale setpoint control loops. Designers often pair it with a digital isolator (e.g. MAX14850) on the SPI bus so the MCU side operates on a floating ground plane.
Recommended
Portable Instrumentation and Handheld Meters
Portable handheld meters benefit from the MAX1274BETC+'s single 5V supply and low TQFN-12 (4x4 mm) PCB footprint. The exposed pad dissipates conversion heat into the handheld's ground plane while the SPI interface saves pins on the meter's microcontroller. A typical implementation pairs it with a low-power Cortex-M0 MCU and a Li-ion battery management IC; the ADC samples sensor signals only on demand so the average current stays low. Compared with built-in MCU ADCs the MAX1274BETC+ adds true-differential inputs that cancel ground bounce from the meter's boost converter.
Recommended
Medical Monitoring Front-End
Medical monitoring equipment such as pulse oximeters and ECG front-ends use the MAX1274BETC+ to digitize low-level differential biosignals. True-differential inputs reject 50/60 Hz mains common-mode noise that would otherwise saturate single-ended ADCs, and the SPI output simplifies digital isolation for patient-safety designs. With 1.8 Msps the ADC can oversample pulse waveforms at >10x for digital filtering. The exposed pad helps the device tolerate the higher ambient inside an enclosure. Designers should add ESD protection on the analog input lines (e.g. MAX3207) to meet IEC 61000-4-2 contact-discharge specifications for medical electrical equipment.
Recommended
Sensor Signal Conditioning Modules
Multi-sensor signal conditioning modules use the MAX1274BETC+ as a high-speed digitizer for strain, pressure, or load-cell sensor bridges where a single channel runs at high speed. True-differential inputs cancel ground-shift between sensor and conditioner, and the external reference supports ratiometric measurement against bridge excitation. The 12-TQFN (4x4 mm) package simplifies compact DIN-rail-mount module designs. In a typical load-cell module the bridge is excited by a low-noise reference (MAX6126) and the ADC digitizes the differential bridge output at 1.8 Msps through an instrumentation front-end (MAX4194).
Recommended
Recommended Products Summary
Engineering reference data for MAX1274BETC+ — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | MAX1274BETC+T | MAX1274AETC+ | MAX1275BETC+ | MAX1209ETL+TG3U |
|---|---|---|---|---|---|
| Brand | Analog Devices / Maxim Integrated | Analog Devices / Maxim Integrated - same brand | Analog Devices / Maxim Integrated - same brand | Analog Devices / Maxim Integrated - same brand | Analog Devices / Maxim Integrated - same brand |
| Package | 12-TQFN (4x4 mm) | 12-TQFN (4x4 mm) - same | 12-TQFN (4x4 mm) - same | 12-TQFN (4x4 mm) - same | 40-TQFN (5x5 mm) - DIFFERENT |
| Resolution | 12 bit | 12 bit | 12 bit | 12 bit | 14 bit |
| Number of Channels | 1 (differential) | 1 (differential) | 1 (differential) | Multi-channel | Multi-channel |
| Input Type | True Differential | True Differential | True Differential | True Differential / Single-ended | Single-ended |
| Reference Type | External | External | External | External | External |
| Architecture | SAR | SAR | SAR | SAR | SAR |
| Supply Voltage | 5 V | 5 V | 5 V | 5 V | 5 V |
| Interface | SPI / QSPI / MICROWIRE | SPI / QSPI / MICROWIRE | SPI / QSPI / MICROWIRE | SPI / QSPI / MICROWIRE | SPI |
Key Differentiators
- True-differential input on a single 12-TQFN channel (vs MAX1270BENG)
- 1.8 Msps in 4x4 mm TQFN (vs MAX12528ETK+)
- External reference for ratiometric bridge measurement (vs MAX1139MEEE+)
Design Notes
Decouple the AVDD and DVDD pins with both a 100 nF and a 10 uF ceramic capacitor placed within 3 mm of the IC pins. Use a low-noise 5V LDO (e.g. MAX8887) to feed AVDD from the system 5V rail to keep switching-converter ripple out of the ADC reference chain. DVDD can be tied to AVDD for short traces or driven from a separate 3.3V rail with a series ferrite if the SPI host runs on 3.3V logic levels.
Route the analog differential input traces as a tightly coupled pair (matched length, ground-guarded) to preserve the common-mode rejection the MAX1274BETC+ ADC was designed for. The exposed thermal pad on pin 12 must be soldered to the analog ground plane with at least 8 thermal vias for heat dissipation; failing to solder the EP increases junction-to-ambient thermal resistance and degrades linearity at full 1.8 Msps.
Estimated: with a 1.8 Msps sample clock the input bandwidth must stay below 900 kHz (Nyquist) to avoid aliasing. Add an anti-alias RC filter (typically 1 kohm + 330 pF, fc ~= 480 kHz) between the input driver op-amp and the AIN+/AIN- pins. Drive the inputs with a low-output-impedance op-amp (e.g. MAX4475) so the ADC input S/H settles within the acquisition time specified in the datasheet.
Do not let the REF pin float - without an external reference the ADC output code is undefined. Use a low-drift, low-noise 4.096V reference (e.g. MAX6126) for full 12-bit accuracy. Also avoid sampling the analog input before the AVDD rail reaches 4.75V - the datasheet specifies that conversion results are only valid after power-on reset completes, typically 1 ms after the supply settles.
Compliance Information
RoHS compliant per Maxim Integrated product marking (+ suffix indicates lead-free). Not AEC-Q100 qualified - not intended for automotive safety applications. Halogen-free status not stated in available datasheet excerpts.
