MAX144BEUA - 12-Bit 108ksps 2-Ch Serial ADC | Maxim
MPN: MAX144BEUA ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $6.18 | $6.18 |
| 10 | $5.42 | $54.20 |
| 100 | $4.55 | $455.00 |
| 500 | $3.79 | $1,895.00 |
| 1,000 | $3.21 | $3,210.00 |
MAX144BEUA Overview
A SAR ADC (successive-approximation-register analog-to-digital converter) is a type of data converter that uses a binary-search algorithm against an internal DAC to resolve one bit per clock cycle. SAR ADCs occupy the middle ground between flash converters (fast but power-hungry, large) and sigma-delta ADCs (high resolution but lower speed, requires filtering). They are favored for multiplexed multi-channel data acquisition, sensor front-ends, and portable instrumentation where deterministic latency, low latency, low power, and small packages are simultaneously required.
Key features of the MAX144BEUA include 2 single-ended analog input channels (AIN1, AIN2), an external reference input (REF), a low 1.6 mA typical supply current at 108 ksps, automatic power-down to < 1 µA between conversions, and the 8-pin µMAX (uSOP) footprint that saves board area versus 8-pin SOIC. The serial interface is compatible with SPI, QSPI, and MICROWIRE devices, simplifying connections to most microcontrollers and DSPs.
The MAX144 family uses a charge-distribution DAC architecture combined with an on-chip clock and sample-and-hold, achieving ±1 LSB INL and DNL with no missing codes at 12 bits. Power-down is automatic at the end of each conversion, dropping the supply current to < 1 µA - critical for battery-powered applications that need long run-time. The fast 2.5 µs wake-up allows high throughput without duty-cycling penalty in burst-mode sampling.
Typical applications include portable data logging, handheld multimeters and test instruments, battery-powered sensor readouts, industrial process control front ends, and medical instruments such as glucose meters and patient monitors. Two single-ended channels make the part especially suited to dual-sensor measurement (e.g., temperature + pressure, or two thermocouples).
When designing with the MAX144BEUA, place the 0.1 µF supply bypass capacitor as close as possible to VDD and use a low-impedance external reference (such as MAX6126 or MAX6160) to maximize SNR. The serial interface is read-only on the MAX144 - host software must provide SCLK and read DOUT within the conversion window; consult the datasheet timing diagram before wiring to a busy SPI bus.
This page synthesizes distributor pricing, drop-in and same-family alternatives from Maxim Integrated's MAX14x portfolio, and practical design notes not collected in the manufacturer datasheet alone.
Drop-in alternatives for MAX144BEUA — 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 MAX144BEUA (same form factor and footprint) — differing in Package, Conversion Time, Number of Channels, RoHS Status, INL (max).
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
MAX144AEUA+
✅ Drop-In📋 Reference alternative (not in catalog)
MAX144BEUA+
✅ Drop-In📋 Reference alternative (not in catalog)
MAX144BEUA+T
✅ Drop-In📋 Reference alternative (not in catalog)
MAX145BEUA+
✅ Drop-In📋 Reference alternative (not in catalog)
MAX144BEUA Maximum Ratings & Electrical Characteristics
| Resolution | 12 bits |
| Number of Channels | 2 single-ended |
| Sampling Rate | 108 ksps |
| Conversion Architecture | SAR (Successive Approximation) |
| Supply Voltage (Analog/Digital) | +2.7 V to +5.25 V |
| Supply Current (108 ksps) | 1.6 mA typ |
| Supply Current (Power-Down) | < 1 µA |
| Wake-Up Time | 2.5 µs |
| Conversion Time | 7.4 µs |
| INL (max) | ±1 LSB |
| DNL (max) | ±1 LSB (no missing codes) |
| Reference Input | External (REF pin) |
| Serial Interface | SPI / MICROWIRE / QSPI-compatible, 3-wire |
| Operating Temperature (B grade) | -40 °C to +85 °C |
| Package | 8-pin µMAX / uSOP (TSSOP-compatible 3.00 mm body) |
| RoHS Status | Compliant |
| Lead-Free | Yes |
MAX144BEUA Pin Configuration
| Pin 1 | AIN1 — Analog Input 1 (single-ended) |
| Pin 2 | AIN2 — Analog Input 2 (single-ended) |
| Pin 3 | REF — External Reference Input |
| Pin 4 | AGND — Analog Ground |
| Pin 5 | SCLK — Serial Clock Input |
| Pin 6 | DOUT — Serial Data Output |
| Pin 7 | CS — Chip Select (active low) |
| Pin 8 | VDD — Supply Voltage (+2.7 V to +5.25 V) |
Typical Applications
MAX144BEUA is suitable for 7 applications: Portable Data Loggers, Handheld Multimeters and Test Instruments, Industrial Process Control Front Ends, Battery-Powered Sensor Readout, Medical Instruments (Glucose Meters, Patient Monitors), Solar/Battery Charger Monitoring, HVAC Sensor Readout.
Portable Data Loggers
The MAX144BEUA's 108 ksps throughput and 1.6 mA active current make it a strong fit for portable data loggers capturing two sensor channels at moderate rates. Two single-ended inputs (AIN1/AIN2) cover common sensor pairs such as temperature + humidity probes, and the automatic power-down dropping to < 1 µA between conversions extends battery life by orders of magnitude. In a typical 2-channel battery logger running at 1 ksps/channel, average supply current falls below 200 µA. Place a 0.1 µF bypass on VDD and use a low-noise external reference such as MAX6126A to maximize SNR.
Recommended
Handheld Multimeters and Test Instruments
Handheld DMMs and bench DMMs benefit from the MAX144BEUA's -40 °C to +85 °C industrial temperature range, 12-bit resolution (sufficient for 4000-count display), and µMAX package that drops onto compact instrument PCBs. The 2-channel input handles voltage and current sense paths switched via an external mux or relays. Combined with the MAX6143 high-precision reference and MAX4475 op-amp front end, a designer can build a complete 2-channel ADC subsystem in less than 1 cm². Automatic power-down preserves battery life in the field.
Recommended
Industrial Process Control Front Ends
The MAX144BEUA fits industrial 4-20 mA loop and 0-10 V process control front ends where 12-bit resolution meets the typical 0.1% setpoint accuracy requirement. The two channels allow simultaneous or multiplexed reading of two process variables (e.g., pressure and temperature) at the same node. The industrial temperature range supports factory-floor deployment, and the SPI-compatible interface connects directly to industrial PLC/MCU backplanes. Pair with MAX31855 thermocouple-to-digital companion (when thermocouple inputs are needed) or MAX31865 RTD-to-digital for adjacent sensor chains.
Recommended
Battery-Powered Sensor Readout
For battery-powered sensor readouts such as wireless environmental sensor nodes, the MAX144BEUA's < 1 µA power-down current and 2.5 µs wake-up time enable aggressive duty cycling that extends coin-cell battery life into years. Two single-ended channels handle the most common sensor pairing of temperature + humidity or temperature + pressure. The 108 ksps headroom also allows short oversampling bursts for averaging to improve effective resolution beyond the 12-bit native resolution. A complete wireless sensor node pairs this ADC with MAX1472/MAX1479 RF transmitters or low-power BLE SoCs.
Recommended
Medical Instruments (Glucose Meters, Patient Monitors)
The MAX144BEUA's low power consumption and small µMAX package suit battery-powered medical instruments such as glucose meters, pulse oximeter front ends, and portable patient monitors where board area is at a premium. The 12-bit resolution is sufficient for the analog front-end signals from electrochemical test strips or photodiode current-to-voltage converter outputs. The industrial temperature range allows instruments to be used in ambulances and clinical environments. Combined with the MAX4475 low-noise op-amp and a low-leakage analog mux, designers build a compact, low-power 2-channel acquisition chain.
Recommended
Solar/Battery Charger Monitoring
In solar charge controllers and battery management systems, the MAX144BEUA measures panel voltage and battery voltage simultaneously using its two single-ended inputs, providing closed-loop feedback to the charge controller MCU. The wide +2.7 V to +5.25 V supply matches directly to single-cell Li-ion or 3.3 V/5 V regulated rails without level shifting. Automatic power-down allows the MCU to disable the ADC between measurements, reducing quiescent draw on the battery. The MAX144BEUA's accuracy is sufficient for state-of-charge calculations when paired with coulomb-counter ICs such as MAX17201G+.
Recommended
HVAC Sensor Readout
Building automation and HVAC systems use the MAX144BEUA to digitize temperature and humidity sensor outputs with two channels of single-ended analog input. The industrial temperature range allows mounting near the air-handling unit, and the small µMAX package fits inside compact sensor housings. The SPI/MICROWIRE interface connects to standard HVAC controller MCUs without protocol glue logic. Combined with the MAX31865 RTD frontend or a 4-20 mA loop receiver built from MAX4475, designers cover most commercial HVAC sensor needs at low BOM cost.
Recommended
Recommended Products Summary
Engineering reference data for MAX144BEUA — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | MAX144AEUA+ | MAX144BEUA+ | MAX144BEUA+T | MAX145BEUA+ | MAX1270BENG+ |
|---|---|---|---|---|---|---|
| Brand | Analog Devices | Analog Devices | Analog Devices | Analog Devices | Analog Devices | Analog Devices |
| Package | 8-pin µMAX (uSOP) | 8-pin µMAX - same | 8-pin µMAX - same | 8-pin µMAX - same | 8-pin µMAX - same | 24-pin DIP - different |
| Resolution | 12 bits | 12 bits | 12 bits | 12 bits | 12 bits | 12 bits |
| Sampling Rate | 108 ksps | 108 ksps | 108 ksps | 108 ksps | 108 ksps | 200 ksps |
| Channels | 2 single-ended | 2 single-ended | 2 single-ended | 2 single-ended | 4 single-ended | 8 single-ended |
| Operating Temperature | -40 °C to +85 °C (B grade) | 0 °C to +70 °C (A grade) | -40 °C to +85 °C (B grade) | -40 °C to +85 °C (B grade) | -40 °C to +85 °C (B grade) | -40 °C to +85 °C (B grade) |
| Supply Voltage | +2.7 V to +5.25 V | +2.7 V to +5.25 V | +2.7 V to +5.25 V | +2.7 V to +5.25 V | +2.7 V to +5.25 V | +4.5 V to +5.5 V |
| Supply Current (Active) | 1.6 mA | 1.6 mA | 1.6 mA | 1.6 mA | 1.6 mA | 3.0 mA |
| Interface | SPI / MICROWIRE 3-wire | SPI / MICROWIRE 3-wire | SPI / MICROWIRE 3-wire | SPI / MICROWIRE 3-wire | SPI / MICROWIRE 3-wire | SPI / QSPI / MICROWIRE |
| Reference | External | External | External | External | Internal 4.096 V | Internal/External software-switchable |
Key Differentiators
- Industrial temperature range with full electrical compatibility to commercial-temp MAX144AEUA (vs MAX144AEUA+)
- Best-in-class low active current for a 108 ksps 12-bit SAR ADC (vs MAX1270BENG+ (8-channel 200 ksps))
- Compact 8-pin µMAX package with full SPI/MICROWIRE compatibility (vs MAX1270BENG+ in 24-pin DIP)
Design Notes
Place a 0.1 µF X7R or C0G ceramic bypass capacitor within 5 mm of the VDD pin and connect its ground side directly to the AGND pin with a short trace or via. For wide-band noise rejection, add a 10 µF tantalum or ceramic bulk capacitor on the same VDD rail near the part. The MAX144BEUA draws 1.6 mA at 108 ksps and < 1 µA in power-down, so the bulk capacitor must be sized to supply the inrush current when the part wakes up (2.5 µs); a 10 µF bulk cap handles a single-conversion burst without significant droop.
Estimated: when driving the MAX144BEUA from a busy SPI bus shared with other peripherals, ensure the host MCU releases SCLK high between conversions and does not leave it toggling. Continuous SCLK activity can wake the part from power-down and increase average supply current by orders of magnitude. Also, the MAX144's DOUT is read-only (no daisy-chain input), so multiple MAX144s on one bus each require their own CS line - they cannot share SCLK and DOUT simultaneously. Verify the MCU's SPI mode (CPOL/CPHA) matches the MAX144's Mode 0 (CPOL=0, CPHA=0) per the datasheet timing diagram.
Route the analog input traces (AIN1, AIN2, REF) as short, guarded differential pairs to minimize coupling from digital lines (SCLK, DOUT, CS). Keep the digital bus on the opposite side of the µMAX package from the analog inputs, and use a ground plane stitched with vias around the analog section to form a Faraday cage. For best SNR performance at 108 ksps, ensure the analog ground pin (pin 4) ties to the same ground plane as the host MCU's analog ground, not the digital ground plane.
The MAX144BEUA requires a low-impedance, low-noise external reference to achieve full 12-bit performance. A series resistor between the reference source and REF pin (a few ohms) can be added to isolate reference noise, but if added, must be bypassed with a 0.1 µF cap close to the REF pin. Reference ICs such as MAX6126 (2.5 V) or MAX6143 (3.3 V) are recommended companions; do not use the host MCU's supply rail directly as a reference for ADC work above 10 ksps.
Compliance Information
RoHS-compliant MAX144BEUA+ variant is the recommended order code for new designs. The legacy MAX144BEUA (without +) may not be fully RoHS-compliant; check manufacturer documentation before placing into RoHS-restricted markets.
