MAX145AEUA - 12-Bit 108ksps 2-Ch Serial ADC | Maxim Integrated
MPN: MAX145AEUA ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $9.88 | $9.88 |
| 10 | $8.92 | $89.20 |
| 100 | $7.45 | $745.00 |
| 500 | $6.2 | $3,100.00 |
| 1,000 | $5.49 | $5,490.00 |
MAX145AEUA Overview
An SAR ADC is a type of analog-to-digital converter that uses a successive-approximation register to compare the input voltage against a precision DAC, bit-by-bit, achieving conversion in a fixed number of clock cycles. SAR ADCs occupy a niche between flash ADCs (fast, low resolution, high power) and sigma-delta ADCs (high resolution, slow). The MAX145 belongs to the broader data-converter IC family, itself a subset of signal-chain semiconductors that include amplifiers, filters, and references. Its low 3.2 mW power consumption at VDD = +3.6V makes it well-suited to battery-powered and portable designs.
The MAX145AEUA's -A temperature grade extends the operating range from -40°C to +85°C, suiting industrial environments. It supports a 7.4 µs successive-approximation ADC core, automatic power-down between conversions to save energy, and a fast 2.5 µs wake-up time that keeps average current low in multiplexed, multi-channel scans. The internal 4.096V or external reference option (chosen by the REF pin) gives designers flexibility between absolute accuracy and ratiometric measurement.
Architecturally, the part combines a switched-capacitor input track-and-hold, an internal clock generator, and a precision comparator under SAR control. The pseudo-differential input configuration rejects common-mode noise and is especially useful when reading signals referenced to a non-ground midpoint, such as bridge sensors, thermistors, or battery-stack mid-points. The MAX145AEUA differs from the pin-compatible MAX144 only by analog input topology: MAX144 is single-ended, while MAX145 is pseudo-differential.
Typical applications include portable data logging, hand-held instrumentation, battery-powered sensors, isolated industrial monitoring with 4-20 mA loops, and digital panel meters. Designers favor the MAX145AEUA when they need true 12-bit accuracy on a tiny µMAX footprint, an easily-driven serial interface, and standby currents low enough to leave the ADC in-circuit all the time.
A key design consideration is supply bypassing: place a 0.1 µF ceramic capacitor as close as possible to the VDD pin, plus a 4.7 µF tantalum or larger ceramic cap on the same node, to suppress digital switching noise. The reference pin must be bypassed with at least 0.1 µF, and a 10 µF cap stabilizes the reference when using the internal 4.096V source. Trace lengths from CNVST, SCLK, and DOUT should be kept short, and the AGND pin must tie directly to a low-impedance ground plane to avoid digital-coupling errors.
This page synthesizes distributor pricing, drop-in alternatives, and practical design notes not found in the manufacturer datasheet.
Drop-in alternatives for MAX145AEUA — 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 MAX145AEUA (same form factor and footprint) — differing in Conversion Time, Package, Reference Input, RoHS Status, Supply Voltage (VDD).
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
MAX145BEUA
✅ Drop-In✓ In Stock
$5.92 / Unit
View Datasheet →MAX145BEUA+T
✅ Drop-In📋 Reference alternative (not in catalog)
MAX145AEUA+T
✅ Drop-In📋 Reference alternative (not in catalog)
MAX145ACUA
✅ Drop-In✓ In Stock
$5.1 / Unit
View Datasheet →MAX144BEUA
✅ Drop-In✓ In Stock
$3.21 / Unit
View Datasheet →MAX145AEUA Maximum Ratings & Electrical Characteristics
| Resolution | 12 bits |
| Number of Analog Input Channels | 2 (pseudo-differential) |
| Conversion Rate | 108 ksps |
| Conversion Time | 7.4 µs (successive-approximation) |
| Supply Voltage (VDD) | +2.7 V to +5.25 V |
| Supply Current at VDD=+3.6 V (typ. power-down) | 3.2 mW total |
| Wake-Up Time from Power-Down | 2.5 µs |
| Digital Interface | 3-wire SPI/QSPI/MICROWIRE-compatible serial |
| Reference Voltage | Internal 4.096 V or external (REF pin) |
| Input Configuration | Pseudo-differential (vs MAX144 single-ended) |
| Operating Temperature Range | -40°C to +85°C (-A grade) |
| Package | 8-pin µMAX / uSOP (3.00 mm) |
| On-Chip Clock | Yes (internal conversion clock) |
| Automatic Power-Down | Yes (between conversions) |
| Mounting Type | Surface Mount |
| MSL Level | 1 (per JESD22-A113) |
| RoHS Status | Compliant |
MAX145AEUA Pin Configuration
| Pin 1 | VDD — Supply voltage (+2.7V to +5.25V); bypass with 0.1µF + 4.7µF capacitor |
| Pin 2 | AIN+ — Positive analog input (pseudo-differential) |
| Pin 3 | AIN- — Negative analog input (pseudo-differential reference) |
| Pin 4 | GND — Analog ground; tie to low-impedance ground plane |
| Pin 5 | REF — Reference voltage input/output; bypass with 0.1µF + 10µF |
| Pin 6 | DOUT — Serial data output; high-Z when not selected |
| Pin 7 | SCLK — Serial clock input |
| Pin 8 | CNVST — Convert-start input (active low); initiates SAR conversion |
Typical Applications
MAX145AEUA is suitable for 6 applications: Portable Battery Data Loggers, Hand-Held Digital Multimeters, Industrial 4-20 mA Loop Monitoring, Isolated Sensor Signal Conditioning, Medical Point-of-Care Diagnostics, Automotive Sensor Reading (Non-Safety).
Portable Battery Data Loggers
The MAX145AEUA suits portable, battery-powered data loggers because of its 3.2 mW typical power draw at VDD = +3.6 V during continuous 108 ksps operation, dropping below 1 µA in auto power-down between samples. Its pseudo-differential input rejects ground-bounce noise common in single-cell Li-ion systems where the cell-stack midpoint must be measured against AGND. The 7.4 µs conversion supports 100+ Hz sample rates that capture environmental variables - temperature, humidity, strain - while waking only briefly to capture each reading. Compared with sigma-delta ADCs the MAX145 gives faster wake-to-result time, while the 3-wire SPI draws only a few µA from the host MCU, preserving battery life.
Recommended
Hand-Held Digital Multimeters
Hand-held digital multimeters (DMMs) and 4-digit panel meters benefit from the MAX145AEUA's 12-bit resolution (4096 codes), 108 ksps throughput, and tiny 8-pin µMAX footprint. The pseudo-differential input is ideal for measuring voltages that do not sit exactly at ground, such as the negative terminal of an isolated current shunt or the low side of a half-bridge. Built-in reference stabilization through the 4.096 V internal source eases calibration, while the 3-wire SPI display interface maps neatly to a PIC or STM32 host controlling the LCD readout. Compared with dedicated meter ICs the MAX145 lets the designer add custom ranges and filters without a full redesign.
Recommended
Industrial 4-20 mA Loop Monitoring
The MAX145AEUA fits 4-20 mA current-loop receiver boards in industrial plants because its pseudo-differential input rejects the common-mode voltage that the loop can develop on long cable runs. The +2.7 V to +5.25 V supply range lets the loop interface run from the same 24 V-to-5 V isolated rail that powers the MCU and the HART modem. Auto power-down shuts down the converter between conversions, keeping average loop-card power in the single-digit mW range. Compared with 24-bit sigma-delta ADCs the MAX145 is faster but coarser; choose the MAX145 when 12-bit accuracy and high throughput outweigh the need for 0.001% precision.
Recommended
Isolated Sensor Signal Conditioning
Isolated sensor modules - thermocouple amplifiers, strain-gauge bridges, RTD front-ends - need a fast ADC whose small footprint does not crowd the isolation barrier footprint. The MAX145AEUA occupies only 3 mm x 3 mm on the secondary side and consumes under 4 mW even at full speed, so an isolated DC-DC can stay small. Its pseudo-differential input pairs cleanly with instrumentation amplifiers like the MAX4193, while the SPI output drives the optocoupler or digital isolator back to the primary-side MCU. Compared with bigger 14-bit ADCs the MAX145 surrenders resolution for board area and BOM simplicity.
Recommended
Medical Point-of-Care Diagnostics
Point-of-care diagnostic readers benefit from the MAX145AEUA's low 0.9 mA supply current at 3.6 V, its 12-bit resolution (sufficient for colorimetric strip readers, glucometers, and pulse-oximeter front-ends), and its SPI interface that easily talks to low-power ARM Cortex-M0 hosts. The pseudo-differential input rejects the 50/60 Hz mains pickup present in clinical environments. Compared with higher-resolution ADCs, the MAX145 trades bit-depth for sub-$10 pricing in volume, matching the cost target of disposable test cartridges. AEC-Q100 is not required for medical non-implant use.
Recommended
Automotive Sensor Reading (Non-Safety)
For non-safety automotive accessories such as battery monitors, climate-control sensors, and seat-occupancy detectors, the MAX145AEUA's industrial -40°C to +85°C range covers cabin and engine-bay-far-edge locations. The pseudo-differential input tolerates the common-mode shifts caused by load-dump events and ground-loop offsets on the chassis wiring. Note: select the MAX145Q (AEC-Q100 qualified variant) when designing safety-relevant sensors such as airbag or ABS wheel-speed systems. Compared with dedicated -Q grade ADCs the MAX145AEUA is a cost-effective signal-acquisition block in body-electronics modules.
Recommended
Recommended Products Summary
Engineering reference data for MAX145AEUA — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | MAX145BEUA | MAX145BEUA+T | MAX145AEUA+T | MAX145ACUA | MAX144BEUA |
|---|---|---|---|---|---|---|
| Package | 8-µMAX (uSOP) | 8-µMAX - same | 8-µMAX - same | 8-µMAX - same | 8-µMAX - same | 8-µMAX - same |
| Brand | Analog Devices (Maxim) | Analog Devices (Maxim) | Analog Devices (Maxim) | Analog Devices (Maxim) | Analog Devices (Maxim) | Analog Devices (Maxim) |
| Resolution | 12 bits | 12 bits | 12 bits | 12 bits | 12 bits | 12 bits |
| Analog Input Type | Pseudo-differential | Pseudo-differential | Pseudo-differential | Pseudo-differential | Pseudo-differential | Single-ended 2-ch |
| Conversion Rate | 108 ksps | 108 ksps | 108 ksps | 108 ksps | 108 ksps | 108 ksps |
| Supply Voltage | +2.7V to +5.25V | +2.7V to +5.25V | +2.7V to +5.25V | +2.7V to +5.25V | +2.7V to +5.25V | +2.7V to +5.25V |
| Temperature Grade | -40°C to +85°C (A grade) | -40°C to +85°C (B grade) | -40°C to +85°C (B grade) | -40°C to +85°C (A grade) | -40°C to +85°C (A grade) | -40°C to +85°C (B grade) |
| Approx. 1k Unit Price | $9.88 (as of 2026-10-14) | $10.50 - $12.00 | $10.50 - $12.00 | $9.88 - $10.50 | $8.50 - $9.50 | $9.88 - $11.00 |
Key Differentiators
- Pseudo-differential input on the smallest pin-compatible 8-µMAX footprint (vs MAX144BEUA)
- Tighter linearity B grade available in same package (vs MAX145AEUA (A grade))
- Auto power-down keeps standby below 1 µA (vs MAX145ACUA (-A grade lower-cost version))
Design Notes
Estimated: at VDD = +3.6 V continuous 108 ksps operation, IDD ~ 0.9 mA gives P_DD ~ 3.2 mW per the manufacturer datasheet. In auto power-down mode with intermittent sampling, average current falls below 1 µA, so a CR2032 cell can power years of data-logging operation if the host MCU also sleeps. Place a 0.1 µF X7R bypass capacitor within 3 mm of the VDD pin plus a bulk 4.7 µF on the same node.
Routing CNVST, SCLK, and DOUT traces: keep them short (under 25 mm) and parallel-routed over a continuous ground plane to avoid coupling the SAR strobe into the analog input. The pseudo-differential AIN- pin is NOT a ground pin; connecting it to a noisy ground shifts the conversion baseline. Use the package's exposed-pad analog ground (pin 4) as the single point of return for the input filter.
Reference decoupling: bypass REF with a 0.1 µF + 10 µF capacitor pair when using the internal 4.096 V source. A noisy reference couples directly into INL, so pull REF away from SCLK/DOUT traces. When driving REF with an external source (MAX6125 recommended), keep the trace short and guard it with ground pours to avoid board-level voltage drops.
Apply a simple RC anti-aliasing filter on AIN+ (typically 1 kΩ + 1 nF, fc ~ 160 kHz) so the SAR input samples a clean signal above the 108 ksps Nyquist. The MAX145 accepts up to 1 GHz input bandwidth but the converter is only 12 bits, so attenuation above ~100 kHz is wasted noise; tight filtering improves real SNR and prevents alias spurs in multiplexed scans.
Compliance Information
RoHS compliant per Maxim Integrated product page. Lead-free matte tin plating. The MAX145AEUA itself is not AEC-Q100 qualified - choose the MAX145Q variants for automotive safety applications.
