MAX159ACUA - 10-Bit, 108ksps, 2-Ch Serial ADC µMAX | Maxim
MPN: MAX159ACUA ✗ End of Life| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $4.92 | $4.92 |
| 10 | $4.42 | $44.20 |
| 100 | $3.94 | $394.00 |
| 500 | $3.55 | $1,775.00 |
| 1,000 | $3.16 | $3,160.00 |
MAX159ACUA Overview
An analog-to-digital converter is a mixed-signal integrated circuit that samples an analog input voltage and converts it into a discrete digital code proportional to the input magnitude. Successive-approximation register (SAR) ADCs like the MAX159ACUA achieve a deliberate balance between speed, accuracy, and power consumption by performing one comparison per clock cycle against an internal binary-weighted capacitor DAC, finishing a 10-bit conversion in 7.4µs. SAR ADCs sit within the broader hierarchy: ADC -> data converter -> mixed-signal IC -> semiconductor, and are preferred over flash and sigma-delta converters in cost-sensitive, low-power, multiplexed-channel applications such as sensor front ends.
Key features include 108 ksps throughput, ±0.5 LSB INL (max), single +2.7V to +5.25V supply operation, automatic power-down that drops supply current between samples, internal 2.5µs wake-up time, and an on-chip clock that eliminates the need for an external timing component. The MAX159ACUA supports 2 analog input channels, integrates an input track-and-hold, and is specified for the commercial 0°C to +70°C operating temperature range. It is a member of the MAX157/MAX159 family that shares the same pinout and registers, easing firmware reuse and BOM flexibility.
Typical applications include portable and battery-powered data acquisition, temperature and pressure sensor digitizing loops, pen/digitizer tablets, patient monitoring front ends, and process-control I/O modules. Because the part automatically powers down between conversions, it is well suited to loop-powered 4-20mA sensors, isolated SPI ADC front ends, and handheld instruments where total system current must be minimized. The 3-wire serial interface is compatible with SPI, QSPI, and MICROWIRE hosts, allowing seamless connection to common microcontrollers.
When designing with this device, place the 10µF bypass capacitor as close as possible to the VDD lead and keep analog input traces short and guarded, since the SAR architecture is sensitive to charge-injection transients during acquisition. Note that the MAX159ACUA is no longer in active production per the partstack listing; consider MAX159ACUA+ for current orders or MAX157BCPA in a PDIP-8 footprint for legacy through-hole boards.
This page synthesizes distributor pricing, drop-in 8-pin µMAX alternatives, and practical design notes that go beyond the manufacturer datasheet alone.
Drop-in alternatives for MAX159ACUA — 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 MAX159ACUA (same form factor and footprint) — differing in Number of Channels, Package, Conversion Time, Architecture, INL (max).
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
MAX159ACUA+
✅ Drop-In📋 Reference alternative (not in catalog)
MAX159BCUA
✅ Drop-In📋 Reference alternative (not in catalog)
MAX157BCUA
✅ 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 →MAX159ACUA Maximum Ratings & Electrical Characteristics
| Resolution | 10 bit |
| Number of Channels | 2 |
| Sample Rate | 108 ksps |
| Conversion Time | 7.4 µs |
| Architecture | SAR (Successive Approximation) |
| Supply Voltage (VDD) | +2.7 V to +5.25 V |
| Supply Current (active, VDD=3.6V) | 3.2 mW typical |
| Wake-Up Time | 2.5 µs |
| INL (max) | ±0.5 LSB |
| Input Voltage Range | 0 V to 5.3 V |
| Analog Input Type | Single-ended, 2-channel mux |
| Digital Interface | 3-wire SPI/QSPI/MICROWIRE-compatible serial |
| Operating Temperature | 0 °C to +70 °C (commercial) |
| Package | 8-pin µMAX (UMAX-8 / M0-187) |
| Mounting Type | Surface Mount |
| Internal Clock | Yes (on-chip) |
MAX159ACUA Pin Configuration
| Pin 1 | VDD — Positive analog supply, +2.7V to +5.25V |
| Pin 2 | AIN1 — Analog input channel 1 |
| Pin 3 | AIN0 — Analog input channel 0 |
| Pin 4 | GND — Analog and digital ground |
| Pin 5 | SCLK — Serial clock input for 3-wire SPI/QSPI/MICROWIRE interface |
| Pin 6 | DOUT — Serial data output, MSB-first |
| Pin 7 | CS/ — Active-low chip select, also controls power-down (high = power-down) |
| Pin 8 | REF — Reference voltage input for ADC |
Typical Applications
MAX159ACUA is suitable for 6 applications: Portable Battery-Powered Data Acquisition, Temperature and Pressure Sensor Digitizing, Pen/Digitizer Tablet Position Sensing, Patient Monitoring and Medical Instrumentation, Process Control and Industrial I/O Modules, Handheld Test and Measurement Instruments.
Portable Battery-Powered Data Acquisition
The MAX159ACUA is ideal for portable, battery-powered data-acquisition front ends because its automatic power-down between conversions drops supply current to a few microamps, while its 2.5µs wake-up lets the system return to active conversion within one clock cycle of a CS/ edge. With 10-bit resolution and 108 ksps throughput, the part captures slow analog signals such as thermistor bridges, strain gauges, and electrochemical sensors at sample rates well under 1 ksps in real systems. The 2.7V to 5.25V supply range supports direct connection to single-cell Li-ion (3.7V nominal) and 3.3V or 5V microcontroller rails without level shifters. Designers can pair the MAX159ACUA with a low-quiescent LDO and a small microcontroller to build weeks-of-runtime sensor loggers for field-deployed IoT and environmental monitoring. Compared to a microcontroller's internal ADC, the MAX159ACUA offers galvanic isolation of the analog path, reducing digital switching noise coupled into the measurement.
Recommended
Temperature and Pressure Sensor Digitizing
The MAX159ACUA suits temperature and pressure sensor digitizing loops in HVAC, weather stations, and process-control modules because its 2-channel input multiplexer handles dual-element sensors and ratiometric bridge outputs in a single IC. The ±0.5 LSB INL provides enough accuracy for thermistor-to-temperature conversion across -20°C to +80°C with proper linearization, and the SPI-compatible 3-wire serial interface reads out conversion results at rates far above typical thermal sensor bandwidths. The 7.4µs successive-approximation conversion time prevents aliasing of slowly varying analog signals, while the on-chip clock removes the need for an external timing capacitor. For pressure transducers with 0-5V output swing, the part's 0V to 5.3V input range accommodates the full transducer scale. Designers should add an RC anti-alias filter ahead of AIN0/AIN1 to limit out-of-band noise.
Recommended
Pen/Digitizer Tablet Position Sensing
The MAX159ACUA is a workhorse ADC for pen/digitizer tablets and graphics tablets because its 108 ksps sample rate comfortably exceeds the bandwidth of stylus position updates while its small 8-pin µMAX package fits inside slim stylus-side PCBs. Two analog input channels let the digitizer read pen-tip pressure and side-button state in a single part, reducing BOM cost compared to a two-ADC design. The 3-wire SPI/QSPI/MICROWIRE-compatible interface connects directly to the host microcontroller without glue logic, easing firmware development across product variants. Power consumption at 3.2 mW typical at 3.6V suits battery-powered tablets that prioritize hours of runtime. Designers should keep the analog input traces short and guard them with a ground pour to minimize pickup from the digitizer's active感应 matrix.
Recommended
Patient Monitoring and Medical Instrumentation
The MAX159ACUA fits patient monitoring and medical instrumentation front ends because its 10-bit resolution and 108 ksps throughput adequately digitize ECG, pulse-oximeter, and respiration waveforms within their clinically relevant bandwidths. The 2.7V to 5.25V supply range accepts the common 3.3V regulated rails used in battery-powered patient monitors, and the small µMAX-8 footprint leaves room for additional analog signal conditioning on the same PCB. Automatic power-down between conversions extends battery life in wearable patient monitors that sample intermittently rather than continuously. The 3-wire serial interface reduces pin count on the host microcontroller, freeing GPIO for alarms, displays, and wireless links. Designers must add ESD protection and patient isolation barriers per IEC 60601 when using this ADC in medical devices.
Recommended
Process Control and Industrial I/O Modules
The MAX159ACUA is suitable for process-control I/O modules and 4-20mA loop-powered sensor transmitters because its low power consumption and automatic power-down make it ideal for energy-constrained loop-powered applications. Two analog input channels can monitor both the loop current sense resistor and a secondary sensor such as temperature or pressure, simplifying the analog front end. The 0°C to +70°C commercial operating range suits control-room equipment; for harsh industrial environments migrate to the MAX159BCUA industrial-temperature variant. The SPI-compatible 3-wire interface connects directly to low-cost MCUs used in PLC and DCS I/O cards. Designers should include TVS protection and a 4-20mA loop surge arrestor when interfacing the ADC to long cable runs.
Recommended
Handheld Test and Measurement Instruments
The MAX159ACUA suits handheld multimeters, oscilloscope front ends, and field-test instruments because its small 8-pin µMAX package, low 3.2 mW active power, and 2.5µs wake-up enable long battery runtime in intermittent-sampling tools. Two input channels let a single instrument digitize both voltage and current simultaneously in a DMM/DAC topology, while the 10-bit resolution suffices for general-purpose field measurements where 1% accuracy is acceptable. The SPI/QSPI/MICROWIRE-compatible digital interface is compatible with virtually all low-pin-count MCUs used in handheld product designs. The 0V to 5.3V input range covers most low-voltage signal levels without external attenuators. Designers should add input protection resistors and clamping diodes to survive over-voltage events on the test leads.
Recommended
Recommended Products Summary
Engineering reference data for MAX159ACUA — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | MAX159ACUA+ | MAX159BCUA | MAX157BCUA | MAX145ACUA | MAX144BEUA |
|---|---|---|---|---|---|---|
| Brand | Maxim Integrated | Maxim Integrated | Maxim Integrated | Maxim Integrated | Maxim Integrated | Maxim Integrated |
| Package | 8-pin µMAX (UMAX-8) | 8-pin µMAX (UMAX-8) - same | 8-pin µMAX (UMAX-8) - same | 8-pin µMAX (UMAX-8) - same | 8-pin µMAX (UMAX-8) - same | 8-pin µMAX (UMAX-8) - same |
| Resolution | 10 bit | 10 bit | 10 bit | 10 bit | 12 bit (higher) | 12 bit (higher) |
| Number of Channels | 2 | 2 | 2 | 1 (single-ended) | 1 | 1 |
| Digital Interface | 3-wire SPI/QSPI/MICROWIRE | 3-wire SPI/QSPI/MICROWIRE | 3-wire SPI/QSPI/MICROWIRE | 3-wire SPI/QSPI/MICROWIRE | 3-wire SPI-compatible | 3-wire SPI-compatible |
Key Differentiators
- Pb-free RoHS compliance for new designs (vs MAX159ACUA+)
- Industrial -40C to +85C operating range (vs MAX159BCUA)
- True 2-channel input multiplexer (vs MAX157BCUA)
Design Notes
Place a 10µF tantalum or ceramic bypass capacitor as close as possible to the VDD pin (pin 1) and a 0.1µF ceramic capacitor in parallel to filter both low- and high-frequency noise. The MAX159ACUA's SAR architecture injects charge onto AIN0/AIN1 during acquisition, so a stable VDD with low source impedance is critical for accurate conversions. Driving CS/ high forces the part into automatic power-down, dropping supply current between conversions; pull CS/ low at least 2.5µs before SCLK to allow wake-up and reference settling.
Route analog input traces (AIN0, AIN1) over a continuous ground pour and keep them short to minimize pickup of digital switching noise from the SPI bus. Per Maxim application guidance, surround the analog traces with a guard trace tied to AGND to shield them from the SCLK and DOUT edges. Keep the REF pin bypassed with at least 0.1µF close to the IC, since reference noise directly couples into conversion results. Maintain symmetry between input trace lengths when using both channels to preserve channel-to-channel gain matching.
Estimated: at 108 ksps with 7.4µs conversion time, the analog acquisition window is on the order of 1.5 clock cycles (1.5 × SCLK period), so SCLK should be set between 1 MHz and 4 MHz for reliable operation. Drive SCLK from a clean microcontroller GPIO and avoid routing the SPI clock near high-current switching traces. Use an anti-alias RC filter (typically 1kΩ + 10nF for 10kHz bandwidth) on each AIN input to bandlimit wideband noise before the ADC's internal track-and-hold captures the input.
Do not leave the CS/ pin floating - a floating CS/ can cause spurious wake-up events and corrupt the serial frame. Avoid reading DOUT while CS/ is high, because DOUT is high-impedance in power-down and the line state is undefined. For ratiometric measurements, derive REF from the same supply as the sensor bridge to cancel supply drift; for absolute measurements, use a dedicated low-noise reference such as the MAX6033 or equivalent. When migrating to the MAX159ACUA+ RoHS variant, verify land pattern compatibility - the + variant uses lead-free plating but the same µMAX-8 mechanical outline.
Compliance Information
MAX159ACUA uses leaded finish per Maxim's legacy part numbering convention; for RoHS compliance choose MAX159ACUA+ suffix variant. AEC-Q100 not applicable as this part targets commercial-grade data acquisition, not automotive.
