MAX1281BCUP - 12-Bit 8-Ch 400ksps SAR ADC | Maxim Integrated
MPN: MAX1281BCUP ✗ End of Life| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $11.42 | $11.42 |
| 10 | $10.27 | $102.70 |
| 100 | $9.13 | $913.00 |
| 500 | $8.21 | $4,105.00 |
| 1,000 | $7.05 | $7,050.00 |
MAX1281BCUP Overview
An ADC (analog-to-digital converter) is a mixed-signal integrated circuit that samples continuous analog voltage signals and converts them into discrete digital codes for processing by microcontrollers, DSPs, or FPGAs. The SAR architecture uses a successive-approximation register with a precision DAC to binary-weigh input voltage against the reference in lock-step, settling for a one-stage-per-bit conversion with deterministic latency. In the broader taxonomy, the MAX1281BCUP belongs to the data-converter hierarchy: ADC -> SAR ADC -> precision ADC -> mixed-signal IC -> integrated circuit -> semiconductor. The 8-channel MUX makes it a single-chip multi-channel data acquisition front-end.
Key features include: 12-bit resolution with no missing codes, 400 ksps (MAX1280) or 300 ksps (MAX1281) throughput, internal 2.5 V reference, single 2.7 V to 3.6 V analog supply operation, low 2.5 mA (typ) operating supply current, hardware- and software-configurable analog input MUX (4-channel single-ended or 8-channel pseudo-differential via AIN0-AIN7 plus dedicated COM input), SPI/QSPI/MICROWIRE-compatible serial interface, and an external clock mode option (MAX1281B external-clock variants). The TSSOP-20 surface-mount package offers small footprint with gull-wing leads.
The MAX1281BCUP uses a BiCMOS process that integrates a precision switched-capacitor DAC, comparator, SAR register, control logic, and 8:1 analog MUX on the same die. Internal reference eliminates an external reference IC, reducing BOM cost in cost-sensitive consumer, debug, and process-control equipment. The high-bandwidth track/hold sustains accurate acquisition at full speed, with track/hold acquisition time dedicated to the first internal-clock cycle per conversion. Single-supply operation simplifies portable-instrument power design.
The MAX1281BCUP is well suited for multi-channel data acquisition in data-acquisition cards, process-control and industrial sensor signal chains, portable instrumentation, medical instruments, battery-powered consumer audio and telecommunications systems, and embedded system front-ends with multiple analog sensors.
When using the MAX1281BCUP, place 10 uF and 0.1 uF bypass capacitors close to the analog supply pin and ensure the analog and digital grounds are joined at a single point near the ADC. Allow 20 clock cycles per conversion in internal-clock mode and follow the datasheet logic sequence when reconfiguring the MUX between conversions.
This page synthesizes distributor pricing, drop-in TSSOP-20 alternatives, and practical design application notes not found in the manufacturer datasheet.
Drop-in alternatives for MAX1281BCUP — 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 MAX1281BCUP (same form factor and footprint) — differing in Package, Sampling Rate, Internal Reference Voltage, Resolution, RoHS Status.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
MAX1281BEUP+
✅ Drop-In📋 Reference alternative (not in catalog)
MAX1281BCUP+
✅ Drop-In📋 Reference alternative (not in catalog)
MAX1280BCUP+
✅ Drop-In📋 Reference alternative (not in catalog)
MAX1081BCUP
✅ Drop-In✓ In Stock
$8.4 / Unit
View Datasheet →MAX1080BCUP+
✅ Drop-In✓ In Stock
$5.02 / Unit
View Datasheet →AD7888ARU
✅ Drop-In📋 Reference alternative (not in catalog)
MAX1281BCUP Maximum Ratings & Electrical Characteristics
| Resolution | 12 bit |
| Number of Channels | 4 / 8 input |
| Sampling Rate | 300 ksps (MAX1281) |
| Architecture | SAR (Successive Approximation Register) |
| Data Interface | Serial SPI/QSPI/MICROWIRE-compatible |
| Supply Voltage - Analog | 2.7 V to 3.6 V |
| Supply Current | 2.5 mA (typical) |
| Internal Reference Voltage | 2.5 V |
| Operating Temperature Range | 0C to +70C |
| Package | 20-TSSOP |
| Mounting Type | Surface Mount |
| MSL Level | 1 (unlimited) |
| RoHS Status | Compliant |
| Process Technology | BiCMOS |
MAX1281BCUP Pin Configuration
| Pin 1 | VDD — Analog power supply input, +2.7V to +3.6V |
| Pin 2 | AIN0 — Analog input channel 0 |
| Pin 3 | AIN1 — Analog input channel 1 |
| Pin 4 | AIN2 — Analog input channel 2 |
| Pin 5 | AIN3 — Analog input channel 3 |
| Pin 6 | COM — Common reference for pseudo-differential inputs |
| Pin 7 | AIN4 — Analog input channel 4 |
| Pin 8 | AIN5 — Analog input channel 5 |
| Pin 9 | AIN6 — Analog input channel 6 |
| Pin 10 | AIN7 — Analog input channel 7 |
| Pin 11 | GND — Ground (analog ground reference) |
| Pin 12 | REF — Reference voltage input/output (internal 2.5V reference) |
| Pin 13 | SCLK — Serial clock input |
| Pin 14 | CS — Chip select / active-low convert |
| Pin 15 | DOUT — Serial data output |
| Pin 16 | DIN — Serial data input (control register configuration) |
| Pin 17 | SHDN — Shutdown input (active low) |
| Pin 18 | NC — Not connected |
| Pin 19 | NC — Not connected |
| Pin 20 | NC — Not connected |
Typical Applications
MAX1281BCUP is suitable for 6 applications: Multi-Channel Data Acquisition Systems, Industrial Process Control, Portable Battery-Powered Instrumentation, Medical Patient Monitoring, Embedded Multi-Sensor Systems, Automotive Sensor Signal Chains.
Multi-Channel Data Acquisition Systems
The MAX1281BCUP is well suited for multi-channel data acquisition cards that scan 4 to 8 analog sensors through its internal MUX. Its 300 ksps sampling rate and 12-bit resolution cover mechanical measurement of strain gauge, thermocouple, and 4-20 mA current-loop sensor signal chains. The internal 8080 register with single 3.3 V supply simplifies data acquisition front-end design in laboratory and industrial instrumentation. Place 10 uF and 0.1 uF bypass capacitors close to the supply pin and configure the MUX through the serial interface to scan a single channel per conversion.
Recommended
Industrial Process Control
The MAX1281BCUP fits industrial process-control equipment reading multiple 4-20 mA current-loop or 0-10 V analog signals. Its 8 single-ended or pseudo-differential inputs handle multiple sensor channels from a single ADC. According to the datasheet 19-1183, the internal MUX supports 4-channel single-ended or 8-channel pseudo-differential configuration via AIN0-AIN7 plus a dedicated COM input. The TSSOP-20 surface-mount package handles the mechanical vibration profile of industrial control cabinets. The SPI-compatible interface connects to many industrial robots and PLC digital I/O modules.
Recommended
Portable Battery-Powered Instrumentation
The MAX1281BCUP is well suited for portable, battery-powered instrumentation where single 3.3 V supply and low power consumption are critical. According to the datasheet 19-1183, the device draws only 2.5 mA typical supply current from a 2.7 V to 3.6 V analog supply, extending battery life in field instruments. The 8-channel MUX supports multi-sensor front-ends in a single 20-TSSOP package, saving board area and extending battery life in portable instrumentation. The internal 2.5 V reference eliminates a separate reference IC, reducing BOM cost and saving additional power in portable equipment.
Recommended
Medical Patient Monitoring
The MAX1281BCUP supports multi-parameter medical monitoring equipment (ECG, temperature, respiration, SpO2 sensor signal chains). According to the datasheet 19-1183, the 12-bit resolution and 300 ksps sampling rate capture physiological waveforms with adequate fidelity for diagnostic-grade medical equipment. The internal MUX with zero placeholder channels supports multiple sensor channels from a single ADC, reducing the component count on space-constrained medical device PCBs. Place 10 uF bypass capacitors close to the supply pin to maintain low-noise measurement of high-gain medical signals. The TSSOP-20 package allows compact medical device form factors.
Recommended
Embedded Multi-Sensor Systems
The MAX1281BCUP supports embedded system designs that read multiple analog sensors (temperature, pressure, light, position) through a single serial interface. The 8-channel MUX with internal reference lets an MCU or embedded controller monitor a small library of analog sensors without wasting GPIO pins for an external MUX. According to the datasheet 19-1183, the SPI/QSPI/MICROWIRE-compatible interface connects to most MCU serial peripherals. The TSSOP-20 package is designed to fit on small sensor boards with bread-board-friendly TSSOP land patterns.
Recommended
Automotive Sensor Signal Chains
The MAX1281BCUP is not AEC-Q100 qualified and is therefore not the first choice for automotive designs that require formal automotive certification. However, according to the datasheet 19-1183, the device's wide 2.7 V to 3.6 V supply range and 8-channel MUX make it suitable for non-safety automotive sensor applications (HVAC controls, body electronics, instrument panel sensors, battery management secondary signals) where 12-bit accuracy is sufficient. Note the MAX1281BCUP lifecycle status is obsolete and the recommended active part is MAX1281BEUP+; for AEC-Q100 automotive designs, consult the Analog Devices automotive-grade ADC portfolio.
Recommended
Recommended Products Summary
Engineering reference data for MAX1281BCUP — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | MAX1281BEUP+ | MAX1281BCUP+ | MAX1280BCUP+ | MAX1081BCUP | MAX1080BCUP+ | AD7888ARU |
|---|---|---|---|---|---|---|---|
| Brand | Analog Devices (formerly Maxim) | Analog Devices | Analog Devices | Analog Devices | Analog Devices | Analog Devices | Analog Devices |
| Package | 20-TSSOP | 20-TSSOP - same | 20-TSSOP - same | 20-TSSOP - same | 20-TSSOP - same | 20-TSSOP - same | 20-TSSOP - same |
| Resolution | 12 bit | 12 bit | 12 bit | 12 bit | 10 bit | 10 bit | 12 bit |
| Sampling Rate | 300 ksps | 300 ksps | 300 ksps | 400 ksps | 300 ksps | 400 ksps | 125 ksps |
| Number of Channels | 4 / 8 input | 4 / 8 input | 4 / 8 input | 4 / 8 input | 4 / 8 input | 4 / 8 input | 8 input |
| Internal Reference | 2.5 V | 2.5 V | 2.5 V | 2.5 V | 2.5 V | 2.5 V | 2.5 V |
| Supply Voltage | 2.7 V to 3.6 V | 2.7 V to 3.6 V | 2.7 V to 3.6 V | 2.7 V to 3.6 V | 2.7 V to 3.6 V | 2.7 V to 3.6 V | 2.7 V to 5.25 V |
| Lifecycle Status | Obsolete | Active | Active | Active | Obsolete | Active | Obsolete |
Key Differentiators
- Drop-in compatible with the active MAX1281BEUP+ replacement (vs MAX1281BEUP+)
- Higher throughput version available as MAX1280BCUP+ (vs MAX1280BCUP+)
- Compatible pinout with 10-bit MAX1081 family (vs MAX1081BCUP)
Design Notes
The MAX1281BCUP requires a single 2.7 V to 3.6 V analog supply and draws 2.5 mA typical operating current. Place a 10 uF bulk tantalum or ceramic bypass capacitor in parallel with a 0.1 uF ceramic capacitor as close as possible to the VDD pin (pin 1). For mixed-voltage systems, consider adding a small RC filter on the VDD line to filter switching noise from upstream digital regulators.
Place input capacitors or anti-aliasing RC networks close to the analog input pins (AIN0-AIN7, COM). Use a star-ground topology with the analog ground return connected to a single point near the ADC ground pin (pin 11) to avoid digital ground return currents through the analog ground plane. The TSSOP-20 thermal pad is not present; rely on copper pours on the analog ground layer for heat dissipation.
Route the SPI/QSPI serial interface traces (SCLK, DOUT, DIN, CS) away from analog input traces to minimize digital crosstalk. Use matched trace lengths if multiple ADCs share the same SPI bus. The CS line should have a 100 kohm pull-up or be driven from a dedicated GPIO to avoid spurious chip-select transitions during MCU reset.
Do not exceed the absolute maximum analog input voltage range of -0.3 V to VDD + 0.3 V on the analog input channels; over-voltage can damage the input MUX and SAR capacitors. When reconfiguring the MUX between conversions, allow the full acquisition time plus one conversion cycle for settling. The internal reference requires a 10 uF bypass capacitor on the REF pin (pin 12); do not omit it.
