MAX146BCAP - 12-Bit 8-Ch 133kSPS Serial ADC | Maxim Integrated
MPN: MAX146BCAP ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $15.66 | $15.66 |
| 10 | $14.32 | $143.20 |
| 100 | $12.74 | $1,274.00 |
| 500 | $11.2 | $5,600.00 |
| 1,000 | $9.95 | $9,950.00 |
MAX146BCAP Overview
An ADC (Analog-to-Digital Converter) is a mixed-signal integrated circuit that quantizes a continuous-time analog input voltage into a discrete digital code. The MAX146 belongs to the successive-approximation register (SAR) ADC family, which trades raw speed for excellent DC accuracy and very low power consumption per conversion. In a typical signal chain (sensor -> amplifier -> ADC -> microcontroller), the ADC digitizes the conditioned analog signal so that a digital controller can process, log, or transmit the reading. MAX146-class devices sit between precision delta-sigma ADCs (slower, higher resolution) and high-speed flash ADCs (faster, lower resolution) on the performance-versus-speed spectrum, and they are widely used in industrial control, instrumentation, and embedded monitoring designs.
Key features of the MAX146BCAP include 133 kSPS maximum sampling rate, an 8-channel single-ended or 4-channel differential input multiplexer, software-configurable unipolar/bipolar input ranges, an internal 2.5V reference with a ±1.5% buffer adjustment range, a hardware SHDN-bar pin plus software power-down that drops supply current to under 10 uA between conversions, and an automatic end-of-conversion shutdown mode for battery-aware applications. Operating supply range spans +2.7V to +3.6V on AVDD and +2.7V to DVDD +0.3V on DVDD, and the device is specified over the 0C to +70C temperature range in this CAP commercial-grade variant.
Typical applications for the MAX146BCAP include portable data loggers, patient-monitoring and medical instruments, battery-powered sensor front ends, factory-automation signal conditioning, and embedded system analog I/O expansion for microcontrollers lacking an internal ADC. Its low-power operation and integrated multiplexer make it well-suited for multi-sensor monitoring in remote or wearable nodes.
When designing with this device, use a clean analog ground plane and keep digital traces away from analog inputs; place the 10uF X7R bypass capacitor on AVDD as close to the pin as possible. The serial-interface SCLK should be kept under 2 MHz to preserve ADC linearity and avoid coupling digital noise into the analog input. Drive SHDN-bar high during normal operation and pull it low only between conversions to enter shutdown.
Drop-in alternatives for MAX146BCAP — 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 MAX146BCAP (same form factor and footprint) — differing in Operating Temperature Range, Package, Resolution, Sampling Rate.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
MAX146BCAP+
✅ Drop-In📋 Reference alternative (not in catalog)
MAX146BEAP+
✅ Drop-In📋 Reference alternative (not in catalog)
MAX1134BCAP+
✅ Drop-In ⚠️ Specs Unverified✓ In Stock
$8.3 / Unit
View Datasheet →MAX146BCAP Maximum Ratings & Electrical Characteristics
| Resolution | 12 bit |
| Number of Input Channels | 8 single-ended / 4 differential |
| Sampling Rate | 133 kSPS |
| Converter Architecture | SAR (Successive Approximation Register) |
| Input Signal Type | Single-ended, Differential |
| Supply Voltage AVDD | +2.7 V to +3.6 V |
| Supply Voltage DVDD | +2.7 V to +3.6 V |
| Analog Input Voltage Range | 0 V to AVDD (software configurable bipolar modes) |
| Internal Reference Voltage | 2.5 V (with +/-1.5% buffer adjustment) |
| External Reference Support | Yes (MAX147 variant; this part has internal 2.5V reference) |
| Interface | SPI / QSPI / MICROWIRE-compatible serial |
| Shutdown Current | < 10 uA (typ. software per SHDN-bar) |
| Operating Temperature Range | 0 C to +70 C (CAP commercial grade) |
| Package | 20-pin SSOP |
| Mounting Type | Surface Mount |
| MSL Level | 1 (unlimited) |
| RoHS Status | Compliant |
| Lead-Free Reflow | Yes |
MAX146BCAP Pin Configuration
| Pin 1 | AIN0 — Analog input channel 0 |
| Pin 2 | AIN1 — Analog input channel 1 |
| Pin 3 | AIN2 — Analog input channel 2 |
| Pin 4 | AIN3 — Analog input channel 3 |
| Pin 5 | AIN4 — Analog input channel 4 |
| Pin 6 | AIN5 — Analog input channel 5 |
| Pin 7 | AIN6 — Analog input channel 6 |
| Pin 8 | AIN7 — Analog input channel 7 |
| Pin 9 | AGND — Analog ground |
| Pin 10 | REF — Reference voltage (internal 2.5V or external input) |
| Pin 11 | AVDD — Analog supply +2.7V to +3.6V |
| Pin 12 | DVDD — Digital supply +2.7V to +3.6V |
| Pin 13 | DGND — Digital ground |
| Pin 14 | SCLK — Serial clock input |
| Pin 15 | DIN — Serial data input (configuration writes) |
| Pin 16 | DOUT — Serial data output (conversion results) |
| Pin 17 | CS-bar — Active-low chip select |
| Pin 18 | SHDN-bar — Active-low shutdown input |
| Pin 19 | NC — Not connected (per datasheet) |
| Pin 20 | NC — Not connected (per datasheet) |
Typical Applications
MAX146BCAP is suitable for 6 applications: Portable Battery-Powered Data Loggers, Patient Monitoring and Medical Instrumentation, Industrial Process Sensor Monitoring, Embedded Microcontroller Analog I/O Expansion, Remote Wireless Sensor Nodes, Test and Measurement Front End.
Portable Battery-Powered Data Loggers
The MAX146BCAP's 133 kSPS sampling rate, 12-bit resolution, and sub-10 uA shutdown current make it ideal for portable battery-powered data loggers. Its integrated 8-channel analog multiplexer lets one ADC digitize eight different sensors (temperature, pressure, voltage, current) without an external mux, while the SHDN-bar pin and automatic end-of-conversion shutdown extend battery life between samples. The internal 2.5 V reference eliminates the need for a separate reference IC in cost-sensitive designs. Place the device on a clean analog ground plane and supply it from a regulated 3.3V rail; it draws only a few mA during active conversion and is fully specified for lithium-cell-powered designs.
Recommended
Patient Monitoring and Medical Instrumentation
The MAX146BCAP's 12-bit resolution and 8-channel input multiplexer suit medical patient-monitoring designs that need to digitize several physiological signals at low power. With 133 kSPS throughput it can sample ECG or pulse-oximeter front-ends while consuming only a few mW from a 3.3 V rail. The SHDN-bar pin enables sleep modes between patient measurements, prolonging battery life in portable monitors. Design tip: dedicate separate analog and digital ground planes joined at a single point near the IC, and add a 10 uF X7R bypass on AVDD placed within 1 cm of the pin to preserve linearity on small high-impedance bio-potential signals.
Recommended
Industrial Process Sensor Monitoring
The MAX146BCAP's differential-input capability, bipolar software-configurable ranges, and 8-channel integration simplify industrial process-control boards that monitor multiple 4-20 mA loops, RTDs, or thermocouples. Its 12-bit resolution provides adequate accuracy for trend monitoring, while the SPI interface lets a single microcontroller poll up to eight field sensors with minimal pin count. For noisy factory environments, choose the MAX146BEAP+ extended-temperature variant. Best practice: insert a unity-gain buffer amplifier and RC anti-aliasing filter in front of each AIN channel, and run SCLK below 2 MHz to keep digital switching noise out of the analog input band.
Recommended
Embedded Microcontroller Analog I/O Expansion
Many low-cost microcontrollers lack an internal ADC, or provide only 10-bit resolution. The MAX146BCAP lets a designer add 8 channels of 12-bit ADC over a 4-wire SPI bus with only a few GPIO pins consumed. With 133 kSPS sampling and software-controllable channels, it can digitize potentiometers, thermistors, light sensors, and current-sense amplifier outputs on a single PCB. Use it as a stand-alone peripheral alongside an 8051, PIC, or ARM Cortex-M0 microcontroller and store calibration coefficients in non-volatile memory to compensate for the +/-1 LSB INL typical of SAR converters in this class.
Recommended
Remote Wireless Sensor Nodes
The MAX146BCAP's 2.7 V minimum supply, sub-10 uA shutdown current, and 8-channel multiplexer suit remote wireless sensor nodes powered by 2xAA cells or coin-cell batteries. It can digitize multiple environmental sensors before sleeping in SHDN-bar mode while a radio module transmits data, then wake on CS-bar assertion for the next sample. Compared to a delta-sigma ADC of similar channel count, the SAR conversion architecture completes in microseconds and lets the radio sleep for longer between bursts, saving system-level power. For best battery life, drive SHDN-bar high only during conversion, then return to shutdown between samples.
Recommended
Test and Measurement Front End
The MAX146BCAP's 12-bit resolution, 133 kSPS throughput, and 8 input channels let bench-test designers build a low-cost multi-channel data-acquisition front end. The internal multiplexer and reference simplify the analog path, while the SPI bus streams conversion results to a host PC over USB. For bench instrumentation that needs guaranteed accuracy at room temperature, the commercial CAP grade is appropriate; for field-deployed test gear, the BEAP extended-temperature grade in the same SSOP-20 footprint is the recommended drop-in. Add an input protection clamp and a unity-gain buffer to drive the AIN pins from external BNC connectors safely.
Recommended
Recommended Products Summary
Engineering reference data for MAX146BCAP — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | MAX146BCAP+ | MAX146BEAP+ | MAX146BCPP+ | MAX146BEPP+ | MAX1134BCAP+ |
|---|---|---|---|---|---|---|
| Brand | Analog Devices / Maxim Integrated | Analog Devices | Analog Devices | Analog Devices | Analog Devices | Analog Devices |
| Package | SSOP-20 | SSOP-20 - same | SSOP-20 - same | PDIP-20 - different | PDIP-20 - different | SSOP-20 - same |
| Resolution | 12 bit | 12 bit | 12 bit | 12 bit | 12 bit | 12 bit |
| Sampling Rate | 133 kSPS | 133 kSPS | 133 kSPS | 133 kSPS | 133 kSPS | 400 kSPS |
| Serial Interface | SPI/QSPI/MICROWIRE | SPI/QSPI/MICROWIRE | SPI/QSPI/MICROWIRE | SPI/QSPI/MICROWIRE | SPI/QSPI/MICROWIRE | SPI/QSPI/MICROWIRE |
Key Differentiators
- Integrated 8-channel multiplexer in SSOP-20 (vs MAX1240 single-channel 8-pin SOIC ADC)
- Internal 2.5V reference vs MAX147 external reference (vs MAX147 external-reference variant)
- Software and hardware shutdown modes (vs MAX1243 with hardware shutdown only)
- 133 kSPS throughput at low supply current (vs MAX1134BCAP+ 400 kSPS upgrade variant)
Design Notes
Provide separate AVDD and DVDD rails or tie them together at a single ferrite bead to keep digital switching noise out of the analog supply. Add a 10uF X7R bypass capacitor as close as possible to the AVDD pin (less than 1 cm trace) and a 0.1uF ceramic in parallel for high-frequency decoupling. Keep the SHDN-bar pin high during normal operation and pull it low only between conversions to enter the sub-10 uA shutdown mode.
Use a star-ground topology with AGND and DGND connected at a single point near the IC. Keep digital interface traces (CS-bar, SCLK, DIN, DOUT) short and routed on a different layer from the analog input traces to minimize coupling. Place the analog input RC anti-aliasing filter components near each AIN pin. Avoid running digital traces directly under the IC or near the analog input channels to preserve 12-bit linearity.
Limit SCLK to 2 MHz maximum to maintain ADC linearity and avoid injecting clock harmonics into the analog input. Drive SCLK with a clean low-jitter source; for slower MCUs use the lowest SPI divider that still exceeds the conversion rate. Source impedance above 1 kohm degrades INL, so add a unity-gain buffer amplifier (such as a MAX4475) on each analog input channel when driving from high-impedance sensors.
Do not apply input voltages to AIN0-AIN7 that exceed AVDD or go below AGND; the absolute maximum input range is AVDD + 0.3V to AGGN - 0.3V. In differential mode, ensure both inputs are within the common-mode range. Avoid leaving unused analog inputs floating - tie them to AGND or a known mid-rail voltage to prevent spurious conversion results from injected noise. Always enter shutdown mode (SHDN-bar low) before changing configuration registers.
Compliance Information
RoHS compliant per Maxim Integrated product page (lead-free finish on MAX146BCAP+). Not AEC-Q100 qualified - choose MAX146BEAP+ extended-temperature grade for industrial applications.
