MAX1229ACEP+ - 12-Bit 300ksps 12-Ch SAR ADC | Maxim Integrated
MPN: MAX1229ACEP+ ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $11.45 | $11.45 |
| 10 | $10.3 | $103.00 |
| 100 | $9.15 | $915.00 |
| 500 | $8.2 | $4,100.00 |
| 1,000 | $7.45 | $7,450.00 |
MAX1229ACEP+ Overview
A SAR ADC is a type of analog-to-digital converter that uses a binary-search successive-approximation algorithm combined with an internal DAC to convert an input voltage into a digital code. SAR ADCs are favored for medium-resolution, high-throughput, low-latency conversions because every conversion completes in a fixed number of clock cycles with no pipeline delay. Within the broader signal-chain hierarchy, the MAX1229 sits at the conversion stage between analog front ends (amplifiers, multiplexers, sensors) and digital processors (MCUs, FPGAs, DSPs), and it belongs to Maxim's MAX1227/MAX1229/MAX1231 family of multi-channel precision converters.
Key specifications include 12-bit resolution, 12 analog input channels (6 in differential mode), a 300 ksps maximum sampling rate, an internal 4.096 V reference, an internal temperature sensor with ±1 °C accuracy, and a 25-sample FIFO that offloads interrupt service on the host. The serial interface is SPI/QSPI/MICROWIRE-compatible, which simplifies connection to most microcontrollers and DSPs. An integrated 16-channel analog input mux allows direct connection to a bank of sensors without external switching.
Architecturally, the device pairs a charge-redistribution DAC with a precision comparator and on-chip calibration logic, allowing the converter to deliver 12-bit linearity without external trimming. The internal reference is factory-trimmed for low drift, and the wide 2.7 V to 3.6 V analog/digital supply range supports single-rail 3.3 V systems as well as battery-powered designs.
Typical applications include industrial data acquisition, multi-sensor monitoring boards, patient-monitoring front ends, and portable instrumentation that benefits from the integrated FIFO and temperature sensor. Engineers choose this part when they need to scan multiple analog channels quickly while keeping the host MCU free for higher-level tasks.
A practical design consideration is that the analog input signals must be referenced to the same ground as the AGND pin, and decoupling must be placed close to AVDN and DVDD pins to keep the internal reference stable under load. Use the FIFO depth to buffer burst conversions, allowing the host to sleep between conversions and reduce average power.
Drop-in alternatives for MAX1229ACEP+ — 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 MAX1229ACEP+ (same form factor and footprint) — differing in Architecture, Mounting Type, Resolution, Analog Input Type, Analog Supply Voltage.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
MAX1227ACEP+
✅ Drop-In📋 Reference alternative (not in catalog)
MAX1231ACEP+
✅ Drop-In📋 Reference alternative (not in catalog)
MAX1229ACEP+T
✅ Drop-In✓ In Stock
$7.2 / Unit
View Datasheet →MAX1229ACEP
✅ Drop-In📋 Reference alternative (not in catalog)
MAX1229ACEP+ Maximum Ratings & Electrical Characteristics
| Resolution | 12 bits |
| Number of Channels | 12 single-ended / 6 differential |
| Sampling Rate | 300 ksps |
| Architecture | SAR (Successive Approximation) |
| Input Type | Pseudo-Differential / Single-Ended |
| Data Interface | SPI, QSPI, MICROWIRE-compatible serial |
| Analog Supply Voltage | 2.7 V to 3.6 V |
| Digital Supply Voltage | 2.7 V to 3.6 V |
| Internal Reference | 4.096 V |
| Reference Type | Internal, factory-trimmed |
| FIFO Buffer | 25 samples |
| Temperature Sensor | Internal, ±1 °C accuracy |
| Package Type | 20-QSOP (0.154 inch / 3.90 mm width) |
| Mounting Type | Surface Mount |
| Operating Temperature | 0 °C to +70 °C |
| Temperature Grade | Commercial |
| RoHS Status | Compliant |
MAX1229ACEP+ Pin Configuration
| Pin 1 | AIN1 — Analog input channel 1 |
| Pin 2 | AIN2 — Analog input channel 2 |
| Pin 3 | AIN3 — Analog input channel 3 |
| Pin 4 | AIN4 — Analog input channel 4 |
| Pin 5 | AIN5 — Analog input channel 5 |
| Pin 6 | AIN6 — Analog input channel 6 |
| Pin 7 | AIN7 — Analog input channel 7 |
| Pin 8 | AIN8 — Analog input channel 8 |
| Pin 9 | AGND — Analog ground |
| Pin 10 | AVDD — Analog supply voltage |
| Pin 11 | REF — Reference bypass / external ref input |
| Pin 12 | AIN9 — Analog input channel 9 |
| Pin 13 | AIN10 — Analog input channel 10 |
| Pin 14 | AIN11 — Analog input channel 11 |
| Pin 15 | AIN12 — Analog input channel 12 |
| Pin 16 | DVDD — Digital supply voltage |
| Pin 17 | DGND — Digital ground |
| Pin 18 | CS — Active-low chip select |
| Pin 19 | DOUT/DRDY — Serial data output / data ready |
| Pin 20 | SCLK — Serial clock input |
Typical Applications
MAX1229ACEP+ is suitable for 6 applications: Industrial Data Acquisition Systems, Multi-Sensor Monitoring Boards, Patient Monitoring Front Ends, Portable Test and Measurement Instruments, Data Logging and Process Control, Audio Signal Acquisition and Measurement.
Industrial Data Acquisition Systems
The MAX1229ACEP+'s 12 single-ended / 6 differential input channels, 300 ksps throughput, and on-chip FIFO make it a natural fit for industrial data-acquisition front ends. With 12-bit resolution and an integrated 4.096 V internal reference, it acquires multiple sensor outputs (temperature, pressure, current) with a single IC while the 25-sample FIFO keeps the host MCU free for higher-level processing. Compared to a discrete mux plus a discrete ADC, this design reduces board area and BOM, and the 2.7 V to 3.6 V supply simplifies integration with 3.3 V industrial controllers.
Recommended
Multi-Sensor Monitoring Boards
Battery- and solar-powered sensor nodes benefit from the MAX1229ACEP+'s 25-sample FIFO that lets the host MCU burst-convert multiple channels then enter deep sleep until results are ready. The 12 single-ended inputs accept up to 12 analog sensors directly, the 12-bit result is plenty for most environmental monitoring, and the integrated ±1 °C temperature sensor eliminates a separate thermistor ADC channel. Estimated typical power at 3.3 V and 100 ksps averages around a few mW, well below any external analog switching solution.
Recommended
Patient Monitoring Front Ends
Medical-grade multi-parameter patient monitors benefit from the MAX1229ACEP+'s ability to scan several analog signals (ECG, temperature, SpO2 front end, respiration) through a single ADC. The 300 ksps sampling rate is more than adequate for low-frequency physiological signals, the integrated reference removes the need for periodic calibration against a separate reference IC, and the temperature sensor supports on-board health monitoring. Commercial temperature grade (0 °C to +70 °C) suits portable medical devices that are not used in acute care settings.
Recommended
Portable Test and Measurement Instruments
Handheld multimeters and bench instruments use the MAX1229ACEP+ to acquire multiple measurement channels simultaneously while keeping power and board area low. The 12-bit resolution is sufficient for general-purpose instruments, the FIFO allows burst sampling without losing samples to processor interrupt latency, and the small 20-QSOP package fits easily into portable enclosures. Compared to a discrete ADC + mux architecture, this part reduces assembly cost and improves long-term reliability of the analog front end.
Recommended
Data Logging and Process Control
PLC analog input modules and data loggers use the MAX1229ACEP+ to scan many analog channels with deterministic per-channel latency thanks to the SAR architecture. With 300 ksps and 12 channels, an effective aggregate throughput of up to 25 ksps per channel is achievable, more than adequate for thermocouple, RTD-conditioned, and 4-20 mA loop inputs. The wide 2.7 V to 3.6 V supply allows direct connection to 3.3 V backplanes without level shifters.
Recommended
Audio Signal Acquisition and Measurement
Although the MAX1229ACEP+ is designed for DC-precision data acquisition, its 300 ksps bandwidth and 12-bit linearity can serve low-bandwidth audio measurement tasks such as periodic level metering, headroom monitoring, and slow-spectrum capture. The internal FIFO buffers 25 consecutive samples which is useful for triggered audio events, and the SPI interface easily hooks up to a DSP for visualization. For high-fidelity audio, however, a higher-resolution dedicated audio ADC like the MAX1154 family will deliver better dynamic range than this 12-bit part.
Recommended
Recommended Products Summary
Engineering reference data for MAX1229ACEP+ — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | MAX1227ACEP+ | MAX1231ACEP+ | MAX1229ACEP+T | MAX1229ACEP | MAX1162ACUB+T |
|---|---|---|---|---|---|---|
| Brand | Maxim Integrated | Maxim Integrated | Maxim Integrated | Maxim Integrated | Maxim Integrated | Maxim Integrated |
| Package | 20-QSOP | 20-QSOP - same | 20-QSOP - same | 20-QSOP - same | 20-QSOP - same | 10-µMAX - different |
| Resolution | 12 bits | 12 bits | 12 bits | 12 bits | 12 bits | 14 bits |
| Sampling Rate | 300 ksps | 225 ksps | 300 ksps | 300 ksps | 300 ksps | 200 ksps |
| Number of Channels | 12 single-ended / 6 differential | 12 / 6 | 8 / 4 | 12 / 6 | 12 / 6 | 1 / 1 |
| FIFO Buffer | 25 samples | 25 samples | 25 samples | 25 samples | 25 samples | No FIFO |
| Internal Reference | 4.096 V | 4.096 V | 4.096 V | 4.096 V | 4.096 V | No internal ref |
| Internal Temp Sensor | Yes (±1 °C) | Yes (±1 °C) | Yes (±1 °C) | Yes (±1 °C) | Yes (±1 °C) | No |
| Supply Voltage Range | 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 |
Key Differentiators
- Highest sampling rate in MAX1227/29/31 family (vs MAX1227ACEP+)
- Most analog input channels in family (vs MAX1231ACEP+)
- Family-identical internal features (vs MAX1162ACUB+T)
Design Notes
Both AVDD and DVDD must be tied to the same 2.7 V to 3.6 V supply, but their decoupling should be local to the IC with separate 100 nF and 10 µF ceramic capacitors on each pin according to the datasheet. A low-impedance ground plane connects AGND and DGND at a single point to prevent digital switching currents from corrupting the analog conversion path.
Route the SPI signals (SCLK, DOUT, CS) with ground-referenced traces and keep analog input traces away from digital signals to minimize coupling. Use a star-ground topology with the AGND to DGND return tied at one point under the IC. Place the reference bypass capacitor as close to the REF pin as possible; the value recommended by the datasheet is typically 4.7 µF or 10 µF depending on noise requirements.
Do not apply analog voltages beyond AVDD + 0.3 V to any AINx pin; this will forward-bias the input ESD clamp and inject current into the analog supply. The CS pin must be held low for the entire SPI transaction because a mid-transaction deassertion will corrupt the conversion register and trigger a data-ready mismatch on the next conversion.
Estimated: driving the SPI bus from an MCU at > 10 MHz of trace length can introduce ringing; a series 33 ohm resistor close to the driver and a 10 pF to 22 pF load on DOUT can typically clean up the waveform on a 20-QSOP pin pitch. Always verify with scope probing at the MAX1229ACEP+ pins rather than at the source MCU.
Compliance Information
Maxim Integrated product is RoHS compliant with lead-free plating per the '+' suffix on the MPN. AEC-Q100 qualification is not applicable to this commercial-temperature-grade part; consider the automotive-grade variant if required.
