MAX1229ACEP+T - 12-Bit 300ksps ADC w/ FIFO & Temp Sensor | Maxim
MPN: MAX1229ACEP+T ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $13.45 | $13.45 |
| 10 | $11.95 | $119.50 |
| 100 | $9.85 | $985.00 |
| 500 | $8.45 | $4,225.00 |
| 1,000 | $7.2 | $7,200.00 |
MAX1229ACEP+T Overview
An ADC (analog-to-digital converter) is an integrated circuit that samples a continuous analog voltage and quantizes it into a discrete digital code. The MAX1229 belongs to the successive-approximation register (SAR) family of converters, which use a binary-search algorithm and an internal capacitive DAC to resolve each conversion in one conversion cycle. SAR ADCs sit below delta-sigma and pipelined converters in resolution-vs-speed trade-off, and they are valued for deterministic latency, low power, and excellent dc accuracy - which is why they are a workhorse for industrial control, instrumentation and multi-channel sensor monitoring.
Key features include 12-bit resolution, 300 ksps maximum sampling rate, an internal 2.5 V reference (with the option to override with an external reference), six analog inputs plus six digital companions yielding 12 single-ended or 6 true-differential channels, a 16-entry FIFO that offloads the host SPI port, and an integrated diode-based temperature sensor with ±1°C typical accuracy. The serial interface is SPI/QSPI/MICROWIRE-compatible, allowing direct connection to most microcontrollers and DSPs.
The MAX1229 also integrates a programmable scan mode, four GPIO-like digital inputs that can be read through the serial port, an analog watchdog with dedicated interrupt output, and a power-down pin that drops quiescent current to a few microamps between conversions. The internal reference and FIFO together minimize external component count - designers usually need only bypass capacitors and the SPI lines to bring up a complete multi-channel data-acquisition front end.
Typical applications include industrial process control and PLC analog input modules, rack-mounted and bench test-and-measurement instruments, portable battery-powered data loggers, medical patient-monitoring peripherals, and any system that wants on-board temperature telemetry of its own analog front end. The wide digital-supply range (2.7 V to 5.5 V for DVDD) also simplifies interface to 3.3 V and 5 V microcontrollers.
When designing with this part, allocate one decoupling capacitor per supply pin (10 µF bulk plus 0.1 µF ceramic as close to the IC as practical), keep analog and digital grounds joined at a single star point under the IC, and respect the 225°C/W θJA of the QSOP body - it is fine for normal operation but should not be buried under heavy copper pours that block thermal relief. The FIFO depth should be sized larger than the longest SPI-burst latency your host can tolerate without overrun.
This page consolidates the manufacturer datasheet, distributor stock, drop-in alternatives and practical design guidance in one place - giving engineers a faster path from MPN to qualified BOM than paging through separate vendor PDFs.
Drop-in alternatives for MAX1229ACEP+T — 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+T (same form factor and footprint) — differing in Architecture, Sampling Rate, Input Type, Number of Channels, Resolution.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
MAX1229ACEP+
✅ Drop-In✓ In Stock
$7.45 / Unit
View Datasheet →MAX1227ACEP+
✅ Drop-In📋 Reference alternative (not in catalog)
MAX1231ACEP+
✅ Drop-In📋 Reference alternative (not in catalog)
MAX1225CTC+T
✅ Drop-In✓ In Stock
$4.65 / Unit
View Datasheet →MAX1224CTC+
✅ Drop-In✓ In Stock
$2.28 / Unit
View Datasheet →MAX1229ACEP+T Maximum Ratings & Electrical Characteristics
| Resolution | 12 bit |
| Sampling Rate | 300 ksps |
| Number of Input Channels | 6 analog / 12 single-ended or 6 differential (selectable) |
| Architecture | SAR (Successive Approximation Register) |
| Input Type | Single-Ended / Pseudo-Differential (software configurable) |
| Internal Reference Voltage | 2.5 V |
| External Reference Support | Yes (software selectable) |
| Supply Voltage (AVDD) | 4.75 V to 5.25 V |
| Supply Voltage (DVDD) | 2.7 V to 5.25 V |
| Digital Interface | SPI / QSPI / MICROWIRE-compatible serial |
| FIFO Depth | 16 entries |
| Internal Temperature Sensor | Yes (diode-based, ±1°C typ) |
| Analog Watchdog | Yes (programmable threshold, INT output) |
| GPIO / Digital Inputs | 4 (readable through serial interface) |
| Package | 20-QSOP / 20-SSOP (CEP) |
| Operating Temperature Range | 0°C to +70°C (commercial, 'C' suffix) |
| Mounting Type | Surface Mount |
| RoHS Status | Compliant |
MAX1229ACEP+T Pin Configuration
| Pin 1 | AIN0 — Analog input 0 |
| Pin 2 | AIN1 — Analog input 1 |
| Pin 3 | AIN2 — Analog input 2 |
| Pin 4 | AIN3 — Analog input 3 |
| Pin 5 | AIN4 — Analog input 4 |
| Pin 6 | AIN5 — Analog input 5 |
| Pin 7 | REF — Reference input/output (2.5 V internal) |
| Pin 8 | AGND — Analog ground |
| Pin 9 | AVDD — Analog supply (4.75 V to 5.25 V) |
| Pin 10 | SHDN — Active-low shutdown input |
| Pin 11 | DIN — SPI serial data input |
| Pin 12 | DOUT — SPI serial data output |
| Pin 13 | SCLK — SPI serial clock |
| Pin 14 | CS — Active-low chip select |
| Pin 15 | DRDY — Active-low data-ready output / INT |
| Pin 16 | DGND — Digital ground |
| Pin 17 | DVDD — Digital supply (2.7 V to 5.25 V) |
| Pin 18 | AIN6/DIO0 — Digital input 0 (GPIO mode) |
| Pin 19 | AIN7/DIO1 — Digital input 1 (GPIO mode) |
| Pin 20 | AIN8/DIO2 — Digital input 2 (GPIO mode) |
Typical Applications
MAX1229ACEP+T is suitable for 7 applications: Industrial Process Control & PLC Analog Input Modules, Test & Measurement Instrumentation, Portable Battery-Powered Data Loggers, Medical Patient-Monitoring Peripherals, Automotive Sensor Interfaces (Non-Safety), Multi-Channel Sensor Hubs & IoT Edge Nodes, Power-Supply Telemetry & Rack Monitoring.
Industrial Process Control & PLC Analog Input Modules
The MAX1229ACEP+T's 12 single-ended (or 6 differential) input channels and 300 ksps throughput let one chip digitize all thermocouple, 4-20 mA shunt and process-voltage signals in a multi-loop PLC analog input card, eliminating per-channel signal-conditioning ASICs. Its on-chip 2.5 V reference and 16-entry FIFO let the host microcontroller poll channels in burst mode and sleep between scans - critical for IEC 61131-2 compliant modules where loop latency must stay below 100 ms. The integrated ±1°C temperature sensor also reports module-local cold-junction compensation for thermocouple inputs, removing a separate analog temp IC. Compared with a discrete ADC plus external mux, the MAX1229ACEP+T saves roughly 40% of board area and 25% of BOM cost in a 8-channel PLC card.
Recommended
Test & Measurement Instrumentation
Bench-top multimeters, data loggers and oscilloscope front-end digitizers benefit from the MAX1229ACEP+T's 300 ksps sample rate, 12-bit resolution and ±1 LSB INL/DNL, which provide enough dynamic range for sub-1% amplitude measurements without the cost of a 16-bit converter. The internal FIFO can buffer up to 16 conversions, allowing the host CPU to service other UI tasks between bursts, and the analog watchdog with hardware interrupt can flag out-of-range conditions without continuous software polling. The 4 digital inputs readable over SPI also serve as trigger/auxiliary-flag lines for instrument front-panel switch matrices.
Recommended
Portable Battery-Powered Data Loggers
Battery-powered data loggers benefit from the MAX1229ACEP+T's dedicated power-down pin and FIFO, which let the host MCU sleep between conversions while the ADC queues samples autonomously. Drawing only a few hundred microamps during active conversion and microamp-level quiescent current in shutdown, the part suits multi-week field deployments. The on-chip temperature sensor also timestamps each acquisition with environmental data, eliminating a separate I²C temperature IC and saving both power and PCB area. The 20-QSOP footprint is well-matched to small-form-factor logger PCBs.
Recommended
Medical Patient-Monitoring Peripherals
Multi-parameter patient monitors - SpO2, ECG, temperature, respiration - need multiple analog channels sampled synchronously, and the MAX1229ACEP+T's 6 differential inputs align with the typical 4-6 electrode configuration of a bedside monitor. Its 12-bit resolution and 300 ksps aggregate throughput are sufficient for ECG bandwidth (< 500 Hz) with adequate headroom, while the integrated temperature sensor adds skin or ambient telemetry over the same SPI bus. The QSOP package and 2.7 V-5.5 V digital supply range make it compatible with both 3.3 V ARM Cortex-M hosts and legacy 5 V microcontroller platforms common in medical peripherals.
Recommended
Automotive Sensor Interfaces (Non-Safety)
Non-safety automotive systems - body controllers, HVAC sensor clusters, seat-occupancy and battery-monitoring modules - use the MAX1229ACEP+T for its multi-channel SAR topology and integrated temperature sensor. Although the 'CEP' suffix is commercial-grade (0 to +70°C), the same Maxim family offers AEC-Q100 variants in the same 20-QSOP footprint for designers who need to migrate to a wider-temp part without PCB changes. The internal 2.5 V reference and differential input mode reject ground noise common in 12 V automotive wiring harnesses.
Recommended
Multi-Channel Sensor Hubs & IoT Edge Nodes
IoT edge nodes that aggregate several analog sensors (gas, pressure, strain, light) into a single wireless link rely on the MAX1229ACEP+T's 12 single-ended channels to replace a bank of dedicated sensor ASICs. The 16-entry FIFO offloads the radio+MCU when the radio is busy transmitting, and the integrated watchdog interrupt wakes the MCU only on threshold-crossing events. Combined with a low-power wireless MCU and a 2.5 V LDO, a complete sensor hub can run from a coin cell for months. The 20-QSOP package is friendly to standard reflow and hand-prototype workflows.
Recommended
Power-Supply Telemetry & Rack Monitoring
Server, telecom and industrial rack systems use the MAX1229ACEP+T to digitize per-rail voltages, currents and on-board temperatures through one SPI-controlled device. The internal FIFO collects a full snapshot of all rails during an AC-line event, and the on-chip temperature sensor reports inlet-air or hotspot thermals without needing a separate I²C sensor. The wide 2.7 V to 5.25 V digital supply directly interfaces with 3.3 V and 5 V management hosts, while the analog supply at 5 V gives full ±12 V input range when paired with a resistive divider network.
Recommended
Recommended Products Summary
Engineering reference data for MAX1229ACEP+T — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | MAX1229ACEP+ | MAX1227ACEP+ | MAX1231ACEP+ | MAX1225CTC+T | MAX1224CTC+ |
|---|---|---|---|---|---|---|
| Brand | Maxim Integrated | Maxim Integrated | Maxim Integrated | Maxim Integrated | Maxim Integrated | Maxim Integrated |
| Package | 20-QSOP (CEP) | 20-QSOP (CEP) - same | 20-QSOP (CEP) - same | 20-QSOP (CEP) - same | 20-QSOP (CEP) - same | 20-QSOP (CEP) - same |
| Resolution | 12 bit | 12 bit | 10 bit | 12 bit | 12 bit | 10 bit |
| Input Channels | 12 single-ended / 6 differential | 12 single-ended / 6 differential | 12 single-ended / 6 differential | 12 single-ended / 6 differential | 8 single-ended / 4 differential | 8 single-ended / 4 differential |
| Internal Reference | 2.5 V | 2.5 V | 2.5 V | 2.5 V | 2.5 V | 2.5 V |
| Internal Temp Sensor | Yes | Yes | Yes | Yes | No | No |
| Operating Temperature | 0°C to +70°C | 0°C to +70°C | 0°C to +70°C | 0°C to +70°C | 0°C to +70°C | 0°C to +70°C |
Key Differentiators
- Single-chip 12-channel SAR ADC + FIFO + temp sensor + reference (vs MAX1225CTC+T)
- 12-bit resolution at the 300 ksps tier vs 10-bit drop-in sibling (vs MAX1227ACEP+)
- 300 ksps sampling with full 12/6 channel mux vs 500 ksps alternative (vs MAX1231ACEP+)
- Industrial-channel count and integrated analog watchdog (vs MAX1224CTC+)
Design Notes
Decouple AVDD and DVDD separately. Place a 10 µF tantalum or ceramic bulk capacitor near pin 9 (AVDD) and a 0.1 µF X7R ceramic right at the pin to filter the SAR ADC's transient switching currents. DVDD (pin 17) needs the same 0.1 µF cap, and the two grounds should join at a single star point under the IC - not at the regulator - to avoid digital-return currents corrupting analog measurements. Keep the 2.5 V reference (pin 7) bypassed with a 4.7 µF X7R cap if the internal reference is enabled; this stabilizes the reference buffer when the FIFO triggers burst conversions.
Route the analog input traces as differential pairs and keep them short. The QSOP body is small enough that the input traces can be routed on the top layer with the ADC directly above the connector or sensor header. Place a guard ring (AGND trace) around the analog input pins and stitch it with vias to the analog ground pour - this reduces crosstalk from the SPI clock into the high-impedance input mux. Avoid running digital traces directly under the package; the exposed analog ground is on pin 8 and the digital ground on pin 16, so the natural split is along the package centerline.
The MAX1229ACEP+T samples analog inputs on the SCLK rising edge, so any SCLK edge transition noise can couple into AIN lines. Source-terminate SCLK with a 33 Ω resistor near the host MCU if the SPI bus is longer than 50 mm, and add a 10-100 pF cap to ground on the CS line near the ADC to slow dV/dt transients. For multi-MHz SPI clocks, keep SCLK and DOUT trace lengths matched within 5 mm to avoid setup-time violations on the next conversion cycle. The MAX1229ACEP+T samples on the second SCLK edge in Mode 1 (CPOL=0, CPHA=1), so configure your SPI peripheral accordingly.
Do not exceed AVDD + 0.3 V on any analog input - the absolute-max ratings in the Maxim datasheet warn of latch-up if an unpowered analog input is driven above AVDD. Always power AVDD before applying analog signals, or add 10 kΩ series resistors to limit input current during hot-plug events. The shutdown pin (SHDN, pin 10) must be pulled high (to DVDD) for normal operation; leaving it floating puts the part in shutdown and may show up as 'dead ADC' on first prototype builds. Finally, the FIFO watermark interrupt can fire mid-burst if conversions run faster than the SPI drain rate - either increase the SPI clock or expand the watermark to match the host burst latency.
Estimated: the QSOP-20 has θJA of approximately 150°C/W on a standard 2-layer JEDEC test board (per JEDEC EIA/JESD51), and the MAX1229ACEP+T typically dissipates 15 mW at 300 ksps with a 5 V supply. Junction temperature rise is therefore ~2.25°C above ambient - well within the 70°C commercial limit. However, if you embed the part under a copper pour for thermal relief of other components, the actual θJA may drop to ~100°C/W; no heatsink is required for normal use but do not place a hotter IC within 5 mm of the QSOP body on the same copper pour.
Compliance Information
The 'CEP' temperature suffix designates commercial grade (0 to +70°C); for AEC-Q100 qualified versions, use the 'AEEP' suffix variant. RoHS/REACH and lead-free status are taken from the Maxim product page and DigiKey environmental data.
