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Analog Devices Inc./Maxim Integrated MAX1231BCTI+
- Part No.:
- MAX1231BCTI+
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Analog to Digital Converters (ADC)
- Package:
- 28-WFQFN Exposed Pad
- Datasheet:
-
MAX1231BCTI+.pdf
- Description:
- IC ADC 12BIT SAR 28TQFN
- Quantity:
- Payment:
- Shipping:
Inventory:1,849
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Product details
Overview
MAX1231BCTI+ from Maxim Integrated is a 12-bit, 300ksps serial analog-to-digital converter with integrated temperature sensor (±0.7°C accuracy), 16-entry FIFO, internal 2.5V reference, and SPI/QSPI/MICROWIRE-compatible 3-wire interface. It supports 16 single-ended or 8 true differential input channels in unipolar/bipolar modes and operates from a single +3V supply. It is used in industrial control systems for multichannel sensor data acquisition with on-chip temperature monitoring.
For engineers reviewing the MAX1231BCTI+ datasheet, MAX1231BCTI+ pinout, MAX1231BCTI+ application, or MAX1231BCTI+ equivalent, this page delivers verified specifications, package mapping to 28-pin TQFN-EP (5mm × 5mm), confirmed FIFO depth and conversion timing behavior, real-world input configuration options, and two validated alternative parts for system-level design continuity.
Technical Context
The MAX1231BCTI+ employs a fully differential successive-approximation register (SAR) architecture with on-chip track-and-hold, supporting both single-ended and true differential inputs. Its internal oscillator enables internally timed conversions in clock modes 00/01/10, while mode 11 supports externally clocked operation up to 10MHz SCLK for full 300ksps throughput.
It integrates a dedicated temperature-sensing path using the internal reference, delivering 1/8°C resolution in two's complement format. The 16-deep FIFO buffers ADC results and temperature readings independently, allowing background conversions without serial bus contention - critical for deterministic sampling in embedded control loops.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Resolution | 12-bit SAR - delivers 1 LSB INL/DNL accuracy with no missing codes over -40°C to +85°C. |
| Max Sampling Rate | 300ksps with external clock - enables high-speed transient capture in process monitoring applications. |
| Input Channels | 16 single-ended or 8 true differential - supports scalable sensor arrays without external multiplexers. |
| Internal Reference | 2.50V ±2mV (±30ppm/°C TC) - eliminates need for external precision reference in cost-sensitive designs. |
| Temperature Sensor | ±0.7°C accuracy at +25°C, ±1.2°C over full range - provides calibrated board-level thermal feedback without calibration overhead. |
| Digital Interface | 10MHz SPI/QSPI/MICROWIRE-compatible 3-wire - interoperates with standard microcontroller peripherals without protocol translation. |
| Supply Current | 1mA at 300ksps (internal ref), 0.2–5µA in AutoShutdown™ - enables battery-powered data loggers with multi-week runtime. |
Pinout & Package
The MAX1231BCTI+ is packaged in a 28-pin TQFN with exposed pad (5mm × 5mm), requiring GND connection of the EP for thermal and electrical performance. Pin functions are validated per Maxim's official pin description table and functional diagram (Rev 7, April 2012).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| AIN0–AIN15 | Analog Input Channels | 16 configurable inputs; each may serve as single-ended channel or differential pair (e.g., AIN0/AIN1), with programmable unipolar/bipolar mode. |
| REF+/REF− | Reference Inputs | REF+ accepts 1.0V to VDD+50mV; REF− serves as negative reference or alternate analog input (AIN14/AIN10/AIN6 depending on variant). |
| CNVST/AIN15 | Conversion Start / Analog Input | Active-low hardware trigger for scan initiation; when configured as analog input, AIN15 is excluded from conversion requests. |
| SCLK, DIN, DOUT, CS | Serial Interface Signals | 3-wire SPI-compatible interface; DOUT updates on falling SCLK edge; CS enables tri-state output and initiates command byte transfer. |
| EOC | End-of-Conversion Flag | Active-low open-drain output signaling completion of last requested operation; behavior varies by clock mode (e.g., pulses per conversion in mode 01). |
| VDD, GND, EP | Power & Ground | +2.7V to +3.6V supply; EP must be soldered to PCB ground plane for thermal dissipation and noise immunity. |
Key Features
| Feature | Design Value |
|---|---|
| On-chip 16-entry FIFO | Buffers up to 16 ADC results plus one temperature reading - decouples conversion timing from host processor latency, enabling deterministic real-time sampling. |
| True differential track-and-hold | Rejects common-mode noise on matched input pairs (e.g., AIN0/AIN1) - preserves signal integrity in noisy industrial environments without external instrumentation amps. |
| Internal temperature sensor | Delivers calibrated die temperature with ±0.7°C accuracy at +25°C - eliminates external sensor BOM cost and layout area in thermal management subsystems. |
| AutoShutdown™ mode | Reduces supply current to ≤5µA between conversions - extends battery life in portable data-acquisition devices and reduces self-heating error during idle periods. |
| Configurable clock modes | Four CKSEL settings (00–11) support hardware-triggered scans, software-controlled single conversions, or externally timed high-speed acquisition - adapts to diverse system timing architectures. |
Applications
| Industrial Process Monitoring | Patient Vital Sign Acquisition |
|---|---|
Use Scenario: Continuous logging of pressure, flow, and temperature signals from multiple sensors in PLC-based control cabinets. IC Role / Device Role / Timing Role: Central multichannel ADC managing 12+ analog inputs with synchronized sampling and on-chip temperature compensation. Use Value: Reduces external component count by integrating FIFO, reference, and temp sensor - simplifies certification for IEC 61000-4 EMC compliance in factory automation. |
Use Scenario: Portable ECG and SpO₂ monitor acquiring biopotential signals with simultaneous ambient temperature tracking for sensor drift correction. IC Role / Device Role / Timing Role: High-accuracy front-end digitizer with true differential inputs rejecting 50/60Hz mains interference and internal thermal reference. Use Value: Enables clinical-grade measurement stability (±1 LSB INL) across operating temperature range without recalibration - meets ISO 80601-2-61 requirements. |
| Data Logger for Environmental Sensing | Smart Energy Meter Sensor Hub |
Use Scenario: Solar-powered remote node measuring soil moisture, air temperature, and humidity over extended duty cycles. IC Role / Device Role / Timing Role: Low-power ADC performing scheduled conversions and periodic temperature reads, then entering AutoShutdown™ between samples. Use Value: Achieves 1mA active current and sub-5µA shutdown - enables >6-month battery life on two AA cells while maintaining 12-bit resolution. |
Use Scenario: Sub-metering module capturing voltage, current, and neutral current waveforms in residential energy monitors. IC Role / Device Role / Timing Role: Simultaneous sampling engine using differential inputs for CT/PT interfaces and internal temp sensor for gain drift compensation. Use Value: Internal 2.5V reference (±30ppm/°C) ensures <0.1% gain error shift over temperature - satisfies ANSI C12.20 Class 0.5 accuracy class. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar multichannel, temperature-integrated ADC applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| ADS8684IPWR | 16-bit resolution, 500ksps, external reference only, no integrated temp sensor | Higher precision required; thermal compensation handled externally | Select when absolute accuracy >±0.5LSB is mandatory and system already includes precision reference and temp sensing. |
| AD7949BCPZ-RL7 | 14-bit, 250ksps, SPI interface, no FIFO, no temp sensor, requires external reference | Lower cost, lower power, simpler interface - suited for non-critical monitoring | Choose when FIFO buffering and on-die temperature measurement are not required and board space is constrained. |
Compared with MAX1231BCTI+, ADS8684IPWR offers higher resolution but lacks integrated temperature sensing and FIFO - increasing BOM and firmware complexity. AD7949BCPZ-RL7 reduces integration level significantly, requiring external reference and separate thermal monitoring, making it suitable only for less demanding applications where cost outweighs feature consolidation.
Availability
MAX1231BCTI+ is available at Aetrix Electronics and suitable for industrial control systems, portable medical devices, environmental data loggers, and smart energy metering requiring stable component supply and long-term lifecycle support.
Supply support for MAX1231BCTI+ includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.
Manufacturer
Maxim Integrated (now part of Analog Devices) designs precision analog and mixed-signal ICs for industrial, automotive, and communications applications, emphasizing integration, reliability, and low-power operation.
The MAX1227/MAX1229/MAX1231 product line was engineered for embedded data-acquisition systems needing multichannel conversion, on-chip intelligence (FIFO, averaging, temp sensing), and minimal external components - targeting space-constrained, thermally variable environments.
FAQ
What is the maximum sampling rate achievable with MAX1231BCTI+ using its internal clock?
The MAX1231BCTI+ achieves up to 300ksps only when using an external clock source (CKSEL = 11). With its internal oscillator (CKSEL = 00/01/10), the maximum sampling rate is limited to approximately 200ksps due to ±10% oscillator tolerance and acquisition time constraints. For deterministic high-speed acquisition, external clocking is required - the MAX1231BCTI+ datasheet specifies 300ksps strictly under externally clocked conditions.
Does MAX1231BCTI+ support true differential input across all 16 channels?
No. MAX1231BCTI+ supports true differential input only on predefined channel pairs: AIN0/AIN1, AIN2/AIN3, AIN4/AIN5, AIN6/AIN7, AIN8/AIN9, AIN10/AIN11, AIN12/AIN13, and AIN14/AIN15 - totaling eight differential channels. Individual channels cannot be arbitrarily paired; the pairing is fixed in hardware and selected via the setup register. AIN15 is only available as part of the AIN14/AIN15 pair or as CNVST/AIN15, not as a standalone differential input.
How is the internal temperature sensor of MAX1231BCTI+ calibrated and what is its output format?
The MAX1231BCTI+ internal temperature sensor outputs a 12-bit two's complement code representing temperature in 1/8°C increments (e.g., 0x0000 = 0°C, 0x0008 = +1°C). It is factory-calibrated to ±0.7°C accuracy at +25°C and ±1.2°C over –40°C to +85°C. The sensor uses the internal 2.5V reference exclusively and cannot operate with external references - the value is read from the FIFO alongside ADC results, with the first two bytes after a temperature request containing the sensor reading.
Can MAX1231BCTI+ operate with a 5V supply voltage?
No. MAX1231BCTI+ is specified for operation only within VDD = +2.7V to +3.6V. Applying 5V exceeds the Absolute Maximum Rating of +6V on VDD but violates the recommended operating conditions and risks parametric degradation, increased leakage, or permanent damage. Systems requiring 5V rails must use a dedicated LDO or DC-DC converter to generate a compliant +3.3V supply - the device does not support 5V-tolerant I/O or wide-supply operation.
What happens to the FIFO in MAX1231BCTI+ when it overflows during continuous conversion?
When the 16-entry FIFO in MAX1231BCTI+ fills and additional conversions complete, new results overwrite the oldest unread entries - a circular buffer behavior with no overflow flag or interrupt. The DOUT pin outputs the oldest available byte on each CS falling edge, MSB first. If the host fails to read before overflow, data loss occurs silently; robust firmware must monitor EOC timing and maintain read rate ≥ conversion rate to prevent undetected corruption of time-series data.
MAX1231BCTI+ Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- 28-WFQFN Exposed Pad
- Packaging:
- Tube
- Product Status:
- Active
- Number of Bits:
- 12
- Sampling Rate (Per Second):
- 300k
- Number of Inputs:
- 8, 16
- Input Type:
- Differential, Single Ended
- Data Interface:
- SPI
- Configuration:
- S/H-ADC
- Ratio - S/H:ADC:
- 1:1
- Number of A/D Converters:
- 1
- Architecture:
- SAR
- Reference Type:
- External, Internal
- Voltage - Supply, Analog:
- 2.7V ~ 3.6V
- Voltage - Supply, Digital:
- 2.7V ~ 3.6V
- Features:
- Temperature Sensor
- Operating Temperature:
- 0°C ~ 70°C
- Supplier Device Package:
- 28-TQFN (5x5)
- Mounting Type:
- Surface Mount
- Grade:
- -
- Qualification:
- -
MAX1231BCTI+ FAQ
1.How can I place an order for MAX1231BCTI+ through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX1231BCTI+ on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for MAX1231BCTI+ reliable?
The price and inventory of MAX1231BCTI+ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX1231BCTI+ is usually 5 days.
3.What payment methods are accepted for MAX1231BCTI+?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX1231BCTI+ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX1231BCTI+?
MAX1231BCTI+ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX1231BCTI+ order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for MAX1231BCTI+?
For technical support, including MAX1231BCTI+ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX1231BCTI+ requirements.
6.How does Aetrix verify that MAX1231BCTI+ is sourced from the original manufacturer or authorized distributors?
All MAX1231BCTI+ products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that MAX1231BCTI+ meets industry standards.
7.What is the process for return or replacement of MAX1231BCTI+?
All MAX1231BCTI+ units undergo pre-shipment inspection (PSI). If there is an issue with MAX1231BCTI+, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The MAX1231BCTI+ part is unused and in its original packaging.
Return procedure for MAX1231BCTI+:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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