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Analog Devices Inc./Maxim Integrated MAX149AEAP
- Part No.:
- MAX149AEAP
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Analog to Digital Converters (ADC)
- Package:
- 20-SSOP (0.209", 5.30mm Width)
- Datasheet:
-
MAX149AEAP.pdf
- Description:
- IC ADC 10BIT SAR 20SSOP
- Quantity:
- Payment:
- Shipping:
Inventory:3,769
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Product details
Overview
MAX149AEAP from Maxim Integrated is a 10-bit, 8-channel serial analog-to-digital converter (ADC) with integrated track/hold, software-configurable unipolar/bipolar and single-ended/differential inputs, internal 2.5V reference, and SPI/QSPI/MICROWIRE-compatible 4-wire interface. It operates from +2.7V to +5.25V, achieves 133ksps sampling rate, and draws only 1.2mA at 3V - enabling high-accuracy data acquisition in portable medical instruments and battery-powered sensor nodes.
For engineers reviewing the MAX149AEAP datasheet, MAX149AEAP pinout, MAX149AEAP application, or MAX149AEAP equivalent, this page delivers verified technical context, real-world design meaning for key specs, validated pin functions, confirmed alternative parts with documented differences, and supply-ready availability details - all grounded in Maxim's official MAX149 datasheet Rev 5 (1/12).
Technical Context
The MAX149AEAP implements a successive-approximation register (SAR) ADC architecture with an integrated track/hold circuit, supporting both internal clock mode (1.8MHz typical) and external clock mode (up to 2.0MHz). Its analog front-end allows per-conversion software configuration of input polarity (unipolar/bipolar) and topology (single-ended/differential), with COM pin serving as zero-code reference in single-ended mode.
It features a dedicated reference-buffer amplifier with ±1.5% voltage-adjustment range via REFADJ, and supports two power-down states: full power-down (1µA) and fast power-down (30–70µA, MAX149-specific). The 4-wire serial interface includes SSTRB for direct TMS320-family DSP synchronization and operates without external logic across SPI/QSPI/MICROWIRE protocols.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Resolution | 10-bit - delivers 1024 discrete digital codes over full-scale range, sufficient for 0.1% measurement accuracy in industrial sensing. |
| Sampling Rate | 133ksps - enables real-time capture of signals up to ~66kHz (Nyquist), suitable for vibration monitoring and ECG waveform digitization. |
| INL (Max) | ±0.5 LSB (MAX149A grade) - ensures monotonicity and <0.05% integral nonlinearity error after calibration, critical for closed-loop control feedback. |
| Supply Current | 1.2mA @ 133ksps / 3V - enables >100-hour operation on a 120mAh coin cell when paired with duty-cycled sampling. |
| Reference | Internal 2.500V ±0.3% (25°C), ±30ppm/°C TC - eliminates need for external reference IC, reducing BOM count and layout area in space-constrained designs. |
| Input Range | Single-ended: 0 to VREF; Bipolar: ±VREF/2 - supports direct connection to transducer bridges and op-amp outputs without level-shifting circuitry. |
| Serial Interface | SPI/QSPI/MICROWIRE/TMS320-compatible 4-wire - interoperates natively with STM32, MSP430, and C2000 microcontrollers without glue logic or level shifters. |
Pinout & Package
MAX149AEAP is housed in a 20-pin SSOP (Shrink Small Outline Package) with 0.65mm lead pitch, RoHS-compliant and lead(Pb)-free.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| CH0–CH7 (Pins 1–8) | Analog input channels | Software-selectable as 8 single-ended or 4 differential pairs (e.g., CH0/CH1); each channel has ≤16pF input capacitance and ±0.01µA leakage. |
| COM (Pin 9) | Analog common reference | Sets zero-code voltage in single-ended mode; must remain stable to ±0.5 LSB - requires low-noise AGND connection and optional 0.1µF bypass. |
| SHDN (Pin 10) | Three-level shutdown control | Low = full shutdown (1µA); high = internal compensation mode; floating = external compensation mode - enables flexible power management without external GPIO. |
| VREF (Pin 11) | Reference buffer output / ADC reference input | Delivers 2.500V ±0.3% (MAX149); used directly as conversion reference - no external buffer needed unless load exceeds 0.2mA. |
| REFADJ (Pin 12) | Reference buffer gain adjustment | Allows ±1.5% fine-tuning of VREF; tie to VDD to disable internal buffer when using external reference (MAX148-only behavior, not applicable here). |
| AGND / DGND (Pins 13–14) | Analog and digital ground returns | Must be separated and joined at single point near VDD decoupling; AGND carries sensitive analog return current, DGND handles digital switching noise. |
| DOUT / SSTRB (Pins 15–16) | Serial data output / strobe sync | DOUT clocks MSB-first on SCLK falling edge; SSTRB pulses high before MSB in external clock mode - enables precise timing alignment with TMS320 DSP interrupt inputs. |
| DIN / CS / SCLK (Pins 17–19) | Serial command input / chip select / clock | Accepts standard SPI framing (CPOL=0, CPHA=0); CS must be held low during full 15-clock conversion cycle to avoid data corruption. |
| VDD (Pin 20) | Positive supply | Operates from +2.7V to +5.25V; requires 0.1µF ceramic + 4.7µF tantalum decoupling at pin - PSR of ±0.3mV ensures stable conversion under supply ripple. |
Key Features
| Feature | Design Value |
|---|---|
| 8-channel multiplexer with pseudo-differential architecture | Supports true differential measurements across four independent channel pairs (CH0/CH1, CH2/CH3, etc.) while maintaining single-ended pinout compatibility. |
| Internal 2.5V reference with ±1.5% adjustability | Eliminates external reference IC and associated passive components, reducing total solution size by ≥30% and improving long-term drift stability vs. resistor-divider references. |
| Two-stage power-down (full/fast) | Reduces supply current from 1.2mA to 1µA (full) or 30–70µA (fast), enabling adaptive sampling strategies where wake-up latency (<1.5µs) is acceptable. |
| 15-clock conversion cycle with SSTRB synchronization | Guarantees deterministic timing for real-time systems - SSTRB pulse aligns precisely with MSB output, simplifying FPGA or DSP firmware timing loops. |
| Software-configurable unipolar/bipolar and single/diff modes | Per-conversion register programming allows mixed-signal acquisition (e.g., temperature + strain gauge + accelerometer) without hardware reconfiguration. |
Applications
| Portable ECG Monitor | Battery-Powered Environmental Sensor Node |
|---|---|
|
Use Scenario: Continuous 3-lead ECG waveform digitization in handheld clinical device powered by CR2032 battery. IC Role / Device Role / Timing Role: Primary ADC acquiring analog leads at 1ksps with bipolar ±1.25V input range, synchronized to MCU timer via SSTRB. Use Value: 10-bit resolution + ±0.5 LSB INL ensures accurate R-wave amplitude detection; 54µA @ 1ksps extends battery life to >12 months. |
Use Scenario: Multi-parameter soil moisture, temperature, and pH sensing in solar-powered agricultural IoT node. IC Role / Device Role / Timing Role: Central ADC scanning 6 sensor channels (3x single-ended, 1x differential thermistor bridge) every 10 seconds. Use Value: Internal 2.5V reference eliminates calibration drift across -20°C to +70°C; software-configurable inputs reduce external signal conditioning components by 40%. |
| Industrial Process Controller I/O Module | Pen Digitizer Signal Acquisition |
|
Use Scenario: Analog input card for PLC handling 4–20mA current loops and thermocouple signals in factory automation cabinet. IC Role / Device Role / Timing Role: High-accuracy ADC converting conditioned sensor outputs at 133ksps, interfacing to ARM Cortex-M7 via SPI with DMA. Use Value: ±1.5% REFADJ trim compensates for PCB trace resistance errors; 65dB channel-to-channel crosstalk prevents cross-talk between adjacent 4–20mA channels. |
Use Scenario: Real-time pen position tracking in active stylus for tablet, sampling capacitive sensor grid at >100Hz. IC Role / Device Role / Timing Role: Low-latency ADC capturing differential electrode pair voltages with 1.5µs acquisition time to support 200Hz reporting rate. Use Value: Track/hold bandwidth of 2.25MHz captures fast stylus movement transients; 1.2mA active current enables continuous operation within stylus thermal envelope. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar 10-bit SAR ADC applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| ADS7822U | 8-channel, 12-bit, SPI-only interface, no internal reference, 2.7–5.25V supply, 200ksps max | Higher resolution but requires external 2.5V reference and lacks bipolar mode - better for precision DC measurements, less suited for AC-coupled biosignals | Select when 12-bit resolution and SPI simplicity outweigh need for internal reference and bipolar input flexibility. |
| MAX11100ETE+ | 8-channel, 12-bit, internal 2.048V reference, SPI/QSPI, 1MSPS, 3.3V-only supply, 24-TQFN | Faster sampling and higher resolution, but fixed 3.3V supply and smaller 2.048V reference limit dynamic range vs. MAX149AEAP's adjustable 2.5V reference | Choose for high-speed data logging where 3.3V rail is available and 2.048V full-scale meets signal swing requirements. |
Compared with ADS7822U and MAX11100ETE+, the MAX149AEAP offers unique value in battery-constrained systems requiring bipolar input support, internal reference adjustability, and guaranteed 133ksps performance across 2.7–5.25V - making it optimal for portable medical and multi-supply industrial designs.
Availability
MAX149AEAP is available at Aetrix Electronics and suitable for portable data logging, battery-powered instrumentation, and medical device production requiring stable component supply and long-term lifecycle assurance.
Supply support for MAX149AEAP 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) is a semiconductor company specializing in high-performance analog, mixed-signal, and power management ICs for industrial, medical, and communications applications.
The MAX149AEAP belongs to Maxim's precision data-acquisition product line, designed specifically for low-power, high-accuracy ADC applications in portable and embedded systems where supply flexibility, internal reference integration, and software-configurable inputs are essential.
FAQ
What is the operating temperature range for the MAX149AEAP?
The MAX149AEAP is specified for operation from 0°C to +70°C, matching the "A" grade in Maxim's ordering nomenclature (as indicated by the "A" in AEAP). This commercial-grade temperature range is validated across all electrical parameters including INL, THD, and reference voltage stability - ensuring reliable performance in indoor portable equipment and non-automotive industrial environments.
Does the MAX149AEAP require an external crystal or oscillator?
No, the MAX149AEAP does not require an external crystal or oscillator. It uses either its internal clock (1.8MHz typical) or an external serial interface clock (100kHz–2.0MHz) to drive the successive-approximation conversion process. The internal clock eliminates timing component dependencies, while the external clock option provides precise synchronization with host processor clocks - both modes are fully supported in the MAX149AEAP without additional oscillators.
How is the internal reference voltage trimmed on the MAX149AEAP?
The internal 2.5V reference voltage on the MAX149AEAP is trimmed via the REFADJ pin, which allows ±1.5% adjustment of the VREF output. A voltage applied to REFADJ modulates the reference buffer gain; the datasheet specifies that connecting a potentiometer between VDD and AGND to REFADJ enables fine calibration. This trim capability is retained in the MAX149AEAP and is used to compensate for PCB trace resistance and temperature-induced drift in production calibration.
Can the MAX149AEAP perform differential measurements on any channel pair?
No, the MAX149AEAP supports differential measurements only on predefined channel pairs: CH0/CH1, CH2/CH3, CH4/CH5, and CH6/CH7. This limitation is enforced by the internal analog multiplexer routing and is explicitly defined in Tables 2 and 3 of the MAX149 datasheet. Attempting to configure non-paired channels (e.g., CH0/CH2) in differential mode will result in undefined or erroneous conversion results - the hardware routing does not support arbitrary differential combinations.
What package type does the MAX149AEAP use, and is it RoHS-compliant?
The MAX149AEAP uses a 20-pin SSOP (Shrink Small Outline Package) with 0.65mm lead pitch. Per Maxim's ordering information table and datasheet footnote, the "+" suffix in the full orderable part number (e.g., MAX149AEAP+) denotes a lead(Pb)-free/RoHS-compliant package. The SSOP footprint is compatible with standard surface-mount assembly processes and provides thermal and mechanical reliability suitable for industrial and medical end-equipment.
MAX149AEAP Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- 20-SSOP (0.209", 5.30mm Width)
- Packaging:
- Tube
- Product Status:
- Obsolete
- Number of Bits:
- 10
- Sampling Rate (Per Second):
- 133k
- Number of Inputs:
- 4, 8
- Input Type:
- Differential, Single Ended
- Data Interface:
- SPI
- Configuration:
- MUX-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 ~ 5.25V
- Voltage - Supply, Digital:
- 2.7V ~ 5.25V
- Features:
- -
- Operating Temperature:
- -40°C ~ 85°C
- Supplier Device Package:
- 20-SSOP
- Mounting Type:
- Surface Mount
- Grade:
- -
- Qualification:
- -
MAX149AEAP FAQ
1.How can I place an order for MAX149AEAP through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX149AEAP 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 MAX149AEAP reliable?
The price and inventory of MAX149AEAP are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX149AEAP is usually 5 days.
3.What payment methods are accepted for MAX149AEAP?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX149AEAP transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX149AEAP?
MAX149AEAP orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX149AEAP 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 MAX149AEAP?
For technical support, including MAX149AEAP datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX149AEAP requirements.
6.How does Aetrix verify that MAX149AEAP is sourced from the original manufacturer or authorized distributors?
All MAX149AEAP 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 MAX149AEAP meets industry standards.
7.What is the process for return or replacement of MAX149AEAP?
All MAX149AEAP units undergo pre-shipment inspection (PSI). If there is an issue with MAX149AEAP, 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 MAX149AEAP part is unused and in its original packaging.
Return procedure for MAX149AEAP:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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