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Analog Devices Inc./Maxim Integrated MAX149BCAP+
- Part No.:
- MAX149BCAP+
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Analog to Digital Converters (ADC)
- Package:
- 20-SSOP (0.209", 5.30mm Width)
- Datasheet:
-
MAX149BCAP+.pdf
- Description:
- IC ADC 10BIT SAR 20SSOP
- Quantity:
- Payment:
- Shipping:
Inventory:2,621
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Product details
Overview
MAX149BCAP+ 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 MAX149BCAP+ datasheet, MAX149BCAP+ pinout, MAX149BCAP+ application, or MAX149BCAP+ 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 MAX149BCAP+ 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 or pseudo-differential across four channel pairs).
Digital interfacing uses a 4-wire serial protocol compatible with SPI (CPOL=0, CPHA=0), QSPI, and MICROWIRE; SSTRB provides timing synchronization for TMS320-family DSPs. The device features dual power-down modes - full shutdown (1µA) and fast power-down (30–70µA for MAX149) - with automatic wake-on-CS activation and sub-8µs turn-on time.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Resolution | 10-bit - delivers 1024 discrete output codes with ±1 LSB INL (B-grade), sufficient for 0.1% full-scale measurement accuracy in industrial sensors. |
| Sampling Rate | 133ksps - supports Nyquist-limited bandwidth up to ~66kHz, suitable for vibration monitoring and ECG signal digitization. |
| Supply Range | +2.7V to +5.25V - enables direct operation from Li-ion (3.0–4.2V), USB (5V), or regulated 3.3V rails without level-shifting. |
| Reference | Internal 2.500V ±0.030V (±30ppm/°C) - eliminates external reference component cost and layout area; adjustable ±1.5% via REFADJ pin. |
| Power Consumption | 1.2mA @ 133ksps / 3V - enables >100-hour battery life in 10ksps logging systems using a 1200mAh coin cell. |
| SINAD / THD | 66dB / –70dB - supports 10.7-bit effective resolution and clean spectral performance for audio-grade and medical waveform capture. |
| Input Configuration | 8 single-ended or 4 pseudo-differential channels - allows flexible sensor interfacing (e.g., thermocouples with cold-junction compensation on COM). |
Pinout & Package
MAX149BCAP+ 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 single-ended inputs referenced to COM, or as 4 differential pairs (CH0/CH1, CH2/CH3, etc.); input capacitance 16pF limits source impedance to ≤4kΩ for full AC performance. |
| COM (Pin 9) | Analog ground reference | Sets zero-code voltage in single-ended mode; must be stable to ±0.5 LSB - requires low-noise AGND plane and local 0.1µF bypass. |
| SHDN (Pin 10) | Three-level shutdown control | Pulled low → full shutdown (1µA); left floating → external reference compensation mode; pulled high → internal compensation mode for VREF stability. |
| VREF (Pin 11) | Reference buffer output / ADC reference input | Delivers 2.500V ±0.030V (MAX149 only); requires 4.7µF capacitor for internal compensation or 0µF + 0.01µF at REFADJ for external compensation. |
| REFADJ (Pin 12) | Reference buffer gain adjustment | Adjusts VREF ±1.5%; tie to VDD to disable internal buffer when using external reference (not applicable to MAX149 in standard use). |
| AGND / DGND (Pins 13–14) | Analog and digital ground returns | Must be separated on PCB and joined at single point near VDD decoupling; AGND-DGND voltage difference limited to ±0.3V per absolute max ratings. |
| DOUT / SSTRB / DIN / CS / SCLK (Pins 15–19) | 4-wire serial interface | Full SPI/QSPI/MICROWIRE compatibility; DOUT active-low SSTRB synchronizes conversion completion; CS enables three-state outputs and auto-wake. |
| VDD (Pin 20) | Positive supply | Accepts +2.7V to +5.25V; requires 0.1µF ceramic + 4.7µF tantalum local bypass; PSR ±0.3mV ensures stable conversion under supply ripple. |
Key Features
| Feature | Design Value |
|---|---|
| Internal 2.5V reference | Eliminates external reference IC and trimming components; ±30ppm/°C drift meets medical-grade temperature stability requirements without calibration. |
| Configurable input topology | Single control byte selects unipolar/bipolar and single-ended/differential mode per conversion - enables mixed-signal acquisition (e.g., pressure + temperature on same device) without hardware reconfiguration. |
| Low-power shutdown modes | 1µA full shutdown and 30–70µA fast shutdown allow duty-cycled operation; auto-wake on CS reduces firmware overhead in microcontroller-based loggers. |
| SPI/QSPI/MICROWIRE compatibility | Direct connection to common MCU peripherals without glue logic; CPOL=0/CPHA=0 configuration matches most ARM Cortex-M and PIC SPI controllers out-of-box. |
| Track/hold acquisition time | 1.5µs maximum acquisition window enables accurate sampling of signals up to 2.25MHz small-signal bandwidth - supports undersampling of RF or ultrasonic signals. |
Applications
| Portable Data Logging | Medical Instruments |
|---|---|
|
Use Scenario: Battery-powered environmental sensor node recording temperature, humidity, and barometric pressure every 10 seconds. IC Role / Device Role / Timing Role: ADC digitizes conditioned analog outputs from multiple sensors; internal reference ensures consistent full-scale across temperature; low 1.2mA active current extends 2-year battery life. Use Value: Single-chip solution replaces discrete reference + ADC + level shifter, reducing BOM count by 3 components and PCB area by 25mm². |
Use Scenario: Portable ECG monitor acquiring lead-I and lead-II differential signals at 500Hz with 50Hz notch filtering. IC Role / Device Role / Timing Role: Configured in pseudo-differential mode to reject common-mode noise; 66dB SINAD preserves diagnostic waveform fidelity; 133ksps headroom supports oversampling for digital filtering. Use Value: Internal 2.5V reference eliminates drift-induced baseline wander in long-duration recordings, meeting IEC 60601-2-27 DC accuracy requirements. |
| Battery-Powered Instruments | Process Control |
|
Use Scenario: Handheld multimeter measuring DC voltage, resistance, and continuity with autoranging and backlit LCD. IC Role / Device Role / Timing Role: Uses unipolar mode for voltage ranges and bipolar mode for continuity test; software-selectable gain eliminates external PGA; SHDN pin enables instant power-off. Use Value: 1µA shutdown current prevents battery drain during storage; 20-pin SSOP footprint fits compact handheld enclosure with minimal layer count. |
Use Scenario: DIN-rail mounted PLC analog input module conditioning 4–20mA current loop signals from flow and pressure transmitters. IC Role / Device Role / Timing Role: Interfaces to isolated current-to-voltage converters; COM pin referenced to system AGND; INL ±1 LSB ensures <0.1% total error over 0–70°C operating range. Use Value: SPI interface simplifies isolation barrier design - only 4 digital lines require optocouplers or digital isolators instead of parallel bus. |
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; requires external 2.5V ref; 1µA shutdown; 200ksps max. | Higher resolution but lacks bipolar input support and internal reference - increases BOM cost and calibration complexity. | Choose ADS7822U only if 12-bit resolution is mandatory and external reference infrastructure already exists. |
| MAX11131AUT+ | 8-channel, 12-bit, internal 4.096V ref; SPI/QSPI; 1.5µA shutdown; 500ksps; 24-pin TSSOP package. | Higher speed and resolution, but larger footprint and incompatible reference voltage - requires redesign of signal scaling and power rail. | Choose MAX11131AUT+ only when upgrading legacy designs needing >133ksps or >10-bit ENOB, accepting PCB layout change. |
Compared with ADS7822U and MAX11131AUT+, the MAX149BCAP+ offers optimal balance of integrated functionality (internal 2.5V ref, bipolar mode, low 1.2mA active current) and compact 20-pin SSOP packaging - making it the most cost- and space-efficient choice for new portable and medical designs targeting 10-bit precision.
Availability
MAX149BCAP+ is available at Aetrix Electronics and suitable for portable data logging, medical instrumentation, and battery-powered test equipment requiring stable component supply, long-term lifecycle support, and RoHS-compliant sourcing.
Supply support for MAX149BCAP+ 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 MAX148/MAX149 family was designed specifically for low-power, multi-channel data acquisition in space- and energy-constrained systems - emphasizing integrated references, flexible input configurations, and SPI-compatible serial interfaces to reduce system-level design complexity.
FAQ
What is the guaranteed integral nonlinearity (INL) specification for MAX149BCAP+?
The MAX149BCAP+ is specified with ±1 LSB maximum integral nonlinearity (INL) over the full operating temperature range (0°C to +70°C). This B-grade accuracy is confirmed in the Maxim datasheet Rev 5, Table "DC ACCURACY", and ensures monotonicity and <0.1% full-scale measurement error after end-point calibration - critical for closed-loop control and precision instrumentation where code missing or code repetition must be avoided. The MAX149BCAP+ achieves this without requiring external trimming.
Does MAX149BCAP+ support differential input mode, and how is it configured?
Yes, MAX149BCAP+ supports pseudo-differential input mode across four channel pairs: CH0/CH1, CH2/CH3, CH4/CH5, and CH6/CH7. Configuration is done via the 8-bit control byte written to DIN: setting bit 2 (SGL/DIF) = 0 selects differential mode, and bits 4–6 (SEL2–SEL0) select the pair. In this mode, the ADC samples the voltage difference between the two channels, with the negative input required to remain stable within ±0.5 LSB relative to AGND during conversion - achieved using a 0.1µF capacitor from the selected IN– channel to AGND.
What is the function of the SHDN pin on MAX149BCAP+, and what are its three states?
The SHDN pin on MAX149BCAP+ provides three distinct operating states: pulling SHDN low enables full power-down (1µA supply current); leaving SHDN unconnected configures the internal reference buffer for external compensation (requires 4.7µF at VREF); pulling SHDN high enables internal compensation mode (no external capacitor needed). This triple-state capability allows flexible power management and reference optimization without adding external logic - a key differentiator versus simpler shutdown-only ADCs like the ADS7822U.
Can MAX149BCAP+ operate with a 3.3V supply, and what is its typical current draw at that voltage?
Yes, MAX149BCAP+ is fully specified for operation from +2.7V to +5.25V, including standard 3.3V logic rails. At 3.3V supply and 133ksps sampling rate, the typical supply current is 1.2mA - confirmed in the "POWER REQUIREMENTS" table of the datasheet. This low active current, combined with 1µA full shutdown, makes MAX149BCAP+ ideal for 3.3V battery-powered systems such as handheld meters and wireless sensor nodes where energy efficiency directly impacts field deployment duration.
How does the internal reference of MAX149BCAP+ differ from that of MAX148, and why does it matter for system design?
The MAX149BCAP+ integrates a factory-trimmed 2.500V ±0.030V reference with ±30ppm/°C temperature coefficient and ±1.5% adjustability via REFADJ, while the MAX148 requires an external reference applied to the VREF pin. This means MAX149BCAP+ eliminates the need for external reference ICs, trimming resistors, and associated PCB area - reducing BOM cost by ~$0.35 and simplifying layout. For medical and portable applications where size and calibration stability are critical, the MAX149BCAP+'s self-contained reference significantly lowers system-level design risk and qualification effort.
MAX149BCAP+ 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:
- Active
- 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:
- 0°C ~ 70°C
- Supplier Device Package:
- 20-SSOP
- Mounting Type:
- Surface Mount
- Grade:
- -
- Qualification:
- -
MAX149BCAP+ FAQ
1.How can I place an order for MAX149BCAP+ through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX149BCAP+ 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 MAX149BCAP+ reliable?
The price and inventory of MAX149BCAP+ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX149BCAP+ is usually 5 days.
3.What payment methods are accepted for MAX149BCAP+?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX149BCAP+ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX149BCAP+?
MAX149BCAP+ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX149BCAP+ 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 MAX149BCAP+?
For technical support, including MAX149BCAP+ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX149BCAP+ requirements.
6.How does Aetrix verify that MAX149BCAP+ is sourced from the original manufacturer or authorized distributors?
All MAX149BCAP+ 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 MAX149BCAP+ meets industry standards.
7.What is the process for return or replacement of MAX149BCAP+?
All MAX149BCAP+ units undergo pre-shipment inspection (PSI). If there is an issue with MAX149BCAP+, 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 MAX149BCAP+ part is unused and in its original packaging.
Return procedure for MAX149BCAP+:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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