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Analog Devices Inc./Maxim Integrated MAX149ACAP
- Part No.:
- MAX149ACAP
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Analog to Digital Converters (ADC)
- Package:
- 20-SSOP (0.209", 5.30mm Width)
- Datasheet:
-
MAX149ACAP.pdf
- Description:
- IC ADC 10BIT SAR 20SSOP
- Quantity:
- Payment:
- Shipping:
Inventory:3,801
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Product details
Overview
MAX149ACAP 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 portable data logging and battery-powered medical instrumentation.
For engineers reviewing the MAX149ACAP datasheet, MAX149ACAP pinout, MAX149ACAP application, or MAX149ACAP equivalent, this page delivers verified technical context, real-world design meaning of key specs, validated pin functions, confirmed alternative parts with documented differences, and supply-chain support for industrial embedded and medical device programs.
Technical Context
The MAX149ACAP uses successive-approximation architecture with an internal track/hold circuit that acquires input signals in ≤1.5μs and supports both internal clock mode (1.8MHz typical) and external clock mode (up to 2.0MHz). Its analog front-end allows flexible configuration: 8 single-ended or 4 pseudo-differential input pairs (CH0/CH1 through CH6/CH7), with COM pin serving as zero-code reference in single-ended mode.
Digital control is implemented via an 8-bit serial command word defining channel selection, unipolar/bipolar mode, single-ended/differential mode, and power-down/clock source. The device features dual shutdown paths - hardware SHDN pin and software-selectable power-down - enabling automatic shutdown after conversion and sub-1μA quiescent current in full power-down mode.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Resolution | 10-bit - delivers 1024 discrete output codes for precision measurement applications. |
| Sampling Rate | 133ksps - supports real-time acquisition of signals up to ~66kHz (Nyquist-limited) without aliasing when properly filtered. |
| INL (Max) | ±0.5 LSB (MAX149A grade) - ensures <0.05% full-scale linearity error after calibration, critical for sensor signal fidelity. |
| Supply Current (Active) | 1.2mA @ 3V - enables >800hr runtime on a 1000mAh Li-ion cell at 1ksps with duty-cycled operation. |
| Reference | Internal 2.500V ±0.3% (25°C), ±30ppm/°C TC - eliminates external reference component cost and layout area while maintaining medical-grade accuracy. |
| Interface | SPI/QSPI/MICROWIRE/TMS320-compatible 4-wire serial - connects directly to common microcontrollers without level shifters or glue logic. |
| Power-Down Current | 1μA - reduces average system power by >99% between conversions in low-duty-cycle monitoring systems. |
Pinout & Package
MAX149ACAP is housed in a 20-pin SSOP (Shrink Small Outline Package) with 0.65mm pitch, footprint-compatible with industry-standard 20-SSOP layouts and suitable for high-density PCB designs.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| CH0–CH7 (Pins 1–8) | Analog input channels | Support 8 single-ended or 4 differential (CH0/CH1 etc.) configurations; input range 0 to VREF (unipolar) or ±VREF/2 (bipolar). |
| COM (Pin 9) | Analog ground reference | Sets zero-code voltage in single-ended mode; must be stable to ±0.5 LSB - requires low-noise local AGND connection. |
| SHDN (Pin 10) | Three-level shutdown control | Low = full shutdown; high = internal compensation mode; open = external compensation mode - enables reference buffer tuning. |
| VREF (Pin 11) | Reference buffer output / ADC reference input | Delivers 2.500V ±0.3% (MAX149); bypassed with 4.7μF capacitor for stability - no external reference needed. |
| REFADJ (Pin 12) | Reference buffer adjustment input | Allows ±1.5% fine-tuning of VREF; tie to VDD to disable internal buffer when using external reference (MAX148 only). |
| AGND / DGND (Pins 13–14) | Analog and digital ground returns | Must be separated and joined at single point near device - prevents digital noise from corrupting analog measurements. |
| DOUT / SSTRB (Pins 15–16) | Serial data output / strobe sync | DOUT outputs MSB-first 10-bit result on SCLK falling edge; SSTRB pulses before MSB in external mode or indicates conversion start/end in internal mode. |
| DIN / CS / SCLK (Pins 17–19) | Serial command input / chip select / clock | Standard SPI timing (CPOL=0, CPHA=0); CS must be held low during full 8-bit control byte transfer and subsequent data reads. |
| VDD (Pin 20) | Positive supply | Accepts +2.7V to +5.25V - supports direct connection to 3.3V or 5V rails; PSR ±0.3mV ensures stable conversion across supply variation. |
Key Features
| Feature | Design Value |
|---|---|
| Software-configurable input modes | Single-ended (8 ch) or pseudo-differential (4 ch) with unipolar/bipolar selection per conversion - eliminates need for external multiplexers or signal conditioning. |
| Integrated 2.5V reference | ±0.3% initial accuracy and ±30ppm/°C drift - removes external reference IC, saves BOM cost and board space, and improves thermal tracking vs. separate components. |
| Ultra-low power operation | 1.2mA active current at 133ksps and 1μA shutdown - enables multi-year battery life in portable instruments with intermittent sampling. |
| Flexible clock architecture | Supports internal clock (no external timing source required) or external clock (up to 2MHz) - simplifies system clock tree design and accommodates variable throughput needs. |
| Hardware + software shutdown | SHDN pin enables immediate power-off; software PD bits allow automatic post-conversion shutdown - maximizes energy efficiency in event-driven sensing. |
Applications
| Portable Data Logging | Medical Instrumentation |
|---|---|
Use Scenario: Battery-powered environmental sensor node recording temperature, humidity, and pressure over weeks. IC Role / Device Role / Timing Role: Primary ADC acquiring 8 analog sensor outputs sequentially with configurable gain and offset correction. Use Value: Internal 2.5V reference and 1μA shutdown current extend battery life beyond 2 years; SPI interface simplifies MCU firmware integration. |
Use Scenario: Handheld ECG monitor digitizing lead I, II, III, aVR, aVL, aVF, V1–V6 signals with baseline stabilization. IC Role / Device Role / Timing Role: High-fidelity analog front-end ADC supporting bipolar ±1.25V input range and 133ksps sampling for accurate QRS complex capture. Use Value: ±0.5 LSB INL ensures diagnostic-grade linearity; low 1.2mA supply current enables continuous 24/7 operation on rechargeable LiPo. |
| Battery-Powered Test Equipment | Industrial Process Monitoring |
Use Scenario: Pocket-sized multimeter measuring DC voltage, current, and resistance with autoranging and auto-zero. IC Role / Device Role / Timing Role: Precision ADC performing rapid channel switching and self-calibration sequences under microcontroller control. Use Value: Software-selectable unipolar/bipolar and single-ended/differential modes eliminate external op-amp reconfiguration; 1.5μs acquisition time supports fast settling. |
Use Scenario: DIN-rail mounted PLC analog input module acquiring 4–20mA loop signals from pressure, flow, and level transmitters. IC Role / Device Role / Timing Role: Isolated ADC subsystem digitizing conditioned 0–5V or 0–10V field signals with high CMRR and low drift. Use Value: 65dB channel-to-channel crosstalk and ±0.25ppm/°C gain TC ensure accurate multi-channel correlation; SSOP package fits compact industrial enclosures. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar 10-bit serial ADC applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| ADS7822U | 8-channel, 12-bit, SPI interface, no internal reference, 2.7–5.5V supply, 200ksps max | Higher resolution but requires external reference and lacks bipolar input support | Select when 12-bit precision is mandatory and system already provides stable 2.5V reference; not drop-in due to different command structure and missing bipolar mode. |
| MAX11131ETE+ | 8-channel, 12-bit, internal 2.048V reference, SPI, 2.7–3.6V only, 500ksps | Narrower supply range, higher speed, lower reference voltage limits full-scale input range | Prefer for 3.3V-only systems needing faster sampling; MAX149ACAP remains optimal for 5V compatibility, bipolar inputs, and wider supply tolerance. |
Compared with ADS7822U and MAX11131ETE+, the MAX149ACAP uniquely combines internal 2.5V reference, true bipolar input capability, 2.7–5.25V operation, and hardware/software shutdown - making it the most balanced choice for portable, battery-constrained, and mixed-supply industrial designs requiring 10-bit fidelity.
Availability
MAX149ACAP 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 packaging.
Supply support for MAX149ACAP 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 product line was designed specifically for low-power, multi-channel data acquisition in space- and energy-constrained systems - emphasizing integrated references, flexible input architectures, and minimal external component count.
FAQ
What is the maximum sampling rate of the MAX149ACAP?
The MAX149ACAP achieves a maximum sampling rate of 133ksps when using the internal clock at 1.8MHz or an external clock at 2.0MHz. This rate is sustained across the full operating temperature range (0°C to +70°C) and supply range (+2.7V to +5.25V), with conversion time specified at 5.5–7.5μs depending on SHDN state. The MAX149ACAP maintains this performance without requiring external timing components.
Does the MAX149ACAP require an external voltage reference?
No, the MAX149ACAP does not require an external voltage reference because it integrates a precision 2.500V ±0.3% reference with ±30ppm/°C temperature coefficient. This internal reference is enabled by default and bypassed with a 4.7μF capacitor on the VREF pin. External reference use is reserved for the MAX148 variant; attempting to disable the MAX149ACAP's reference buffer will result in undefined operation.
How many analog input channels does the MAX149ACAP support, and what configurations are available?
The MAX149ACAP supports eight analog input channels (CH0–CH7) configurable as either eight single-ended inputs referenced to the COM pin or four pseudo-differential pairs (CH0/CH1, CH2/CH3, CH4/CH5, CH6/CH7). Input polarity is software-selectable per conversion - unipolar (0 to VREF) or bipolar (±VREF/2) - via the UNI/BIP bit in the 8-bit control byte. Channel selection is controlled by SEL2–SEL0 bits.
What power-saving features does the MAX149ACAP offer?
The MAX149ACAP offers three complementary power-saving mechanisms: (1) hardware SHDN pin for immediate full shutdown (<1μA), (2) software-selectable fast power-down (70μA for MAX149), and (3) automatic post-conversion shutdown triggered by PD bits in the control byte. Additionally, serial interface activity automatically powers up the device, and its quick turn-on time (≤1.5μs) enables efficient duty-cycled operation in battery-powered systems.
Is the MAX149ACAP compatible with standard microcontroller SPI interfaces?
Yes, the MAX149ACAP is fully compatible with standard SPI interfaces when configured with CPOL = 0 and CPHA = 0 - meaning data is sampled on the rising edge of SCLK and shifted out on the falling edge. It supports SPI, QSPI, and MICROWIRE protocols natively, requires no external logic, and operates with SCLK frequencies from 100kHz to 2.0MHz. The DOUT pin is three-state and controlled by CS, enabling bus sharing with other peripherals.
MAX149ACAP 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:
- 0°C ~ 70°C
- Supplier Device Package:
- 20-SSOP
- Mounting Type:
- Surface Mount
- Grade:
- -
- Qualification:
- -
MAX149ACAP FAQ
1.How can I place an order for MAX149ACAP through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX149ACAP 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 MAX149ACAP reliable?
The price and inventory of MAX149ACAP are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX149ACAP is usually 5 days.
3.What payment methods are accepted for MAX149ACAP?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX149ACAP transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX149ACAP?
MAX149ACAP orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX149ACAP 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 MAX149ACAP?
For technical support, including MAX149ACAP datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX149ACAP requirements.
6.How does Aetrix verify that MAX149ACAP is sourced from the original manufacturer or authorized distributors?
All MAX149ACAP 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 MAX149ACAP meets industry standards.
7.What is the process for return or replacement of MAX149ACAP?
All MAX149ACAP units undergo pre-shipment inspection (PSI). If there is an issue with MAX149ACAP, 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 MAX149ACAP part is unused and in its original packaging.
Return procedure for MAX149ACAP:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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