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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:1,881
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Product details
Overview
MAX149ACAP+ from Maxim Integrated is a 10-bit, 8-channel serial analog-to-digital converter (ADC) with internal 2.5V reference, single-supply operation from +2.7V to +5.25V, 133ksps sampling rate, and SPI/QSPI/MICROWIRE-compatible 4-wire interface - used in portable data loggers for battery-efficient signal digitization.
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, and two confirmed alternative parts for low-power, multi-channel ADC selection in space-constrained industrial and medical instruments.
Technical Context
The MAX149ACAP+ employs successive-approximation register (SAR) architecture with integrated track/hold circuitry, enabling precise 10-bit conversion without external sample-hold components. It supports software-configurable unipolar/bipolar and single-ended/differential input modes across eight analog channels.
Its serial interface operates in either internal clock mode (self-timed conversion, SSTRB indicates completion) or external clock mode (SCLK drives both data transfer and conversion timing), with direct compatibility to TMS320-family DSPs via SSTRB strobe output.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Resolution | 10-bit - delivers 1024 discrete digital codes for accurate representation of analog sensor or signal sources. |
| Sampling Rate | 133ksps - supports real-time acquisition of audio-band and control-loop signals without undersampling artifacts. |
| Supply Voltage | +2.7V to +5.25V - enables direct interfacing with 3.3V and 5V microcontrollers and battery-powered systems. |
| INL (Max) | ±0.5 LSB - ensures monotonicity and <0.05% full-scale linearity error after calibration, critical for precision instrumentation. |
| Power Consumption | 1.2mA at 133ksps / 3V - allows continuous high-speed sampling in portable devices with >100-hour battery life at reduced rates. |
| Reference | Internal 2.5V ±0.3% (25°C) - eliminates need for external reference IC or trimming, reducing BOM count and layout area. |
| Interface | 4-wire SPI/QSPI/MICROWIRE - connects directly to standard MCU peripherals without level shifters or glue logic. |
Pinout & Package
MAX149ACAP+ is housed in a 20-pin SSOP (Shrink Small Outline Package) with 0.65mm lead pitch, optimized for compact PCB layouts in handheld and embedded applications.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| CH0–CH7 (Pins 1–8) | Analog Input Channels | Eight single-ended or four differential inputs; software-selectable via control byte for flexible sensor multiplexing. |
| COM (Pin 9) | Analog Ground Reference | Sets zero-code voltage in single-ended mode; must be stable to ±0.5 LSB to avoid INL degradation. |
| SHDN (Pin 10) | Three-Level Shutdown Control | Low = full shutdown (1µA); high = internal buffer compensation; open = external compensation (4.7µF at VREF). |
| VREF (Pin 11) | Reference Output/Input | 2.5V nominal output (MAX149 only); accepts external reference when REFADJ tied to VDD. |
| REFADJ (Pin 12) | Reference Buffer Adjustment | Enables ±1.5% fine-tuning of internal reference; tie to VDD to disable buffer for external reference use. |
| AGND/DGND (Pins 13–14) | Analog/Digital Ground | Separate ground pins minimize digital noise coupling into analog conversion path. |
| DOUT/SSTRB (Pins 15–16) | Data Output / Strobe Signal | DOUT outputs MSB-first 10-bit result on SCLK falling edge; SSTRB pulses high before MSB in external mode or indicates conversion status in internal mode. |
| DIN/CS/SCLK (Pins 17–19) | Serial Interface Inputs | Standard SPI-compatible control: CS enables interface, DIN loads 8-bit control byte, SCLK clocks data at 100kHz–2MHz. |
| VDD (Pin 20) | Positive Supply | Single supply powers analog core, reference, and digital interface - no separate AVDD/DVDD required. |
Key Features
| Feature | Design Value |
|---|---|
| Software-configurable input modes | Unipolar (0 to VREF) or bipolar (±VREF/2), single-ended or pseudo-differential - adapts to diverse sensor outputs without hardware changes. |
| Auto power-down after conversion | Reduces average current to <60µA at 1ksps - extends battery life in intermittent-sampling applications like environmental monitors. |
| Internal reference with ±30ppm/°C drift | Stable 2.5V reference over temperature eliminates external component while maintaining <0.1% gain error across 0°C to +70°C range. |
| Fast wake-up from shutdown | Quick turn-on time allows full reactivation between conversions - enables burst-mode acquisition with minimal latency penalty. |
| Channel-to-channel crosstalk <−75dB | Prevents signal leakage between active and inactive channels - essential for accurate multi-sensor measurements in medical diagnostics. |
Applications
| Portable Data Logging | Medical Instruments |
|---|---|
|
Use Scenario: Battery-powered field recorder capturing temperature, humidity, and pressure from multiple sensors over days. IC Role / Device Role / Timing Role: 8-channel ADC digitizes analog sensor outputs sequentially using internal clock mode, minimizing MCU intervention. Use Value: 1.2mA active current and 1µA shutdown enable >6-month operation on two AA cells; internal reference reduces calibration overhead. |
Use Scenario: Handheld ECG device acquiring biopotential signals from electrode pairs with high common-mode rejection. IC Role / Device Role / Timing Role: Configured in differential mode (CH0/CH1, CH2/CH3) to reject 50/60Hz interference while preserving signal integrity. Use Value: −75dB channel crosstalk and ±0.5 LSB INL ensure accurate waveform morphology for arrhythmia detection. |
| Battery-Powered Instruments | Process Control Sensors |
|
Use Scenario: Wireless pH meter with onboard microcontroller performing periodic calibration and measurement cycles. IC Role / Device Role / Timing Role: Uses SHDN pin to enter full power-down between readings; wakes on timer interrupt to initiate conversion. Use Value: Sub-µA shutdown current and fast wake-up (<1µs) eliminate standby power waste without sacrificing responsiveness. |
Use Scenario: Industrial transmitter converting 4–20mA loop signals and thermocouple outputs into digital data for PLC interface. IC Role / Device Role / Timing Role: Accepts external reference for ratiometric measurement against loop supply; supports bipolar input for thermocouple cold-junction compensation. Use Value: ±1.5% REFADJ adjustment enables precise offset correction; 2.25MHz small-signal bandwidth captures transient faults. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar 10-bit, multi-channel ADC applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| ADS7822U | 8-channel, 12-bit, SPI interface, no internal reference, requires external 2.5V ref; 50ksps max. | Higher resolution but lower speed; lacks integrated reference and shutdown control. | Choose when 12-bit precision outweighs power savings and reference integration needs. |
| MAX11100ETK+ | 8-channel, 12-bit, internal 2.048V ref, 1MSPS, 3.3V-only supply, 20-pin TQFN. | Faster sampling and smaller package, but incompatible 3.3V-only supply and different reference voltage. | Choose for higher-speed designs with 3.3V rails and space constraints - not drop-in compatible. |
Compared with MAX149ACAP+, ADS7822U trades resolution for simplicity in reference design but sacrifices low-power shutdown and bipolar support, while MAX11100ETK+ offers speed and density at the cost of supply flexibility and legacy interface compatibility.
Availability
MAX149ACAP+ is available at Aetrix Electronics and suitable for portable data logging, medical instrumentation, and battery-powered test equipment requiring stable component supply and long-term production continuity.
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) designs precision analog and mixed-signal ICs for demanding industrial, medical, and communications applications.
The MAX148/MAX149 family was engineered for low-power, multi-channel data acquisition in size- and energy-constrained systems - emphasizing integrated references, flexible input configurations, and robust serial interfacing.
FAQ
What is the reference voltage source for MAX149ACAP+?
The MAX149ACAP+ integrates a precision 2.5V internal reference with ±0.3% initial accuracy and ±30ppm/°C temperature coefficient. This eliminates the need for an external reference IC in most applications. The REFADJ pin allows ±1.5% fine adjustment, and tying REFADJ to VDD disables the internal buffer for use with an external reference - a capability confirmed in the MAX149ACAP+ datasheet's Electrical Characteristics table.
Does MAX149ACAP+ support differential input mode?
Yes, MAX149ACAP+ supports pseudo-differential input mode by selecting channel pairs (CH0/CH1, CH2/CH3, CH4/CH5, CH6/CH7) via the control byte's SEL2–SEL0 and SGL/DIF bits. In this mode, the device samples the voltage difference between two inputs, with IN− held stable to ±0.5 LSB relative to AGND. The datasheet confirms this behavior in Tables 2 and 3 and the Detailed Description section.
What is the maximum sampling rate of MAX149ACAP+?
The MAX149ACAP+ achieves a maximum sampling rate of 133ksps when using a 2.0MHz external serial clock and 15 clock cycles per conversion. This value is explicitly specified in the General Description and confirmed in the Electrical Characteristics table under "Conversion Rate." Internal clock mode yields slightly lower effective throughput due to fixed conversion time (5.5–7.5µs).
How does the SHDN pin function on MAX149ACAP+?
The SHDN pin on MAX149ACAP+ provides three-level control: pulled low → full power-down (1µA); pulled high → internal reference buffer in internal compensation mode; left unconnected → external compensation mode (requiring 4.7µF at VREF). This behavior is documented in the Pin Description table and verified in the Typical Operating Characteristics plots for shutdown current vs. temperature.
Is MAX149ACAP+ compatible with standard SPI interfaces?
Yes, MAX149ACAP+ is fully compatible with SPI, QSPI, and MICROWIRE protocols. It uses CPOL = 0 and CPHA = 0 timing, with data latched on SCLK rising edge (DIN) and output on falling edge (DOUT). The datasheet confirms direct connection to SPI peripherals without external logic, and Figure 20 illustrates QSPI wiring - all verified for the MAX149ACAP+ variant.
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:
- 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:
- -
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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