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Analog Devices Inc./Maxim Integrated MAX146ACAP+
- Part No.:
- MAX146ACAP+
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Analog to Digital Converters (ADC)
- Package:
- 20-SSOP (0.209", 5.30mm Width)
- Datasheet:
-
MAX146ACAP+.pdf
- Description:
- IC ADC 12BIT SAR 20SSOP
- Quantity:
- Payment:
- Shipping:
Inventory:875
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Product details
Overview
MAX146ACAP+ from Maxim Integrated is a 12-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 serial interface. It operates from a single +2.7V to +3.6V supply, consumes 1.2mA at 133ksps, and supports portable data logging and battery-powered medical instrumentation.
For engineers reviewing the MAX146ACAP+ datasheet, MAX146ACAP+ pinout, MAX146ACAP+ application, or MAX146ACAP+ equivalent, key selection criteria include its 20-pin SSOP package, ±0.5 LSB INL, 1.5µs acquisition time, internal reference accuracy of ±0.2% over temperature, and shutdown current of 1µA - all critical for low-power, precision sensor interfacing in space-constrained embedded systems.
Technical Context
The MAX146ACAP+ implements a successive-approximation register (SAR) architecture with an integrated track/hold circuit and programmable input configuration. Its analog front-end supports eight single-ended or four pseudo-differential input pairs, with COM pin serving as zero-code reference in single-ended mode and common-mode point in differential mode.
Conversion timing is governed by either internal clock or external SCLK (up to 2MHz), with 15-clock cycles per conversion in external mode. The device features a hard-wired SHDN pin and software-selectable power-down modes - full (1µA), fast (54µA), and automatic end-of-conversion shutdown - enabling dynamic power management in intermittent-sampling applications.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Resolution | 12-bit - delivers 1 LSB = 610µV at 2.5V reference, sufficient for 0.025% full-scale measurement accuracy. |
| INL (Integral Nonlinearity) | ±0.5 LSB max - ensures monotonicity and <0.012% full-scale error after calibration, critical for closed-loop control feedback. |
| Conversion Rate | 133ksps with 2MHz external clock - enables real-time sampling of signals up to 66.5kHz (Nyquist), suitable for motor current sensing. |
| Supply Current | 1.2mA at 133ksps / 54µA at 1ksps - allows adaptive sampling to extend battery life in portable instruments without sacrificing responsiveness. |
| Reference | Internal 2.500V ±0.2% (0°C to +70°C) - eliminates need for external reference IC, reducing BOM count and layout area in compact designs. |
| Input Configuration | Software-selectable unipolar (0V–VREF) or bipolar (±VREF/2) and single-ended/differential - supports diverse sensor types (RTDs, strain gauges, thermocouples) with one hardware design. |
| Serial Interface | SPI/QSPI/MICROWIRE/TMS320-compatible 4-wire - integrates directly with ARM Cortex-M, TI C2000, and legacy microcontrollers without level-shifting or glue logic. |
Pinout & Package
MAX146ACAP+ is housed in a 20-pin SSOP (Shrink Small Outline Package) with 0.65mm lead pitch, optimized for high-density PCB layouts in portable equipment. Thermal resistance θJA = 125°C/W supports operation at full speed without heatsinking in ambient temperatures up to +70°C.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| CH0–CH7 (Pins 1–8) | Analog input channels | Eight single-ended inputs or four differential pairs (CH0/CH1, CH2/CH3, etc.); each channel has ±0.3V absolute max rating beyond supplies. |
| COM (Pin 9) | Analog common reference | Sets zero-code voltage in single-ended mode; must be stable to ±0.5 LSB during conversion - requires local 0.1µF bypass to AGND. |
| SHDN (Pin 10) | Three-level shutdown control | Pull low → full shutdown (1µA); float → external compensation mode; pull high → internal compensation mode - enables flexible power sequencing. |
| VREF (Pin 11) | Reference buffer output / ADC reference input | Delivers 2.500V ±0.2% (typical) for MAX146; buffered output drives external loads up to 0.2mA with <0.35mV load regulation. |
| REFADJ (Pin 12) | Reference buffer adjustment input | Allows ±1.5% fine-tuning of VREF; tie to VDD to disable internal reference when using external reference (not applicable to MAX146ACAP+). |
| DIN (Pin 17) | Serial data input | Accepts 8-bit control byte on SCLK rising edge; START bit defines MSB position - tolerant of leading zeros for robust firmware timing. |
| SCLK (Pin 19) | Serial clock input | Drives data transfer and (in external mode) conversion timing; 40–60% duty cycle required; max 2MHz frequency ensures 133ksps throughput. |
| CS (Pin 18) | Active-low chip select | Enables serial interface and powers up device; DOUT and SSTRB go high-Z when CS = high - prevents bus contention in multi-peripheral systems. |
| DOUT (Pin 15) | Serial data output | Outputs 12-bit result MSB-first on SCLK falling edge; high-Z when CS = high - supports daisy-chaining or shared bus architectures. |
| SSTRB (Pin 16) | Serial strobe output | Pulses high for one SCLK period before MSB in external mode; indicates conversion start/end - synchronizes DSP capture (e.g., TMS320C2xx) without polling. |
| AGND / DGND (Pins 13, 14) | Analog and digital ground | Separate pins minimize digital noise coupling into analog path; require star grounding at single-point AGND/DGND connection near VDD decoupling. |
| VDD (Pin 20) | Positive supply | +2.7V to +3.6V single supply; 4.7µF capacitor required at VREF pin in internal reference mode to stabilize reference during conversion. |
Key Features
| Feature | Design Value |
|---|---|
| 8-channel multiplexer with pseudo-differential architecture | Supports simultaneous monitoring of multiple sensors (e.g., 4 RTD channels + 4 thermistor channels) using only one ADC, reducing system cost and board area. |
| Internal 2.5V reference with ±1.5% adjustability | Eliminates external reference IC and associated passive components; REFADJ pin allows factory calibration to compensate for board-level drift. |
| Three power-down modes (full/fast/auto) | Reduces average supply current to <60µA at reduced sampling rates - extends battery life in wireless sensor nodes from days to months. |
| Track/hold acquisition time of 1.5µs | Enables accurate sampling of fast transients (e.g., motor phase currents) without external sample-hold circuitry, simplifying analog front-end design. |
| ±0.5 LSB INL and ±0.5 LSB DNL | Guarantees no missing codes and monotonic response across full temperature range - essential for precision closed-loop control in medical infusion pumps. |
| SPI/QSPI/MICROWIRE/TMS320 compatibility | Integrates with industry-standard microcontroller peripherals without custom driver development; CPOL=0/CPHA=0 configuration matches most default SPI settings. |
Applications
| Portable Data Logging | Medical Instrumentation |
|---|---|
Use Scenario: Battery-powered environmental monitor recording temperature, humidity, and CO₂ levels every 10 seconds in remote field deployments. IC Role / Device Role / Timing Role: ADC digitizes analog sensor outputs; internal reference and low shutdown current enable >1-year battery life; SSTRB synchronizes with microcontroller's low-power wake-up timer. Use Value: Eliminates external reference and reduces active current by 99.9% between samples - extends CR2032 coin-cell life from weeks to 14+ months. |
Use Scenario: Handheld blood glucose meter requiring precise, repeatable measurement of electrochemical test-strip current under varying ambient temperatures. IC Role / Device Role / Timing Role: ADC converts amperometric sensor output; software-configurable unipolar/bipolar mode accommodates different strip chemistries; ±0.5 LSB INL ensures clinical-grade accuracy. Use Value: Meets ISO 15197:2013 accuracy requirements (<15% deviation at 100 mg/dL) without post-fabrication trimming, lowering manufacturing cost. |
| Battery-Powered Test Equipment | Industrial Process Control |
Use Scenario: Pocket-sized multimeter measuring DC voltage, current, and resistance with autoranging and backlit LCD. IC Role / Device Role / Timing Role: ADC provides 12-bit resolution for 4½-digit display; single +3V supply simplifies power architecture; 20-pin SSOP fits tight mechanical envelope. Use Value: Internal reference stability (±30 ppm/°C) maintains calibration across -10°C to +50°C operating range - avoids frequent recalibration in field service. |
Use Scenario: PLC analog input module acquiring 4–20mA loop signals from pressure and flow transmitters in factory automation cabinets. IC Role / Device Role / Timing Role: ADC interfaces to isolated current-input front-end; software-selectable differential mode rejects common-mode noise on long industrial cables. Use Value: Channel-to-channel offset matching <±0.5 LSB ensures consistent gain across all 8 channels - eliminates per-channel calibration in production test. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar 12-bit SAR ADC applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| ADS7822U | 8-channel, 12-bit, SPI interface, but requires external reference and operates from +2.7V to +5.25V; no internal track/hold; higher 2.5mW power at 100ksps. | Best suited for systems already using external precision reference and needing wider supply range; lacks auto-shutdown and SSTRB sync signal. | Select ADS7822U only if external reference is preferred and TMS320 synchronization is unnecessary; MAX146ACAP+ offers lower system-level BOM cost and better power efficiency. |
| AD7490BRUZ | 16-channel, 12-bit, SPI-compatible, but uses external reference only; higher 1.5mA typical supply current at 1MSPS; no internal track/hold; 24-pin TSSOP package. | Ideal for high-channel-count data acquisition where board space permits larger package and external reference is acceptable. | Choose AD7490BRUZ when expanding beyond 8 channels is anticipated; MAX146ACAP+ remains superior for compact, low-power, reference-integrated designs. |
Compared with ADS7822U and AD7490BRUZ, MAX146ACAP+ uniquely integrates a stable 2.5V reference, track/hold, and three-level shutdown in a 20-pin SSOP - delivering lowest total solution size and power for portable 8-channel applications without compromising accuracy or interface flexibility.
Availability
MAX146ACAP+ is available at Aetrix Electronics and suitable for portable data logging, battery-powered medical instrumentation, and industrial process control requiring stable component supply, long-term lifecycle support, and guaranteed traceable sourcing.
Supply support for MAX146ACAP+ 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 MAX146ACAP+ belongs to Maxim's precision data-acquisition product line, designed specifically for low-power, high-accuracy sensor interfacing in space- and energy-constrained embedded systems.
FAQ
What is the operating temperature range for the MAX146ACAP+?
The MAX146ACAP+ is specified for operation from 0°C to +70°C - the 'C' grade commercial temperature range. This is confirmed in the Ordering Information table, where MAX146ACAP corresponds to 0°C to +70°C. The device's internal reference exhibits ±30 ppm/°C drift and INL remains within ±0.5 LSB across this full range, making it suitable for indoor and controlled-environment applications.
Does the MAX146ACAP+ require external capacitors for stable operation?
Yes, the MAX146ACAP+ requires a 4.7µF capacitor at the VREF pin when using the internal reference - as explicitly stated in the Typical Operating Circuit and Electrical Characteristics tables. Additionally, a 0.1µF capacitor is recommended from COM to AGND to maintain ±0.5 LSB stability, and a 0.047µF capacitor is needed at REFADJ for internal compensation mode. These values are non-negotiable for achieving datasheet performance.
Can the MAX146ACAP+ interface directly with a TMS320C28x DSP?
Yes, the MAX146ACAP+ can interface directly with TMS320C28x DSPs via its SSTRB output, which pulses high for one SCLK period before the MSB is shifted out - enabling hardware-triggered capture without CPU intervention. The 4-wire serial interface is fully compatible with the DSP's SPI peripheral when configured for CPOL = 0 and CPHA = 0, as documented in the MAX146/MAX147 datasheet.
What is the maximum source impedance supported for analog inputs on the MAX146ACAP+?
The MAX146ACAP+ supports analog source impedances up to 1kΩ without degrading AC performance; for higher impedances, a 0.01µF capacitor must be placed at each input to limit bandwidth and ensure proper acquisition. The datasheet specifies tACQ = 9 × (RS + 9kΩ) × 16pF, with minimum acquisition time of 1.5µs - meaning 10kΩ source impedance increases tACQ to ~1.6µs, still within specification.
How does the SHDN pin function in the MAX146ACAP+?
The SHDN pin on the MAX146ACAP+ is a three-level control: pulled low → full shutdown (1µA); pulled high → internal compensation mode for VREF; left floating → external compensation mode. This is distinct from simple on/off control - the state directly configures the reference buffer's compensation network, affecting VREF stability and settling time, as detailed in the Pin Description section.
MAX146ACAP+ 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:
- 12
- 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 ~ 3.6V
- Voltage - Supply, Digital:
- 2.7V ~ 3.6V
- Features:
- -
- Operating Temperature:
- 0°C ~ 70°C
- Supplier Device Package:
- 20-SSOP
- Mounting Type:
- Surface Mount
- Grade:
- -
- Qualification:
- -
MAX146ACAP+ FAQ
1.How can I place an order for MAX146ACAP+ through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX146ACAP+ 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 MAX146ACAP+ reliable?
The price and inventory of MAX146ACAP+ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX146ACAP+ is usually 5 days.
3.What payment methods are accepted for MAX146ACAP+?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX146ACAP+ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX146ACAP+?
MAX146ACAP+ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX146ACAP+ 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 MAX146ACAP+?
For technical support, including MAX146ACAP+ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX146ACAP+ requirements.
6.How does Aetrix verify that MAX146ACAP+ is sourced from the original manufacturer or authorized distributors?
All MAX146ACAP+ 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 MAX146ACAP+ meets industry standards.
7.What is the process for return or replacement of MAX146ACAP+?
All MAX146ACAP+ units undergo pre-shipment inspection (PSI). If there is an issue with MAX146ACAP+, 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 MAX146ACAP+ part is unused and in its original packaging.
Return procedure for MAX146ACAP+:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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