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Analog Devices Inc./Maxim Integrated MAX146ACPP+
- Part No.:
- MAX146ACPP+
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Analog to Digital Converters (ADC)
- Package:
- 20-DIP (0.300", 7.62mm)
- Datasheet:
-
MAX146ACPP+.pdf
- Description:
- IC ADC 12BIT SAR 20DIP
- Quantity:
- Payment:
- Shipping:
Inventory:2,007
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Product details
Overview
MAX146ACPP+ from Maxim Integrated is a 12-bit, 8-channel serial analog-to-digital converter (ADC) with integrated track/hold, internal 2.5V reference, and SPI/QSPI/MICROWIRE-compatible 4-wire interface. It operates from a single +2.7V to +3.6V supply, delivers 133ksps conversion rate, ±0.5 LSB INL, and consumes only 1.2mA at full speed-enabling high-precision data acquisition in battery-powered medical instruments and portable data loggers.
For engineers reviewing the MAX146ACPP+ datasheet, MAX146ACPP+ pinout, MAX146ACPP+ application, or MAX146ACPP+ equivalent, key selection considerations include its internal reference accuracy (±0.5% initial, ±30 ppm/°C drift), software-configurable unipolar/bipolar and single-ended/differential input modes, low-power shutdown (1µA), and 20-pin plastic DIP package compatibility with legacy industrial control designs.
Technical Context
The MAX146ACPP+ uses successive-approximation architecture with a capacitive DAC and integrated track/hold circuitry. Its analog front-end supports pseudo-differential sampling across eight inputs (CH0–CH7) referenced to COM, with configurable channel pairing for four differential measurements (e.g., CH0/CH1, CH2/CH3).
Conversion is clocked either by an internal oscillator or externally via SCLK (up to 2.0MHz), with timing controlled by an 8-bit software-programmable control byte. The device features a three-level SHDN pin enabling full shutdown, fast power-down, or reference-buffer compensation mode selection-critical for dynamic power management in embedded systems.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Resolution | 12-bit - delivers 1 LSB = 610 µV at 2.5V reference, sufficient for 0.024% full-scale precision in sensor signal chains. |
| INL (Integral Nonlinearity) | ±0.5 LSB max - ensures monotonicity and <0.012% measurement error after calibration, critical for closed-loop control feedback. |
| Conversion Rate | 133 ksps (external clock @ 2MHz) - supports real-time sampling of audio-band signals (≤66.5 kHz Nyquist) without undersampling artifacts. |
| Supply Current | 1.2 mA @ 133 ksps / 3V - enables >100-hour operation on a 1200 mAh Li-ion cell when paired with duty-cycled sampling. |
| Reference | Internal 2.500 V ±0.5% (0°C to +70°C), ±30 ppm/°C TC - eliminates external reference component cost and layout area while maintaining ±0.15% total drift over temperature. |
| Input Configuration | Software-selectable unipolar (0V to VREF) or bipolar (±VREF/2), single-ended or differential - allows reuse across voltage-sense, current-sense, and bridge transducer applications. |
| Serial Interface | SPI/QSPI/MICROWIRE/TMS320-compatible 4-wire - connects directly to common microcontrollers (e.g., STM32, MSP430) without level shifters or glue logic. |
Pinout & Package
MAX146ACPP+ is housed in a 20-pin plastic DIP (Dual In-line Package) with 0.3-inch body width and 0.1-inch pin pitch, compatible with through-hole prototyping and legacy industrial PCBs.
| Pin | Circuit Role | Design Meaning |
|---|---|---|
| 1–8 | CH0–CH7 | Analog input channels - support 8 single-ended or 4 differential measurements; each has ±0.3V overvoltage tolerance relative to supplies. |
| 9 | COM | Common-mode reference node - sets zero-code voltage in single-ended mode; must be stable to ±0.5 LSB for full accuracy. |
| 10 | SHDN | Three-level shutdown control - low = full shutdown (1µA), high = internal compensation, float = external compensation (via REFADJ). |
| 11 | VREF | Reference buffer output / ADC reference input - provides 2.500 V nominal (MAX146 only); bypassed with 4.7µF capacitor for stability. |
| 12 | REFADJ | Reference buffer adjustment input - ±1.5% fine-tuning range; tie to VDD to disable internal reference for external reference use. |
| 13 | AGND | Analog ground - separate return path for analog circuitry; must be star-connected to DGND at single point to minimize noise coupling. |
| 14 | DGND | Digital ground - return for digital I/O and serial interface; isolation from AGND prevents digital switching noise from corrupting conversions. |
| 15 | DOUT | Serial data output - MSB-first, clocked on SCLK falling edge; high-impedance when CS is high to allow bus sharing. |
| 16 | SSTRB | Serial strobe output - pulses high one SCLK period before MSB in external clock mode; synchronizes DSP capture of conversion result. |
| 17 | DIN | Serial data input - accepts 8-bit control byte on SCLK rising edge; START bit defines MSB position regardless of leading zeros. |
| 18 | CS | Active-low chip select - enables serial interface and powers up ADC; must remain low during full 24-clock conversion cycle. |
| 19 | SCLK | Serial clock input - drives data transfer and (in external mode) conversion timing; 40–60% duty cycle required for reliable operation. |
| 20 | VDD | Positive supply - +2.7V to +3.6V only; exceeds absolute max rating if extended to +5.25V (MAX147 domain). |
Key Features
| Feature | Design Value |
|---|---|
| Integrated 2.5V reference with ±0.5% initial accuracy | Eliminates need for external reference IC and associated decoupling, reducing BOM count and PCB area by ≥3 components. |
| Software-configurable input polarity and topology | Single control byte selects unipolar/bipolar and single-ended/differential modes - enables one hardware design to serve multiple sensor types. |
| Three-level SHDN pin with reference-buffer mode control | Enables adaptive power management: full shutdown (1µA), fast wake-up (<1µs), or reference compensation tuning without firmware overhead. |
| Track/hold acquisition time ≤1.5µs | Supports accurate sampling of signals with source impedances up to 1kΩ without external buffering - simplifies front-end design. |
| Internal clock option with 2.25MHz small-signal bandwidth | Permits self-contained operation without external clock generator; 2.25MHz bandwidth allows alias-free digitization of transient events. |
| Robust analog input protection | Clamps CHx/COM pins to AGND −0.3V and VDD +0.3V - withstands ESD and miswiring in field-deployed instrumentation. |
Applications
| Portable Data Logging | Medical Instrumentation |
|---|---|
|
Use Scenario: Battery-powered environmental sensor node recording temperature, humidity, and pressure over 72-hour deployments. IC Role / Device Role / Timing Role: Primary ADC acquiring synchronized multi-channel analog sensor outputs at 1ksps with automatic power-down between samples. Use Value: 54µA average current at 1ksps extends lithium primary cell life beyond 5 years; internal reference ensures consistent calibration across units and temperature. |
Use Scenario: Handheld ECG monitor capturing lead-II differential signals with 12-bit resolution and clinical-grade linearity. IC Role / Device Role / Timing Role: Front-end ADC converting amplified biopotential signals using CH0/CH1 differential pair with programmable gain stage interface. Use Value: ±0.5 LSB INL and <−85 dB THD meet AAMI EC11 requirements; software-selectable bipolar mode accommodates ±2.5V ECG swing without external level-shifting. |
| Battery-Powered Test Equipment | Industrial Process Control |
|
Use Scenario: Pocket-sized multimeter measuring DC voltage, current, and resistance with autoranging and auto-zero functions. IC Role / Device Role / Timing Role: Precision ADC performing ratiometric measurements against internal reference, with COM tied to sense resistor common. Use Value: Internal 2.5V reference stability (±30 ppm/°C) ensures <0.01% reading drift from 0°C to 70°C - meets handheld DMM Class II accuracy specs. |
Use Scenario: PLC analog input module conditioning 4–20mA loop signals and thermocouple outputs in factory automation cabinets. IC Role / Device Role / Timing Role: Channel-multiplexed ADC scanning 8 isolated current/voltage inputs at 100Hz with simultaneous digital filtering in host MCU. Use Value: 8-channel integration reduces per-channel component count vs. discrete ADCs; SPI interface enables deterministic scan timing under RTOS scheduling. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar 12-bit serial ADC applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| ADS7822U | 12-bit, 200ksps, +2.7V to +5.25V supply, no internal reference, requires external 2.5V ref. | Higher speed but lacks integrated reference and bipolar mode - needs additional ref IC and op-amp for bipolar signal conditioning. | Choose when sampling rate >133ksps is mandatory and board space allows external reference + level-shifting circuitry. |
| MAX11131AUT+T | 12-bit, 1MSPS, +2.7V to +3.6V, internal reference (2.048V), SPI-only interface, 8-pin µDFN. | Higher speed and smaller footprint, but only 4-channel mux and no TMS320 strobe output - incompatible with legacy DSP interfaces. | Choose for space-constrained, high-throughput designs where TMS320 sync or 8-channel count is not required. |
Compared with ADS7822U and MAX11131AUT+T, the MAX146ACPP+ uniquely combines 8-channel multiplexing, internal 2.5V reference, bipolar input support, and TMS320-compatible SSTRB output in a through-hole DIP package-making it optimal for cost-sensitive, maintenance-friendly industrial and medical retrofits.
Availability
MAX146ACPP+ 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 obsolescence management.
Supply support for MAX146ACPP+ 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 MAX146ACPP+ belongs to Maxim's precision data-acquisition product line, designed specifically for low-power, high-accuracy ADC applications in resource-constrained embedded systems where integration, reliability, and ease of interface are critical.
FAQ
What is the operating temperature range for the MAX146ACPP+?
The MAX146ACPP+ is rated for 0°C to +70°C ambient operation, matching the 'C' grade specification in Maxim's ordering table. This range covers commercial and industrial indoor environments, including portable medical devices and factory-floor data loggers. The device maintains full DC accuracy (±0.5 LSB INL, ±0.5 LSB DNL) and dynamic performance (73dB SINAD) across this range, with reference voltage drift limited to ±50 ppm/°C maximum.
Does the MAX146ACPP+ require an external reference voltage?
No, the MAX146ACPP+ includes an internal 2.500V reference buffer with ±0.5% initial accuracy and ±30 ppm/°C temperature coefficient - fully sufficient for most precision applications. External reference is only needed if higher initial accuracy (e.g., ±0.1%) or different voltage (e.g., 3.0V) is required. When using the internal reference, a 4.7µF capacitor must be placed at the VREF pin per the datasheet layout guidelines.
How does the SHDN pin function on the MAX146ACPP+?
The MAX146ACPP+ SHDN pin supports three distinct states: pulled low → full shutdown (1µA supply current); pulled high → internal reference compensation enabled; left floating → external compensation mode (via REFADJ). This three-level control allows flexible power management without firmware intervention - for example, tying SHDN to a GPIO enables hardware-triggered deep sleep, while floating it permits precise reference trimming during calibration.
Can the MAX146ACPP+ perform differential measurements?
Yes, the MAX146ACPP+ supports true pseudo-differential measurements across four channel pairs: CH0/CH1, CH2/CH3, CH4/CH5, and CH6/CH7. In differential mode, the device samples the voltage difference |IN+ − IN−| with the same 12-bit resolution and ±0.5 LSB INL as single-ended mode. The COM pin serves as the common reference, and stability of the IN− node to ±0.5 LSB is required during conversion - typically achieved with a 0.1µF capacitor to AGND.
What serial interface protocols is the MAX146ACPP+ compatible with?
The MAX146ACPP+ supports SPI, QSPI, and MICROWIRE protocols natively via its 4-wire interface (CS, SCLK, DIN, DOUT). It requires CPOL = 0 and CPHA = 0 for SPI compatibility and operates up to 2MHz SCLK. The SSTRB output provides direct TMS320-family DSP synchronization, allowing deterministic capture of conversion results without polling. No external logic or level shifters are needed for interfacing with standard microcontrollers.
MAX146ACPP+ Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- 20-DIP (0.300", 7.62mm)
- Packaging:
- Bulk
- Product Status:
- Obsolete
- 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-PDIP
- Mounting Type:
- Through Hole
- Grade:
- -
- Qualification:
- -
MAX146ACPP+ FAQ
1.How can I place an order for MAX146ACPP+ through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX146ACPP+ 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 MAX146ACPP+ reliable?
The price and inventory of MAX146ACPP+ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX146ACPP+ is usually 5 days.
3.What payment methods are accepted for MAX146ACPP+?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX146ACPP+ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX146ACPP+?
MAX146ACPP+ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX146ACPP+ 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 MAX146ACPP+?
For technical support, including MAX146ACPP+ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX146ACPP+ requirements.
6.How does Aetrix verify that MAX146ACPP+ is sourced from the original manufacturer or authorized distributors?
All MAX146ACPP+ 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 MAX146ACPP+ meets industry standards.
7.What is the process for return or replacement of MAX146ACPP+?
All MAX146ACPP+ units undergo pre-shipment inspection (PSI). If there is an issue with MAX146ACPP+, 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 MAX146ACPP+ part is unused and in its original packaging.
Return procedure for MAX146ACPP+:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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