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Analog Devices Inc./Maxim Integrated MAX1281BCUP+
- Part No.:
- MAX1281BCUP+
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Analog to Digital Converters (ADC)
- Package:
- 20-TSSOP (0.173", 4.40mm Width)
- Datasheet:
-
MAX1281BCUP+.pdf
- Description:
- IC ADC 12BIT SAR 20TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:2,420
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Product details
Overview
The MAX1281BCUP+ from Maxim Integrated is a 12-bit, 8-channel serial analog-to-digital converter (ADC) with integrated track/hold, multiplexer, and internal +2.5V reference. It operates from a single +2.7V to +3.6V supply, delivers 300ksps sampling rate, supports software-configurable unipolar/bipolar and single-ended/pseudo-differential inputs, and targets battery-powered data acquisition systems requiring low power and compact size.
For engineers reviewing the MAX1281BCUP+ datasheet, MAX1281BCUP+ pinout, MAX1281BCUP+ application, or MAX1281BCUP+ equivalent, this page provides verified technical context, real-world design meanings for key specs, validated pin functions, confirmed application use cases, and two rigorously cross-checked alternative parts - all grounded in the official MAX1280/MAX1281 datasheet Rev 2 (10/10).
Technical Context
The MAX1281BCUP+ uses successive-approximation register (SAR) architecture with an integrated track/hold circuit and 8-channel analog multiplexer. Its conversion timing is synchronized to an external serial clock (fSCLK = 4.8MHz max), requiring 16 clock cycles per 12-bit result, with acquisition time of 625ns and aperture jitter under 50ps.
It features dual power domains (VDD1/VDD2), a reference buffer with ±1.5% adjustment range via REFADJ, and four software-selectable power modes - including full power-down (2µA) and fast power-down (0.9mA) - enabling dynamic current scaling between conversions without external logic.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Resolution | 12-bit - delivers 4096 discrete output codes for high-fidelity signal digitization in precision measurement. |
| Sampling Rate | 300ksps - supports real-time capture of signals up to 150kHz bandwidth (full-linear) in battery-constrained systems. |
| Supply Voltage | +2.7V to +3.6V - enables direct interface with 3.3V microcontrollers and Li-ion/Li-poly battery rails without regulation. |
| INL / DNL | ±1.0 LSB / ±1.0 LSB - ensures monotonicity and <0.024% integral nonlinearity error across temperature for calibrated sensor interfaces. |
| Reference | Internal +2.500V ±0.020V - eliminates external reference component count while maintaining ±15ppm/°C tempco for stable DC accuracy. |
| Power Modes | Full power-down (2µA), fast power-down (0.9mA), reduced-power (1.3mA), normal (2.5mA) - allows adaptive current control per sample interval. |
| SPI/QSPI/MICROWIRE | 4-wire serial interface - connects directly to TMS320 DSPs or standard MCU SPI peripherals without level shifters or glue logic. |
Pinout & Package
The MAX1281BCUP+ is housed in a 20-pin TSSOP package (4.4mm × 6.5mm, 0.65mm pitch), optimized for space-constrained portable instrumentation and embedded data loggers.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| CH0–CH7 (Pins 1–8) | Analog input channels | Eight single-ended or four pseudo-differential input pairs (CH0/CH1, CH2/CH3, etc.) - selectable via software control byte; each channel supports ±VREF/2 differential or 0–VREF unipolar ranges. |
| COM (Pin 9) | Common-mode reference | Sets zero-code voltage in single-ended mode; must remain stable within ±0.5LSB during conversion to avoid gain/offset errors. |
| SHDN (Pin 10) | Hardware shutdown enable | Active-low input that forces full power-down (2µA ICC) independent of software state - used for system-level sleep coordination. |
| REF (Pin 11) | Reference buffer output / external ref input | Provides +2.500V nominal output when internal reference enabled; accepts 1.0V to VDD1 external reference when REFADJ tied to VDD1. |
| REFADJ (Pin 12) | Reference buffer adjustment | Allows ±1.5% fine-tuning of internal reference voltage; disable buffer by connecting to VDD1 - required for external reference use. |
| GND (Pin 13) | Analog/digital ground | Single ground plane for both analog and digital sections - layout requires low-impedance connection to minimize noise coupling into ADC core. |
| DOUT (Pin 14) | Serial data output | 3-state output delivering 12-bit conversion result MSB-first on SCLK rising edge; high-impedance when CS is high. |
| SSTRB (Pin 15) | Serial strobe output | Pulses high for one SCLK period before MSB appears on DOUT - provides hardware-ready signal for TMS320-family DSPs to latch data. |
| DIN (Pin 16) | Serial data input | Accepts 8-bit control byte (channel select, polarity, power mode) on SCLK rising edge; first '1' bit defines MSB position. |
| CS (Pin 17) | Chip select | Active-low enable for serial interface - disables DOUT/SSTRB and places device in standby when high; required for multi-device SPI bus sharing. |
| SCLK (Pin 18) | Serial clock input | Drives internal timing; 4.8MHz max frequency sets 300ksps throughput - duty cycle must be 40–60% for reliable sampling. |
| VDD2 (Pin 19) | Digital supply | Supplies digital core (serial interface, logic); must match VDD1 voltage (±0.3V) and be decoupled with 0.1µF ceramic capacitor near pin. |
| VDD1 (Pin 20) | Analog supply | Supplies analog front-end (mux, T/H, SAR); shares same 2.7–3.6V rail as VDD2 but requires separate 4.7µF bulk + 0.01µF bypass at REF/REFADJ. |
Key Features
| Feature | Design Value |
|---|---|
| 8-channel analog multiplexer + track/hold | Reduces external signal conditioning components; enables sequential sampling of multiple sensors without external mux or sample-hold IC. |
| Software-configurable input modes | Supports unipolar (0–VREF) or bipolar (±VREF/2) operation per channel - simplifies firmware adaptation across diverse sensor types (e.g., thermocouples vs. pressure transducers). |
| Internal +2.5V reference with REFADJ | Eliminates need for external precision reference IC; ±1.5% adjustability compensates for system-level gain calibration drift over temperature. |
| Four selectable power modes | Enables sub-µA average current at low sampling rates - critical for multi-year battery life in remote data loggers operating at ≤1ksps. |
| SPI/QSPI/MICROWIRE/TMS320 compatibility | Direct interface to industry-standard controllers without protocol translation - reduces firmware development time and eliminates external level-shifting circuitry. |
Applications
| Portable Data Logging | Data Acquisition |
|---|---|
Use Scenario: Standalone environmental monitor logging temperature, humidity, and light intensity every 10 seconds using coin-cell battery. IC Role / Device Role / Timing Role: ADC digitizes sensor outputs sequentially via CH0–CH3; internal reference ensures consistent 12-bit resolution across battery discharge curve. Use Value: Full power-down mode (2µA) between samples extends battery life beyond 5 years; 20-pin TSSOP fits compact PCB footprint. | Use Scenario: Industrial PLC module acquiring analog signals from 6 pressure transducers and 2 thermocouples. IC Role / Device Role / Timing Role: Configured in pseudo-differential mode (CH0/CH1, CH2/CH3, etc.) to reject common-mode noise on long sensor cables. Use Value: ±1.0 LSB INL guarantees <0.024% measurement linearity; 300ksps rate supports oversampling for noise reduction. |
| Medical Instruments | Battery-Powered Instruments |
Use Scenario: Handheld ECG device capturing lead-II waveform at 250SPS with real-time QRS detection. IC Role / Device Role / Timing Role: Single-ended unipolar mode digitizes amplified biopotential signal; SSTRB synchronizes DSP interrupt for immediate post-processing. Use Value: 625ns track/hold acquisition time captures fast-rising R-wave edges; internal reference avoids drift-induced baseline wander. | Use Scenario: Wireless pH meter using Bluetooth LE MCU and disposable glass electrode. IC Role / Device Role / Timing Role: Converts high-impedance electrode output with COM referenced to buffered mid-supply; reduced-power mode cuts active current to 1.3mA. Use Value: 2.7–3.6V supply range matches BLE SoC I/O voltage; 20-pin TSSOP allows integration into pen-sized enclosure. |
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, 200ksps, +2.7V to +5.25V supply, no internal reference - requires external 2.5V ref. | Lacks integrated reference and REFADJ; lower sampling rate limits high-speed transient capture. | Choose when external reference already exists in system and 200ksps suffices; adds BOM cost but offers wider supply range. |
| MAX11126ETE+ | 8-channel, 12-bit, 500ksps, +2.7V to +3.6V supply, internal 2.048V ref, SPI-only interface (no SSTRB). | Higher speed and lower reference voltage; missing SSTRB limits direct TMS320 interfacing. | Prefer for higher-throughput systems where DSP sync is handled in firmware; 2.048V ref simplifies math with 4096-code full scale. |
Compared with ADS7822U and MAX11126ETE+, the MAX1281BCUP+ uniquely combines TMS320-compatible SSTRB strobe, adjustable internal 2.5V reference, and four hardware/software power modes - making it optimal for ultra-low-power, DSP-coupled, field-deployable instrumentation where board space and supply simplicity are critical.
Availability
The MAX1281BCUP+ is available at Aetrix Electronics and suitable for portable data logging, medical instruments, and battery-powered instruments requiring stable component supply, RoHS-compliant packaging, and guaranteed long-term availability.
Supply support for MAX1281BCUP+ 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, mixed-signal, and power management ICs for demanding industrial, medical, and communications applications.
The MAX1280/MAX1281 product line delivers low-power, multi-channel SAR ADCs with integrated references and flexible serial interfaces - engineered specifically for portable, battery-operated measurement systems needing high accuracy without external support components.
FAQ
What is the maximum sampling rate of the MAX1281BCUP+?
The MAX1281BCUP+ achieves a maximum sampling rate of 300ksps, defined by its 4.8MHz serial clock and fixed 16-clock conversion cycle. This rate is guaranteed across the full operating temperature range (0°C to +70°C) and supply voltage (2.7V to 3.6V), supporting real-time digitization of signals up to 150kHz full-linear bandwidth.
Does the MAX1281BCUP+ require an external reference voltage?
No, the MAX1281BCUP+ includes an internal +2.500V reference with ±0.020V initial accuracy and ±15ppm/°C temperature coefficient. An external reference can be used by disabling the internal buffer via REFADJ, but it is not required - the internal reference eliminates BOM cost and layout complexity for most portable applications.
How does the power-down functionality work on the MAX1281BCUP+?
The MAX1281BCUP+ supports four power modes controlled by PD1/PD0 bits in the command byte: normal (2.5mA), reduced-power (1.3mA), fast power-down (0.9mA), and full power-down (2µA). Accessing the serial interface automatically wakes the device, and the quick turn-on time allows powering down between every conversion to minimize average current.
Can the MAX1281BCUP+ interface directly with a TMS320 DSP?
Yes, the MAX1281BCUP+ features a dedicated SSTRB (serial strobe) output that pulses high for one SCLK period before the MSB appears on DOUT. This hardware-ready signal is explicitly designed for direct connection to TMS320-family DSPs, eliminating the need for polling or additional timing logic in firmware.
What is the input voltage range for single-ended operation on the MAX1281BCUP+?
In single-ended unipolar mode, the MAX1281BCUP+ accepts analog inputs from 0V to VREF (2.5V) referenced to COM. In single-ended bipolar mode, the range is ±VREF/2 (±1.25V) referenced to COM. The absolute pin voltage must stay within GND – 0.3V to VDD1 + 0.3V to avoid damage, with full-scale accuracy maintained only within GND to VDD1 ±50mV.
MAX1281BCUP+ Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- 20-TSSOP (0.173", 4.40mm Width)
- Packaging:
- Tube
- Product Status:
- Active
- Number of Bits:
- 12
- Sampling Rate (Per Second):
- 300k
- Number of Inputs:
- 4, 8
- Input Type:
- Pseudo-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-TSSOP
- Mounting Type:
- Surface Mount
- Grade:
- -
- Qualification:
- -
MAX1281BCUP+ FAQ
1.How can I place an order for MAX1281BCUP+ through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX1281BCUP+ 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 MAX1281BCUP+ reliable?
The price and inventory of MAX1281BCUP+ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX1281BCUP+ is usually 5 days.
3.What payment methods are accepted for MAX1281BCUP+?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX1281BCUP+ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX1281BCUP+?
MAX1281BCUP+ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX1281BCUP+ 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 MAX1281BCUP+?
For technical support, including MAX1281BCUP+ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX1281BCUP+ requirements.
6.How does Aetrix verify that MAX1281BCUP+ is sourced from the original manufacturer or authorized distributors?
All MAX1281BCUP+ 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 MAX1281BCUP+ meets industry standards.
7.What is the process for return or replacement of MAX1281BCUP+?
All MAX1281BCUP+ units undergo pre-shipment inspection (PSI). If there is an issue with MAX1281BCUP+, 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 MAX1281BCUP+ part is unused and in its original packaging.
Return procedure for MAX1281BCUP+:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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