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Analog Devices Inc./Maxim Integrated MAX1291BEEI+
- Part No.:
- MAX1291BEEI+
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Analog to Digital Converters (ADC)
- Package:
- 28-SSOP (0.154", 3.90mm Width)
- Datasheet:
-
MAX1291BEEI+.pdf
- Description:
- IC ADC 12BIT 250KSPS 28-QSOP
- Quantity:
- Payment:
- Shipping:
Inventory:1,511
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Product details
Overview
MAX1291BEEI+ from Maxim Integrated is a 12-bit, 250ksps successive-approximation ADC with integrated +2.5V reference, 8-channel single-ended / 4-channel pseudo-differential analog input multiplexer, and byte-wide parallel (8+4) interface. It operates from a single +3V analog supply and supports digital logic levels from +1.8V to +3.6V via VLOGIC. Designed for battery-powered data acquisition, it delivers ±0.5 LSB INL, 67dB SINAD, and 3MHz full-power bandwidth.
For engineers reviewing the MAX1291BEEI+ datasheet, MAX1291BEEI+ pinout, MAX1291BEEI+ application, or MAX1291BEEI+ equivalent, key selection criteria include its -40°C to +85°C industrial temperature range, QSOP-28 package, software-configurable unipolar/bipolar input mode, low 1.9mA active current at 250ksps, and internal track/hold with 3.2µs acquisition time.
Technical Context
The MAX1291BEEI+ implements a charge-redistribution SAR architecture with an integrated track/hold stage, supporting both internal and external clock modes (up to 4.8MHz) and internal/external acquisition control via software-configurable ACQMOD bit. Its analog front-end allows dynamic reconfiguration between single-ended and pseudo-differential input modes using SGL/DIF bit, with COM referenced zero-code voltage.
Conversion timing is deterministic: 13 clock cycles per conversion, with aperture jitter as low as 50ps in external acquisition mode. The device uses a 12-bit capacitive DAC and supports two power-down modes-standby (10µA) and full shutdown (2µA)-triggered by PD0/PD1 bits in the control byte, enabling precise energy management in intermittent-sampling systems.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Resolution | 12-bit - delivers 4096 discrete output codes for high-fidelity signal digitization |
| Sampling Rate | 250ksps - supports real-time monitoring of fast transients in industrial sensors |
| INL | ±0.5 LSB - ensures monotonicity and <0.012% full-scale linearity error over temperature |
| Supply Current | 1.9mA at 250ksps - enables >500-hour operation on a 1000mAh Li-ion cell |
| Reference | +2.5V internal - eliminates external reference component count and layout area |
| Input Channels | 8 single-ended or 4 pseudo-differential - provides flexible sensor interfacing without external MUX |
| Package | 28-pin QSOP - 9.9mm × 3.9mm footprint compatible with standard automated assembly |
| Temperature Range | -40°C to +85°C - qualified for industrial control and patient monitoring environments |
Pinout & Package
MAX1291BEEI+ is housed in a 28-pin QSOP (Quad Small Outline Package) with 0.65mm lead pitch and exposed pad not present. Pin functions are validated per Maxim's official MAX1291/MAX1293 datasheet Rev 3 (12/02), Figure "Pin Configurations" and "Pin Description" sections.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| HBEN | High-byte enable control | Selects MSB (D8–D11) or LSB (D0–D7) output on shared data bus |
| D0/D8–D7/D11 | Three-state bidirectional data I/O | Byte-multiplexed 12-bit result delivery; reduces microcontroller bus width requirement |
| INT | Open-drain interrupt output | Active-low flag signals conversion completion; tri-states when CS = high |
| WR, RD, CS | Parallel interface control inputs | Enable register write, data read, and chip select with TTL/CMOS-compatible thresholds |
| CH0–CH7 | Analog input channels | Software-selectable inputs; CH0–CH7 active in single-ended mode per MAX1291 spec |
| COM | Analog common reference | Sets zero-code voltage in single-ended mode; must remain stable to ±0.5 LSB |
| REF, REFADJ | Internal reference buffer I/O | REF outputs +2.5V; REFADJ disables internal bandgap when tied to VDD for external ref use |
| VDD, VLOGIC | Separate analog/digital supplies | VDD = +2.7V to +3.6V analog rail; VLOGIC = +1.8V to +3.6V logic rail enables mixed-voltage system interfacing |
Key Features
| Feature | Design Value |
|---|---|
| Software-configurable input mode | Single-ended (8 ch) or pseudo-differential (4 ch) selection via SGL/DIF bit - eliminates external analog switching components |
| Adjustable logic supply range | VLOGIC = +1.8V to +3.6V - interfaces directly with 1.8V, 2.5V, or 3.3V microcontrollers without level shifters |
| Low-power acquisition control | Two software-selectable power-down modes (standby/fully shut down) - cuts supply current to 10µA or 2µA between conversions |
| Integrated track/hold | 3MHz full-power bandwidth - supports undersampling of kHz-range transients without external T/H circuitry |
| Internal +2.5V reference | ±20ppm/°C tempco, ±100mV adjust range via REFADJ - achieves 0.04% initial accuracy without calibration |
| Fast wake-up | 2µs wake-from-shutdown - enables rapid response to event-triggered sampling in energy-harvesting systems |
Applications
| Industrial Process Monitoring | Patient Vital Sign Acquisition |
|---|---|
Use Scenario: Continuous logging of pressure, temperature, and flow sensor outputs in PLC-based control cabinets. IC Role / Device Role / Timing Role: Primary ADC digitizing 8 analog sensor channels with synchronized sampling and interrupt-driven data transfer. Use Value: Single-chip solution eliminates external reference and level-shifting ICs, reducing BOM cost by $0.85 and PCB area by 24mm². |
Use Scenario: Portable ECG and SpO₂ monitor acquiring biopotential signals with low noise and high DC accuracy. IC Role / Device Role / Timing Role: High-precision front-end ADC operating in bipolar mode with COM-referenced inputs for differential electrode pairs. Use Value: ±0.5 LSB INL and 67dB SINAD ensure diagnostic-grade waveform fidelity; 1.9mA active current extends battery life to 12 hours. |
| Energy Metering Subsystem | Touch Screen Controller Interface |
Use Scenario: Residential smart meter measuring voltage/current waveforms across multiple phases with anti-alias filtering. IC Role / Device Role / Timing Role: Simultaneous sampling of voltage and current channels using pseudo-differential mode to reject common-mode noise. Use Value: 3MHz full-power bandwidth enables accurate capture of harmonic content up to 1.5MHz; internal reference ensures metrology-grade stability. |
Use Scenario: Resistive touch overlay digitizing X/Y coordinate voltages in handheld HMI panels. IC Role / Device Role / Timing Role: Low-latency ADC converting analog touch voltages with fast 250ksps rate and hardware-ready interrupt signaling. Use Value: 2µs wake-up and 3.6µs conversion time enable sub-10ms touch response; VLOGIC compatibility simplifies integration with 1.8V display controllers. |
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-bit resolution, SPI interface, no internal reference, 200ksps max rate | Limited to lower-accuracy sensor readouts; requires external ref and level shifters for 1.8V logic | Choose only if 8-bit resolution suffices and serial interface is preferred over parallel. |
| MAX11607ETE+ | 12-bit, I²C interface, internal reference, 94.4ksps, 16-pin TQFN | Lower sampling rate; lacks pseudo-differential mode and software-configurable unipolar/bipolar operation | Select when board space is critical and I²C bus availability permits reduced pin count. |
Compared with MAX1291BEEI+, ADS7822U trades resolution and integration for interface simplicity, while MAX11607ETE+ sacrifices speed and analog flexibility for compact packaging and I²C compatibility-neither offers the same combination of parallel throughput, software-configurable analog front-end, and industrial temperature rating.
Availability
MAX1291BEEI+ is available at Aetrix Electronics and suitable for industrial process monitoring, patient vital sign acquisition, energy metering subsystems, and touch screen controller interfaces requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for MAX1291BEEI+ 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 industrial, medical, and communications applications.
The MAX1291BEEI+ belongs to Maxim's low-power SAR ADC product line, engineered for space-constrained, battery-operated data acquisition systems demanding high DC accuracy, flexible input configuration, and minimal external component count.
FAQ
What is the operating temperature range of the MAX1291BEEI+?
The MAX1291BEEI+ is rated for operation from -40°C to +85°C, making it suitable for industrial control cabinets, outdoor energy meters, and portable medical devices exposed to wide ambient conditions. This extended temperature grade is confirmed in the "Ordering Information" table of the MAX1291/MAX1293 datasheet Rev 3, where MAX1291BEEI+ is explicitly listed with "-40°C to +85°C" under TEMP RANGE.
Does the MAX1291BEEI+ require an external reference voltage?
No, the MAX1291BEEI+ includes a factory-trimmed +2.5V internal reference with ±20ppm/°C temperature coefficient and ±100mV adjustment range via REFADJ. External reference is optional: tie REFADJ to VDD to disable the internal reference and drive REF with an external source. The internal reference eliminates BOM cost and layout complexity unless higher initial accuracy or different voltage is required.
How many analog input channels does the MAX1291BEEI+ support?
The MAX1291BEEI+ supports eight single-ended analog input channels (CH0–CH7) or four pseudo-differential channel pairs (CH0/CH1, CH2/CH3, CH4/CH5, CH6/CH7), as defined in the "Features" and "Pin Configurations" sections of the datasheet. This 8-/4-channel capability is specific to the MAX1291 variant; the MAX1293 offers only four single-ended inputs.
What package type is used for the MAX1291BEEI+?
The MAX1291BEEI+ is supplied in a 28-pin QSOP (Quad Small Outline Package) with 0.65mm lead pitch and dimensions of 9.9mm × 3.9mm. This package is confirmed in the "Ordering Information" table and "Pin Configurations" diagram of the MAX1291/MAX1293 datasheet, where MAX1291BEEI+ is listed as "28 QSOP" under PIN-PACKAGE.
Can the MAX1291BEEI+ interface directly with a 1.8V microcontroller?
Yes, the MAX1291BEEI+ supports direct interfacing with 1.8V microcontrollers via its VLOGIC pin, which accepts a digital supply voltage from +1.8V to +3.6V. Input thresholds scale with VLOGIC, and output drive strength is specified down to 1.8V, eliminating the need for external level shifters when connecting to low-voltage logic systems.
MAX1291BEEI+ Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- 28-SSOP (0.154", 3.90mm Width)
- Packaging:
- Tube
- Product Status:
- Active
- Number of Bits:
- 12
- Sampling Rate (Per Second):
- 250k
- Number of Inputs:
- 4, 8
- Input Type:
- Pseudo-Differential, Single Ended
- Data Interface:
- Parallel
- 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:
- 1.8V ~ 3.6V
- Features:
- -
- Operating Temperature:
- -40°C ~ 85°C
- Supplier Device Package:
- 28-QSOP
- Mounting Type:
- Surface Mount
- Grade:
- -
- Qualification:
- -
MAX1291BEEI+ FAQ
1.How can I place an order for MAX1291BEEI+ through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX1291BEEI+ 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 MAX1291BEEI+ reliable?
The price and inventory of MAX1291BEEI+ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX1291BEEI+ is usually 5 days.
3.What payment methods are accepted for MAX1291BEEI+?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX1291BEEI+ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX1291BEEI+?
MAX1291BEEI+ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX1291BEEI+ 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 MAX1291BEEI+?
For technical support, including MAX1291BEEI+ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX1291BEEI+ requirements.
6.How does Aetrix verify that MAX1291BEEI+ is sourced from the original manufacturer or authorized distributors?
All MAX1291BEEI+ 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 MAX1291BEEI+ meets industry standards.
7.What is the process for return or replacement of MAX1291BEEI+?
All MAX1291BEEI+ units undergo pre-shipment inspection (PSI). If there is an issue with MAX1291BEEI+, 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 MAX1291BEEI+ part is unused and in its original packaging.
Return procedure for MAX1291BEEI+:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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