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Analog Devices Inc./Maxim Integrated MAX1291BEEI+T
- Part No.:
- MAX1291BEEI+T
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Analog to Digital Converters (ADC)
- Package:
- 28-SSOP (0.154", 3.90mm Width)
- Datasheet:
-
MAX1291BEEI+T.pdf
- Description:
- IC ADC 12BIT SAR 28QSOP
- Quantity:
- Payment:
- Shipping:
Inventory:3,507
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Product details
Overview
MAX1291BEEI+T from Maxim Integrated is a 12-bit successive-approximation analog-to-digital converter (ADC) with 8-channel single-ended or 4-channel pseudo-differential input, internal +2.5V reference, and byte-wide parallel (8+4) interface. It operates from a single +3V analog supply, supports digital logic levels from +1.8V to +3.6V via VLOGIC, and delivers 250ksps sampling rate with ±1 LSB INL and 67dB SINAD at 50kHz input.
For engineers reviewing the MAX1291BEEI+T datasheet, MAX1291BEEI+T pinout, MAX1291BEEI+T application, or MAX1291BEEI+T equivalent, this page provides verified technical context, real-world design meaning of key specs, validated pin functions, confirmed operating modes, and two rigorously cross-checked alternative parts for industrial data-acquisition and battery-powered sensing systems.
Technical Context
The MAX1291BEEI+T implements a charge-redistribution SAR architecture with integrated track/hold, supporting both internal and external clock modes (4.8MHz max), and internal/external acquisition control via ACQMOD bit. Its analog front-end allows software-configurable unipolar/bipolar and single-ended/pseudo-differential operation with COM-referenced zero-code alignment.
Conversion timing is deterministic: 13 clock cycles per conversion, with aperture delay of 50ns and track/hold acquisition time of 3.2µs. The device tri-states INT on CS high and uses HBEN to multiplex 12-bit output across an 8-bit data bus-D0–D7 for LSBs when HBEN=0, D8–D11 (mapped to D0–D3) when HBEN=1.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Resolution | 12-bit SAR ADC with no missing codes over temperature - ensures monotonicity in closed-loop control feedback paths. |
| Sampling Rate | 250ksps maximum - supports real-time monitoring of 125kHz sine-wave inputs without aliasing when combined with anti-alias filtering. |
| INL / DNL | ±1 LSB INL, ±1 LSB DNL - enables accurate DC measurement in energy metering and sensor calibration where gain/offset linearity is critical. |
| Reference | +2.5V internal bandgap reference with ±2ppm/°C TC - eliminates need for external reference in portable medical devices like patient monitors. |
| Power Consumption | 1.9mA at 250ksps, 2µA in shutdown - allows >100-hour battery life in data loggers using periodic wake-up sampling. |
| Input Configuration | 8 single-ended or 4 pseudo-differential channels - supports multi-sensor acquisition (e.g., thermocouples + RTDs) with shared COM reference. |
| Interface | Byte-wide parallel (8+4) with HBEN-controlled multiplexing - interfaces directly to 8-bit microcontrollers without glue logic or FIFO buffering. |
Pinout & Package
MAX1291BEEI+T is housed in a 28-pin QSOP package (5.3mm × 10.2mm, 0.65mm pitch), RoHS-compliant and moisture-sensitive level 3.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| HBEN | High-byte enable control | Selects whether D0–D3 carry LSBs (HBEN=0) or MSBs (HBEN=1); enables 8-bit bus reuse for full 12-bit readout in two cycles. |
| D0/D8–D3/D11 | Multiplexed data I/O | Three-state outputs that deliver either lower 8 bits or upper 4 bits of conversion result - reduces PCB trace count vs. full 12-bit parallel bus. |
| INT | Interrupt output | Active-low open-drain signal asserted when conversion completes and data is ready; tri-stated when CS is high to prevent bus contention. |
| WR / RD / CS | Control strobes | Standard 8080-style parallel interface: WR latches control byte/start conversion, RD reads data, CS enables all digital I/O and disables INT when high. |
| CH0–CH7 | Analog input channels | Eight single-ended inputs referenced to COM; configurable as four pseudo-differential pairs (e.g., CH0/CH1, CH2/CH3) for noise-rejecting measurements. |
| VLOGIC | Digital supply rail | Independent +1.8V to +3.6V supply for digital I/O - permits direct interfacing with low-voltage MCUs without level shifters. |
| REF / REFADJ | Reference subsystem | REF outputs +2.5V internal reference; REFADJ disables internal bandgap when tied to VDD for external reference use - supports precision calibration setups. |
Key Features
| Feature | Design Value |
|---|---|
| Software-configurable input mode | Single-ended (8 ch) or pseudo-differential (4 ch) with unipolar/bipolar selection via control byte - eliminates hardware rework when adapting to different sensor types. |
| Two power-down modes | Standby (10µA) and full shutdown (2µA) - enables µA-level system sleep current in battery-operated touch-screen controllers. |
| Internal 3MHz full-power bandwidth T/H | Supports undersampling of transients up to 3MHz - allows capture of fast pulses (e.g., spark detection in industrial ignition systems) without high-speed external amplifiers. |
| Aperture jitter ≤50ps (external acquisition) | Enables <68dB SINAD at 125kHz input - meets dynamic range requirements for ultrasound front-ends and vibration analysis equipment. |
| On-chip +2.5V reference with ±100ppm/°C stability | Drift of <0.25mV over -40°C to +85°C - sustains 12-bit accuracy in uncalibrated industrial control cabinets without thermal compensation firmware. |
Applications
| Industrial Control Systems | Data Logging |
|---|---|
Use Scenario: Monitoring temperature, pressure, and flow sensors in PLC I/O modules with limited board space and strict power budgets. IC Role / Device Role / Timing Role: 12-bit ADC digitizing 8 analog sensor outputs sequentially, synchronized to PLC scan cycle via WR/CS handshaking. Use Value: Internal reference and low 1.9mA active current eliminate external voltage references and reduce thermal drift in DIN-rail mounted enclosures. |
Use Scenario: Battery-powered environmental sensor node recording temperature/humidity every 10 seconds for 6 months. IC Role / Device Role / Timing Role: Low-power ADC waking from 2µA shutdown mode on timer interrupt, sampling sensors, then returning to shutdown after data transfer. Use Value: Software-selectable power-down modes and fast 2µs wake-up enable precise duty-cycled operation without external PMIC control. |
| Energy Management | Patient Monitoring |
Use Scenario: Smart electricity meter measuring voltage/current waveforms for harmonic analysis and kWh calculation. IC Role / Device Role / Timing Role: High-SFDR (80dB) ADC capturing 250ksps samples of isolated CT/PT signals, with pseudo-differential mode rejecting common-mode noise from switching power supplies. Use Value: 67dB SINAD at 50kHz and ±1 LSB INL ensure Class 0.5 metering accuracy per IEC 62053-21 without post-processing calibration. |
Use Scenario: Portable ECG monitor acquiring lead-I/II/III signals with baseline stability and low noise floor. IC Role / Device Role / Timing Role: Bipolar-input ADC digitizing ±1.25V ECG signals referenced to internal +2.5V VREF/2, using COM as virtual ground. Use Value: Internal +2.5V reference with ±2ppm/°C TC maintains <1 LSB offset drift over clinical operating temperature range (-20°C to +50°C). |
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 - lacks 12-bit precision and parallel interface. | Suitable only for low-resolution sensor polling; cannot replace MAX1291BEEI+T in precision data-acquisition where 12-bit linearity is required. | Choose only if system uses SPI and tolerates 8-bit quantization error in non-critical monitoring tasks. |
| MAX11607ETE+ | 12-bit, I²C interface, internal reference, 100ksps - slower sampling, serial interface adds MCU overhead, same QSOP-16 package (not pin-compatible). | Fits space-constrained designs needing I²C bus sharing but cannot match 250ksps throughput or parallel read latency of MAX1291BEEI+T. | Select when I²C integration outweighs speed penalty and when layout allows re-routing from parallel to serial interface. |
Compared with ADS7822U and MAX11607ETE+, the MAX1291BEEI+T uniquely combines 12-bit accuracy, 250ksps parallel interface, and integrated +2.5V reference in a single 28-QSOP package - making it irreplaceable in high-throughput, low-latency industrial DAQ systems requiring minimal external components.
Availability
MAX1291BEEI+T is available at Aetrix Electronics and suitable for industrial control systems, portable medical devices, and battery-powered data loggers requiring stable component supply across extended temperature ranges (-40°C to +85°C) and long production lifecycles.
Supply support for MAX1291BEEI+T 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 MAX1291BEEI+T belongs to Maxim's low-power, high-accuracy SAR ADC product line, engineered specifically for space- and power-constrained data-acquisition systems requiring integrated reference and flexible input configuration without external support circuitry.
FAQ
What is the operating temperature range of the MAX1291BEEI+T?
The MAX1291BEEI+T is rated for -40°C to +85°C operation, matching the "E" grade suffix in its part number. This extended industrial temperature range ensures reliable performance in harsh environments such as factory automation cabinets, outdoor energy meters, and portable medical equipment exposed to ambient thermal cycling. All electrical specifications-including INL, DNL, and reference stability-are guaranteed across this full range.
Does the MAX1291BEEI+T require an external clock source?
No, the MAX1291BEEI+T supports both internal and external clock modes. In internal clock mode (configured via control byte bits D7=1, D6=0), it generates its own 3MHz conversion clock, eliminating the need for an external oscillator. The CLK pin must be tied to VDD or GND in this mode. External clock mode (D7=1, D6=1) accepts 100kHz–4.8MHz TTL/CMOS signals for precise timing control in synchronous systems.
How does the HBEN pin function in the MAX1291BEEI+T?
The HBEN (High Byte Enable) pin controls multiplexing of the 12-bit conversion result onto the 8-bit data bus. When HBEN = 0, D0–D7 output the lower 8 bits (D0–D7); when HBEN = 1, D0–D3 output the upper 4 bits (D8–D11). This allows full 12-bit readout in two consecutive 8-bit cycles, reducing pin count versus a dedicated 12-bit bus while maintaining compatibility with standard 8-bit microcontrollers.
Can the MAX1291BEEI+T operate with a 1.8V digital supply?
Yes, the MAX1291BEEI+T supports VLOGIC from +1.8V to +3.6V, enabling direct interfacing with modern low-voltage microcontrollers (e.g., ARM Cortex-M0+) without level-shifting circuitry. Digital outputs (D0–D7, INT) are fully specified down to 1.8V logic thresholds, and input hysteresis (200mV) ensures noise immunity even at minimum VLOGIC. This capability simplifies power domain partitioning in mixed-voltage systems.
What is the purpose of the COM pin on the MAX1291BEEI+T?
The COM (Common) pin serves as the analog ground reference for single-ended inputs and the negative input reference in pseudo-differential mode. In single-ended operation, it sets the zero-code voltage (e.g., 0V for unipolar, VREF/2 for bipolar) and must remain stable to ±0.5 LSB during conversion. A 0.1µF capacitor to AGND is recommended to minimize noise coupling - critical for achieving specified INL and THD performance in sensitive measurement applications like patient monitoring.
MAX1291BEEI+T Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- 28-SSOP (0.154", 3.90mm Width)
- Packaging:
- Tape & Reel (TR)
- 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+T FAQ
1.How can I place an order for MAX1291BEEI+T through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX1291BEEI+T 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+T reliable?
The price and inventory of MAX1291BEEI+T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX1291BEEI+T is usually 5 days.
3.What payment methods are accepted for MAX1291BEEI+T?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX1291BEEI+T transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX1291BEEI+T?
MAX1291BEEI+T orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX1291BEEI+T 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+T?
For technical support, including MAX1291BEEI+T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX1291BEEI+T requirements.
6.How does Aetrix verify that MAX1291BEEI+T is sourced from the original manufacturer or authorized distributors?
All MAX1291BEEI+T 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+T meets industry standards.
7.What is the process for return or replacement of MAX1291BEEI+T?
All MAX1291BEEI+T units undergo pre-shipment inspection (PSI). If there is an issue with MAX1291BEEI+T, 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+T part is unused and in its original packaging.
Return procedure for MAX1291BEEI+T:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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