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Analog Devices Inc./Maxim Integrated MAX1291AEEI+T
- Part No.:
- MAX1291AEEI+T
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Analog to Digital Converters (ADC)
- Package:
- 28-SSOP (0.154", 3.90mm Width)
- Datasheet:
-
MAX1291AEEI+T.pdf
- Description:
- IC ADC 12BIT SAR 28QSOP
- Quantity:
- Payment:
- Shipping:
Inventory:2,073
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Product details
Overview
MAX1291AEEI+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, +2.5V internal 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 ±0.5 LSB INL at -40°C to +85°C. It is used in portable patient monitoring systems requiring low power, small footprint, and direct microprocessor interfacing.
For engineers reviewing the MAX1291AEEI+T datasheet, MAX1291AEEI+T pinout, MAX1291AEEI+T application, or MAX1291AEEI+T equivalent, key selection criteria include its software-configurable unipolar/bipolar input mode, 2µs wake-up from shutdown, tri-state INT output, internal 3MHz track/hold bandwidth, and QSOP-28 package compatibility with industrial data-acquisition layouts.
Technical Context
The MAX1291AEEI+T implements a charge-redistribution SAR architecture with integrated track/hold, supporting both internal and external clock modes. Its analog input multiplexer enables runtime selection between single-ended (8 channels) and pseudo-differential (4 channel pairs) configurations, with software-controlled unipolar/bipolar range switching referenced to COM or VREF/2.
Conversion is initiated by a control byte written via the parallel interface, defining acquisition mode (internal/external), clock source, input configuration, and power-down state. The device uses HBEN to multiplex 12-bit results across an 8-bit data bus, and asserts INT low upon conversion completion - tri-stated when CS is high.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Resolution | 12-bit SAR ADC with no missing codes over temperature |
| Sampling Rate | 250ksps maximum; conversion time fixed at 3.6µs in internal clock mode |
| INL / DNL | ±0.5 LSB integral nonlinearity; ±1 LSB differential nonlinearity |
| Reference | +2.5V internal bandgap reference (±20ppm/°C TC); adjustable via REFADJ |
| Power Consumption | 1.9mA at 250ksps; 2µA in full shutdown; 10µA in standby |
| Analog Input Range | Single-ended: 0 to VREF (unipolar) or –VREF/2 to +VREF/2 (bipolar) |
| Dynamic Performance | 70dB SINAD, 80dB SFDR, –78dB THD at 50kHz input, 250ksps |
Pinout & Package
MAX1291AEEI+T is housed in a 28-pin QSOP (Quarter-Size Outline Package) with 3.9mm body width and 0.635mm lead pitch, optimized for space-constrained PCB layouts in battery-powered instrumentation.
| 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 | Multiplexed 12-bit parallel interface; requires external pull-ups if tri-stated |
| INT | Open-drain interrupt output | Active-low flag indicating conversion completion; tri-stated when CS = high |
| WR / RD / CS | Control strobes | Edge-triggered write/read/chip-select; define acquisition start, data latch, and bus isolation |
| CH0–CH7 | Analog input channels | Eight single-ended inputs; configurable as four pseudo-differential pairs (CH0/CH1, etc.) |
| COM | Analog common reference | Zero-code reference in single-ended mode; must be stable to ±0.5 LSB during conversion |
| VLOGIC | Digital supply rail | Independent +1.8V to +3.6V supply for logic interface; decouples ADC core from µP voltage swing |
| REF / REFADJ | Reference buffer terminals | Internal +2.5V reference output (REF); REFADJ disables internal ref when tied to VDD for external ref use |
Key Features
| Feature | Design Value |
|---|---|
| Software-configurable input topology | Runtime selection of 8-channel single-ended or 4-pair pseudo-differential mode via control byte |
| Flexible logic-level interface | VLOGIC pin enables direct connection to +1.8V, +2.5V, or +3.3V microprocessors without level shifters |
| Low-power operation with fast wake-up | 2µs wake-up from shutdown; 5.7mW total power at 250ksps (VDD = VLOGIC = +3V) |
| Integrated timing and reference | On-chip 3MHz track/hold and +2.5V reference eliminate need for external clock generator or precision reference IC |
| Robust analog input protection | Clamp diodes allow safe overvoltage up to (GND – 300mV) and (VDD + 300mV); full-scale accuracy maintained within ±50mV of rails |
Applications
| Portable Patient Monitoring | Industrial Data Logging |
|---|---|
Use Scenario: Continuous acquisition of ECG, SpO₂, and temperature signals in handheld clinical devices with limited battery capacity. IC Role / Device Role / Timing Role: Primary ADC digitizing analog sensor outputs; provides synchronized 12-bit samples at 250ksps with <2µs wake-up for event-triggered capture. Use Value: Enables >100-hour battery life via 2µA shutdown current and eliminates external reference/clock components, reducing BOM count by 3 parts. |
Use Scenario: Multi-sensor environmental monitoring in remote industrial nodes measuring vibration, pressure, and humidity over extended periods. IC Role / Device Role / Timing Role: Central 8-channel ADC managing cyclic polling of transducers; uses software-configurable unipolar/bipolar mode to accommodate diverse sensor output ranges. Use Value: Reduces firmware complexity through single-control-byte configuration of input mode, channel, and power state - cutting driver development time by ~30%. |
| Energy Management Systems | Touch Screen Controllers |
Use Scenario: Real-time current/voltage sampling in smart circuit breakers and energy meters deployed in harsh electrical environments. IC Role / Device Role / Timing Role: High-accuracy ADC capturing AC line waveforms; leverages 3MHz full-power bandwidth for undersampling of 50/60Hz fundamentals and harmonics. Use Value: Achieves Class 0.5 metering accuracy (±0.5% error) without anti-alias filter redesign, thanks to ±0.5 LSB INL and low THD (–78dB). |
Use Scenario: Resistive touch panel digitization in kiosks and HMIs where rapid coordinate updates and low idle power are critical. IC Role / Device Role / Timing Role: Dedicated ADC scanning X/Y electrode pairs; uses pseudo-differential mode to reject common-mode noise from display backlight interference. Use Value: Improves touch accuracy by 40% in noisy environments via channel-to-channel crosstalk suppression (<–78dB) and COM-referenced sampling stability. |
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 |
|---|---|---|---|
| ADS7816U | 8-channel, 12-bit, SPI interface; no internal reference; 200ksps max; SO-16 package | Requires external reference and serial interface logic; lower sampling rate limits high-speed waveform capture | Choose for space-constrained designs needing SPI compatibility and lower cost, accepting trade-offs in speed and integration. |
| MAX11131ETE+ | 8-channel, 12-bit, SPI interface; integrated +2.048V reference; 1MSPS; 16-pin TQFN | Higher speed and smaller package, but SPI-only interface increases µP overhead vs. parallel bus simplicity | Prefer when system already uses SPI peripherals and demands >500ksps throughput; avoid if parallel bus timing budget is tight. |
Compared with ADS7816U and MAX11131ETE+, the MAX1291AEEI+T offers unique value in microprocessor-native parallel interfacing, integrated +2.5V reference with REFADJ trim, and dual acquisition modes - making it optimal for legacy 8051/ARM7-based data loggers where bus timing predictability and component count reduction are primary design drivers.
Availability
MAX1291AEEI+T is available at Aetrix Electronics and suitable for portable medical devices, industrial data loggers, and energy metering systems requiring stable component supply across extended product lifecycles and temperature ranges (–40°C to +85°C).
Supply support for MAX1291AEEI+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) is a semiconductor company specializing in high-performance analog, mixed-signal, and power-management ICs for industrial, medical, and communications applications.
The MAX1291AEEI+T belongs to Maxim's precision data-acquisition ADC family, designed specifically for battery-powered instrumentation requiring low quiescent current, integrated references, and minimal external components.
FAQ
What is the operating temperature range for the MAX1291AEEI+T?
The MAX1291AEEI+T is rated for industrial operation from –40°C to +85°C. This extended range is confirmed in the Ordering Information table and Absolute Maximum Ratings section of the datasheet, where the "E" grade suffix (as in MAX1291AEEI+T) explicitly denotes the –40°C to +85°C specification. It ensures reliable performance in outdoor data loggers and medical field equipment exposed to ambient thermal extremes.
Does the MAX1291AEEI+T include an internal voltage reference?
Yes, the MAX1291AEEI+T integrates a +2.5V bandgap voltage reference with ±20ppm/°C temperature coefficient and 2.49V to 2.51V output tolerance at +25°C. The REF pin delivers this reference, while REFADJ allows disabling the internal reference (by tying to VDD) when using an external reference - a capability verified in the Electrical Characteristics and Pin Description sections.
How many analog input channels does the MAX1291AEEI+T support?
The MAX1291AEEI+T supports eight single-ended analog input channels (CH0–CH7) or four pseudo-differential channel pairs (CH0/CH1, CH2/CH3, CH4/CH5, CH6/CH7), as specified in the General Description and Pin Configurations. This 8-/4-channel flexibility is exclusive to the MAX1291 variant; the MAX1293 offers only four single-ended inputs.
What package type is used for the MAX1291AEEI+T?
The MAX1291AEEI+T is supplied in a 28-pin QSOP (Quarter-Size Outline Package) with standard 0.635mm lead pitch and 3.9mm body width. This package is explicitly listed in the Ordering Information table and Pin Configurations diagram, and matches the mechanical dimensions defined in Maxim's packaging documentation for the "EEI" suffix.
Can the MAX1291AEEI+T interface directly with a +1.8V microprocessor?
Yes, the MAX1291AEEI+T supports direct interfacing with +1.8V logic systems via its dedicated VLOGIC pin, which accepts +1.8V to +3.6V supplies independently of the +3V analog rail (VDD). The datasheet confirms VIH/VIL thresholds scale with VLOGIC, and timing parameters (e.g., tDS, tDH) are guaranteed down to VLOGIC = +1.8V in the Electrical Characteristics tables.
MAX1291AEEI+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:
- -
MAX1291AEEI+T FAQ
1.How can I place an order for MAX1291AEEI+T through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX1291AEEI+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 MAX1291AEEI+T reliable?
The price and inventory of MAX1291AEEI+T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX1291AEEI+T is usually 5 days.
3.What payment methods are accepted for MAX1291AEEI+T?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX1291AEEI+T transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX1291AEEI+T?
MAX1291AEEI+T orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX1291AEEI+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 MAX1291AEEI+T?
For technical support, including MAX1291AEEI+T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX1291AEEI+T requirements.
6.How does Aetrix verify that MAX1291AEEI+T is sourced from the original manufacturer or authorized distributors?
All MAX1291AEEI+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 MAX1291AEEI+T meets industry standards.
7.What is the process for return or replacement of MAX1291AEEI+T?
All MAX1291AEEI+T units undergo pre-shipment inspection (PSI). If there is an issue with MAX1291AEEI+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 MAX1291AEEI+T part is unused and in its original packaging.
Return procedure for MAX1291AEEI+T:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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