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Analog Devices Inc./Maxim Integrated MAX1291BCEI+T
- Part No.:
- MAX1291BCEI+T
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Analog to Digital Converters (ADC)
- Package:
- 28-SSOP (0.154", 3.90mm Width)
- Datasheet:
-
MAX1291BCEI+T.pdf
- Description:
- IC ADC 12BIT SAR 28QSOP
- Quantity:
- Payment:
- Shipping:
Inventory:4,163
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Product details
Overview
MAX1291BCEI+T 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 I/O voltage from +1.8V to +3.6V via VLOGIC. Used in portable patient monitoring systems for high-accuracy biopotential signal digitization.
For engineers reviewing the MAX1291BCEI+T datasheet, MAX1291BCEI+T pinout, MAX1291BCEI+T application, or MAX1291BCEI+T equivalent, key selection criteria include its ±1 LSB INL at 0°C to +70°C, 3MHz full-power bandwidth track/hold, software-configurable unipolar/bipolar mode, and QSOP-28 package compatibility with space-constrained data-acquisition PCBs.
Technical Context
The MAX1291BCEI+T implements a charge-redistribution SAR architecture with an internal 3MHz full-power bandwidth track/hold stage and on-chip 12-bit capacitive DAC. Its control byte (D7–D0) configures acquisition mode (internal/external), clock source (internal/external), input polarity (unipolar/bipolar), and channel selection - all without external timing components.
It supports two power-down modes: standby (10µA) and full shutdown (2µA), triggered by software bits PD0/PD1. The HBEN pin enables high-byte/low-byte multiplexing of the 12-bit result across the 8-bit data bus, reducing microprocessor bus width requirements while maintaining full resolution.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Resolution | 12-bit - delivers 1 LSB = 610 µV step size with 2.5V reference for precise sensor signal quantization. |
| Sampling Rate | 250ksps - supports Nyquist-compliant sampling of up to 125kHz baseband signals in data-logging applications. |
| INL | ±1 LSB (max) over 0°C to +70°C - ensures monotonicity and <0.025% absolute linearity error in industrial control feedback loops. |
| Power Consumption | 1.9mA at 250ksps - enables battery operation for >10 hours in handheld energy management meters with 100mAh Li-ion cells. |
| Reference | +2.5V internal - eliminates need for external reference IC and associated decoupling, reducing BOM count and layout area. |
| Input Channels | 8 single-ended or 4 pseudo-differential - allows simultaneous monitoring of multiple transducers (e.g., temperature, pressure, strain) in compact PLC modules. |
| Package | 28-pin QSOP - 7.6mm × 10.2mm footprint fits dense mixed-signal layouts without requiring thermal vias or special assembly processes. |
Pinout & Package
MAX1291BCEI+T 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 MAX1291/MAX1293 datasheet Rev 3 (12/02), Figure "Pin Configurations" and "Pin Description" sections.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| HBEN | High-Byte Enable | Selects MSB nibble (D8–D11) or LSB byte (D0–D7) on shared data bus - enables 8-bit µP interfacing without external latch. |
| D0/D8–D7/D11 | Three-State Data Bus | Multiplexed 12-bit output: D0–D7 carry LSBs when HBEN=0; D0–D3 and D8–D11 carry full 12-bit result when HBEN=1. |
| INT | Interrupt Output | Active-low open-drain flag signaling conversion completion - directly drives µP IRQ lines without pull-up resistor if VLOGIC ≤ 3.6V. |
| WR / RD / CS | Control Interface | Standard 8080-style parallel bus: WR latches control byte, RD reads result, CS enables digital outputs - no glue logic required. |
| CH0–CH7 | Analog Input Channels | Eight single-ended inputs referenced to COM; configurable as four pseudo-differential pairs (e.g., CH0/CH1) for noise-rejecting measurements. |
| VLOGIC | Digital Supply | Independent +1.8V to +3.6V rail - permits direct interfacing with low-voltage FPGAs or ARM Cortex-M0+ MCUs without level shifters. |
| REF / REFADJ | Reference System | REF outputs +2.5V bandgap; REFADJ disables internal ref when tied to VDD - supports external reference upgrade path. |
Key Features
| Feature | Design Value |
|---|---|
| Software-configurable input topology | Single-ended (8 ch) or pseudo-differential (4 ch) mode selected via SGL/DIF bit - adapts to sensor output type without hardware change. |
| Auto power-down between conversions | Reduces average current to <10µA at 10ksps - extends battery life in intermittent-sampling IoT edge nodes. |
| Internal 3MHz track/hold bandwidth | Supports accurate undersampling of 100kHz+ transients (e.g., motor current spikes) without external anti-alias filter complexity. |
| Tri-state INT output | INT goes high-impedance when CS is high - allows wired-OR interrupt busing across multiple ADCs on same µP IRQ line. |
| Aperture jitter <50ps (external acquisition) | Enables >70dB SINAD at 50kHz input - meets ENOB >11.3-bit requirement for Class II medical ECG front-ends. |
Applications
| Patient Monitoring | Industrial Control Systems |
|---|---|
|
Use Scenario: Digitizing ECG, EEG, and EMG signals in portable diagnostic devices with strict power and size constraints. IC Role / Device Role / Timing Role: Primary analog front-end ADC acquiring 12-bit samples at 250ksps with <1 LSB INL to preserve clinical waveform fidelity. Use Value: Integrated +2.5V reference and 8-channel mux eliminate 3 external components, reducing PCB area by 22mm² versus discrete reference + mux solutions. |
Use Scenario: Monitoring temperature, pressure, and flow sensors in distributed PLC I/O modules operating at ambient temperatures up to +70°C. IC Role / Device Role / Timing Role: Multi-channel data acquisition node converting sensor outputs with software-selectable unipolar/bipolar range to match transducer output spans. Use Value: ±1 LSB INL and 3MHz T/H bandwidth ensure <0.1% measurement error across 0–100°C thermal ranges without calibration drift compensation. |
| Data Logging | Energy Management |
|
Use Scenario: Battery-powered environmental sensors logging temperature, humidity, and light intensity over multi-day deployments. IC Role / Device Role / Timing Role: Low-power ADC entering full shutdown (2µA) between 10s-interval conversions to maximize runtime. Use Value: 1.9mA active current at 250ksps and 2µA shutdown enable >1-year operation on CR2032 coin cell in periodic wake-up architectures. |
Use Scenario: Smart metering subsystems measuring AC voltage/current harmonics and power factor in residential energy monitors. IC Role / Device Role / Timing Role: High-fidelity sampling of isolated current transformer outputs using pseudo-differential mode to reject common-mode noise. Use Value: 76dB channel-to-channel crosstalk and 80dB SFDR suppress interference from switching power supplies, ensuring <0.5% kWh billing accuracy. |
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 | 12-bit, 200ksps, SPI interface, no internal reference - requires external +2.5V ref and level-shifting for 1.8V logic. | Best suited for designs already using SPI peripherals and needing lower pin count; lacks parallel bus simplicity. | Choose ADS7822U when board space is critical and µP lacks parallel I/O but has spare SPI channels. |
| MAX11131ETE+ | 12-bit, 500ksps, internal +2.048V ref, 10-pin µMAX package - higher speed but smaller input channel count (4 SE). | Ideal for high-speed single-channel applications like motor phase current sensing where density outweighs channel count. | Choose MAX11131ETE+ when sampling rate >300ksps is required and only 4 input channels are needed. |
Compared with MAX1291BCEI+T, ADS7822U trades parallel simplicity for SPI flexibility and adds external reference overhead, while MAX11131ETE+ doubles speed but halves channel count and uses a non-drop-in µMAX package - making MAX1291BCEI+T optimal for cost-sensitive, multi-channel, 250ksps embedded systems.
Availability
MAX1291BCEI+T is available at Aetrix Electronics and suitable for patient monitoring, industrial control systems, and data-logging applications requiring stable component supply with guaranteed long-term sourcing.
Supply support for MAX1291BCEI+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 and mixed-signal ICs for demanding industrial, medical, and communications applications.
The MAX1291BCEI+T belongs to Maxim's low-power SAR ADC product line, engineered specifically for battery-operated instrumentation and space-constrained data-acquisition systems requiring integrated reference and flexible input configuration.
FAQ
What is the operating temperature range for the MAX1291BCEI+T?
The MAX1291BCEI+T is specified for operation from 0°C to +70°C, as indicated by the "C" grade suffix in its ordering code. This commercial temperature range is validated per Maxim's datasheet Rev 3, with all electrical characteristics (including ±1 LSB INL and 1.9mA supply current) guaranteed across this span. The device is not rated for extended industrial (-40°C to +85°C) operation - that capability is reserved for the MAX1291EEI+T variant.
Does the MAX1291BCEI+T require an external clock source?
No, the MAX1291BCEI+T does not require an external clock source. It includes an internal 3MHz clock generator usable in internal clock mode (configured via D7/D6 control bits). When enabled, the internal clock delivers a fixed 3.6µs conversion time. External clock mode (4.8MHz, 30–70% duty cycle) is optional and used only when precise aperture control or synchronization with system clocks is needed.
How does the HBEN pin affect data readout on the MAX1291BCEI+T?
The HBEN pin on the MAX1291BCEI+T controls multiplexing of the 12-bit conversion result onto the 8-bit data bus. When HBEN = 0, D0–D7 output the LSB byte; when HBEN = 1, D0–D3 and D8–D11 output the full 12-bit word (with D0–D3 = bits 0–3, D8–D11 = bits 8–11). This eliminates the need for external byte-latching logic in 8-bit microprocessor systems.
Can the MAX1291BCEI+T interface directly with a +1.8V microcontroller?
Yes, the MAX1291BCEI+T can interface directly with a +1.8V microcontroller via its VLOGIC pin, which accepts +1.8V to +3.6V. Digital outputs (D0–D7, INT) are fully compatible with 1.8V logic thresholds: VOL ≤ 0.4V and VOH ≥ VLOGIC − 0.5V (≥ 1.3V at 1.8V), satisfying standard CMOS input requirements without level-shifting circuitry.
What is the maximum analog input voltage range for the MAX1291BCEI+T in unipolar mode?
In unipolar mode, the MAX1291BCEI+T accepts analog input voltages from 0V to VREF (2.5V) when using the internal reference. The absolute input voltage range is GND to VDD (+3V), but full-scale accuracy is only guaranteed within 0V to +2.5V. Exceeding +2.5V risks missing codes or increased DNL, as confirmed by the "DC ACCURACY" table in the datasheet showing ±4 LSB gain error beyond VREF.
MAX1291BCEI+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:
- 0°C ~ 70°C
- Supplier Device Package:
- 28-QSOP
- Mounting Type:
- Surface Mount
- Grade:
- -
- Qualification:
- -
MAX1291BCEI+T FAQ
1.How can I place an order for MAX1291BCEI+T through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX1291BCEI+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 MAX1291BCEI+T reliable?
The price and inventory of MAX1291BCEI+T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX1291BCEI+T is usually 5 days.
3.What payment methods are accepted for MAX1291BCEI+T?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX1291BCEI+T transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX1291BCEI+T?
MAX1291BCEI+T orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX1291BCEI+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 MAX1291BCEI+T?
For technical support, including MAX1291BCEI+T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX1291BCEI+T requirements.
6.How does Aetrix verify that MAX1291BCEI+T is sourced from the original manufacturer or authorized distributors?
All MAX1291BCEI+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 MAX1291BCEI+T meets industry standards.
7.What is the process for return or replacement of MAX1291BCEI+T?
All MAX1291BCEI+T units undergo pre-shipment inspection (PSI). If there is an issue with MAX1291BCEI+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 MAX1291BCEI+T part is unused and in its original packaging.
Return procedure for MAX1291BCEI+T:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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