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Analog Devices Inc./Maxim Integrated MAX1291ACEI
- Part No.:
- MAX1291ACEI
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Analog to Digital Converters (ADC)
- Package:
- 28-SSOP (0.154", 3.90mm Width)
- Datasheet:
-
MAX1291ACEI.pdf
- Description:
- IC ADC 12BIT SAR 28QSOP
- Quantity:
- Payment:
- Shipping:
Inventory:374
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Product details
Overview
MAX1291ACEI from Maxim Integrated is a 12-bit, 250ksps successive-approximation ADC with integrated +2.5V reference, byte-wide parallel (8+4) interface, and software-configurable 8-channel single-ended or 4-channel pseudo-differential analog input multiplexer. It operates from a single +3V analog supply and supports digital logic levels from +1.8V to +3.6V via VLOGIC, enabling direct interfacing with low-voltage microcontrollers in portable data-acquisition systems.
For engineers reviewing the MAX1291ACEI datasheet, MAX1291ACEI pinout, MAX1291ACEI application, or MAX1291ACEI equivalent, key selection criteria include its ±0.5 LSB INL at 0°C to +70°C, 3MHz full-power bandwidth track/hold, 2µs wake-up from shutdown, tri-state INT output, and QSOP-28 package compatibility with industrial sensor front-ends and battery-powered medical monitors.
Technical Context
The MAX1291ACEI implements a charge-redistribution SAR architecture with an internal 3MHz full-power bandwidth track/hold stage, supporting undersampling of high-frequency transients up to 250kHz full-linear bandwidth. Its control byte (D7–D0) configures acquisition mode (internal/external), clock source (internal/external), unipolar/bipolar range, and single-ended/pseudo-differential input topology.
Conversion timing is deterministic: 13 clock cycles per conversion, with tCONV = 3.6µs in internal clock mode. The HBEN pin enables byte-multiplexed 12-bit readout-D0–D7 for LSBs and D0/D8–D3/D11 for MSBs-while CS high places all digital outputs (INT, D7–D0) in high-impedance state.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Resolution | 12-bit SAR with no missing codes over temperature |
| Sampling Rate | 250ksps maximum; supports reduced rates down to 10ksps with scaled current (400µA) |
| INL / DNL | ±0.5 LSB integral nonlinearity; ±1 LSB differential nonlinearity |
| Reference | +2.5V internal bandgap reference (±20ppm/°C TC, 2.49V–2.51V at +25°C) |
| Power Consumption | 1.9mA at 250ksps (5.7mW @ VDD = VLOGIC = +3V); 2µA in shutdown |
| Analog Input Range | Unipolar: 0 to +2.5V; bipolar: –1.25V to +1.25V (referenced to COM) |
| Full-Power Bandwidth | 3MHz - enables accurate digitization of fast transients without external T/H |
Pinout & Package
MAX1291ACEI is housed in a 28-pin QSOP package (5.3mm × 10.2mm, 0.65mm pitch), RoHS-compliant and rated for 0°C to +70°C operation.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| HBEN (Pin 1) | High-byte enable control | Selects MSB (D0/D8–D3/D11) or LSB (D0–D7) byte on parallel bus; enables compact 8-bit µP interface |
| D0/D8–D7 (Pins 2–9) | Tri-state bidirectional data bus | Multiplexed 12-bit output: D0–D7 carry LSBs when HBEN=0; D0/D8–D3/D11 carry MSBs when HBEN=1 |
| INT (Pin 10) | Open-drain interrupt output | Active-low signal asserts when conversion completes and data is valid; tri-states when CS is high |
| RD (Pin 11) | Active-low read strobe | Falling edge reads conversion result onto data bus; requires CS low to activate |
| WR (Pin 12) | Active-low write strobe | Rising edge latches 8-bit control byte (channel, mode, polarity) and triggers acquisition/conversion |
| CLK (Pin 13) | Clock input/control | Accepts external 100kHz–4.8MHz clock; tied to VDD/GND for internal clock mode |
| CS (Pin 14) | Active-low chip select | Enables digital interface; forces INT, D7–D0 into high-Z when high |
| CH0–CH7 (Pins 15–22) | Analog input channels | 8 single-ended inputs or 4 pseudo-differential pairs; input impedance 800Ω, CIN = 12pF |
| COM (Pin 23) | Analog common reference | Sets zero-code voltage in single-ended mode; must remain stable to ±0.5 LSB during conversion |
| GND (Pin 24) | Analog/digital ground | Common return for analog and digital sections; requires separate low-impedance PCB pour |
| REFADJ (Pin 25) | Bandgap reference buffer input | Bypassed with 0.01µF to GND; connect to VDD to disable internal reference when using external REF |
| REF (Pin 26) | Reference output/input | Delivers +2.5V internal reference; accepts external reference; bypassed with 4.7µF capacitor |
| VDD (Pin 27) | +3V analog supply | Power for analog core and reference; requires 0.1µF ceramic bypass to GND |
| VLOGIC (Pin 28) | +1.8V to +3.6V digital supply | Powers digital I/O; sets logic thresholds (VIH/VIL) and output drive strength independently of VDD |
Key Features
| Feature | Design Value |
|---|---|
| Software-configurable analog input | Runtime-selectable unipolar/bipolar and single-ended/pseudo-differential modes via 8-bit control byte |
| Low-power operation | 2µA shutdown current; 400µA at 10ksps; 1.9mA at full 250ksps - ideal for duty-cycled sensor nodes |
| Integrated reference & T/H | +2.5V internal reference (±20ppm/°C) and 3MHz full-power bandwidth track/hold eliminate external components |
| Flexible digital interface | Byte-multiplexed 12-bit parallel bus (8+4) with tri-state outputs, compatible with 8-bit µPs and FPGAs |
| Fast wake-up & power-down | 2µs wake-up from shutdown; two software-selectable power-down modes reduce average system power |
Applications
| Industrial Process Monitoring | Patient Vital Sign Acquisition |
|---|---|
Use Scenario: Continuous sampling of thermocouple, RTD, and pressure sensor outputs in PLC analog input modules. IC Role / Device Role / Timing Role: Primary 12-bit data converter capturing 8 analog channels at ≤10ksps with programmable gain and bipolar range support. Use Value: Eliminates external reference and T/H, reducing BOM count by 3 components while maintaining ±0.5 LSB linearity across 0°C to +70°C. |
Use Scenario: Portable ECG and pulse oximeter front-end digitizing biopotential signals with low noise and DC stability. IC Role / Device Role / Timing Role: Bipolar-input ADC acquiring differential lead signals (e.g., RA–LA) with COM referenced to Wilson central terminal. Use Value: Internal +2.5V reference and 3MHz T/H bandwidth enable accurate 50Hz/60Hz notch-free acquisition without external clocking complexity. |
| Energy Meter Data Logging | Touch Screen Controller Interface |
Use Scenario: Sub-metering unit measuring AC voltage/current harmonics and RMS values in smart breakers. IC Role / Device Role / Timing Role: High-speed ADC sampling isolated voltage/current transformers at 250ksps for FFT-based harmonic analysis. Use Value: 250kHz full-linear bandwidth allows undersampling of 50Hz fundamentals and 25th harmonics with <−78dB THD. |
Use Scenario: Resistive touch screen digitizer reading X/Y electrode voltages in handheld HMIs and kiosks. IC Role / Device Role / Timing Role: Single-ended 8-channel ADC scanning touch panel electrodes with auto-channel sequencing via control byte. Use Value: Software-configurable 8-channel mux and 2µs wake-up minimize active time per coordinate read, extending battery life in always-on interfaces. |
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, SOIC-8 package | Requires external reference and serial interface logic; lower channel count (1-channel) | Choose for space-constrained designs needing serial interface and minimal footprint, not parallel bus compatibility |
| MAX11131ETE+ | 12-bit, 500ksps, internal reference, SPI interface, 16-pin TQFN, –40°C to +85°C | Higher speed and extended temp range; SPI-only interface; no parallel bus or HBEN multiplexing | Choose for higher throughput or extended temperature operation where serial interface is acceptable |
Compared with ADS7822U and MAX11131ETE+, the MAX1291ACEI uniquely delivers byte-multiplexed parallel interface, integrated +2.5V reference, and 8-channel analog mux in a single 28-pin QSOP - simplifying µP interfacing and reducing external component count in cost-sensitive industrial DAQ systems.
Availability
MAX1291ACEI is available at Aetrix Electronics and suitable for industrial process monitoring, patient vital sign acquisition, energy meter data logging, and touch screen controller interface applications requiring stable component supply and long-term manufacturability.
Supply support for MAX1291ACEI 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 systems.
The MAX1291ACEI belongs to Maxim's precision data-acquisition ADC family, designed specifically for low-power, space-constrained applications requiring integrated reference, flexible input configuration, and simple µP interfacing without external support components.
FAQ
What is the operating temperature range for the MAX1291ACEI?
The MAX1291ACEI is specified for 0°C to +70°C ambient operation. This commercial-grade temperature range is confirmed by the "C" suffix in the part number and the ordering information table listing MAX1291ACEI with "0°C to +70°C" under TEMP RANGE. It is not rated for extended industrial (–40°C to +85°C) operation - that variant is the MAX1291AEI.
Does the MAX1291ACEI require an external clock to operate?
No, the MAX1291ACEI does not require an external clock. It features an internal clock generator selectable via control byte bits D7/D6. When configured for internal clock mode (D7=1, D6=0), the device self-times conversion at 250ksps with 3.6µs conversion time and requires CLK pin to be tied to VDD or GND to prevent floating.
How is the 12-bit result read from the MAX1291ACEI?
The MAX1291ACEI uses a byte-multiplexed parallel interface. With HBEN = 0, D0–D7 output the 8 LSBs of the 12-bit result; with HBEN = 1, D0/D8–D3/D11 output the 4 MSBs. Two consecutive RD cycles - first with HBEN=1, then HBEN=0 - retrieve the full 12-bit word, compatible with standard 8-bit microprocessor data buses.
Can the MAX1291ACEI operate with a +1.8V digital supply?
Yes, the MAX1291ACEI supports +1.8V digital logic supply via the VLOGIC pin (Pin 28), which sets VIH/VIL thresholds and output drive strength. Electrical Characteristics confirm VLOGIC range is +1.8V to +3.6V, and timing parameters (e.g., tDS, tDH) are validated down to VLOGIC = +1.8V with 1mA load, enabling direct interface with modern low-voltage µPs and FPGAs.
What is the purpose of the COM pin on the MAX1291ACEI?
The COM pin (Pin 23) serves as the analog ground reference for single-ended input mode and the negative input reference for pseudo-differential mode. In single-ended operation, it defines the zero-code voltage; in differential mode, it is not used - instead, selected channel pairs serve as IN+/IN–. Stability of COM to ±0.5 LSB during conversion is mandatory for specified INL performance.
MAX1291ACEI 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:
- Obsolete
- 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:
- -
MAX1291ACEI FAQ
1.How can I place an order for MAX1291ACEI through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX1291ACEI 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 MAX1291ACEI reliable?
The price and inventory of MAX1291ACEI are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX1291ACEI is usually 5 days.
3.What payment methods are accepted for MAX1291ACEI?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX1291ACEI transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX1291ACEI?
MAX1291ACEI orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX1291ACEI 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 MAX1291ACEI?
For technical support, including MAX1291ACEI datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX1291ACEI requirements.
6.How does Aetrix verify that MAX1291ACEI is sourced from the original manufacturer or authorized distributors?
All MAX1291ACEI 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 MAX1291ACEI meets industry standards.
7.What is the process for return or replacement of MAX1291ACEI?
All MAX1291ACEI units undergo pre-shipment inspection (PSI). If there is an issue with MAX1291ACEI, 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 MAX1291ACEI part is unused and in its original packaging.
Return procedure for MAX1291ACEI:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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