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Analog Devices Inc./Maxim Integrated MAX1240BESA+
- Part No.:
- MAX1240BESA+
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Analog to Digital Converters (ADC)
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
MAX1240BESA+.pdf
- Description:
- IC ADC 12BIT SAR 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:302
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Product details
Overview
MAX1240BESA+ from Maxim Integrated is a low-power, 12-bit successive-approximation analog-to-digital converter (ADC) with internal 2.5V reference, 7.5µs conversion time, and SPI/QSPI/MICROWIRE-compatible 3-wire serial interface. It operates from a single +2.7V to +3.6V supply, consumes only 3.7µW at 73ksps, and features an integrated track/hold with 1.5µs acquisition time - optimized for battery-powered sensor interfaces and portable data loggers.
For engineers reviewing the MAX1240BESA+ datasheet, MAX1240BESA+ pinout, MAX1240BESA+ application, or MAX1240BESA+ equivalent, this page delivers verified electrical specs, validated SO-8 pin mapping, real-world use cases in isolated data acquisition and instrumentation, and two confirmed alternative parts with documented functional and parametric differences.
Technical Context
The MAX1240BESA+ implements a SAR architecture with on-chip track/hold and internal clock, eliminating external timing components. Its unipolar transfer function maps 0V–VREF input range to 12-bit binary output (4096 codes), with EOC signaled by DOUT high transition after conversion completion.
It supports three-level shutdown control via SHDN: pulled high enables internal reference; floating disables it for external reference use; pulled low reduces supply current to ≤2µA. The 3-wire serial interface requires no level-shifting for standard microcontroller I/O ports and tolerates SCLK duty cycles ≥200ns per phase.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Resolution | 12-bit - delivers 1 LSB = 610 µV step size with 2.500V reference, enabling sub-millivolt measurement precision. |
| Conversion Time | 7.5 µs - defines minimum inter-conversion interval of 132.5 ns overhead, supporting up to 73 ksps sustained throughput. |
| Supply Voltage Range | +2.7V to +3.6V - compatible with single-cell Li-ion and 3.3V logic rails without regulation. |
| INL (Integral Nonlinearity) | ±1 LSB - ensures monotonicity and <0.024% full-scale error across temperature, critical for calibration-sensitive instrumentation. |
| Power Consumption | 3.7 µW at 73 ksps (VDD = 3V) - enables multi-year operation on coin-cell batteries in remote sensing nodes. |
| Reference | Internal 2.500V ±30 ppm/°C - factory-trimmed, bypassed with 4.7µF capacitor; eliminates need for external voltage reference IC. |
| Small-Signal Bandwidth | 2.25 MHz - supports undersampling of kHz-range transients without aliasing when paired with anti-alias filter. |
Pinout & Package
MAX1240BESA+ is housed in an 8-pin SO (Small Outline) package, RoHS-compliant and lead-free (+ suffix), with 1.27 mm pitch and JEDEC MS-012AC outline. Thermal resistance θJA = 160°C/W.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VDD (Pin 1) | Positive supply input | Accepts +2.7V to +3.6V; powers analog core, digital interface, and internal reference; requires 0.1µF + 4.7µF bypassing. |
| AIN (Pin 2) | Analog input | Single-ended unipolar input (0V to VREF); 9 kΩ input impedance; protected to GND −0.3V / VDD +0.3V. |
| SHDN (Pin 3) | Three-level control input | Pulled high → internal reference enabled; floating → internal reference disabled; pulled low → shutdown mode (≤2 µA). |
| REF (Pin 4) | Reference node | 2.500V output (MAX1240 only); must be bypassed with 4.7µF capacitor; supplies DAC and sets full-scale range. |
| GND (Pin 5) | Analog/digital common ground | Single-point star ground connection required; separates analog and digital return paths to minimize noise coupling. |
| DOUT (Pin 6) | Serial data output | 3-wire interface output; tri-state (high-Z when CS = high); data valid on SCLK falling edge; MSB-first format. |
| CS (Pin 7) | Active-low chip select | Falling edge initiates conversion; holds DOUT in high-Z until conversion completes; controls interface enable/disable timing. |
| SCLK (Pin 8) | Serial clock input | External clock up to 2.1 MHz; no duty cycle restriction if each phase ≥200 ns; clock not required during conversion. |
Key Features
| Feature | Design Value |
|---|---|
| Internal 2.5V reference | Factory-trimmed ±0.5% initial accuracy, ±30 ppm/°C drift, capable of sourcing 400 µA - replaces discrete reference ICs and saves board space. |
| Low-power shutdown | Reduces supply current to ≤2 µA; wake-up delay depends on shutdown duration due to 4.7µF REF capacitor discharge - enables duty-cycled sensor polling. |
| Integrated track/hold | Acquires signal in 1.5 µs with no external hold capacitor; supports source impedances ≤1 kΩ without performance degradation. |
| SPI/QSPI/MICROWIRE compatibility | Direct connection to standard MCU serial peripherals with CPOL=0/CPHA=0; no glue logic or level shifters needed for 3.3V systems. |
| Small footprint | 8-pin SO package (4.9 mm × 6.0 mm) - fits compact PCB layouts in handheld instruments and wearable sensors. |
Applications
| Battery-Powered Sensor Node | Portable Data Logger |
|---|---|
|
Use Scenario: Continuous temperature/humidity monitoring in remote environmental stations powered by AA batteries. IC Role / Device Role / Timing Role: Primary ADC digitizing conditioned analog outputs from thermistors and capacitive humidity sensors at 10–100 Hz sample rate. Use Value: 3.7 µW active power and 2 µA shutdown current extend battery life beyond 5 years; internal reference eliminates calibration drift over temperature. |
Use Scenario: Field-deployable vibration and strain data recorder capturing industrial machine health metrics over 72-hour periods. IC Role / Device Role / Timing Role: High-accuracy front-end ADC interfacing with bridge-based strain gauges and piezoelectric accelerometers. Use Value: ±1 LSB INL and 70 dB SINAD ensure repeatable measurements across operating temperature (−40°C to +85°C); SO-8 package withstands mechanical shock. |
| Isolated Data Acquisition | Process Control Transmitter |
|
Use Scenario: 4–20 mA loop-powered transmitter with galvanic isolation between field-side analog inputs and controller-side digital outputs. IC Role / Device Role / Timing Role: Isolated-side ADC converting sensor signals before opto-coupled or transformer-isolated serial transmission. Use Value: Single-supply +2.7V operation simplifies isolated DC-DC design; 2.25 MHz input bandwidth supports fast transient capture across isolation barrier. |
Use Scenario: Smart pressure transmitter in chemical plant requiring NAMUR-compliant analog input conditioning and HART digital overlay. IC Role / Device Role / Timing Role: Precision ADC providing 12-bit resolution for analog input scaling prior to microcontroller-based linearization and communication. Use Value: Internal 2.5V reference stability (±30 ppm/°C) meets long-term zero-shift requirements; 8-pin SO allows compact layout within explosion-proof housing. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar 12-bit serial ADC applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| ADS7822U | 12-bit, 200 ksps, +2.7V to +5.25V supply, no internal reference, requires external REF and clock; higher speed but 3× higher power (1.2 mW @ 200 ksps). | Used where higher throughput is mandatory and external reference already exists; unsuitable for ultra-low-power battery operation. | Select ADS7822U only when sampling >100 ksps is required and system-level power budget permits 300× higher active current. |
| MAX11100ETE+ | 12-bit, 100 ksps, +2.7V to +3.6V supply, internal 2.048V reference, 10-pin TDFN package, built-in PGA (0.5×–4×), lower INL (±0.5 LSB). | Preferred for variable-gain sensor interfaces needing programmable amplification; incompatible pinout and smaller footprint limit drop-in replacement. | Choose MAX11100ETE+ when gain flexibility and tighter linearity are prioritized over identical form factor and legacy software compatibility. |
Compared with MAX1240BESA+, ADS7822U trades ultra-low power for higher speed and lacks integrated reference, while MAX11100ETE+ adds PGA functionality and improved INL but requires PCB redesign due to different pin count and package.
Availability
MAX1240BESA+ is available at Aetrix Electronics and suitable for battery-powered systems, portable data logging, and isolated data acquisition requiring stable component supply across extended temperature ranges (−40°C to +85°C) and long production lifecycles.
Supply support for MAX1240BESA+ 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 MAX1240 series targets low-power, space-constrained data acquisition systems - emphasizing single-supply operation, integrated references, and minimal external components to reduce system cost and complexity.
FAQ
What is the maximum sampling rate of the MAX1240BESA+?
The MAX1240BESA+ achieves a maximum throughput rate of 73 ksps, limited by its 7.5 µs conversion time and serial interface timing. This rate assumes continuous operation with CS toggling at minimum tCS (240 ns) and SCLK running at 2.1 MHz. At lower rates, power consumption scales down - e.g., 66 µW at 1 ksps - making it ideal for duty-cycled sensor nodes where the MAX1240BESA+ spends most time in shutdown.
Does the MAX1240BESA+ require an external reference voltage?
No, the MAX1240BESA+ includes a factory-trimmed 2.500V internal reference with ±30 ppm/°C temperature coefficient. It is enabled by pulling SHDN high and requires a 4.7 µF capacitor at the REF pin for stability. An external reference may be used only if SHDN is left floating to disable the internal reference - but doing so forfeits the key low-power and calibration advantages of the MAX1240BESA+ design.
How does the SHDN pin function on the MAX1240BESA+?
The SHDN pin on the MAX1240BESA+ provides three distinct modes: pulled high enables the internal 2.5V reference; left floating disables the internal reference (allowing external REF use); pulled low places the device in shutdown mode, reducing supply current to ≤2 µA. Wake-up time after shutdown depends on how long it was held low, due to discharge of the 4.7 µF REF bypass capacitor - a unique behavior confirmed in the MAX1240BESA+ datasheet Figure 7.
Which microcontroller interfaces are compatible with the MAX1240BESA+ serial port?
The MAX1240BESA+ 3-wire serial interface is fully compatible with SPI, QSPI, and MICROWIRE protocols when configured with CPOL = 0 and CPHA = 0. It connects directly to standard GPIO or hardware SPI peripherals on ARM Cortex-M, PIC, MSP430, and AVR microcontrollers without level shifters. Data is MSB-first, with a leading EOC bit followed by 12 data bits, and supports clock rates up to 2.1 MHz.
What is the guaranteed integral nonlinearity (INL) specification for the MAX1240BESA+?
The MAX1240BESA+ guarantees ±1 LSB integral nonlinearity over its full operating temperature range (−40°C to +85°C) and supply voltage range (+2.7V to +3.6V). This value is specified in the Ordering Information table for the "B" grade (MAX1240BESA+) and confirmed in the Electrical Characteristics section under Relative Accuracy (INL), ensuring monotonic behavior and predictable full-scale error in precision measurement applications using the MAX1240BESA+.
MAX1240BESA+ Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- 8-SOIC (0.154", 3.90mm Width)
- Packaging:
- Tube
- Product Status:
- Active
- Number of Bits:
- 12
- Sampling Rate (Per Second):
- 73k
- Number of Inputs:
- 1
- Input Type:
- Single Ended
- Data Interface:
- SPI
- Configuration:
- 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:
- 2.7V ~ 3.6V
- Features:
- -
- Operating Temperature:
- -40°C ~ 85°C
- Supplier Device Package:
- 8-SOIC
- Mounting Type:
- Surface Mount
- Grade:
- -
- Qualification:
- -
MAX1240BESA+ FAQ
1.How can I place an order for MAX1240BESA+ through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX1240BESA+ 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 MAX1240BESA+ reliable?
The price and inventory of MAX1240BESA+ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX1240BESA+ is usually 5 days.
3.What payment methods are accepted for MAX1240BESA+?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX1240BESA+ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX1240BESA+?
MAX1240BESA+ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX1240BESA+ 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 MAX1240BESA+?
For technical support, including MAX1240BESA+ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX1240BESA+ requirements.
6.How does Aetrix verify that MAX1240BESA+ is sourced from the original manufacturer or authorized distributors?
All MAX1240BESA+ 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 MAX1240BESA+ meets industry standards.
7.What is the process for return or replacement of MAX1240BESA+?
All MAX1240BESA+ units undergo pre-shipment inspection (PSI). If there is an issue with MAX1240BESA+, 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 MAX1240BESA+ part is unused and in its original packaging.
Return procedure for MAX1240BESA+:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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