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Analog Devices Inc./Maxim Integrated MAX1237LEUA+
- Part No.:
- MAX1237LEUA+
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Analog to Digital Converters (ADC)
- Package:
- 8-TSSOP, 8-MSOP (0.118", 3.00mm Width)
- Datasheet:
-
MAX1237LEUA+.pdf
- Description:
- IC ADC 12BIT SAR 8UMAX
- Quantity:
- Payment:
- Shipping:
Inventory:3,403
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Product details
Overview
The MAX1237LEUA+ from Maxim Integrated is a low-power, 12-bit, 4-channel analog-to-digital converter (ADC) with integrated track/hold, 2.048V internal reference, I²C-compatible 2-wire serial interface, and operation from 2.7V to 3.6V supply. It delivers 94.4ksps throughput, ±1 LSB INL/DNL accuracy, and auto-shutdown current <1µA-enabling precision sensing in battery-powered portable instrumentation.
For engineers reviewing the MAX1237LEUA+ datasheet, MAX1237LEUA+ pinout, MAX1237LEUA+ application, or MAX1237LEUA+ equivalent, this page provides verified technical context, real-world design meaning for key specs, validated pin functions, confirmed alternative options, and supply-chain support for production deployment.
Technical Context
The MAX1237LEUA+ employs successive-approximation architecture with fully differential track/hold circuitry and software-configurable unipolar/bipolar, single-ended/differential input modes. Its internal 2.048V reference supports full-scale ranges of 0–2.048V (unipolar SE) or ±1.024V (bipolar DE), and it accepts external references from 1V to VDD.
It operates in Fast Mode (400kHz) or High-Speed Mode (1.7MHz) I²C, with conversion timing governed by internal 2.8MHz clock or external SCL. Acquisition time is 800ns, aperture delay is 30ns in HS mode, and channel-scan FIFO enables automated multi-channel sequencing without host intervention.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Resolution | 12-bit - delivers 1 LSB = 0.5mV step size with 2.048V reference for sub-millivolt measurement resolution. |
| INL / DNL | ±1 LSB - ensures monotonicity and ≤0.024% full-scale linearity error across temperature (−40°C to +85°C). |
| Throughput Rate | 94.4 ksps - supports real-time sampling of signals up to ~3 MHz bandwidth (5 MHz small-signal BW) using undersampling. |
| Supply Current | 670 µA at 94.4 ksps - enables >100-hour runtime on a 60mAh coin cell when paired with duty-cycled wake-up logic. |
| I²C Interface | Up to 1.7 MHz High-Speed Mode - reduces conversion-readout latency to <13 µs per 12-bit result, critical for closed-loop control. |
| Input Configuration | 4 single-ended or 2 fully differential channels - allows flexible sensor interfacing (e.g., thermocouples, RTDs, bridge transducers) without external signal conditioning. |
| Reference | Internal 2.048V ±0.5% (25°C), 25 ppm/°C TC - eliminates external reference IC, simplifies layout, and maintains <0.2% full-scale drift over industrial temperature range. |
Pinout & Package
MAX1237LEUA+ is housed in an 8-pin µMAX® package (3mm × 3mm, 0.8mm height), optimized for space-constrained portable designs. Pin assignments are validated per Maxim's official datasheet Rev 7 (19-2333).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 2, 3 | AIN0–AIN2 | Analog input channels 0–2 - support single-ended (vs. GND) or differential (vs. AIN3/REF) acquisition; max source impedance 1.5kΩ. |
| 4 | AIN3/REF | Configurable terminal: analog input 3 (SE) or reference I/O (DE); when used as REF output, requires 0.1µF decoupling to GND. |
| 5 | SCL | I²C clock input - accepts 400kHz (Fast) or 1.7MHz (HS) rates; internal pull-down disabled; requires external pull-up ≥750Ω. |
| 6 | SDA | I²C bidirectional data line - open-drain structure; supports multi-master arbitration; must be pulled high externally. |
| 7 | GND | Analog/digital ground reference - must be connected to low-impedance system ground plane; separate AGND/DGND not required. |
| 8 | VDD | Positive supply (2.7V–3.6V) - bypass with 0.1µF ceramic capacitor placed <1mm from pin to suppress switching noise coupling into ADC core. |
Key Features
| Feature | Design Value |
|---|---|
| AutoShutdown™ | Reduces supply current to <1µA between conversions - extends battery life in intermittent-sampling applications like environmental monitors. |
| Software-Configurable Input Modes | Single-ended/differential and unipolar/bipolar selection via setup register - eliminates hardware jumpers and enables runtime reconfiguration for multi-sensor systems. |
| Internal FIFO with Channel-Scan Mode | Automatically sequences across up to 4 channels and buffers results - offloads microcontroller, enabling deterministic sampling intervals without CPU polling. |
| Low Aperture Jitter | 30ns aperture delay (HS mode) with <1ns jitter - preserves SINAD >70dB at 10kHz input, critical for accurate RMS and harmonic analysis. |
| Robust Analog Input Protection | Clamp diodes allow −0.3V to (VDD + 0.3V) input swing - tolerates transient overvoltage during hot-plug or ESD events without latch-up. |
Applications
| Handheld Portable Instruments | Medical Vital Sign Monitors |
|---|---|
Use Scenario: Battery-powered multimeter measuring DC voltage, resistance, and temperature with autoranging. IC Role / Device Role / Timing Role: Primary ADC digitizing front-end sensor outputs; performs synchronized 4-channel scan for simultaneous voltage/current/thermistor reads. Use Value: 12-bit resolution and ±1 LSB INL ensure 0.025% basic accuracy; 670µA active current enables >200 hours of continuous use on two AAA cells. |
Use Scenario: Wearable pulse oximeter acquiring photodiode currents from red/IR LEDs under varying skin contact conditions. IC Role / Device Role / Timing Role: Dual-channel differential ADC capturing synchronized AC-coupled LED current waveforms for SpO₂ calculation. Use Value: Fully differential inputs reject common-mode noise from motion artifacts; 2.048V reference matches optical sensor dynamic range for optimal SNR. |
| Battery-Powered Test Equipment | Solar-Powered Remote Sensors |
Use Scenario: Portable insulation resistance tester applying 500V DC bias and measuring leakage current through high-impedance loads. IC Role / Device Role / Timing Role: Precision ADC measuring picoamp-level currents via transimpedance amplifier output; uses internal reference for ratio-metric stability. Use Value: 22pF input capacitance and 1.5kΩ max source impedance tolerance simplify TIA design; AutoShutdown cuts quiescent draw to 0.5µA during standby. |
Use Scenario: Off-grid soil moisture node powered by 3.6V LiSOCl₂ battery, logging temperature and volumetric water content hourly. IC Role / Device Role / Timing Role: Low-power ADC sampling resistive/capacitive sensors; wakes every 3600s, converts 4 channels, then returns to shutdown. Use Value: 6µA average current at 1ksps enables >10-year field life; internal 2.048V reference eliminates calibration drift vs. aging external references. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar 12-bit, I²C ADC applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| ADS7822U | 8-pin SOIC, 12-bit, SPI interface only, no internal reference, 2.7–5.25V supply, 1.25µs conversion time. | Requires external reference and SPI host; lacks AutoShutdown and FIFO; higher power (1.25mA active). | Choose when SPI is preferred and external reference already exists; avoid if I²C bus sharing or ultra-low quiescent current is required. |
| MCP3221A0T-E/OT | SOT-23-6, 12-bit, I²C, 2.7–5.5V, internal 2.048V ref, but single-channel only, 10ksps max, no FIFO or differential mode. | Limited to one analog input; no channel scanning or differential capability; lower throughput restricts dynamic signal capture. | Use for cost-sensitive, single-sensor nodes where size is critical and multi-channel or high-speed sampling is unnecessary. |
Compared with ADS7822U and MCP3221A0T-E/OT, the MAX1237LEUA+ uniquely combines 4-channel flexibility, I²C HS-mode speed, integrated FIFO, and sub-µA shutdown-making it the only option supporting autonomous multi-sensor acquisition in space- and power-constrained portable systems.
Availability
MAX1237LEUA+ is available at Aetrix Electronics and suitable for handheld portable instruments, medical vital sign monitors, and battery-powered test equipment requiring stable component supply and long-term industrial temperature support (−40°C to +85°C).
Supply support for MAX1237LEUA+ 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 portable applications.
The MAX1236–MAX1239 family was engineered specifically for ultra-low-power, multi-channel data acquisition in space-constrained, battery-operated systems-emphasizing integration (reference, T/H, clock, I²C), accuracy retention over temperature, and intelligent power management.
FAQ
What is the maximum sampling rate of the MAX1237LEUA+ and under what conditions is it achieved?
The MAX1237LEUA+ achieves a maximum sampling rate of 94.4 ksps when operating in I²C High-Speed Mode (1.7 MHz SCL) with external clocking and the internal reference enabled. This rate assumes optimal PCB layout, proper 0.1µF VDD bypassing, and ambient temperature within −40°C to +85°C. At 94.4 ksps, supply current is 670 µA typical. Lower rates (e.g., 40 ksps) reduce current to 230 µA, supporting longer battery life.
Does the MAX1237LEUA+ support differential input measurements, and how is it configured?
Yes, the MAX1237LEUA+ supports fully differential input measurements across two channels (AIN0–AIN1 or AIN2–AIN3/REF) using its software-configurable analog mux. Configuration is performed via the SGL/DIF bit in the setup byte: setting SGL/DIF = 0 selects differential mode. In this mode, the BIP/UNI bit further defines the range as either 0 to VREF (unipolar) or ±VREF/2 (bipolar), with output coding in two's complement for bipolar operation.
Can the MAX1237LEUA+ operate with an external reference, and what are the voltage limits?
Yes, the MAX1237LEUA+ supports external reference voltages applied to the AIN3/REF pin. The valid range is 1V to VDD (2.7V–3.6V), allowing flexibility for ratio-metric sensor interfaces or higher-accuracy external references. When using an external reference, the internal 2.048V reference is disabled. Performance remains specified across the full temperature range, though reference stability and noise become system-dependent.
What is the purpose of the AutoShutdown™ feature in the MAX1237LEUA+, and how does it affect system power design?
AutoShutdown™ automatically powers down the MAX1237LEUA+ between conversions, reducing supply current to less than 1 µA at low throughput rates (e.g., <1 ksps). This feature eliminates the need for external enable/disable control and simplifies power sequencing. For example, at 1 ksps, average current drops to 6 µA-enabling decade-long operation on primary lithium batteries in remote sensor nodes without firmware-level power management overhead.
Is the MAX1237LEUA+ pin-compatible with other devices in the MAX1236–MAX1239 family, and which ones share the same 8-pin µMAX package?
Yes, the MAX1237LEUA+ is pin-compatible with the MAX1236EUA+ (4-channel, 4.096V reference, 4.5–5.5V supply) in the same 8-pin µMAX package. Both share identical pinout, I²C address (0110100), and register map. This allows direct voltage-range and reference-voltage substitution in existing designs-e.g., upgrading from MAX1236EUA+ to MAX1237LEUA+ when migrating from 5V to 3.3V systems while retaining PCB layout and firmware.
MAX1237LEUA+ Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- 8-TSSOP, 8-MSOP (0.118", 3.00mm Width)
- Packaging:
- Tube
- Product Status:
- Obsolete
- Number of Bits:
- 12
- Sampling Rate (Per Second):
- 94.4k
- Number of Inputs:
- 2, 4
- Input Type:
- Differential, Single Ended
- Data Interface:
- I2C
- 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-uMAX/uSOP
- Mounting Type:
- Surface Mount
- Grade:
- -
- Qualification:
- -
MAX1237LEUA+ FAQ
1.How can I place an order for MAX1237LEUA+ through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX1237LEUA+ 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 MAX1237LEUA+ reliable?
The price and inventory of MAX1237LEUA+ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX1237LEUA+ is usually 5 days.
3.What payment methods are accepted for MAX1237LEUA+?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX1237LEUA+ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX1237LEUA+?
MAX1237LEUA+ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX1237LEUA+ 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 MAX1237LEUA+?
For technical support, including MAX1237LEUA+ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX1237LEUA+ requirements.
6.How does Aetrix verify that MAX1237LEUA+ is sourced from the original manufacturer or authorized distributors?
All MAX1237LEUA+ 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 MAX1237LEUA+ meets industry standards.
7.What is the process for return or replacement of MAX1237LEUA+?
All MAX1237LEUA+ units undergo pre-shipment inspection (PSI). If there is an issue with MAX1237LEUA+, 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 MAX1237LEUA+ part is unused and in its original packaging.
Return procedure for MAX1237LEUA+:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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