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Analog Devices Inc./Maxim Integrated MAX1242ACSA
- Part No.:
- MAX1242ACSA
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Analog to Digital Converters (ADC)
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
MAX1242ACSA.pdf
- Description:
- IC ADC 10BIT SAR 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:2,137
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Product details
Overview
MAX1242ACSA from Maxim Integrated is a low-power, 10-bit successive-approximation analog-to-digital converter (SAR ADC) with internal 2.5V reference, 73ksps throughput, 7.5µs conversion time, and SPI/QSPI/MICROWIRE-compatible 3-wire serial interface - designed for space-constrained remote sensor nodes requiring precision analog digitization under single +2.7V to +5.25V supply.
For engineers reviewing the MAX1242ACSA datasheet, MAX1242ACSA pinout, MAX1242ACSA application, or MAX1242ACSA equivalent, this page delivers verified electrical specs, SO-8 package mapping, real-world timing behavior, functional pin roles, and validated alternative options for portable data logging, isolated acquisition, and battery-powered process monitoring.
Technical Context
The MAX1242ACSA implements a fully integrated SAR architecture with on-chip track/hold (1.5µs acquisition), internal 2.5V reference (±30ppm/°C drift), and unipolar serial output format (MSB-first, EOC flag). Its 3-wire interface operates up to 2.1MHz with no duty-cycle restriction beyond 200ns minimum phase width.
It supports two operational modes: active (3.7mW at 73ksps, VDD = 3V) and shutdown (≤2µA), with SHDN pin enabling/disabling the internal reference. Conversion is initiated by CS falling edge; DOUT transitions on SCLK falling edge and remains high-impedance when CS is high.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Resolution | 10-bit SAR - delivers 1024 discrete codes over full-scale range, sufficient for 0.1% measurement accuracy in industrial sensing. |
| Sampling Rate | 73ksps maximum - enables real-time capture of signals up to ~36kHz Nyquist bandwidth without aliasing. |
| Reference | Internal 2.5V ±0.5% (25°C), ±30ppm/°C TC - eliminates external reference component count while maintaining stable LSB size (2.44mV). |
| Power Consumption | 3.7mW at 73ksps (VDD = 3V); 5µW in shutdown - supports multi-year battery life in intermittent-sampling applications. |
| INL / DNL | ±0.5 LSB / ±1 LSB - ensures monotonicity and <0.05% full-scale linearity error after calibration. |
| SINAD / SFDR | 66dB / 70dB (10kHz input) - supports >10-bit effective resolution in noise-sensitive signal chains. |
| Supply Range | +2.7V to +5.25V - interoperable with Li-ion, 3.3V, and 5V logic domains without level-shifting. |
Pinout & Package
MAX1242ACSA is housed in an 8-pin SO (Small Outline) package (S8+5, outline 21-0041), RoHS-compliant, with gull-wing leads and 1.27mm pitch. Thermal performance: 471mW max continuous dissipation at +70°C (derates 5.88mW/°C above).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VDD (Pin 1) | Positive supply rail | Accepts +2.7V to +5.25V; powers analog core, digital interface, and internal reference - bypass with 0.1µF ceramic near pin. |
| AIN (Pin 2) | Analog input | Unipolar 0V to VREF sampling node; protected to GND−0.3V / VDD+0.3V; source impedance ≤4kΩ recommended for full AC spec compliance. |
| SHDN (Pin 3) | Three-level control input | Pull low → shutdown (≤2µA); leave open → disable internal ref (enable external ref); pull high → enable internal 2.5V ref and normal operation. |
| REF (Pin 4) | Reference I/O | Output of internal 2.5V ref (when SHDN = high); input for external ref (1.0V to VDD); requires 4.7µF bulk cap (internal ref) or ≥0.1µF (external ref). |
| GND (Pin 5) | Analog/digital common ground | Single ground plane required; separates analog and digital return paths internally - must be low-impedance connection to system AGND/DGND star point. |
| CS (Pin 7) | Active-low chip select | Falling edge initiates conversion and forces DOUT low; rising edge disables DOUT (high-Z); minimum pulse width 240ns. |
| SCLK (Pin 8) | Serial clock input | Drives data shift-out timing; accepts up to 2.1MHz; no duty cycle constraint if each phase ≥200ns; must remain low during conversion. |
| DOUT (Pin 6) | Serial data output | 3-wire unidirectional output; MSB-first format with leading EOC bit; transitions on SCLK falling edge; high-Z when CS = high. |
Key Features
| Feature | Design Value |
|---|---|
| Single-supply operation | +2.7V to +5.25V eliminates dual-rail design complexity and reduces BOM cost in portable systems. |
| Integrated track/hold | 1.5µs acquisition time enables accurate sampling of fast transients without external TH circuitry or layout sensitivity. |
| 3-wire SPI/QSPI/MICROWIRE compatibility | Direct connection to standard microcontroller serial peripherals - no glue logic or protocol translation required. |
| Internal 2.5V reference | Factory-trimmed ±0.5% initial accuracy and ±30ppm/°C drift reduce calibration overhead and improve long-term stability vs. discrete references. |
| Low-power shutdown mode | ≤2µA quiescent current allows aggressive duty-cycling in energy-harvesting or battery-operated nodes. |
Applications
| Portable Data Logging | Process Control Monitoring |
|---|---|
Use Scenario: Battery-powered environmental sensor node recording temperature, humidity, and pressure at 10s intervals over weeks. IC Role / Device Role / Timing Role: Primary analog front-end ADC digitizing conditioned sensor outputs; synchronized to µC sleep/wake cycles via SHDN pin. Use Value: 5µW shutdown current extends coin-cell life beyond 5 years; internal reference avoids drift-induced calibration drift across temperature. |
Use Scenario: DIN-rail mounted PLC module monitoring 4–20mA loop signals from flow meters and valve positioners. IC Role / Device Role / Timing Role: Isolated analog input channel ADC interfacing through optocoupled SPI bus; CS-triggered conversions aligned to control loop timing. Use Value: 73ksps throughput supports oversampling for noise reduction; ±0.5 LSB INL ensures <0.1% measurement repeatability across 0–70°C operating range. |
| Test Equipment | Temperature Measurement |
Use Scenario: Handheld multimeter with auto-ranging analog inputs and LCD display driven by low-power MCU. IC Role / Device Role / Timing Role: High-accuracy digitizer for DC voltage/current ranges; internal reference used as precision scaling source for gain calibration. Use Value: 66dB SINAD enables true 10-bit ENOB; SO-8 footprint allows compact PCB layout alongside op-amp signal conditioning stages. |
Use Scenario: Thermistor-based oven temperature controller with 0.1°C resolution requirement and wide ambient range (−20°C to +85°C). IC Role / Device Role / Timing Role: Precision ratiometric ADC measuring thermistor divider output referenced to internal 2.5V; conversion triggered on timer interrupt. Use Value: ±30ppm/°C reference TC contributes <0.03% full-scale drift over 100°C span - negligible vs. thermistor tolerance. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar 10-bit SAR ADC applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX1243ACSA+ | Requires external reference (1.0V–VDD); no internal ref; identical SO-8 package, pinout, and timing. | Better suited when system already provides low-noise, high-accuracy external reference (e.g., REF5025) and needs tighter reference flexibility. | Select MAX1243ACSA+ only if external reference improves overall system accuracy or enables ratiometric measurements with varying supply rails. |
| ADS7822U | TI 10-bit SAR ADC; 200ksps; 2.7–5.25V supply; SPI interface; no internal reference; 8-pin SOIC package. | Lacks integrated reference and track/hold; requires external RC filter and reference buffer; higher power (1.2mW @ 200ksps). | Choose ADS7822U only when higher speed is mandatory and external reference infrastructure already exists - not a drop-in replacement. |
Compared with MAX1242ACSA, MAX1243ACSA+ removes internal reference dependency but adds external component cost and layout complexity, while ADS7822U trades integration for raw speed - making MAX1242ACSA optimal for low-component-count, battery-sensitive designs where 73ksps suffices.
Availability
MAX1242ACSA is available at Aetrix Electronics and suitable for portable data logging, isolated data acquisition, and temperature measurement applications requiring stable component supply, long-lifecycle support, and RoHS-compliant sourcing.
Supply support for MAX1242ACSA 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 MAX1242/MAX1243 product line was designed specifically for ultra-low-power, space-constrained data acquisition - delivering precision ADC functionality in minimal footprint with integrated reference and robust serial interface.
FAQ
What is the maximum sampling rate of the MAX1242ACSA, and under what conditions is it guaranteed?
The MAX1242ACSA achieves a guaranteed maximum sampling rate of 73ksps at VDD = +2.7V to +5.25V, fSCLK = 2.1MHz (50% duty cycle), and TA = 0°C to +70°C. This rate corresponds to a 7.5µs conversion time plus 1.5µs track/hold acquisition, and is validated across the full operating temperature range with internal 2.5V reference enabled.
Does the MAX1242ACSA require an external reference capacitor, and if so, what value and placement is specified?
Yes - when using the internal 2.5V reference (default configuration for MAX1242ACSA), a 4.7µF tantalum or low-ESR ceramic capacitor must be placed directly between REF (Pin 4) and GND (Pin 5). This capacitor stabilizes the reference during conversion and limits wake-up delay after shutdown; placement within 2mm of the pins is required for full AC performance.
How does the SHDN pin function on the MAX1242ACSA, and what are its three valid states?
The SHDN pin on the MAX1242ACSA supports three distinct states: pulled low → device enters shutdown (<2µA supply current); left open → internal reference disabled (enabling external reference use); pulled high → internal 2.5V reference enabled and full operation. All states are electrically defined per datasheet - no pull-up/pull-down resistors needed for open or high states.
Is the MAX1242ACSA pin-compatible with any higher-resolution alternatives, and what are the trade-offs?
Yes - the MAX1242ACSA is pin-compatible with the 12-bit MAX1240ACSA and MAX1241ACSA in the same SO-8 package. Trade-offs include higher power (5.5mW vs. 3.7mW at 73ksps), slightly longer conversion time (9.5µs), and increased code density (4096 levels), but no change to PCB layout, firmware interface, or external components beyond reference decoupling.
What serial interface standards does the MAX1242ACSA support, and what configuration settings are required for SPI compatibility?
The MAX1242ACSA supports SPI, QSPI, and MICROWIRE protocols via its 3-wire interface. For SPI compatibility, configure CPOL = 0 and CPHA = 0; initiate conversion with CS falling edge; read 10-bit result across two bytes (first byte: EOC + 7 MSBs; second byte: 3 LSBs + 2 sub-bits); sample DOUT on SCLK rising edge as data transitions on falling edge.
MAX1242ACSA 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:
- Obsolete
- Number of Bits:
- 10
- 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 ~ 5.25V
- Voltage - Supply, Digital:
- 2.7V ~ 5.25V
- Features:
- -
- Operating Temperature:
- 0°C ~ 70°C
- Supplier Device Package:
- 8-SOIC
- Mounting Type:
- Surface Mount
- Grade:
- -
- Qualification:
- -
MAX1242ACSA FAQ
1.How can I place an order for MAX1242ACSA through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX1242ACSA 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 MAX1242ACSA reliable?
The price and inventory of MAX1242ACSA are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX1242ACSA is usually 5 days.
3.What payment methods are accepted for MAX1242ACSA?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX1242ACSA transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX1242ACSA?
MAX1242ACSA orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX1242ACSA 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 MAX1242ACSA?
For technical support, including MAX1242ACSA datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX1242ACSA requirements.
6.How does Aetrix verify that MAX1242ACSA is sourced from the original manufacturer or authorized distributors?
All MAX1242ACSA 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 MAX1242ACSA meets industry standards.
7.What is the process for return or replacement of MAX1242ACSA?
All MAX1242ACSA units undergo pre-shipment inspection (PSI). If there is an issue with MAX1242ACSA, 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 MAX1242ACSA part is unused and in its original packaging.
Return procedure for MAX1242ACSA:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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