MAX1241AESA - 12-Bit 73kSPS Serial ADC | Maxim Integrated
MPN: MAX1241AESA ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $6.2 | $6.20 |
| 10 | $5.58 | $55.80 |
| 100 | $4.92 | $492.00 |
| 500 | $4.2 | $2,100.00 |
| 1,000 | $3.65 | $3,650.00 |
MAX1241AESA Overview
A successive-approximation register (SAR) ADC is a type of Nyquist-rate data converter that performs one bit-trial per clock cycle using an internal binary-weighted capacitor DAC. SAR ADCs are valued for low latency (single-cycle conversion), deterministic behavior (no pipeline delay), and excellent DC accuracy, making them well suited to multiplexed data acquisition, industrial instrumentation, and sensor readout rather than high-speed waveform capture. The MAX1241 family is positioned at the low-power, low-channel-count end of Maxim's ADC portfolio.
Key specifications include 12-bit resolution, 73 kSPS sampling rate, a single-ended analog input, SPI/QSPI/MICROWIRE-compatible serial interface, external reference input, and 8-pin SOIC packaging. The wide 2.7V to 5.25V supply range allows direct operation from a single lithium cell, a 3.3V logic rail, or a 5V analog rail without level translation. Power dissipation is in the low-milliwatt class during continuous conversion, with automatic power-down between conversions in the internal shutdown mode, which makes the part attractive for battery-powered and duty-cycled applications.
Typical applications include portable instrumentation, pen digitizers, loop-powered industrial transmitters, remote data acquisition nodes, battery chargers (current/voltage monitoring), and PLC analog input modules. The 3-wire serial interface connects directly to standard microcontroller SPI ports from Microchip, ST, NXP, and Renesas families without glue logic.
When designing with this device, ensure the external reference source is low-noise and adequately decoupled at the REF pin. The reference input range includes the positive supply rail, which simplifies 5V ratiometric designs. For best INL/DNL performance, place 0.1 µF ceramic bypass capacitors close to VDD and REF and keep analog/digital ground returns separated until they join at the ADC ground pin.
This page synthesizes distributor pricing, parametric footprint data, and drop-in alternative guidance not present in the bare Maxim datasheet, giving engineers a faster path from datasheet to BOM.
Drop-in alternatives for MAX1241AESA — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
MAX1241AESA+
✅ Drop-In📋 Reference alternative (not in catalog)
MAX1241AESA+T
✅ Drop-In📋 Reference alternative (not in catalog)
MAX1241ACSA+
✅ Drop-In📋 Reference alternative (not in catalog)
MAX1241ACSA+T
✅ Drop-In📋 Reference alternative (not in catalog)
MAX1240AESA+
✅ Drop-In📋 Reference alternative (not in catalog)
MAX1241AESA Maximum Ratings & Electrical Characteristics
| Resolution | 12 bit |
| Sampling Rate | 73 kSPS |
| Number of Channels | 1 |
| Input Type | Single-Ended |
| Architecture | SAR (Successive Approximation) |
| Data Interface | SPI / QSPI / MICROWIRE compatible, 3-wire serial |
| Supply Voltage | +2.7 V to +5.25 V (single supply) |
| Reference Type | External |
| Analog Input Range | 0 V to VREF (REF input range includes VDD) |
| Conversion Time | 7.5 µs (typ) |
| Track/Hold Acquisition Time | 1.5 µs (typ) |
| Number of Converters | 1 |
| S/H:ADC Ratio | 1:1 |
| Configuration | S/H-ADC |
| Package | 8-pin SOIC (NSOIC, 150 mil) |
| Mounting Type | Surface Mount |
| Operating Temperature | -40 C to +85 C (industrial) |
MAX1241AESA Pin Configuration
| Pin 1 | VDD — Positive supply voltage, +2.7 V to +5.25 V; bypass with 0.1 µF to GND |
| Pin 2 | REF — External reference voltage input; range includes VDD; bypass with 0.1 µF to GND |
| Pin 3 | AIN — Analog input, single-ended, range 0 V to VREF |
| Pin 4 | GND — Ground, both analog and digital return |
| Pin 5 | DOUT — Serial data output, three-state, MSB first |
| Pin 6 | SCLK — Serial clock input, external |
| Pin 7 | CS — Active-low chip-select input; tie low to enable continuous conversion mode |
| Pin 8 | SHDN — Active-low shutdown input; tie high for normal operation |
Typical Applications
MAX1241AESA is suitable for 6 applications: Portable Instrumentation and Pen Digitizers, Loop-Powered 4-20 mA Industrial Transmitters, Battery Charger Current and Voltage Monitoring, PLC Analog Input Modules, Remote Data Acquisition Nodes, Audio Peak Detection and Metering.
Portable Instrumentation and Pen Digitizers
The MAX1241AESA is well-suited to portable, battery-powered instrumentation such as handheld multimeters and pen-tablet digitizers. Its 12-bit resolution and 73 kSPS throughput capture sensor or pen-tip signals with low latency, while the wide +2.7 V to +5.25 V supply range allows direct operation from a single lithium cell or two AA cells in series. The integrated 3-wire SPI port connects directly to Microchip PIC, ST STM32, and NXP Kinetis microcontrollers without glue logic. Power-down between conversions reduces average consumption to microamp levels, extending battery life in duty-cycled measurement modes.
Recommended
Loop-Powered 4-20 mA Industrial Transmitters
In 4-20 mA loop-powered smart transmitters, the MAX1241AESA digitizes the bridge or sensor signal with 12-bit resolution while drawing only milliwatts from the loop. The SAR design delivers a single-cycle conversion with no pipeline delay, simplifying synchronization with the loop master. The external reference allows the designer to share a precision shunt-derived reference across multiple channels. With operating temperatures from -40 C to +85 C, the part covers industrial outdoor environments commonly encountered in process plants and field instrumentation.
Recommended
Battery Charger Current and Voltage Monitoring
Lithium-ion and lead-acid battery chargers use the MAX1241AESA to digitize charge current via a shunt resistor and pack voltage via a divider. The 12-bit resolution is sufficient for 1% charge-state estimation, while the 73 kSPS rate captures the dynamics of CC/CV transition without aliasing. The wide supply input is convenient in multi-cell packs because they can support 5.25 V operation. The 3-wire SPI interface attaches to a charger-management microcontroller with minimal firmware changes.
Recommended
PLC Analog Input Modules
Programmable Logic Controller (PLC) analog input modules deploy multiple ADCs to digitize 0-10 V or 4-20 mA field signals. The MAX1241AESA provides a low-power, compact 8-pin SOIC footprint per channel, allowing 4-8 channels to be packed into a small module outline. The SAR architecture guarantees no pipeline delay, simplifying synchronous sampling when several channels share a CS-bar line. Industrial operating temperatures and external reference support ratiometric measurements across long field wiring runs.
Recommended
Remote Data Acquisition Nodes
Remote, wireless or wired sensor nodes use the MAX1241AESA to digitize low-bandwidth analog signals (temperature, pressure, strain) for transmission back to a gateway. The ADC's microamp shutdown current between conversions is critical for duty-cycled nodes that wake, sample, transmit, and sleep. The wide supply input accommodates energy-harvesting power supplies whose voltage varies with available light or vibration. The 12-bit resolution is sufficient for most sensor linearization and calibration tasks.
Recommended
Audio Peak Detection and Metering
Although primarily a DC-accurate SAR ADC, the MAX1241AESA can serve audio-side tasks such as peak-detector readout, VU-meter digitisation, and supply-rail monitoring in audio equipment. Its 12-bit resolution is sufficient for display-grade metering, while the wide supply range allows direct connection to 5 V audio rails. The external reference gives designers flexibility to map peak amplitudes to a specific meter scale, and the SPI port connects to common audio DSP chips for visual feedback rendering.
Recommended
Recommended Products Summary
Engineering reference data for MAX1241AESA — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | MAX1241AESA+ | MAX1241AESA+T | MAX1241ACSA+ | MAX1241ACSA+T | MAX1240AESA+ |
|---|---|---|---|---|---|---|
| Brand | Maxim Integrated (Analog Devices) | Maxim Integrated | Maxim Integrated | Maxim Integrated | Maxim Integrated | Maxim Integrated |
| Package | SOIC-8 (NSOIC, 150 mil) | SOIC-8 - same | SOIC-8 - same | SOIC-8 - same | SOIC-8 - same | SOIC-8 - same |
| Resolution | 12 bit | 12 bit | 12 bit | 12 bit | 12 bit | 12 bit |
| Sampling Rate | 73 kSPS | 73 kSPS | 73 kSPS | 73 kSPS | 73 kSPS | 73 kSPS |
| Supply Voltage Range | +2.7 V to +5.25 V | +2.7 V to +5.25 V | +2.7 V to +5.25 V | +2.7 V to +5.25 V | +2.7 V to +5.25 V | +2.7 V to +3.6 V (narrower) |
| Reference Type | External | External | External | External | External | Internal 2.5 V |
| Input Channels | 1 single-ended | 1 single-ended | 1 single-ended | 1 single-ended | 1 single-ended | 1 single-ended |
| Serial Interface | SPI/QSPI/MICROWIRE, 3-wire | SPI/QSPI/MICROWIRE | SPI/QSPI/MICROWIRE | SPI/QSPI/MICROWIRE | SPI/QSPI/MICROWIRE | SPI/QSPI/MICROWIRE |
| Architecture | SAR | SAR | SAR | SAR | SAR | SAR |
Key Differentiators
- External reference gives design flexibility (vs MAX1240AESA+)
- Wider supply voltage range covers 5 V analog rails (vs MAX1240AESA+)
- Same SOIC-8 footprint across the family for PCB reuse (vs MAX1241BEPA+ (PDIP-8 variant))
Design Notes
The MAX1241AESA enters shutdown mode when SHDN-bar (pin 8) is pulled low, reducing supply current to the microamp range. For duty-cycled measurement (sample, transmit, sleep), drive SHDN-bar from a microcontroller GPIO with a 10 kohm pull-up to VDD to keep the part enabled by default. Decouple VDD (pin 1) with a 0.1 µF ceramic capacitor placed within 2 mm of the pin; add a 1 µF tantalum or ceramic bulk capacitor if the supply is shared with switching circuitry.
Route analog and digital grounds separately and join them only at the ADC ground pin (pin 4) to avoid digital return currents corrupting the analog input. Place REF (pin 2) decoupling (0.1 µF ceramic) directly at the REF pin with the ground via via that series-companion to pin 4. Keep analog input traces short and guarded by a ground pour on both sides. If the analog input is single-ended, do not let the input trace cross noisy digital or switching traces on adjacent layers.
When interfacing MAX1241AESA to a microcontroller SPI port running at higher than 2 MHz, place a 100 ohm series resistor at DOUT (pin 5) to dampen reflections if the trace is longer than 50 mm. SCLK (pin 6) should be clean; if the SPI bus is shared with other peripherals, ensure that only one device drives DOUT at any time to avoid contention. Tie CS-bar (pin 7) low at power-up only if the application runs in continuous-conversion mode; otherwise drive it from the host to frame conversions correctly.
Common pitfalls include (1) forgetting that REF must be present and decoupled before CS-bar is brought low, causing the part to return full-scale values; (2) treating MAX1241AESA and MAX1240AESA as fully interchangeable when the reference is connected externally, since MAX1240 has an internal 2.5 V reference that overrides the external pin; (3) ordering MAX1241AESA when a RoHS build is required - specify MAX1241AESA+ for lead-free RoHS-compliant parts. Always cross-reference the datasheet's timing diagram (CS-bar, SCLK, DOUT) against the microcontroller SPI mode settings before firmware integration.
Compliance Information
Legacy MAX1241AESA suffix (without '+') indicates non-RoHS/lead-bearing finish; RoHS-compliant equivalent is MAX1241AESA+. AEC-Q100 not qualified for automotive applications.
