MAX1241BCSA+T - 12-Bit SAR ADC, 73ksps, 8-SOIC | Maxim Integrated
MPN: MAX1241BCSA+T ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $8.05 | $8.05 |
| 10 | $7.22 | $72.20 |
| 100 | $6.1 | $610.00 |
| 500 | $5.42 | $2,710.00 |
| 1,000 | $4.78 | $4,780.00 |
MAX1241BCSA+T Overview
An ADC is a mixed-signal integrated circuit that converts a continuous analog input voltage into a discrete digital code. The SAR (Successive Approximation Register) architecture is one of the canonical ADC topologies alongside Flash, Sigma-Delta, Pipelined, and Dual-Slope; SAR ADCs are favored in multiplexed data-acquisition systems, sensor front-ends, and embedded control loops because they deliver 8-18 bit resolution with deterministic, low-latency conversion (one sample per N clocks) and very low power consumption. The MAX1241 sits in the SAR hierarchy as: SAR ADC -> data-acquisition ADC -> mixed-signal IC -> semiconductor. It uses an external reference voltage applied to the REF pin, giving the user full control over input span and absolute accuracy.
Key features include a 7.5 us successive-approximation conversion time, an internal track/hold with 1.5 us acquisition, an on-chip oscillator that eliminates the need for an external clock, a hardware shutdown pin (SHDN) that drops quiescent current to under 10 uA for battery-powered designs, and a 3-wire serial interface that supports daisy-chaining of multiple ADCs on a single SPI bus. Industrial-grade (-40C to +85C) operating temperature makes it suitable for factory automation, instrumentation, and portable medical electronics.
Typical applications include portable battery-powered data loggers, loop-powered 4-20 mA sensor transmitters, pen-digitizers and touch-screen controllers, isolated multi-channel data-acquisition modules, and front-end digitizers for strain gauges, thermocouples, and process-control transducers. The 8-SOIC footprint and minimal external parts count (one reference bypass cap and one decoupling cap) make it ideal for compact, cost-sensitive designs.
When designing with this part, route the analog input trace away from the SCLK and CS digital lines, place the 0.1 uF VDD bypass capacitor as close as possible to pin 8, and ensure the external reference source can supply the dynamic REF pin current (typically 50 uA during conversion). The SHDN pin allows the part to enter a 5 uW power-down state between conversions, making it well-suited for duty-cycled battery operation.
Drop-in alternatives for MAX1241BCSA+T — 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:
MAX1241ACSA+T
✅ Drop-In📋 Reference alternative (not in catalog)
MAX1241CCSA+T
✅ Drop-In📋 Reference alternative (not in catalog)
MAX1241AESA+T
✅ Drop-In📋 Reference alternative (not in catalog)
MAX1243BCSA+
✅ Drop-In📋 Reference alternative (not in catalog)
MAX1241BCSA+T Maximum Ratings & Electrical Characteristics
| Manufacturer | Analog Devices Inc./Maxim Integrated |
| Part Number | MAX1241BCSA+T |
| Description | 12-bit, low-power, serial SAR ADC |
| Resolution | 12 bit |
| Number of Channels | 1 |
| ADC Architecture | SAR (Successive Approximation Register) |
| Sampling Rate | 73 ksps |
| Conversion Time | 7.5 us |
| Track/Hold Acquisition Time | 1.5 us |
| Supply Voltage (Single) | +2.7 V to +5.25 V |
| Supply Current (Power-Down) | 5 uW (power-down mode) |
| Reference Type | External (applied to REF pin) |
| Digital Interface | 3-wire SPI/QSPI/MICROWIRE-compatible |
| Shutdown Pin | Yes (SHDN, active-low) |
| Internal Clock | Yes (on-chip oscillator) |
| Operating Temperature | 0C to +70C (commercial grade B) |
| Package / Case | 8-SOIC (SO, 3.90 mm body) |
| Mounting Type | Surface Mount |
| RoHS Status | Compliant |
| MSL Level | 1 (unlimited) |
| Packaging | Tape & Reel (T) |
MAX1241BCSA+T Pin Configuration
| Pin 1 | VDD — Positive supply input, +2.7V to +5.25V |
| Pin 2 | AIN — Analog input channel (single-ended) |
| Pin 3 | GND — Ground |
| Pin 4 | REF — External reference voltage input |
| Pin 5 | SHDN — Active-low shutdown control input |
| Pin 6 | DOUT — Serial data output (SPI/MICROWIRE) |
| Pin 7 | CS — Active-low chip-select input |
| Pin 8 | SCLK — Serial clock input |
Typical Applications
MAX1241BCSA+T is suitable for 6 applications: Portable Battery-Powered Data Loggers, Loop-Powered 4-20 mA Sensor Transmitters, Pen-Digitizer and Touch-Screen Controllers, Isolated Multi-Channel Data-Acquisition Modules, Front-End Digitizer for Strain Gauges and Thermocouples, Medical and Wellness Monitoring Devices.
Portable Battery-Powered Data Loggers
The MAX1241BCSA+T's 5 uW shutdown current and +2.7 V to +5.25 V supply range let it sip power in duty-cycled logging designs. Pull SHDN low between conversions, wake the part on a timer interrupt from the host microcontroller, run a 7.5 us conversion, and read 12 bits over the 3-wire SPI bus before returning to sleep. At one conversion per second the average current is dominated by reference and MCU leakage, not the ADC, so a single CR2032 cell can power multi-week data logging.
Recommended
Loop-Powered 4-20 mA Sensor Transmitters
The MAX1241BCSA+T's wide 2.7 V to 5.25 V supply range accommodates the variable compliance voltage of a loop-powered sensor transmitter fed from a 12 V to 36 V loop. Place the MAX1241 between the loop-powered shunt regulator and a sensor bridge (strain gauge, RTD, or pressure cell); the 12-bit resolution gives 0.024 percent of full scale (FS / 4096), sufficient for most industrial process variables, and the SAR architecture's deterministic single-conversion latency simplifies digital compensation. The on-chip oscillator removes any need for a precision clock in the head.
Recommended
Pen-Digitizer and Touch-Screen Controllers
The MAX1241BCSA+T's 73 ksps throughput and 1.5 us track-and-hold acquisition suit pen-position and touch-screen digitizing where the analog frontend must track a rapidly varying position voltage. Its small 8-SOIC footprint fits alongside the resistive touch-panel connector on a handheld device's main PCB. The SHDN pin lets the host power down the ADC between stylus samples, and the 3-wire serial interface is easy to bit-bang from any microcontroller GPIO if no SPI peripheral is available.
Recommended
Isolated Multi-Channel Data-Acquisition Modules
In isolated DAQ modules the MAX1241BCSA+T is placed on the field (high-voltage) side of a digital isolator, sampling up to 73 ksps and pushing 12-bit words through the isolator to a host microcontroller or DSP. The SHDN pin doubles as an enable for the upstream isolated DC-DC converter, turning the entire analog front-end off when not in use. The internal oscillator eliminates the need to route a precision clock across the isolation barrier, reducing EMI and BOM cost.
Recommended
Front-End Digitizer for Strain Gauges and Thermocouples
The MAX1241BCSA+T pairs naturally with a low-noise instrumentation amplifier to digitize strain-gauge bridge or thermocouple signals. With an external 4.096 V reference and the AMP output scaled to within 0 V to 4.096 V, the MAX1241 provides 1 mV per LSB resolution, adequate for weighing scales, load cells, and precision temperature monitoring through K-type thermocouples. The 7.5 us conversion plus 1.5 us acquisition allows up to ~110 ksps pipeline operation in single-channel systems.
Recommended
Medical and Wellness Monitoring Devices
The MAX1241BCSA+T's low power, single-supply operation, and small 8-SOIC footprint suit wearable medical and wellness monitors such as pulse-oximeters, body-temperature patches, and portable spirometers. The 12-bit dynamic range is sufficient for heart-rate and SpO2 photoplethysmography (PPG) front-ends when paired with an appropriate trans-impedance amplifier. The SHDN pin enables aggressive duty cycling to extend battery life to weeks or months on a single coin cell.
Recommended
Recommended Products Summary
Engineering reference data for MAX1241BCSA+T — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | MAX1241ACSA+T | MAX1241CCSA+T | MAX1241AESA+T |
|---|---|---|---|---|
| Brand | Analog Devices (Maxim) | Analog Devices (Maxim) - same brand | Analog Devices (Maxim) - same brand | Analog Devices (Maxim) - same brand |
| Package | 8-SOIC (narrow, 3.90 mm body) | 8-SOIC (narrow, 3.90 mm body) - same | 8-SOIC (narrow, 3.90 mm body) - same | 8-SOIC (narrow, 3.90 mm body) - same |
| Resolution | 12 bit | 12 bit | 12 bit | 12 bit |
| Sampling Rate | 73 ksps | 73 ksps | 73 ksps | 73 ksps |
| INL (LSB) | +/-1 LSB (B grade) | +/-1 LSB (A grade) | +/-1 LSB (C grade) | +/-1 LSB (A grade) |
| Operating Temperature | 0C to +70C | 0C to +70C | 0C to +70C | -40C to +85C |
| Supply Voltage | +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 |
| Reference | External | External | External | External |
| Package Suffix | BCSA (B grade, SOIC narrow) + T (T&R) | ACSA (A grade, SOIC narrow) + T | CCSA (C grade, SOIC narrow) + T | AESA (A grade, industrial temp) |
Key Differentiators
- Wide single-supply range (2.7 V to 5.25 V) in 8-SOIC (vs MAX1240BCSA+)
- B-grade linearity (industry-standard +/-1 LSB INL) (vs MAX1241ACSA+T (A grade))
- Commercial 0C to +70C temperature range (vs MAX1241BESA+ (industrial))
Design Notes
Decouple VDD (pin 1) with a 0.1 uF ceramic capacitor placed as close as possible to the IC pin, with a short trace to the GND plane. Add a 10 uF bulk capacitor if the supply rail is shared with switching regulators or other noisy loads. The MAX1241BCSA+T's wide supply range (2.7 V to 5.25 V) makes it tolerant of poorly regulated rails, but the analog input range must stay within 0 V to VDD; design the input amplifier accordingly.
Route the AIN analog trace away from SCLK, CS, and DOUT digital traces. Use a guard trace or ground-fill between the analog and digital sections, and place the external reference bypass capacitor (typically 0.1 uF) as close as possible to the REF pin. The 8-SOIC thermal pad is not present on this part, but a continuous ground plane under the IC and short return paths for REF and AIN currents improve noise performance by 0.5-1 LSB.
Do not exceed VDD on the AIN or REF pins; absolute maximum on analog inputs is VDD + 0.3 V. The SHDN pin must be driven high (to VDD) for normal operation - leaving it floating may cause indeterminate behavior. Ensure the external reference can source the dynamic REF pin current (~50 uA during conversion); a high-impedance reference source will introduce gain error. The serial interface is 3-wire SPI-compatible but data is clocked out only while CS is low; release CS to frame each conversion.
The MAX1241BCSA+T uses an on-chip oscillator, so SCLK is only required for serial data read-out and not for the conversion itself. To minimize digital noise coupling into the analog input, gate SCLK only during the read-out phase (after the internal conversion has completed). For highest DC accuracy, average multiple conversions in software; the SAR architecture's inherent zero-latency conversion makes oversampling straightforward.
Compliance Information
RoHS compliant per Maxim Integrated/Analog Devices product page. The MAX1241BCSA+T is supplied in lead-free matte-tin finish with MSL1 rating. Not AEC-Q100 qualified - this part targets commercial/industrial data-acquisition, not automotive.
