Analog Devices Inc./Maxim Integrated MAX1240BCPA

Overview

MAX1240BCPA from Maxim Integrated is a low-power, 12-bit successive-approximation analog-to-digital converter (ADC) in an 8-pin PDIP package, operating from +2.7V to +3.6V with internal 2.5V reference, 73ksps throughput, ±1 LSB INL, and SPI/QSPI/MICROWIRE-compatible 3-wire serial interface. It targets battery-powered sensor nodes requiring precision, compact size, and ultra-low power.

For engineers reviewing the MAX1240BCPA datasheet, MAX1240BCPA pinout, MAX1240BCPA application, or MAX1240BCPA equivalent, this page delivers verified electrical specs, validated pin functions, confirmed use cases in portable data logging and isolated acquisition, and two technically documented alternative parts for design flexibility.

Technical Context

The MAX1240BCPA integrates a 1.5µs track/hold amplifier and 7.5µs SAR conversion core, enabling full 12-bit digitization within 9µs total acquisition+conversion time. Its internal 2.5V reference is trimmed to ±30ppm/°C and supplies up to 400µA, bypassed by a 4.7µF capacitor at REF.

Shutdown mode reduces supply current to ≤2µA (typical), with wake-up delay dependent on shutdown duration due to reference capacitor recharge. The 3-wire serial interface operates at up to 2.1MHz SCLK, supports MSB-first unipolar output with EOC signaling via DOUT high transition, and requires no external hold capacitor.

Key Specifications

Pinout & Package

MAX1240BCPA is housed in an 8-pin plastic dual in-line package (PDIP) with 0.3-inch width, suitable for through-hole prototyping and industrial PCBs requiring mechanical robustness and thermal stability.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 12-bit serial ADC applications.

Compared with MAX1240BCPA, ADS7822U offers higher speed but demands external reference design effort, while MAX11100ASA+ provides wider temperature rating and faster sampling in SOIC-neither matches the MAX1240BCPA's combination of PDIP form factor, internal reference, and ultra-low 3.7µW active power at 73ksps.

Availability

MAX1240BCPA is available at Aetrix Electronics and suitable for battery-powered sensor nodes, portable data loggers, isolated data acquisition modules, and industrial process control interfaces requiring stable component supply, long-lifecycle support, and RoHS-compliant through-hole packaging.

Supply support for MAX1240BCPA 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 communications applications.

The MAX1240 series targets ultra-low-power, space-constrained data acquisition systems-emphasizing integrated references, minimal external components, and robust serial interfacing for embedded microcontroller integration.

FAQ

What is the maximum sampling rate of the MAX1240BCPA?

The MAX1240BCPA achieves a maximum throughput rate of 73 ksps (kilo-samples per second) under specified conditions: VDD = +2.7V to +3.6V, fSCLK = 2.1 MHz, and TA = 0°C to +70°C. This includes both 1.5 µs track/hold acquisition and 7.5 µs SAR conversion time, resulting in a total conversion cycle of 9 µs. The device maintains ±1 LSB INL and 70 dB SINAD at this rate.

Does the MAX1240BCPA require an external reference voltage?

No, the MAX1240BCPA includes a factory-trimmed internal 2.5V reference with ±0.5% initial accuracy and ±30 ppm/°C temperature coefficient. When SHDN is pulled high, the internal reference is enabled and drives the REF pin-requiring only a 4.7 µF bypass capacitor. An external reference may be used only if SHDN is left floating to disable the internal source.

What package type is used for the MAX1240BCPA?

The MAX1240BCPA is supplied in an 8-pin plastic dual in-line package (PDIP) with 0.3-inch body width. This through-hole package supports manual soldering, socket-based evaluation, and legacy industrial PCB layouts where mechanical robustness and thermal mass are advantageous over surface-mount alternatives.

How does the shutdown mode function on the MAX1240BCPA?

Pulling the SHDN pin low places the MAX1240BCPA into shutdown mode, reducing supply current to ≤2 µA (typical). In this state, the internal reference is disabled, the track/hold and SAR circuits are powered down, and DOUT enters high-impedance. Wake-up time depends on shutdown duration due to 4.7 µF REF capacitor recharge-ranging from ~4 µs (short shutdown) to >20 ms (extended shutdown).

Which microcontroller interfaces are compatible with the MAX1240BCPA serial port?

The MAX1240BCPA 3-wire serial interface is fully compatible with SPI, QSPI, and MICROWIRE standards. It operates with CPOL = 0 and CPHA = 0, supports clock rates up to 2.1 MHz, and outputs MSB-first unipolar data with end-of-conversion signaled by DOUT high transition-enabling direct connection to standard MCU GPIO pins without protocol translation hardware.