Analog Devices Inc./Maxim Integrated MAX1243BCPA

Overview

MAX1243BCPA from Maxim Integrated is a low-power, 10-bit successive-approximation analog-to-digital converter (SAR ADC) operating from +2.7V to +5.25V supply, featuring 7.5µs conversion time, 73ksps throughput, and SPI/QSPI/MICROWIRE-compatible 3-wire serial interface. It requires an external reference voltage (1.0V to VDD), supports 0V to VREF input range, and delivers ±1 LSB integral nonlinearity at 0°C to +70°C in 8-pin PDIP package - ideal for portable data loggers and isolated sensor interfaces where space and power are constrained.

For engineers reviewing the MAX1243BCPA datasheet, MAX1243BCPA pinout, MAX1243BCPA application, or MAX1243BCPA equivalent, this page provides verified technical context, real-world design meaning of key specs, validated pin functions, confirmed alternative options with documented differences, and supply-chain support details specific to the MAX1243BCPA variant.

Technical Context

The MAX1243BCPA implements a track/hold circuit with 1.5µs acquisition time and a 10-bit SAR core clocked internally, eliminating need for external conversion timing control. Its 3-wire serial interface operates up to 2.1MHz with no duty-cycle restriction beyond 200ns minimum phase width, and supports unipolar MSB-first output with EOC signaling via DOUT high transition.

It uses an external reference applied to the REF pin (1.0V to VDD), accepts analog inputs from 0V to VREF, and features a three-level SHDN pin that enables shutdown mode (<2µA typical) while allowing operational flexibility - unlike the MAX1242, it lacks internal reference and does not enable reference via SHDN state.

Key Specifications

Pinout & Package

MAX1243BCPA is housed in an 8-pin plastic dual in-line package (PDIP) with gull-wing leads, RoHS-compliant (indicated by '+' suffix), and substrate connected to GND per Maxim package drawing P8+2 (outline 21-0043).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 10-bit serial ADC applications.

Compared with MAX1243BCPA, MAX1243BCSA+ offers identical functionality in a smaller SO package for automated assembly, while ADS7822U trades pin-count simplicity and hardware shutdown for higher resolution and speed - both require layout changes and firmware adaptation.

Availability

MAX1243BCPA is available at Aetrix Electronics and suitable for portable data logging, process control monitoring, and test equipment requiring stable component supply with guaranteed 0°C to +70°C industrial temperature grade and RoHS-compliant PDIP packaging.

Supply support for MAX1243BCPA 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 precision analog, mixed-signal, and high-reliability ICs for industrial, medical, and communications applications.

The MAX1242/MAX1243 product line was designed for ultra-low-power, space-constrained data acquisition systems requiring 10-bit resolution, serial interface simplicity, and single-supply operation - targeting battery-powered and isolated measurement nodes.

FAQ

What is the reference voltage requirement for MAX1243BCPA?

The MAX1243BCPA requires an external reference voltage applied to the REF pin, ranging from 1.0V to VDD. It does not include an internal reference. For optimal accuracy, the reference must provide ≤10Ω output impedance and sustain up to 250µA load during conversion. A minimum 0.1µF ceramic capacitor is required at REF for stability; noisy or high-impedance references benefit from a 4.7µF bulk capacitor. The MAX1243BCPA reference specification directly enables flexible full-scale scaling without additional components.

Does MAX1243BCPA support SPI interface timing?

Yes, MAX1243BCPA is fully compatible with SPI, QSPI, and MICROWIRE protocols. It operates with CPOL = 0 and CPHA = 0, where CS falling edge initiates conversion and DOUT transitions on SCLK falling edge. Data is MSB-first unipolar format with leading EOC bit, requiring ≥13 clock edges for full readout. The MAX1243BCPA timing supports SCLK frequencies up to 2.1MHz with no duty-cycle restriction beyond 200ns minimum high/low time - matching standard SPI controller capabilities.

What is the shutdown current of MAX1243BCPA?

The MAX1243BCPA draws ≤2µA typical supply current in shutdown mode when SHDN is pulled low, with VDD ≤ 3.6V. This value is confirmed in the Electrical Characteristics table under "Power-down" conditions. Shutdown mode disables the internal oscillator, track/hold, and SAR logic while retaining pin-state integrity. Wake-up time is minimal since no internal reference charging is required - unlike the MAX1242, the MAX1243BCPA achieves sub-5µs readiness after SHDN deassertion when paired with a pre-biased external reference.

Can MAX1243BCPA operate with a 3.3V supply and 2.5V reference?

Yes, MAX1243BCPA operates reliably with VDD = 3.3V and VREF = 2.5V. The device's specified supply range (+2.7V to +5.25V) and reference range (1.0V to VDD) fully encompass this configuration. At 3.3V, typical supply current is 1.5mA in active mode (73ksps), delivering 3mW power consumption. The 2.5V reference yields 2.44mV/LSB resolution, and INL remains ±1 LSB over 0°C to +70°C - all parameters confirmed in the MAX1243BCPA ordering table and Electrical Characteristics section.

What is the maximum source impedance supported at AIN for MAX1243BCPA?

The MAX1243BCPA supports analog source impedances up to 4kΩ without degrading AC performance, based on its 1.5µs acquisition time (tACQ) and internal 9kΩ input resistance. For higher impedances, a 0.01µF capacitor at AIN is recommended to maintain signal integrity, though this forms an RC filter limiting input bandwidth. The datasheet specifies tACQ = 7(RS + RIN) × 16pF, confirming that RS > 4kΩ increases acquisition time and may require extended inter-conversion delays to preserve accuracy - a constraint explicitly defined for the MAX1243BCPA variant.