Analog Devices Inc./Maxim Integrated MAX1243BCSA

Overview

MAX1243BCSA from Maxim Integrated is a low-power, 10-bit successive-approximation analog-to-digital converter (ADC) with external reference input, 73ksps throughput, 7.5µs conversion time, and SPI/QSPI/MICROWIRE-compatible 3-wire serial interface. It operates from a single +2.7V to +5.25V supply and targets space-constrained, battery-powered data acquisition systems requiring precision analog sensing.

For engineers reviewing the MAX1243BCSA datasheet, MAX1243BCSA pinout, MAX1243BCSA application, or MAX1243BCSA equivalent, key selection considerations include external reference dependency (0V to VREF input range), SO-8 package footprint, 2µA shutdown current, ±1 LSB INL at 0°C to +70°C, and compatibility with microcontroller I/O ports without level-shifting.

Technical Context

The MAX1243BCSA implements a track/hold circuit with 1.5µs acquisition time and a 10-bit SAR core clocked by an internal oscillator. Conversion is initiated by CS falling edge, with end-of-conversion signaled by DOUT high transition.

Its 3-wire serial interface requires only SCLK, CS, and DOUT - no separate MISO/MOSI lines - and supports unipolar MSB-first output with leading EOC bit. The device accepts external reference voltages from 1.0V to VDD, with REF input impedance ≥18kΩ and ≤10Ω output impedance requirement during conversion.

Key Specifications

Pinout & Package

MAX1243BCSA is housed in an 8-pin SO (Small Outline) package, RoHS-compliant, with 1.27mm pitch and standard JEDEC MO-153 outline. Pin 1 is marked with a dot or bevel; pin numbering follows counter-clockwise convention from top-left when viewed from top with marking side up.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX1242BCSA+, the MAX1243BCSA trades integrated reference for wider VREF scalability; versus ADS7822U, it offers simpler shutdown control and lower active power at 73ksps, at the cost of reduced maximum sample rate and slightly relaxed linearity.

Availability

MAX1243BCSA is available at Aetrix Electronics and suitable for portable data logging, process control monitoring, and isolated data acquisition requiring stable component supply, long-lifecycle support, and RoHS-compliant packaging.

Supply support for MAX1243BCSA 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 power management ICs for industrial, medical, and communications applications.

The MAX1242/MAX1243 product line was designed for ultra-low-power, space-constrained data acquisition systems where serial interface simplicity, single-supply operation, and guaranteed monotonicity are essential.

FAQ

What reference voltage range does the MAX1243BCSA support?

The MAX1243BCSA accepts external reference voltages from 1.0V to VDD. For example, with VDD = 3.3V, VREF may be set to 2.048V, 2.5V, or 3.0V - enabling flexible full-scale adjustment. The REF pin requires ≥0.1µF ceramic bypass and must supply ≤250µA DC load current with ≤10Ω output impedance during conversion to maintain specified accuracy.

How does the MAX1243BCSA enter and exit shutdown mode?

The MAX1243BCSA enters shutdown when the SHDN pin is pulled low, reducing supply current to ≤2µA at VDD ≤3.6V. To exit shutdown, SHDN must be driven high or left open; wake-up time is ~4µs if the external reference remains powered. No reset sequence is required - the first CS pulse after wake-up initiates a valid conversion.

Is the MAX1243BCSA pin-compatible with the MAX1242 series?

Yes, the MAX1243BCSA is pin-compatible with the MAX1242BCSA+ in the same SO-8 package: VDD, AIN, SHDN, REF, GND, CS, SCLK, and DOUT occupy identical positions. However, the MAX1242 includes an internal 2.5V reference tied to REF, while the MAX1243 requires external reference connection to REF - functional behavior differs despite identical pinout.

What is the maximum clock frequency supported by the MAX1243BCSA serial interface?

The MAX1243BCSA supports SCLK frequencies up to 2.1MHz, with no restriction on duty cycle provided each high/low phase is ≥200ns. Clocking above 2.1MHz risks timing violations in data setup/hold windows. For QSPI compatibility, the maximum recommended frequency is 2.097MHz to ensure reliable sub-bit capture.

Does the MAX1243BCSA require external components for stable operation?

Yes, the MAX1243BCSA requires a minimum 0.1µF ceramic capacitor between REF and GND, and a 0.1µF capacitor between VDD and GND placed close to the device. An additional 10µF bulk capacitor on the VDD rail is recommended for systems with noisy supplies. No external clock or reference buffer is mandatory if the reference meets impedance and current specs.