Analog Devices Inc./Maxim Integrated MAX1243BESA+T

Overview

MAX1243BESA+T from Maxim Integrated is a low-power, 10-bit successive-approximation analog-to-digital converter (SAR ADC) with external reference input, 73ksps throughput, 7.5µs conversion time, and SPI/QSPI/MICROWIRE-compatible 3-wire serial interface - designed for space-constrained remote sensor nodes requiring precision analog digitization under +2.7V to +5.25V single-supply operation.

For engineers reviewing the MAX1243BESA+T datasheet, MAX1243BESA+T pinout, MAX1243BESA+T application, or MAX1243BESA+T equivalent, this page delivers verified electrical parameters, SO-8 package mapping, functional pin roles, real-world use cases in isolated data acquisition and portable instrumentation, and two validated alternative parts with documented technical and application differences.

Technical Context

The MAX1243BESA+T implements a track/hold circuit with 1.5µs acquisition time and a 10-bit SAR core clocked by an internal oscillator, eliminating need for external timing components. It operates exclusively with an externally supplied reference voltage (1.0V to VDD), supporting unipolar 0V–VREF input range and delivering ±1 LSB integral nonlinearity over –40°C to +85°C.

Its 3-wire serial interface uses CS-active-low initiation, SCLK-synchronized DOUT output with MSB-first format, and supports up to 2.1MHz clock rate. The device features a three-level SHDN pin enabling shutdown mode (≤2µA supply current) and flexible reference control - unlike the MAX1242, it lacks internal reference and requires external bypassing with ≥0.1µF at REF.

Key Specifications

Pinout & Package

MAX1243BESA+T is housed in an 8-pin SO (Small Outline) package, RoHS-compliant, with gull-wing leads and standard JEDEC MO-153 footprint (S8+5 outline). Thermal performance supports 471mW continuous dissipation at +70°C ambient.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX1242BESA+, MAX1243BESA+ trades integrated reference for reference voltage flexibility and lower BOM count in multi-channel systems; versus ADS7822U, it offers superior shutdown current (2µA vs 12µA) and proven SO-8 manufacturability, at the cost of 27ksps lower maximum sampling rate.

Availability

MAX1243BESA+T is available at Aetrix Electronics and suitable for portable data logging, process control monitoring, and isolated data acquisition requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for MAX1243BESA+T 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 engineered for low-power, high-accuracy data acquisition in size- and energy-constrained systems - emphasizing ease of integration, minimal external components, and robust performance across industrial temperature grades.

FAQ

What is the reference voltage requirement for MAX1243BESA+T?

The MAX1243BESA+T 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 external reference must deliver up to 250µA load current with ≤10Ω output impedance and be bypassed with ≥0.1µF ceramic capacitance placed close to the REF pin. The MAX1243BESA+T achieves ±1 LSB INL only when these conditions are met.

Does MAX1243BESA+T support SPI interface timing with CPOL = 0 and CPHA = 0?

Yes, MAX1243BESA+T fully supports SPI mode 0 (CPOL = 0, CPHA = 0). A CS falling edge initiates conversion; DOUT goes low during conversion and rises to signal end-of-conversion (EOC); data is clocked out MSB-first on SCLK falling edges. Two byte reads are typically used: first byte contains leading '1' plus 7 data bits, second byte contains remaining 3 data bits, 2 sub-bits, and trailing zeros - matching standard SPI controller behavior.

What is the maximum allowable source impedance for the AIN pin of MAX1243BESA+T?

The MAX1243BESA+T specifies a 1.5µs minimum acquisition time, which assumes analog source impedance ≤4kΩ. Higher impedances increase acquisition time per tACQ = 7(RS + RIN) × 16pF (RIN = 9kΩ). Source impedances above 4kΩ degrade AC performance unless a 0.01µF capacitor is added at AIN to form an RC filter - but this limits input signal bandwidth. For full 2.25MHz small-signal bandwidth, keep RS ≤4kΩ and avoid added capacitance.

How does the SHDN pin function on MAX1243BESA+T?

The SHDN pin on MAX1243BESA+T is a three-level input: pulling it low places the device in shutdown mode (<2µA supply current); leaving it open or pulling it high enables normal operation. Unlike the MAX1242, the SHDN state has no effect on reference selection - MAX1243BESA+T always uses external reference regardless of SHDN voltage. Wake-up time after SHDN deassertion is ~4µs if the external reference remains powered.

What package type and RoHS status does MAX1243BESA+T have?

MAX1243BESA+T uses an 8-pin SO (Small Outline) package per JEDEC MO-153 outline (package code S8+5), with gull-wing leads and 1.27mm pitch. The '+' suffix confirms it is lead(Pb)-free and RoHS-compliant. Its land pattern matches standard SO-8 footprints (e.g., IPC-7351B SOIC127P600X210-8), and thermal derating is 5.88mW/°C above +70°C ambient.