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 - designed for precision sensor digitization in space-constrained portable instrumentation.

For engineers reviewing the MAX1243BCSA+ datasheet, MAX1243BCSA+ pinout, MAX1243BCSA+ application, or MAX1243BCSA+ equivalent, this page delivers verified technical context, package-validated pin functions, real-world application mappings, and two confirmed alternative parts with documented functional and selection differences.

Technical Context

The MAX1243BCSA+ implements a 10-bit SAR architecture with integrated track/hold (1.5µs acquisition), on-chip clock generation, and unipolar serial output (MSB-first, EOC-leading). It requires an external reference voltage (1.0V to VDD) applied at the REF pin and operates across +2.7V to +5.25V supply range.

Its 3-wire serial interface (SCLK, CS, DOUT) supports up to 2.1MHz clock rate with no duty-cycle restriction beyond 200ns minimum phase width. Conversion is initiated by CS falling edge; DOUT transitions high to signal end-of-conversion, enabling flexible µP-controlled readout timing.

Key Specifications

Pinout & Package

MAX1243BCSA+ is housed in an 8-pin SO (Small Outline) package, RoHS-compliant, with gull-wing leads and standard JEDEC MS-012AC outline (S8+5).

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX1243ACSA+, the MAX1243BCSA+ trades 0.5 LSB linearity for lower cost and broader availability; versus ADS7822U, it retains identical SO-8 footprint and simpler timing but delivers 10-bit resolution optimized for low-power, space-constrained sensing.

Availability

MAX1243BCSA+ is available at Aetrix Electronics and suitable for portable data logging, process control monitoring, and temperature measurement requiring stable component supply across industrial and medical OEM programs.

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 high-reliability ICs for industrial, medical, and communications systems.

The MAX1242/MAX1243 product line was engineered for ultra-low-power, small-footprint data acquisition in battery-operated and space-constrained instrumentation - emphasizing ease of µP integration and reference flexibility.

FAQ

What is the reference voltage requirement for MAX1243BCSA+?

The MAX1243BCSA+ 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 performance, bypass REF with ≥0.1µF capacitor; if the reference is noisy or high-impedance, use 4.7µF. The MAX1243BCSA+ draws up to 250µA from REF during conversion, so the source must support that load with ≤10Ω output impedance.

Does MAX1243BCSA+ support SPI interface timing with CPOL = 0 and CPHA = 0?

Yes, the MAX1243BCSA+ is fully compatible with SPI mode 0 (CPOL = 0, CPHA = 0). Conversion starts on CS falling edge; DOUT goes low during conversion and high at end-of-conversion (EOC). Data is clocked out MSB-first on SCLK falling edge, with EOC bit leading the 10 data bits and two sub-bits. No special initialization or configuration is required.

What is the maximum sampling rate and corresponding power consumption of MAX1243BCSA+?

The MAX1243BCSA+ achieves a maximum throughput rate of 73ksps. At this rate with VDD = 3V, its typical supply current is 1.0mA, resulting in 3mW power dissipation. At lower rates (e.g., 1ksps), power drops to 66µW; in shutdown mode (SHDN low), it falls to ≤15µA - enabling ultra-low average power in duty-cycled systems.

Can MAX1243BCSA+ be used with a 5V supply and 2.5V external reference?

Yes, the MAX1243BCSA+ operates with VDD from +2.7V to +5.25V and accepts any external reference between 1.0V and VDD. Using a 5V supply with a 2.5V reference is a common configuration - the device digitizes AIN in the 0V to 2.5V range with 2.44mV per LSB (2.5V/1024). Input protection diodes clamp to VDD/GND, so ensure AIN stays within GND −0.3V to VDD +0.3V.

What is the acquisition time specification for MAX1243BCSA+, and how does source impedance affect it?

The MAX1243BCSA+ has a guaranteed maximum acquisition time (tACQ) of 1.5µs for source impedances ≤4kΩ. For higher impedances, tACQ increases per tACQ = 7(RS + RIN) × 16pF (RIN = 9kΩ). Signals from high-Z sources (e.g., thermistors, pH electrodes) may require external buffering or input capacitance (e.g., 0.01µF) to maintain accuracy and avoid extended acquisition delays.