Analog Devices Inc./Maxim Integrated MAX1242AESA+T

Overview

MAX1242AESA+T from Maxim Integrated is a low-power, 10-bit successive-approximation analog-to-digital converter (ADC) with internal 2.5V reference, 73ksps throughput, 7.5µs conversion time, and SPI/QSPI/MICROWIRE-compatible 3-wire serial interface - used in portable data loggers for battery-constrained remote sensor digitization.

For engineers reviewing the MAX1242AESA+T datasheet, MAX1242AESA+T pinout, MAX1242AESA+T application, or MAX1242AESA+T equivalent, this page delivers verified electrical specs, SO-8 package mapping, functional pin roles, real-world use cases, and two confirmed alternative parts - all grounded in Maxim's Rev 3 (Jan 2012) official datasheet.

Technical Context

The MAX1242AESA+T implements a track/hold + SAR architecture with on-chip clock, enabling single-supply operation from +2.7V to +5.25V. Its internal 2.5V reference is trimmed to ±0.25 LSB INL over temperature and bypassed by a 4.7µF capacitor at REF.

Conversion is initiated by CS falling edge; DOUT signals end-of-conversion (EOC) with a high-going pulse, then outputs 10-bit unipolar data MSB-first on SCLK falling edges. The device supports shutdown mode with ≤2µA supply current and wake-up delay dependent on reference capacitor discharge.

Key Specifications

Pinout & Package

MAX1242AESA+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 21-0041).

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX1243AESA+, MAX1242AESA+T offers plug-and-play reference integration; compared with ADS7822U, it trades resolution and speed for lower system-level BOM count and guaranteed ±0.5 LSB linearity without external trimming.

Availability

MAX1242AESA+T is available at Aetrix Electronics and suitable for portable data logging, process control monitoring, and temperature measurement requiring stable component supply across industrial temperature ranges (–40°C to +85°C).

Supply support for MAX1242AESA+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 systems.

The MAX1242/MAX1243 family was designed for ultra-low-power, space-constrained data acquisition where integrated reference, small SO-8 footprint, and 3-wire simplicity reduce system cost and design risk.

FAQ

What is the operating temperature range for MAX1242AESA+T?

The MAX1242AESA+T is rated for –40°C to +85°C ambient operation, matching the "E" grade specification in Maxim's ordering table. This extended temperature range ensures reliable performance in industrial environments, outdoor sensors, and automotive under-hood applications where thermal stress is present. All key specifications - including INL (±0.5 LSB), reference accuracy, and supply current - are guaranteed across this full range.

Does MAX1242AESA+T require an external reference capacitor?

Yes, the MAX1242AESA+T requires a 4.7µF capacitor at the REF pin when using its internal 2.5V reference - as specified in the datasheet's Electrical Characteristics and Pin Description sections. This capacitor stabilizes the reference output and ensures specified accuracy during conversion. Omitting it causes reference droop and increased INL; using a smaller value degrades AC performance and increases wake-up delay after shutdown.

How does the SHDN pin function on MAX1242AESA+T?

On the MAX1242AESA+T, the SHDN pin is a three-level control: pulled low → shutdown mode (≤2µA supply current); pulled high → normal operation with internal 2.5V reference enabled; left open → internal reference disabled, allowing external reference use. This behavior is unique to the MAX1242 variant and differs from the MAX1243, which lacks internal reference regardless of SHDN state.

What is the maximum SCLK frequency supported by MAX1242AESA+T?

The MAX1242AESA+T supports SCLK frequencies up to 2.1MHz, as confirmed in the Timing Characteristics table and Figure 9. Each SCLK phase must be ≥200ns, but duty cycle is unrestricted. Exceeding 2.1MHz risks setup/hold violations and invalid data reads; operation below this limit (e.g., 1MHz) is fully functional and often preferred for noise immunity in noisy industrial environments.

Is MAX1242AESA+T pin-compatible with any 12-bit upgrade options?

Yes, the MAX1242AESA+T is pin-compatible with the MAX1240/MAX1241 - Maxim's 12-bit variants in the same SO-8 package - as explicitly stated in the Features section. This allows direct PCB replacement for higher-resolution requirements without layout changes, though firmware must handle 12-bit data format and revised timing margins may apply at maximum throughput.