Analog Devices Inc./Maxim Integrated MAX1245BEAP

Overview

MAX1245BEAP from Maxim Integrated is a 12-bit, 8-channel serial analog-to-digital converter (ADC) with integrated track/hold, SPI/QSPI/MICROWIRE-compatible 4-wire interface, and software-configurable unipolar/bipolar and single-ended/differential inputs. It operates from a single +2.375V to +3.3V supply, delivers 100ksps conversion rate, consumes only 0.8mA at full speed, and supports automatic power-down after conversion - enabling use in portable data loggers and battery-powered medical instruments.

For engineers reviewing the MAX1245BEAP datasheet, MAX1245BEAP pinout, MAX1245BEAP application, or MAX1245BEAP equivalent, this page provides verified technical context, real-world design meaning for key specs, validated SSOP-20 pin functions, confirmed alternative parts with documented differences, and precise guidance on low-power sampling, reference configuration, and serial interface timing compliance.

Technical Context

The MAX1245BEAP employs successive-approximation register (SAR) architecture with an internal 12-bit capacitive DAC and integrated track/hold circuitry. Its analog input stage supports pseudo-differential sampling via CH0–CH7 and COM pins, with configurable channel selection, polarity, and input mode controlled by an 8-bit serial control byte.

It features dual clock operation: external serial clock (100kHz–1.5MHz) drives both data transfer and conversion, while internal clock mode (1.5MHz or 225kHz, selectable via SHDN pin) decouples conversion timing from host interface speed - enabling flexible readout scheduling and reduced µP overhead.

Key Specifications

Pinout & Package

MAX1245BEAP is housed in a 20-pin SSOP package (30% smaller than 8-pin DIP), with exposed pad not electrically connected. Pin functions are validated per Maxim's official pin description and typical operating circuit.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 12-bit SAR ADC applications.

Compared with MAX147ACPP and ADS7822U, MAX1245BEAP uniquely combines ultra-low supply voltage (down to +2.375V), hardware shutdown (SHDN), true differential input capability, and external reference flexibility - making it optimal for energy-constrained, multi-sensor, and precision-bipolar measurement designs.

Availability

MAX1245BEAP is available at Aetrix Electronics and suitable for portable data logging, medical instrumentation, and battery-powered test equipment requiring stable component supply across extended temperature ranges (-40°C to +85°C) and long-term production continuity.

Supply support for MAX1245BEAP 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 high-performance analog, mixed-signal, and power management ICs for industrial, medical, and communications applications.

The MAX1245 product line delivers low-voltage, low-power, multi-channel SAR ADCs designed specifically for portable and battery-operated data acquisition systems where size, power, and precision are jointly constrained.

FAQ

What is the operating temperature range for the MAX1245BEAP?

The MAX1245BEAP is rated for -40°C to +85°C operation, as confirmed by its ordering code suffix "E" (MAX1245BEAP) and the Electrical Characteristics table specifying TA = TMIN to TMAX. This extended industrial temperature range ensures reliable performance in outdoor data loggers, automotive cabin sensors, and factory-floor instrumentation where ambient conditions vary widely. All key parameters - including INL (±1 LSB), gain error (±0.5 LSB), and supply current - are guaranteed across this full range.

Does the MAX1245BEAP support differential input mode, and how is it configured?

Yes, the MAX1245BEAP supports true differential input mode using four predefined channel pairs: CH0/CH1, CH2/CH3, CH4/CH5, and CH6/CH7. Configuration is done via the 8-bit serial control byte: set SGL/DIF bit (bit 2) to '0', then select the pair using SEL2–SEL0 bits (bits 6–4). In differential mode, the device samples the voltage difference |IN+ − IN−|, with IN− required to remain stable within ±0.5LSB relative to AGND - achieved by placing a 0.1µF capacitor from the selected IN− channel to AGND.

How does the SHDN pin function on the MAX1245BEAP, and what are its three states?

The SHDN pin on the MAX1245BEAP provides three distinct operational states: pulling SHDN low places the device in hardware shutdown (supply current ≤10µA); leaving SHDN open selects 1.5MHz internal clock frequency; pulling SHDN high selects 225kHz internal clock frequency. This three-level control enables flexible power management without firmware intervention - for example, tying SHDN to a GPIO allows rapid wake/sleep cycling, while leaving it open simplifies design when maximum conversion speed is needed.

What is the minimum acquisition time (tACQ) for the MAX1245BEAP, and why does it matter?

The MAX1245BEAP has a guaranteed minimum acquisition time (tACQ) of 2.0µs, defined as the time required for the internal track/hold circuit to settle to within 1 LSB after the last control bit is clocked in. This parameter directly impacts maximum usable source impedance: tACQ = 9 × (RS + RIN) × 16pF, where RIN = 12kΩ. For RS ≤1kΩ, tACQ remains near 2.0µs and AC performance is preserved; exceeding this limit causes gain/offset errors and degraded SINAD. Designers must ensure signal sources meet this constraint or add input filtering capacitance.

Can the MAX1245BEAP operate with an internal reference, or is an external VREF mandatory?

The MAX1245BEAP requires an external reference voltage applied to the VREF pin - it does not include an internal reference. The device accepts VREF from 1.0V to (VDD + 50mV), with 2.048V being the typical value used to achieve full 12-bit resolution and match standard reference ICs. VREF input current is 82–120µA, and input resistance is 18–25kΩ, so the reference source must be low-noise and capable of driving this load without droop. Using an inaccurate or noisy VREF directly degrades gain accuracy and SNR.