Analog Devices Inc./Maxim Integrated MAX1294BCEI

Overview

MAX1294BCEI from Maxim Integrated is a 12-bit, 420ksps successive-approximation ADC with internal +2.5V reference, 6-channel single-ended / 3-channel pseudo-differential analog input multiplexer, and parallel 12-bit interface. It operates from a single +5V supply, consumes 2.8mA at full speed, and supports software-configurable unipolar/bipolar operation - ideal for portable data-acquisition systems requiring low power and compact layout.

For engineers reviewing the MAX1294BCEI datasheet, MAX1294BCEI pinout, MAX1294BCEI application, or MAX1294BCEI equivalent, this page delivers verified technical context, exact pin functions, real-world use cases in patient monitoring and energy management, and two validated alternative parts with documented functional differences.

Technical Context

The MAX1294BCEI implements a SAR architecture with integrated track/hold (6MHz full-power bandwidth), internal bandgap reference (+2.5V ±10mV, ±20ppm/°C TC), and configurable acquisition modes (internal or external). Its control byte (D7–D0) selects channel (A2–A0), input mode (SGL/DIF, UNI/BIP), acquisition method (ACQMOD), and power-down state (PD1/PD0).

It uses a 12-bit capacitive DAC and three-state parallel I/O (D0–D11, RD, WR, CS, INT, CLK) with 2µs wake-up from shutdown. The analog front-end supports ±0.5 LSB INL and ±0.2 LSB channel-to-channel offset matching over 0°C to +70°C, with input protection diodes enabling safe operation from (GND − 300mV) to (VDD + 300mV).

Key Specifications

Pinout & Package

MAX1294BCEI is housed in a 28-pin QSOP package (5.3mm × 10.2mm, 0.635mm pitch), optimized for high-density PCB layouts in space-constrained applications.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX1294ACEI, MAX1294BCEI trades ±0.5 LSB INL for lower cost while retaining identical timing, power, and feature set; versus ADS7822U, it provides 2.1× higher throughput, integrated reference, and direct µP compatibility - eliminating level-shifting and protocol translation overhead.

Availability

MAX1294BCEI is available at Aetrix Electronics and suitable for industrial process monitoring, patient vital sign acquisition, energy metering subsystems, and touchscreen controller interfaces requiring stable component supply across production lifecycles.

Supply support for MAX1294BCEI 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 MAX1294 series was designed for low-power, high-accuracy data acquisition in space- and energy-constrained systems - emphasizing integration (reference, T/H, MUX), µP-friendly parallel interface, and robust operation across commercial temperature ranges.

FAQ

What is the maximum sampling rate supported by the MAX1294BCEI?

The MAX1294BCEI supports a maximum sampling rate of 420ksps under standard operating conditions (VDD = +5V, fCLK = 7.6MHz, TA = 0°C to +70°C). This rate is achievable using either internal or external clock mode, with conversion time fixed at 3.6µs in internal clock mode and 13 clock cycles in external clock mode. At lower sampling rates, power consumption scales down to 400µA at 10ksps and 2µA in shutdown mode.

Does the MAX1294BCEI require an external reference voltage?

No, the MAX1294BCEI includes a factory-trimmed +2.5V internal reference with ±10mV initial accuracy and ±20ppm/°C temperature coefficient. The REF pin outputs this voltage, and REFADJ can be tied to VDD to disable the internal reference when using an external source. A 4.7µF capacitor is required at REF for stability when using the internal reference.

How many analog input channels does the MAX1294BCEI support?

The MAX1294BCEI supports six single-ended analog input channels (CH0–CH5) or three pseudo-differential channel pairs (CH0/CH1, CH2/CH3, CH4/CH5), selectable via the SGL/DIF bit in the control byte. This configuration is exclusive to the MAX1294 family; the MAX1296 variant supports only two single-ended or one pseudo-differential channel.

What power-down modes are available on the MAX1294BCEI?

The MAX1294BCEI offers two software-selectable power-down modes controlled by PD1/PD0 bits: Standby mode (IDD < 2µA) retains register state and reference bias, enabling 2µs wake-up; and Full Power-Down mode (IDD < 2µA) disables the reference and internal clock, requiring longer stabilization on wake-up. Both modes reduce supply current significantly between conversions.

Is the MAX1294BCEI pin-compatible with other devices in the MAX1294/MAX1296 family?

Yes, the MAX1294BCEI shares identical 28-pin QSOP pinout and electrical interface with MAX1294ACEI, MAX1294AEEI, and MAX1294BEEI. All variants maintain full pin compatibility across temperature grades (0°C to +70°C vs. −40°C to +85°C) and INL specifications (±0.5 LSB vs. ±1 LSB), enabling drop-in replacement within the same package footprint and PCB layout.