Analog Devices Inc./Maxim Integrated MAX147CEAP+

Overview

MAX147CEAP+ from Maxim Integrated is a 12-bit, 8-channel serial analog-to-digital converter (ADC) with software-configurable unipolar/bipolar and single-ended/differential inputs, operating from a single +2.7V to +5.25V supply. It integrates an 8-channel multiplexer, high-bandwidth track/hold, and SPI/QSPI/MICROWIRE-compatible 4-wire serial interface. Its external reference architecture supports precision measurement in battery-powered data loggers and portable medical instruments.

For engineers reviewing the MAX147CEAP+ datasheet, MAX147CEAP+ pinout, MAX147CEAP+ application, or MAX147CEAP+ equivalent, key selection considerations include its 133ksps conversion rate, ±0.5 LSB INL, 73dB SINAD at 10kHz, 1.2mA active current at 3V, and requirement for external 2.5V reference - critical for low-power, high-accuracy signal acquisition systems.

Technical Context

The MAX147CEAP+ employs successive-approximation (SAR) architecture with integrated track/hold, supporting both internal clock (for fixed-rate sampling) and external serial clock (for synchronized system timing). Its pseudo-differential input structure enables flexible channel pairing (CH0/CH1, CH2/CH3, etc.) while maintaining ±0.5 LSB COM stability during conversion.

It features a three-level SHDN pin for full power-down (1µA), fast power-down (54µA at 1ksps), or operational mode, with automatic wake-up on serial interface access. The reference buffer is disabled by tying REFADJ to VDD, requiring external 2.5V reference applied directly to VREF - distinguishing it from the MAX146's internal reference variant.

Key Specifications

Pinout & Package

MAX147CEAP+ is housed in a 20-pin SSOP (Shrink Small Outline Package) with 0.65 mm lead pitch, optimized for compact PCB layouts in space-constrained portable equipment.

Key Features

Applications

Equivalent & Alternatives

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

Compared with ADS7822U and MAX11131ETE+, the MAX147CEAP+ uniquely balances wide supply range, external reference dependency, bipolar capability, and ultra-low shutdown current - making it optimal for portable, calibration-critical, multi-sensor systems requiring long battery life and field-referenced accuracy.

Availability

MAX147CEAP+ is available at Aetrix Electronics and suitable for portable data logging, medical instrumentation, and battery-powered test equipment requiring stable component supply, extended temperature validation (0°C to +70°C), and long-term production continuity.

Supply support for MAX147CEAP+ 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 MAX146/MAX147 family was designed for low-power, high-accuracy data acquisition in portable and battery-operated systems - emphasizing flexible input configuration, minimal external components, and seamless microcontroller integration.

FAQ

What is the reference configuration requirement for MAX147CEAP+?

The MAX147CEAP+ requires an external 2.500 V reference applied directly to the VREF pin. Its internal reference buffer must be disabled by connecting REFADJ to VDD. This architecture avoids internal reference drift and enables use of precision external references like the MAX6126AASA+, ensuring system-level accuracy remains stable over temperature and time - a critical distinction from the MAX146 variant.

Does MAX147CEAP+ support differential input mode, and how is it configured?

Yes, MAX147CEAP+ supports pseudo-differential input mode across four channel pairs: CH0/CH1, CH2/CH3, CH4/CH5, and CH6/CH7. Configuration is performed via the 8-bit control byte written to DIN: setting SGL/DIF = 0 and selecting appropriate SEL2–SEL0 bits. In this mode, the negative input (IN−) must remain stable to ±0.5 LSB relative to AGND - typically achieved with a 0.1 µF capacitor from the selected IN− channel to AGND.

What is the minimum acquisition time for MAX147CEAP+, and how does source impedance affect it?

The guaranteed minimum acquisition time (tACQ) for MAX147CEAP+ is 1.5 µs. However, actual acquisition time scales with source impedance: tACQ = 9 × (RS + 9 kΩ) × 16 pF. For RS ≤ 1 kΩ, tACQ remains near 1.5 µs with no AC performance degradation. Higher impedances require longer acquisition intervals or local 0.01 µF bypass capacitors to maintain 12-bit accuracy - a key design constraint for high-impedance sensor interfaces.

How does the SHDN pin function on MAX147CEAP+, and what are its valid states?

The SHDN pin on MAX147CEAP+ operates in three distinct states: pulled low (0V) enables full power-down (1 µA supply current); left floating (high-impedance) configures external compensation mode (REFADJ active); and pulled high (VDD) selects internal compensation mode (not applicable to MAX147, as its reference buffer is disabled). Unlike the MAX146, MAX147CEAP+ does not utilize internal compensation - pulling SHDN high has no functional effect on reference operation.

Can MAX147CEAP+ interface directly with TMS320-series DSPs, and what signal enables synchronization?

Yes, MAX147CEAP+ interfaces directly with TMS320-family DSPs using its dedicated SSTRB (serial strobe) output. In external clock mode, SSTRB pulses high for exactly one SCLK period immediately before the MSB of the 12-bit conversion result is clocked out on DOUT. This precise timing signal allows the DSP to trigger DMA capture or interrupt service routines without additional timing logic - a feature explicitly designed for real-time signal processing systems.