Analog Devices Inc./Maxim Integrated MAX147BCAP

Overview

MAX147BCAP from Maxim Integrated is a 12-bit, 8-channel serial analog-to-digital converter (ADC) with integrated track/hold, software-configurable unipolar/bipolar and single-ended/differential inputs, and SPI/QSPI/MICROWIRE-compatible 4-wire serial interface. It operates from a single +2.7V to +5.25V supply, requires an external reference, and delivers 133ksps conversion rate with ±0.5 LSB INL and 73dB SINAD - used in portable data loggers and battery-powered medical instruments.

For engineers reviewing the MAX147BCAP datasheet, MAX147BCAP pinout, MAX147BCAP application, or MAX147BCAP equivalent, key selection considerations include its 20-pin SSOP package, external reference dependency, 1µA power-down current, and compatibility with TMS320-family DSPs via SSTRB strobe output.

Technical Context

The MAX147BCAP implements successive-approximation architecture with a dedicated track/hold circuit that acquires input signals within 1.5µs. Its analog multiplexer supports eight single-ended or four pseudo-differential input pairs (CH0/CH1 through CH6/CH7), with COM pin serving as common-mode reference.

Conversion timing is governed by either internal clock or externally supplied SCLK (up to 2.0MHz); control byte (8-bit) configures channel, polarity, input mode, and clock/power-down state. The SSTRB output pulses synchronously to indicate conversion start/end in external-clock mode or active conversion window in internal-clock mode.

Key Specifications

Pinout & Package

MAX147BCAP is housed in a 20-pin SSOP (Shrink Small Outline Package) with 0.65mm 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 MAX147BCAP uniquely combines 8-channel multiplexing, TMS320-compatible SSTRB strobe, and external reference flexibility in a 20-pin SSOP - making it optimal for portable, multi-sensor systems requiring deterministic timing and low standby power.

Availability

MAX147BCAP is available at Aetrix Electronics and suitable for portable data logging, battery-powered medical instruments, and industrial process monitoring requiring stable component supply and long-term production support.

Supply support for MAX147BCAP 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) designs precision analog, mixed-signal, and power-management ICs for demanding industrial, medical, and communications applications.

The MAX146/MAX147 product line targets low-power, multi-channel data acquisition in space- and energy-constrained systems - emphasizing software configurability, minimal external components, and robust serial interfacing.

FAQ

What is the reference configuration requirement for MAX147BCAP?

The MAX147BCAP requires an external 2.500V reference applied to the VREF pin; it does not include an internal reference buffer like the MAX146. To disable the reference buffer, REFADJ must be tied to VDD. This configuration ensures stable, high-accuracy conversions across the full +2.7V to +5.25V supply range. MAX147BCAP performance is specified with VREF = 2.500V.

Does MAX147BCAP support differential input measurements?

Yes, MAX147BCAP supports pseudo-differential measurements across four channel pairs: CH0/CH1, CH2/CH3, CH4/CH5, and CH6/CH7. In differential mode, the device samples the voltage difference between selected IN+ and IN− inputs, with COM serving as the reference point for single-ended operation. Configuration is done via the 8-bit control byte's SGL/DIF and SEL bits.

What is the function of the SSTRB pin on MAX147BCAP?

The SSTRB (Serial Strobe) pin on MAX147BCAP provides timing synchronization for external processors - particularly TMS320-family DSPs. In external clock mode, it pulses high for one SCLK period before the MSB of the conversion result is clocked out on DOUT. This allows deterministic sampling alignment without CPU polling, reducing interrupt latency and improving real-time system determinism in MAX147BCAP-based designs.

Can MAX147BCAP operate from a 3.3V supply?

Yes, MAX147BCAP is fully specified for operation from +2.7V to +5.25V, including standard 3.3V logic supplies. At VDD = 3.3V, it maintains 133ksps sampling rate, ±0.5 LSB INL, and 1.2mA active supply current. The digital interface remains compatible with 3.3V SPI peripherals, and the analog input range scales linearly with VREF (e.g., 0V to 2.5V for unipolar mode).

How does the SHDN pin function on MAX147BCAP?

The SHDN pin on MAX147BCAP provides three-level control: pulled low → full shutdown (1µA current); left floating → external compensation mode (REFADJ active); pulled high → internal compensation mode (not used for MAX147, as it lacks internal reference). Unlike the MAX146, MAX147BCAP does not use SHDN to enable/disable the reference buffer - REFADJ must be tied to VDD to disable it.