Analog Devices Inc./Maxim Integrated MAX145BCPA

Overview

MAX145BCPA from Maxim Integrated is a 12-bit, pseudo-differential-input successive-approximation analog-to-digital converter (ADC) operating from +2.7V to +5.25V, delivering 108ksps sampling rate, ±1 LSB INL, and 7.4µs conversion time in an 8-pin plastic DIP package. It integrates on-chip track/hold, SPI/QSPI/MICROWIRE-compatible 3-wire serial interface, and automatic power-down mode (0.2µA), targeting low-power data acquisition in space-constrained industrial monitoring systems.

For engineers reviewing the MAX145BCPA datasheet, MAX145BCPA pinout, MAX145BCPA application, or MAX145BCPA equivalent, this page delivers verified technical context, exact pin functions, real-world use-value per application, and two confirmed alternative parts with documented functional and packaging differences - all grounded in Maxim's official datasheet Rev 2 (10/05).

Technical Context

The MAX145BCPA implements a SAR architecture with integrated track-and-hold, accepting pseudo-differential inputs (CH+, CH−) where only CH+ is sampled while CH− must remain stable within ±0.5 LSB relative to GND. Its internal clock enables flexible serial readout at SCLK frequencies from 0 to 5MHz, while external clock mode supports precise timing control at 100kHz–2.17MHz with 16-clock conversion cycles.

It features a 2.25MHz small-signal bandwidth and 1MHz full-power bandwidth, enabling undersampling of high-frequency transients. Input protection diodes clamp analog inputs to GND − 300mV and VDD + 300mV, but accurate conversion requires input signals to stay within GND − 50mV to VDD + 50mV.

Key Specifications

Pinout & Package

MAX145BCPA is housed in an 8-pin plastic DIP (dual in-line package) with 0.3-inch body width and through-hole mounting. Pin spacing is 0.1 inch (2.54 mm), compatible with standard PCB footprints and prototyping breadboards.

Key Features

Applications

Equivalent & Alternatives

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

Compared with ADS7816U and AD7490BRUZ, the MAX145BCPA uniquely balances ultra-low shutdown current (0.2µA), integrated track/hold, and DIP package for legacy-compatible prototyping - making it optimal for battery-powered field instruments where power, simplicity, and mechanical fit are co-prioritized.

Availability

MAX145BCPA is available at Aetrix Electronics and suitable for portable data logging, isolated data acquisition, and process-control monitoring requiring stable component supply across extended product lifecycles.

Supply support for MAX145BCPA 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 industrial, medical, and communications applications.

The MAX144/MAX145 family was engineered specifically for low-power, space-constrained data acquisition systems requiring 12-bit resolution, serial interfacing, and robust operation from a single supply - exemplified by the MAX145BCPA's DIP-packaged pseudo-differential ADC implementation.

FAQ

What is the maximum sampling rate of the MAX145BCPA, and under what conditions is it achieved?

The MAX145BCPA achieves a maximum sampling rate of 108ksps when operated with an external SCLK frequency of 2.17MHz in external clock mode, using 16 clock cycles per conversion cycle. This rate is guaranteed across the full operating temperature range (0°C to +70°C) and supply voltage range (+2.7V to +5.25V), as specified in the Electrical Characteristics table of the MAX145BCPA datasheet.

Does the MAX145BCPA require an external reference, and what are its key electrical requirements?

Yes, the MAX145BCPA requires an external reference applied to the REF pin. The reference must deliver ≥250µA DC load current during conversion, exhibit ≤10Ω output impedance, and be bypassed with a 0.1µF capacitor. Its voltage sets the full-scale input range (0 to VREF), and it must remain stable within ±1 LSB during wake-up to ensure 2.5µs wake-up time - otherwise, additional stabilization delay is needed before conversion.

How does the pseudo-differential input architecture of the MAX145BCPA differ from true differential input, and what design considerations apply?

The MAX145BCPA's pseudo-differential input samples only CH+ while referencing CH−, which must remain stable within ±0.5 LSB relative to GND during acquisition. Unlike true differential ADCs, it does not reject common-mode voltage swings on CH−. To meet this requirement, a 0.1µF capacitor is recommended from CH− to GND, and source impedance on CH− must be minimized to prevent droop-induced errors.

What are the power consumption characteristics of the MAX145BCPA at different sampling rates?

At 108ksps and +3V supply, the MAX145BCPA draws 0.9mA (2.7mW). At 10ksps, current drops to 100µA; at 1ksps, it falls to 10µA; and in power-down mode (CS/SHDN = VDD), it consumes just 0.2µA. These values are measured per the datasheet's Electrical Characteristics table and reflect the device's adaptive power management without external control circuitry.

Which serial interface standards is the MAX145BCPA compatible with, and what configuration is required?

The MAX145BCPA is fully compatible with SPI, QSPI, and MICROWIRE serial interfaces. It requires CPOL = 0 and CPHA = 0 configuration. Data is MSB-first, with three leading ones followed by channel ID and 12 data bits. DOUT transitions on the falling edge of SCLK and is latched by the host on the rising edge - matching standard SPI master timing without modification.