Analog Devices Inc./Maxim Integrated MAX6325CPA

Overview

MAX6325CPA from Maxim Integrated is a precision 2.5V voltage reference IC using buried-zener technology, delivering ±0.02% initial accuracy, 0.5ppm/°C typical temperature coefficient, and 1.5µV_p-p (0.1Hz–10Hz) output noise. It operates from 8V to 36V input, sources/sinks ±15mA, and is optimized for high-resolution ADC/DAC systems up to 16 bits.

For engineers reviewing the MAX6325CPA datasheet, MAX6325CPA pinout, MAX6325CPA application, or MAX6325CPA equivalent, key selection criteria include its 2.5V fixed output, 8-pin PDIP package, low-noise performance, external trim capability, and compatibility with capacitive loads up to 100µF without instability.

Technical Context

The MAX6325CPA employs a buried-zener core with proprietary low-power temperature compensation, achieving near-zero curvature over 0°C to +70°C. Its output is internally buffered and stable across full load current range (±15mA) and input voltage (8V–36V), with guaranteed line regulation of 10ppm/V and load regulation of 5ppm/mA.

It supports optional external trimming via the TRIM pin (±1% adjustment) and wideband noise reduction via the NR pin (1µF capacitor reduces 0.1Hz–10Hz noise by ~30%). Output impedance remains below 1Ω up to 10kHz, enabling fast transient response (<8µs settling to ±0.01%).

Key Specifications

Pinout & Package

MAX6325CPA is housed in an 8-pin plastic DIP (dual in-line package) with 0.3-inch body width and through-hole mounting. Pin 1 is marked with a notch or dot; pins 1, 7, and 8 are internally connected and must remain unconnected in PCB layout.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar precision voltage reference applications.

Compared with REF5025IDR and ADR441BRZ, MAX6325CPA offers superior tempco (1.0ppm/°C max) and wider input range (8–36V), making it uniquely suited for industrial 24V-powered instrumentation where thermal stability and rail flexibility are primary constraints.

Availability

MAX6325CPA is available at Aetrix Electronics and suitable for high-resolution analog-to-digital converters, precision current sources, digital voltmeters, ATE equipment, and high-accuracy industrial control systems requiring stable component supply across extended temperature ranges and long product lifecycles.

Supply support for MAX6325CPA 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 U.S.-based semiconductor company specializing in high-performance analog, mixed-signal, and power-management ICs for industrial, medical, and communications applications.

The MAX6325CPA belongs to Maxim's precision voltage reference product line, designed specifically for metrology-grade instrumentation, automated test equipment, and high-end data acquisition systems demanding laboratory-level accuracy and stability.

FAQ

What is the maximum input voltage rating for MAX6325CPA?

The MAX6325CPA has an absolute maximum input voltage rating of 40V on the IN pin. However, its specified operational input range is 8V to 36V. Operating above 36V may cause excessive power dissipation or thermal stress, while voltages below 8V fail to maintain regulation. Always use a 2.2µF bypass capacitor between IN and GND to ensure stable operation under transient conditions.

Can MAX6325CPA drive a 100µF output capacitor without instability?

Yes, the MAX6325CPA is explicitly characterized and guaranteed stable with output capacitive loads from 0µF to 100µF across its full operating temperature and load-current range. This eliminates the need for series isolation resistors in applications like motor-drive feedback circuits or industrial PLC analog outputs where large bulk capacitance is used for noise suppression.

Does MAX6325CPA require external components for basic operation?

For basic operation, MAX6325CPA requires only two external components: a 2.2µF capacitor from IN to GND for input bypassing, and a 0.1µF capacitor from OUT to GND for high-frequency noise filtering. The NR and TRIM pins may be left open if noise reduction or output trimming is not needed - no pull-up/down resistors are required.

What is the purpose of the I.C. pins (1, 7, 8) on MAX6325CPA?

Pins 1, 7, and 8 on the MAX6325CPA are internally connected (I.C.) and serve no external function. They must remain unconnected in the PCB layout - routing traces to or from these pins can introduce parasitic coupling, degrade noise performance, or cause unpredictable behavior. The device functions correctly with these pins floating or isolated.

How does the TRIM pin affect temperature coefficient in MAX6325CPA?

The TRIM pin on MAX6325CPA allows ±1% output adjustment via an external voltage divider, and crucially, this trimming does not degrade the device's temperature coefficient - the 1.0ppm/°C max spec is maintained across the full trim range. This is confirmed in the datasheet's "Detailed Description" section, enabling system-level calibration without sacrificing thermal stability.