Analog Devices Inc./Maxim Integrated MAX6325CSA

Overview

MAX6325CSA 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, supplies ±15mA, and targets high-resolution ADC/DAC biasing in industrial instrumentation and ATE systems.

For engineers reviewing the MAX6325CSA datasheet, MAX6325CSA pinout, MAX6325CSA application, or MAX6325CSA equivalent, key selection criteria include its 2.5V output stability under load transients, optional NR-pin noise filtering, TRIM-pin adjustability, and SO-8 package compatibility with legacy 8-pin reference layouts.

Technical Context

The MAX6325CSA employs a buried-zener core with on-chip temperature compensation, achieving flat thermal drift without heater power. Its output stage supports bidirectional ±15mA current, enabling direct driving of DAC reference inputs or op-amp bias networks.

It features dedicated NR and TRIM pins: NR accepts a 1µF capacitor for wideband noise reduction, while TRIM allows ±1% output adjustment via external potentiometer without degrading temperature stability or long-term drift.

Key Specifications

Pinout & Package

MAX6325CSA is housed in an 8-pin SO (Small Outline) package, RoHS-compliant, with standard 1.27mm pitch and gull-wing leads. Pin 1 is marked by 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, the MAX6325CSA uniquely combines 8–36V wide-input operation, ±15mA drive, TRIM adjustability, and NR-based noise filtering in a single SO-8 package-making it optimal for industrial signal chains where supply flexibility and field calibration are required.

Availability

MAX6325CSA is available at Aetrix Electronics and suitable for high-resolution data acquisition, digital voltmeters, precision current sources, and ATE equipment requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for MAX6325CSA 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 high-performance analog and mixed-signal ICs for industrial, automotive, and communications markets, with emphasis on precision, reliability, and integration.

The MAX6325CSA belongs to Maxim's precision voltage reference product line, engineered specifically for metrology-grade stability and low-noise operation in 16-bit+ data conversion systems where thermal drift and broadband noise directly limit measurement fidelity.

FAQ

What is the maximum input voltage rating for the MAX6325CSA?

The MAX6325CSA has an absolute maximum input voltage rating of 40V on the IN pin. However, its specified operating input range is 8V to 36V. Operation above 36V risks exceeding safe power dissipation limits in the SO-8 package, especially at elevated ambient temperatures. For reliable long-term use, maintain VIN ≤36V and verify junction temperature remains below 125°C per derating curves in the datasheet.

Does the MAX6325CSA require an output capacitor to remain stable?

No, the MAX6325CSA is explicitly designed to be stable with any capacitive load from 0µF to 100µF, regardless of load current. Unlike many references that oscillate with large output capacitance, its internal compensation ensures unconditional stability-enabling direct connection to bulk decoupling caps without risk of ringing or instability during load transients.

Can the MAX6325CSA drive a 16-bit SAR ADC reference input directly?

Yes, the MAX6325CSA can directly drive most 16-bit SAR ADC reference inputs. Its ±15mA output capability exceeds typical ADC reference input currents (usually <100µA), and its 1.5µV_p-p low-frequency noise contributes less than 0.001 LSB error in a 2.5V full-scale 16-bit system. Ensure proper PCB layout: short traces, dedicated AGND plane, and local 100nF ceramic bypass at the ADC REF pin.

What is the purpose of the NR pin on the MAX6325CSA?

The NR (Noise Reduction) pin on the MAX6325CSA accepts an external 1µF capacitor to GND to suppress wideband output noise-particularly effective below 10kHz. Adding this capacitor reduces integrated 0.1Hz–10Hz noise by ~50%, improving SNR in precision measurement circuits. Leaving NR open retains full bandwidth but increases low-frequency noise; larger capacitors (>1µF) yield diminishing returns per datasheet characterization.

Is the MAX6325CSA pin-compatible with older Maxim references like the MAX6126?

No, the MAX6325CSA is not pin-compatible with the MAX6126. While both are SO-8 voltage references, their pin functions differ: MAX6126 uses Pin 3 as V_OUT, whereas MAX6325CSA uses Pin 6 as OUT and Pin 3 as NR. Additionally, MAX6325CSA reserves Pins 1/7/8 as internally connected (NC), unlike MAX6126's active pins. Direct substitution requires PCB layout revision to match the MAX6325CSA's unique pin mapping.