REF194ESZ

Overview

The REF194ESZ is a precision micropower low dropout voltage reference from the Analog Devices REF19x series, housed in an 8-lead SOIC package. It provides a fixed nominal output voltage of 4.50 V with an initial accuracy of ±0.04% (±2 mV maximum). The device features a maximum temperature coefficient of 5 ppm/°C and operates over an extended industrial temperature range of −40°C to +85°C. Electrical specifications include a maximum supply current of 45 μA, a sleep mode current of 15 μA, and a maximum load current capability of 30 mA.

Feature Summary

• Utilizes patented temperature drift curvature correction circuitry and laser-trimmed thin-film resistors for high stability.
• Features a dedicated SLEEP pin that reduces supply current to less than 15 μA when activated by TTL or CMOS logic levels.
• Incorporates internal short-circuit protection to safeguard the device during fault conditions.

Applications

• Portable instruments
• Analog-to-digital converters (ADCs) and digital-to-analog converters (DACs)
• Smart sensors
• Solar powered applications
• Loop-current-powered instruments

Procurement Notes

Verify the specific electrical grade (E or G) required for your application, as line regulation and load regulation specifications vary between grades. Confirm the package suffix matches the desired footprint, noting that the ESZ designation corresponds to the 8-lead SOIC variant. Ensure input voltage remains within the specified operating range relative to the output voltage to maintain proper dropout performance.

Selection Notes

Select this component when a stable 4.5 V reference is needed with minimal power consumption. The E grade offers superior line and load regulation compared to the G grade. Consider the low dropout characteristic for battery-operated systems where supply voltage may approach the output level. Verify thermal management requirements if operating at higher ambient temperatures or under heavy load currents.

Part Context

The REF194ESZ belongs to the REF19x family of precision band gap voltage references manufactured by Analog Devices Inc. This series is designed for applications requiring high accuracy and low power dissipation. The ESZ suffix specifically identifies the surface-mount 8-lead Small Outline Integrated Circuit (SOIC) package configuration, distinguishing it from through-hole or other surface-mount variants like TSSOP or PDIP.

Replacement Considerations

Other members of the REF19x series, such as the REF191, REF192, REF193, REF195, REF196, and REF198, offer different nominal output voltages but share similar architectural features and package options. When substituting, ensure the new part's output voltage meets system requirements and verify that the electrical grade specifications align with design tolerances.

FAQ

What is the function of Test Pins 1 and 5 on the REF194ESZ?

Test Pins 1 and 5 are reserved for factory in-package Zener zapping during manufacturing to trim the output voltage. Users should leave these pins unconnected.

How does the REF194ESZ achieve its low temperature coefficient?

It uses a patented temperature drift curvature correction circuit combined with laser trimming of highly stable thin-film resistors to minimize output variation over temperature changes.