REF194ESZ-REEL

Overview

The REF194ESZ-REEL 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 ±2 mV maximum at 25°C. The device features a maximum temperature coefficient of 5 ppm/°C and a supply current of 45 μA maximum. It supports a load current up to 30 mA and includes short-circuit protection. The input voltage range spans from 4.75 V to 15 V for E grade devices.

Feature Summary

• Utilizes patented temperature drift curvature correction circuitry and laser-trimmed thin-film resistors for high stability.
• Operates with low dropout voltage, requiring minimal headroom above the output voltage.
• Includes a dedicated sleep mode pin that reduces supply current significantly when activated by logic levels.

Applications

• Portable instruments
• ADCs and 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 and load regulation specifications vary between grades. Confirm that the REEL suffix matches your automated assembly needs. Ensure the operating temperature range aligns with your system requirements, noting that extended industrial ranges are standard while automotive-grade performance may require characterization beyond standard limits.

Selection Notes

Select this component when a stable 4.5 V reference is needed with low power consumption. Consider the E grade for tighter line and load regulation specifications compared to the G grade. Evaluate the need for the sleep function if power conservation during idle states is critical. Ensure the input voltage stays within the specified minimum dropout requirements to maintain regulation.

Part Context

The REF194ESZ-REEL belongs to the REF19x family of precision band gap voltage references. This series offers various fixed output voltages including 2.048 V, 2.5 V, 3.0 V, 3.3 V, 4.096 V, and 5.0 V. All variants share similar architectural features such as micropower operation and low dropout characteristics, differing primarily in their nominal output voltage and specific electrical grade tolerances.

Replacement Considerations

Other members of the REF19x series, such as REF191, REF192, REF193, REF195, REF196, and REF198, offer different nominal output voltages but share the same package and general functionality. Direct substitution requires matching the required output voltage level. Verify that the alternative part's electrical grade meets the line and load regulation requirements of the design.

FAQ

What is the purpose of Test Pins 1 and 5 on the REF194?

Test Pins 1 and 5 are reserved for in-package Zener zap trimming used during manufacturing to achieve high accuracy. They should be left unconnected by the user.

How does the sleep mode function operate?

Sleep mode is enabled by applying a low TTL or CMOS level to the SLEEP pin. This turns off the output and reduces the supply current to less than 15 μA.