REF191ES

Overview

The REF191ESZ is a precision micropower voltage reference from the Analog Devices REF19x series, housed in an 8-lead SOIC package. It provides a nominal output voltage of 2.048 V with an initial accuracy of ±2 mV maximum. The device features a low temperature coefficient of 5 ppm/°C and operates over an extended industrial temperature range of −40°C to +85°C. It consumes a maximum supply current of 45 μA, which reduces to 15 μA in sleep mode. The unit supports a maximum load current of 30 mA and includes short-circuit protection.

Feature Summary

• Utilizes patented temperature drift curvature correction circuitry and laser-trimmed thin-film resistors for high stability.
• Features a dedicated SLEEP pin that allows the device to enter a low-power state by applying a TTL or CMOS logic level.
• Incorporates internal short-circuit protection to limit supply current during output faults.

Applications

• Portable instrumentation
• Analog-to-digital (ADC) and digital-to-analog (DAC) converters
• Smart sensors
• Solar powered applications
• Loop-current-powered instruments

Procurement Notes

Verify the specific electrical grade suffix (E, F, or G) required for your application's accuracy specifications before ordering. Confirm the package type matches the design requirements, as the REF191ESZ denotes the SOIC variant. Ensure the input voltage remains within the specified dropout limits relative to the 2.048 V output. Check for any recent Product Change Notifications regarding manufacturing site updates.

Selection Notes

Select this component when a stable 2.048 V reference is needed with minimal power consumption. The E-grade offers the highest accuracy and lowest temperature coefficient, while F and G grades provide relaxed specifications. Consider the low dropout characteristic if the supply voltage is close to the output voltage. Verify that the 1 μF output capacitor requirement is met for proper operation.

Part Context

The REF191ESZ belongs to the broader REF19x family of precision band gap voltage references. This series includes various fixed output voltages such as 2.5 V, 3.0 V, and 5.0 V. All members share common architectural features like micropower operation and low dropout capabilities. The 'ES' suffix specifically identifies the 8-lead narrow-body SOIC package option available for the REF191 model.

Replacement Considerations

Direct replacements must match the 2.048 V output and 8-SOIC package. Other REF19x models are not electrically compatible due to different voltage outputs. Cross-brand alternatives require verification of pinout compatibility and thermal performance.

FAQ

What is the function of Test Pins 1 and 5?

Test Pins 1 and 5 are factory test points used for Zener zapping during the trimming process. They should be left unconnected by the user to achieve the highest level of accuracy at the output.

How does the device operate in Sleep Mode?

Sleep mode is enabled by applying a low TTL or CMOS level to the SLEEP pin. In this state, the output is turned off, and the supply current is reduced to less than 15 μA.