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Copyright © 2017, Texas Instruments Incorporated

15

REF2125

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SBAS798 – SEPTEMBER 2017

Product Folder Links: REF2125

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Copyright © 2017, Texas Instruments Incorporated

8 Detailed Description

8.1 Overview

The REF2125 is part of a family of low-noise, precision bandgap voltage references that are specifically designed

for excellent initial voltage accuracy and drift. The Functional Block Diagram is a simplified block diagram of the

REF2125 showing basic band-gap topology.

8.2 Functional Block Diagram

8.3 Feature Description

8.3.1 Supply Voltage

The REF2125 family of references features an extremely low dropout voltage. The REF2125 can be operated

with a supply of only 1 mV above the output voltage in an unloaded condition. For loaded conditions, a typical

dropout voltage versus load is shown on the front page. The REF2125 features a low quiescent current that is

extremely stable over changes in both temperature and supply. The typical room temperature quiescent current

is 72 μA, and the maximum quiescent current over temperature is just 95 μA. Supply voltages below the

specified levels can cause the REF2125 to momentarily draw currents greater than the typical quiescent current.

Use a power supply with a fast rising edge and low output impedance to easily prevent this issue.

8.3.2 Low Temperature Drift

The REF2125 is designed for minimal drift error, which is defined as the change in output voltage over

temperature. The drift is calculated using the box method, as described by Equation 3:

(3)

8.3.3 Load Current

are protected from short circuits by limiting the output short-circuit current to 18 mA. The device temperature

increases according to Equation 4:

where

•

•

•

•

(4)

The REF2125 maximum junction temperature must not exceed the absolute maximum rating of 150°C.