J

A

D

JA

T

T

P

R

T

u

REF(MAX)

REF(MIN)

6

REF

V

V

Drift =

10

V

Temperature Range

·

§

u

¸

¨

u

©

¹

Bandgap

core

Buffer

Digital

Enable

Blocks

Inrush

EN

IN

GNDF

OUTS

Current

Vdd

GNDS

OUTF

Limit

13

REF3425-EP, REF3440-EP

www.ti.com

SBAS942 – DECEMBER 2018

Product Folder Links: REF3425-EP REF3440-EP

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Copyright © 2018, Texas Instruments Incorporated

9 Detailed Description

9.1 Overview

The REF34xx-EP is 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

REF34xx-EP showing basic band-gap topology.

9.2 Functional Block Diagram

9.3 Feature Description

9.3.1 Supply Voltage

The REF34xx-EP family of references features an extremely low dropout voltage. For loaded conditions, a typical

dropout voltage versus load is shown on the front page. The REF34xx-EP 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 REF34xx-EP 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.

9.3.2 Low Temperature Drift

The REF34xx-EP 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 2:

(2)

9.3.3 Load Current

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

increases according to Equation 3:

where

•

•

•

•

(3)

The REF34xx-EP maximum junction temperature must not exceed the absolute maximum rating of 150°C.