10 Detailed Description

10.1 Overview

The REF34-Q1 devices are a family of low-noise, precision bandgap voltage references that are specifically

designed for excellent initial voltage accuracy and drift. The Section 10.2 is a simplified block diagram of the

REF34-Q1 showing basic band-gap topology.

10.2 Functional Block Diagram

Bandgap

core

Buffer

Digital

Enable

Blocks

Inrush

EN

IN

GNDF

OUTS

Current

Vdd

GNDS

OUTF

Limit

10.3 Feature Description

10.3.1 Supply Voltage

The REF34-Q1 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 REF34-Q1 family 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 REF34-Q1 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.

10.3.2 Low Temperature Drift

The REF34-Q1 devices are 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:

REF(MAX)

REF(MIN)

6

REF

V

V

Drift =

10

V

Temperature Range

·

§

u

¸

¨

u

©

¹

(3)

REF34-Q1

SBAS901C – JULY 2018 – REVISED OCTOBER 2020

www.ti.com

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