REF54

GND

OUTF

VIN

EN

VIN

CL

CIN

VREFP

High-pass Filter

FC = 0.07 Hz

Low Noise

Preamplifier

G = 1000

2

nd Order

Low-pass Filter

FC = 10 Hz

G = 1

2

nd Order

Low-pass Filter

FC = 10 Hz

G = 10

2

nd Order

High-pass Filter

FC = 0.1 Hz

G = 10

Scope

NR

CNR

Figure 7-3. 1/f Noise Test Setup

Figure 7-4 shows typical distribution of flicker noise for multiple devices where more than 1000 samples have

been captured for each device.

Flicker Noise (ppmp-p)

0

20

40

60

80

100

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

Figure 7-4. 0.1-Hz to 10-Hz Voltage Noise Distribution

Noise sensitive designs prefer the lowest 1/f noise for the highest precision measurements. REF54 offers NR pin

which creates a low pass filters on the band gap. Connecting 100 μF capacitor on NR pin removes flicker noise

from the band gap refernce as shown in Figure 7-5

REF54

SNVSCN7 – NOVEMBER 2023

www.ti.com

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