Time (1sec/div)

GND

Figure 8-8. 0.1 Hz to 10 Hz Voltage Noise

Figure 8-9 shows the typical 1/f noise (0.1 Hz to 10 Hz) distribution across various load conditions. The

REF35-Q1 device also offers noise reduction functionality by adding an optional capacitor between NR (pin 5)

and ground pins.

Figure 8-10 shows the typical 1/f noise (0.1 Hz to 10 Hz) distribution across REF35-Q1 devices with various

capacitance between NR pin and GND.

Noise Bin (ppmp-p)

0

16

32

48

64

80

1.2

2

2.8 3.6 4.4 5.2

6

6.8 7.6 8.4 9.2 10 10.8

IL = 0mA

IL = 1mA

IL = 10mA

Figure 8-9. 0.1 Hz to 10 Hz Noise Distribution vs

Load Conditions

Noise Bin (ppmp-p)

0

8

16

24

32

40

1.2

2

2.8 3.6 4.4 5.2

6

6.8 7.6 8.4 9.2 10 10.8

CNR = Open

CNR = 1uF

CNR = 10uF

Figure 8-10. 0.1 Hz to 10 Hz Noise Distribution vs

NR Capacitance

8.5.2 Broadband Noise

Broadband noise is a noise that appears at higher frequency compared to 1/f noise. The broadband noise is

measured by high-pass filtering the output of the reference device, followed by a gain stage and measuring the

result on a spectrum analyzer as shown in Figure 8-11

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REF35-Q1

SNAS845 – AUGUST 2023

Copyright © 2023 Texas Instruments Incorporated

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Product Folder Links: REF35-Q1