10.3 Typical Application: Precision Power Supply and Reference

Figure 10-2 shows the basic configuration for the REF35-Q1 device as precision power supply to ADS7038-Q1

data converter which uses its power supply AVDD as reference. Connect bypass capacitors according to the

guidelines in Section 10.3.2.2 section.

ADS7038-Q1

GND

REF35500-Q1

-

+

1

2

3

4

6

5

10 μF

GND

1 μF

AVDD

GND

+6 V

Input

0 V to 5 V

0.1 μF

0.1 μF

Figure 10-2. Basic Reference Connection

10.3.1 Design Requirements

A detailed design procedure is described based on a design example. For this design example, use the

parameters listed in Table 10-1 as the input parameters.

Table 10-1. Design Example Parameters

DESIGN PARAMETER

VALUE

Input voltage range VIN

0 V - 5 V

Output resolution

12-bit

REF input capacitor

1 µF

REF output capacitor

10 µF

10.3.2 Detailed Design Procedure

10.3.2.1 Selection of Reference

The REF35500-Q1 reference is selected for this design. The REF35500-Q1 device operates of very low

quiescent current while offering ±0.05 % initial accuracy and very low noise. These parameters help improve

system accuracy as compared to external LDO based power supply. The 5 V reference voltage supports the 0 V

to 5 V input range specification.

10.3.2.2 Input and Output Capacitors

A 1 μF to 10 μF electrolytic or ceramic capacitor can be connected to the input to improve transient response in

applications where the supply voltage may fluctuate.

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REF35-Q1

SNAS845 – AUGUST 2023

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Product Folder Links: REF35-Q1