UM-GP-005

Advanced Analog GreenPAK Evaluation Board

User Manual

Revision 1.2

21-Mar-2022

CFR0012

14 of 21

© 2022 Renesas Electronics Corporation

5

Application Examples

The key features of the SLG47004 can be combined on a system-level to implement a variety of

different applications. A few examples include instrumentation amplifiers, active filtering, digital

potentiometers, voltage regulation, and variable current sources.

The sections below provide EVB configurations for a few of the examples provided above. The

examples below can be tailored for specific applications by modifying the layout of the schematic or by

selecting different component values.

5.1

Instrumentation Amplifier

The SLG47004 can be configured as an InAmp with trimmable gain and offset voltage. One

configuration of the standard 3-OpAmp topology is implemented in

the EVB’s layout as shown below.

Figure 5: Instrumentation Amplifier Schematic

This Instrumentation Amplifier configuration combines the OpAmp and the digital rheostat structures

into one system. RH0 impacts the differential gain, while RH1 modifies the reference voltage. The

equations below can be used to calculate the output voltage of the overall system.

������������������������ = (������������������+ − ������������������−) ∗ ������������������������ + ������������������������

������������������������ = 1 +

2 ∗ ������������

������������

… ������ℎ������������������ ������������ = 100 ������Ω, ������������ = 43������Ω + (������������0 || 10 ������Ω)

������������������������ =

������������1

������������1 + 47 ������Ω

The InAmp in Figure 5 is designed to introduce a differential gain of 5V/V. RH0 is placed in parallel

with the 10 k

Ω resistor such that the equivalent impedance can be trimmed to accommodate for circuit

tolerance variations throughout the system (IE: Resistor Tolerances, Input Offset Voltage, and others).

Table 8 shows the components used to build this example. Note that the component selection and

schematic layout can be modified to achieve different amounts of gain and offset.