SBOU252 August   2021 OPA4991 , OPA4991-Q1 , TLV9004 , TLV9004-Q1

 

  1.   Trademarks
  2. 1Introduction
  3. 2DYY-AMP-EVM Kit Contents
  4. 3Circuit Configurations
  5. 4Schematic and PCB Layout
    1. 4.1 Schematic
    2. 4.2 Difference Amplifier
    3. 4.3 Non-inverting Amplifier
    4. 4.4 Inverting Amplifier
    5. 4.5 PCB Layout
  6. 5Connections
    1. 5.1 Power
    2. 5.2 Input Connections
    3. 5.3 Output Connections
    4. 5.4 Reference Voltage Connections
  7. 6Bill of Materials (BOM)
  8. 7References

4.4 Inverting Amplifier

Figure 4-7 shows the schematic for the inverting amplifier circuit configuration. To configure the EVM in an inverting configuration short RINP using a 0-Ω resistor or solder bridge, leave RVREF and CVREF unpopulated, and apply the desired common mode voltage(VCM) to the input connection, IN+. The input signal is applied using the input connection IN–.

Figure 4-7 Inverting Amplifier Schematic

Table 4-4 Inverting Amplifier Components
CH RINM RF

CF

 RINP

RIso

CL
1 R1 R2

C3

 R3

R5

C5
2 R7 R8

C6

 R9

R11

C8
3 R13 R14

C9

 R15

R17

C11
4 R19 R20

C12

 R21

R23

C14

Equation 6 displays the DC transfer function for channel 1 of the inverting amplifier circuit configuration. Note, Input signals IN+ and IN- are altered to INP and INM respectively in the transfer function for simplicity of the equation.

Equation 6. OUT = - R F R INM × IN M + 1 + R F R INM × IN P

Capacitor CF provides the option to filter the output. The cutoff frequency, fc, of the filter can be calculated using Equation 7.

Equation 7. f c = 1 2 × π × R F × C F

Resistor Riso, and capacitor CL provide the option to create a RC filter, or test output loads for the amplifier. When not applicable, use a zero ohm resistor for Riso and do not populate CL.

Figure 4-8 shows the DYY-AMP-EVM populated with the required components to configure channel 1 as an inverting amplifier with no load.

Figure 4-8 Inverting Amplifier Configured on DYY-AMP-EVM, Channel 1