SBAU373A April   2021  – June 2022

 

  1.   Abstract
  2.   Trademarks
  3. 1Introduction
    1. 1.1 Features
  4. 2Analog Interface
    1. 2.1 Analog Input
    2. 2.2 Shutdown
    3. 2.3 Analog Output
  5. 3Power Supplies
    1. 3.1 VDD1 Input
    2. 3.2 VDD2 Input
  6. 4EVM Operation
    1. 4.1 Analog Input and VDD1 Power: J3 and J1
    2. 4.2 Analog Outputs and VDD2 Power: J4 and J2
    3. 4.3 Device Operation
  7. 5Board Layout
  8. 6Bill of Materials and Schematics
    1. 6.1 Bill of Materials
    2. 6.2 Schematics
  9. 7Related Documentation
  10. 8Revision History

2.3 Analog Output

The analog output from the EVM is a fully-differential signal centered at 1.44 V. Figure 2-2 shows that the differential output of U1 is available on the two screw terminals of J4. OUTP is available at J4.3 and swings from 0.5 V to 2.5 V when a –250-mV to 250-mV signal is applied to the input of the AMC1400 or from 1.44 V to 2.5 V when a 0-V to 2-V signal is applied to the input of the AMC1411. OUTN is available at J4.2 and swings from 2.5 V to 0.5 V when a –250-mV to 250-mV signal is applied to the input of the AMC1400 or from 1.44 V to 0.5 V when a 0-V to 2-V signal is applied to the input of the AMC1411. The pads of R2, R4, C9, C7, and C12 allow users to install their own output filtering. Table 2-1 lists a few example filters. Common-mode filter capacitors C7 and C12 are recommended to be at least 20 times less than the differential filter capacitor.

Table 2-1 Analog Output Filter Examples
Cutoff Frequency Resistance Differential Capacitor
100 kHz R2 = R4 = 100 Ω C9 = 8.2 nF
300 kHz R2 = R4 = 100 Ω C9 = 2.7 nF
600 kHz R2 = R4 = 100 Ω C9 = 1.3 nF

Use the differential output if the application allows. If a single-ended output is desired, consult the Interfacing a Differential-Output (Isolated) Amplifier to a Single-Ended Input ADC application brief for help with designing the differential to single-ended circuit.

Figure 2-2 AMC1400EVM Schematic: Analog Output Section