SBOU301A July   2023  – January 2024 LOG200

 

  1.   1
  2.   Description
  3.   Features
  4.   Applications
  5.   5
  6. 1Evaluation Module Overview
    1. 1.1 Introduction
    2. 1.2 Kit Contents
    3. 1.3 Specification
    4. 1.4 Device Information
  7. 2Hardware
    1. 2.1 Read this first: EVM Cleaning Guidelines
    2. 2.2 Input and Output Connections
    3. 2.3 Power Requirements
    4. 2.4 Jumper Information
    5. 2.5 Optional Photodiode Connections
  8. 3Hardware Design Files
    1. 3.1 Schematics
    2. 3.2 PCB Layout
    3. 3.3 Bill of Materials (BOM)
  9. 4Additional Information
    1. 4.1 Trademarks
  10. 5Revision History

2.2 Input and Output Connections

The current input signals for the logarithmic numerator, I1, and logarithmic denominator, I2, are provided through SMA connectors J4 and J6. These inputs are located at the left of the EVM. The input connections of the log amplifier have a series 10 kΩ resistors, R9 and R10. The logarithmic output connection is provided through SMA J5 and test point TP4 at the right side of the EVM.

The secondary op-amp inputs are accessible through SMA J14 and the output amplifier connection is provided through SMA connector J14, and test point TP16, located at the right side of the EVM. For a full schematic of the LOG200EVM, see Figure 4-1 and Figure 4-2.

Table 3-1 summarizes the input and output connectors and corresponding test points.

Table 2-1 LOG200EVM Input and Output Connections
DesignatorSignalConnector TypeDescription
J4I1_INSMACurrent input for logarithm numerator
J6I1_INSMACurrent input for logarithm denominator
J5OUT_ASMALogarithm function voltage output
J13IN_AMP_BSMASecondary op-amp voltage non-inverting and inverting input
J14OUT_BSMASecondary op-amp voltage output
J16REF_GNDBanana plugOptional ext voltage reference negative
J10Ext_RefABanana plugOptional ext Logarithm function voltage output reference
J12GNDBanana plugEVM PCB ground
TP1DBIASTest pointOptional ext Photodiode Vbias Cathode
TP4OUT_ATest pointLogarithm function voltage output

TP10

REFA

Test point

REFA: Log diff amp reference connection

TP7

REFA_sense

Test point

REFA: Log diff amp reference connection

through 100kΩ isolation resistor

TP16OUT_BTest pointSecondary op-amp voltage output
TP11VCMTest pointInput common-mode voltage
TP14REF1Test pointREF25: 2.5V reference output
TP15REF2Test pointREF165: 1.65V reference output
TP18REF_GNDTest pointVoltage reference negative
TP2, TP3, TP8, TP12, TP17GNDTest pointEVM PCB ground