SBOU327 December   2025 OPA598

 

  1.   1
  2.   Description
  3.   Get Started
  4.   Features
  5.   Applications
  6.   6
  7. 1Overview
    1. 1.1 Getting Started
      1. 1.1.1 Related Documentation From Texas Instruments
    2. 1.2 High-Voltage Warning and Safe Use
    3. 1.3 Electrostatic Discharge Caution
  8. 2Hardware
    1. 2.1 Jumper Blocks, Jacks, and Test Points
    2. 2.2 Inputs
    3. 2.3 Outputs
    4. 2.4 Enable or Disable
    5. 2.5 Status Flags
      1. 2.5.1 Circuit Protection
  9. 3Application Circuits
    1. 3.1 Setting Dual-Supply or Single-Supply Operation
      1. 3.1.1 Dual-Supply Operation Configuration
      2. 3.1.2 Single-Supply Operation Configuration
    2. 3.2 Common Op-Amp Configurations
      1. 3.2.1 Inverting Gain of –10 V/V
        1. 3.2.1.1 External Connections for –10 V/V Inverting Gain Configuration
        2. 3.2.1.2 Inverting Gain of –10 V/V Configuration Electrical Performance
      2. 3.2.2 Noninverting Gain of +11 V/V
        1. 3.2.2.1 External Connections for Noninverting Gain Configuration
        2. 3.2.2.2 Noninverting Gain Configuration Electrical Performance
      3. 3.2.3 Gain of +10 V/V Difference Amplifier
        1. 3.2.3.1 Jumper Shunt Locations for Difference-Amplifier Configuration
        2. 3.2.3.2 Gain of 10 V/V Difference Amplifier Configuration Electrical Performance
      4. 3.2.4 Improved Howland Current Pump
        1. 3.2.4.1 OPA598EVM Jumper Shunt Locations for an Improved Howland Current Pump
  10. 4Hardware Design Files
    1. 4.1 EVM Schematic
      1. 4.1.1 EVM Default Configuration
    2. 4.2 PCB Layout
    3. 4.3 Bill of Materials
  11. 5Reference
    1.     Trademarks

3.2.4 Improved Howland Current Pump

The OPA598EVM can be configured as an improved Howland current pump that provides a transconductance amplifier function, sometimes called a V‑to‑I converter. Configuring the V‑to‑I converter with the EVM requires that one resistor, Riso2 (a wide 2512 size), be changed on the EVM PCB from 0 Ω to 49.9 Ω (2 W). If a different output current range is required, this resistor may need to be a different value. Section 3.2.3.1 shows the Riso2 relationship to the output current.

Additionally, Rhcp1 (a 0805-size, 10-kΩ resistor) must be installed at that location on the PCB. Rhcp1 resides just above C12, and up and to the right of the current-limit set resistor shorting blocks JP12 through JP16.

Connect jumper shunts as listed in Table 3-4 to configure the OPA598 as an improved Howland current pump. The jumper shunt installations are illustrated in Figure 3-4. The jumper shunts are designated in the BOM as a shunt and have an SH-J# part designator. The jumper shunts appear in the schematic as the red jumpers connected across the various JP# jumper blocks.

Table 3-4 Jumper Shunt Connections for an Improved Howland Current Pump
Jumper NumberJumper Shunt ConnectsNotes
JP1VIN– J5 to OPA598 –IN pin, through Ri1 (10 kΩ)
JP6VIN+ J9 to OPA598 noninverting input through R4 (10 kΩ)
JP9R8 (10 kΩ) from OPA598 noninverting input to GND
JP11OpenEnabled mode
JP13Sets current limit to 100 mA
JP17E/D Com pinE/D Com pin selection GND
JP18RF1 (10 kΩ) inserted in OPA598 feedback path
JP21OpenIOUT flows through external load
OPA598EVM OPA598EVM Jumper Shunt Locations for an Improved Howland Current PumpFigure 3-4 OPA598EVM Jumper Shunt Locations for an Improved Howland Current Pump