While the current limit tolerance of the OPA593 is specified for specific current limit levels, any resistor, SMU,

or DAC inaccuracies add to the listed tolerance. To achieve the desired system level accuracy, take care when

selecting these external components. Figure 7-2 shows a correlation between the ideal or calculated output

current limit and the actual current limit as measured on the OPA593.

Current Limit Resistor, RCL (k )

0

50

100 150 200 250 300 350 400 450 500 550

-260

-220

-180

-140

-100

-60

-20

20

60

100

140

180

220

260

Figure 7-2. Typical Output Current vs Current-Limit Resistor Value

7.3.2 Overcurrent Flag

The OPA593 features an overcurrent flag (Current Flag pin) that indicates a condition where the output current

exceeds the limit established by the ILIMIT pin. For example, in an output short-to-ground fault condition, the

overcurrent flag asserts, which pulls the flag pin low to E/D Com, and the output current is limited to the value

set by ILIMIT. This flag is an open-drain output compatible with standard low-voltage logic circuitry, such as a

microcontroller (MCU). Use a 5

‑kΩ to 10‑kΩ pullup resistor to limit the input current when the flag is asserted. If

this feature is not used, leave this pin floating.

7.3.3 Overtemperature Flag

The OPA593 has internal thermal protection. When the junction temperature reaches approximately 170°C, the

op amp output stage disables and the overtemperature flag (Thermal Flag pin) is asserted, which pulls the

flag pin low to E/D Com. When the junction temperature cools to a safe operating temperature, approximately

150°C, the output stage is enabled, and the op amp resumes normal operation. This flag is an open-drain output

compatible with standard low-voltage logic circuitry, such as an MCU. Use a 5

‑kΩ to 10‑kΩ pullup resistor to limit

the input current when the flag is asserted. If this feature is not used, leave this pin floating.

OPA593

SBOS659C – JANUARY 2022 – REVISED DECEMBER 2022

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