SNVSD08 Data sheet

SNVSD08A February 2026 – October 2026 LM34938-Q1

PRODUCTION DATA

8.3.11.2 Output Current Limitation

In this configuration the current sense has an internal feedback to the peak current limit of the device. The ILIM circuit regulates the ILIMCOMP voltage to V_(ISET), and overrides the voltage loop regulation.

The peak inductor current is reduced as long as the differential voltage between ISNSP and ISNSN exceeds the internal offset voltage of the ILIM circuit. The ILIM threshold can be set via the register programming or via the an ISET resistor in the ILIMCOMP pin.

If the current limit threshold is selected by a resistor the regulation overwrites the voltage loop once V_(ISET) is increasing to the threshold voltage (typ. 1V). The threshold voltage for ISET can be calculated with:

Equation 15.

{V_{(ISET)} = (V_{(ISNSP)} - V_{(ISNSN)}) \times {gm}_{(ISET)} \times R}_{(ISET)}

Hence the resistor value to select the current limit threshold voltage calculates with:

Equation 16.

R_{(ISET)} = \frac{V_{(ISET)}}{(V_{(ISNSP)} {- V_{(ISNSN)}) \times gm}_{(ISET)}}

For high frequency noise suppression a capacitor based on the following equation must be placed in parallel to R_(ISET)

Equation 17.

C_{(ISET)} = \frac{1}{π \times f_{(SW)} \times R_{(ISET)}}

The current limit threshold is selected by a resistor. The regulation overwrites the voltage loop once V_(ISET) is increasing to the threshold voltage (typ. 1V). The threshold voltage for ISET can be calculated with:

Equation 18.

{V_{(ISET)} = (V_{(ISNSP)} - V_{(ISNSN)}) \times {gm}_{(ISET)} \times R}_{(ISET)}

Hence the resistor value to select the current limit threshold voltage calculates with:

Equation 19.

R_{(ISET)} = \frac{V_{(ISET)}}{(V_{(ISNSP)} {- V_{(ISNSN)}) \times gm}_{(ISET)}}

For high frequency noise suppression a capacitor based on the following equation must be placed in parallel to R_(ISET)

Equation 20.

C_{(ISET)} = \frac{1}{π \times f_{(SW)} \times R_{(ISET)}}