LTC3374IFETRPBF (TSSOP package) – “I” indicates industrial temperature grade (-40°C~125°C), “HFE” where “H” indicates high temperature grade (-40°C~150°C).
TSSOP θJA=25°C/W. Under 85°C ambient temperature, HFE allows power dissipation of 2.6W, IFE allows 1.6W.
The I version has an additional derating of approximately 38% in total output current capability compared to the H version. When evenly distributed across 8 channels, the average output current per channel may need to be limited to about 0.6A; otherwise, internal thermal shutdown may be triggered (typical threshold ~160°C, long-term operation above 125°C affects lifetime).

MODE pin behavior

• Forced Continuous Conduction Mode (FCCM): Maintains switching operation under light load, output voltage ripple is low and frequency is constant, light-load efficiency is low, inductor current reverses, not suitable for battery-powered devices.
• Burst Mode®: Skips switching cycles under light load, quiescent current is extremely low (tens of µA), high efficiency, generates low-frequency high-amplitude ripple noise. Selection should be made carefully according to the back-end load (e.g., precision ADC or audio amplifier).

90° phase interleaving behavior
8 channels are interleaved with 90° steps (0°, 90°, 180°, 270° cycle). This does not change the ripple of a single channel but significantly reduces the input capacitor RMS current—approximately 50% reduction compared to 8 channels switching simultaneously—enabling fewer or smaller input ceramic capacitors. This is a core-friendly feature.

EN pin precision enable
The EN pin has a precise voltage threshold (typically 0.8V~1.2V). An external resistor divider can be used to set different turn-on voltage points. By utilizing the rising slope difference of the input voltage, complex power-up/power-down sequencing (e.g., 1.8V first, then 3.3V) can be achieved—a hidden feature when powering multiple FPGAs/ASICs.

Selection recommendations
If the system junction temperature must withstand above 125°C (e.g., sealed high-temperature enclosure), choose HFE over IFE. If the ambient temperature is controllable (<70°C), IFE offers better cost-effectiveness. Use 1.6W as the thermal design limit for IFE and recalculate the load combination.