Device identity and key parametrics
The L5987ATR is a step-down (buck) switching regulator from STMicroelectronics, delivering up to 3 A from an input rail spanning 2.9 V to 18 V. The single positive output is configured for non-synchronous rectification, meaning an external Schottky catch diode handles the low-side current path.
Switching frequency and thermal envelope
The oscillator is programmable from 250 kHz to 1 MHz via an external resistor. A lower frequency reduces switching losses and improves efficiency at high input-to-output differentials, while a higher frequency shrinks the inductor and output capacitor footprint at the cost of increased gate-drive losses. Junction temperature rating spans -40°C to 150°C, placing this device in the industrial-automotive temperature band.
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