LT3508EUF#RPBF

LT3508 refers to dual-channel current-mode synchronous step-down DC-DC switching regulator with integrated power switches. E stands for industrial extended temperature grade. UF denotes 24-lead 4mm×4mm exposed pad QFN surface mount package. #TRPBF represents lead-free 7-inch tape-and-reel packaging for high-volume automated SMT mass production.

This monolithic dual-output buck converter integrates two independent switching power channels, each delivering up to 1.4A continuous output current. It supports an ultra-wide input voltage range of 3.7V to 36V, withstanding automotive load dump voltage transients up to 40V peak, perfectly compatible with 12V vehicle batteries, 24V industrial bus power and unregulated AC-DC wall adapters.

The switching frequency is programmable from 250kHz to 2.5MHz via an external resistor, and can be locked to an external clock signal for multi-power rail frequency synchronization. The two internal converters operate 180 degrees out of phase, which effectively cuts down input ripple current and reduces the required capacitance value of input filter capacitors. High operating frequency enables the adoption of tiny inductors and multilayer ceramic capacitors to realize compact power supply designs.

Output voltage of each channel is adjustable down to 0.8V through external resistive divider networks. Each channel is equipped with independent soft-start, voltage tracking and power-good detection circuits, which greatly simplifies multi-rail power-up sequencing requirements for MCU, FPGA and DSP systems.

Key power consumption and protection features: typical quiescent supply current is 4.3mA under normal operation, while shutdown current is less than 2μA for battery-powered equipment energy conservation. Built-in comprehensive protections include cycle-by-cycle peak current limiting, frequency foldback short-circuit protection and hysteretic thermal shutdown to avoid chip damage caused by overload, short circuit and overheating. The peak power conversion efficiency reaches 89% under typical working conditions. A precision programmable undervoltage lockout function ensures stable startup and avoids unstable operation under low input voltage conditions.

Housed in miniature 24-pin QFN plastic package with central exposed thermal pad, overall dimension 4mm × 4mm. The exposed pad provides excellent thermal conduction performance to dissipate internal heat efficiently during continuous full-load operation and suppress junction temperature rise. Moisture Sensitivity Level is MSL1, there is no time restriction for reflow soldering after the original vacuum packaging is opened. Continuous tape reel feeding mode is configured to fully match the automatic chip mounter workflow for large-scale electronic assembly production.

The industrial operating temperature range covers -40°C to +125°C, enabling reliable long-term continuous operation in automotive electronic control units, industrial automation controllers, communication terminal equipment and portable test instruments under severe temperature fluctuation and electromagnetic interference environments. The device is AEC-Q100 qualified for automotive grade applications, manufactured with lead-free processes and complies with global RoHS environmental directives. The highly integrated dual-channel single-chip architecture reduces the quantity of peripheral discrete components, simplifies dual-output power supply PCB layout and shortens hardware development cycle.

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