L5973D

Voltage Regulators - DC DC Switching Regulators Overview

The L5973D is a monolithic step-down switching regulator manufactured by STMicroelectronics, designed for high-current applications. It features an internal P-channel D-MOS power switch with a minimum current limit of 2.5 A, enabling DC output currents exceeding 2 A depending on thermal conditions. The device operates within an input voltage range of 4 V to 36 V and supports adjustable output voltages from 1.235 V to 35 V. An internal oscillator fixes the switching frequency at 250 kHz. Packaged in an HSOP-8 with an exposed thermal pad, it offers low junction-to-ambient thermal resistance.

Voltage Regulators - DC DC Switching Regulators Feature Summary

• Integrates an internal P-channel D-MOS transistor as the primary switching element, eliminating the need for external bootstrap capacitors and allowing duty cycles up to 100%.
• Includes comprehensive protection mechanisms such as pulse-by-pulse current limiting with frequency foldback, thermal shutdown, and feedback disconnection prevention.
• Features voltage feed-forward capability and a synchronization pin to allow external clocking for higher switching frequencies up to 700 kHz.
• Provides adjustable soft-start timing and an inhibit function to minimize zero-load current consumption.

Voltage Regulators - DC DC Switching Regulators Applications

• Power supply stages for computer-related systems utilizing 5 V buses
• General-purpose DC-DC conversion for embedded electronics requiring wide input ranges
• Industrial control systems operating under variable voltage conditions

Voltage Regulators - DC DC Switching Regulators Procurement Notes

Verify component authenticity through authorized STMicroelectronics distributors or certified partners. Confirm package integrity upon receipt, as the HSOP-8 exposed pad requires proper soldering techniques for thermal performance. Ensure compliance with RoHS directives if required by your specific manufacturing standards. Cross-reference datasheet revisions to confirm feature consistency before finalizing design implementations.

Voltage Regulators - DC DC Switching Regulators Selection Notes

Select this component when designing buck converters requiring robust current handling above 2 A with minimal external component count. The fixed 250 kHz frequency suits general applications, while the sync pin allows optimization for noise-sensitive environments. Consider the thermal requirements of the HSOP-8 package; adequate PCB copper area is necessary to maintain the specified thermal resistance. This regulator is suitable for inputs starting at 4 V, making it compatible with standard 5 V logic supplies.

Voltage Regulators - DC DC Switching Regulators Part Context

The L5973D belongs to the L5973 series of power management ICs from STMicroelectronics. It is part of a family of synchronous buck regulators that utilize BCD5 technology. Related variants include the L5972D and L5973AD, which offer different current ratings or switching frequencies. The STEVAL-ISA101V1 evaluation board is officially associated with this device for development purposes.

Voltage Regulators - DC DC Switching Regulators Replacement Considerations

The L5973AD is a documented alternative within the same product family, offering similar functionality but with a 500 kHz switching frequency. Verify pinout compatibility and thermal characteristics when substituting, as package dimensions may vary slightly between SO8 and HSOP variants.

Voltage Regulators - DC DC Switching Regulators FAQ

Does the L5973D require an external bootstrap capacitor?

No, the device uses an internal P-channel D-MOS transistor which does not require a bootstrap capacitor for driving the high-side switch.

How can the switching frequency be increased beyond the internal 250 kHz?

The device includes a synchronization pin that allows an external clock signal to drive the internal oscillator, supporting frequencies up to 700 kHz.

What protection features are included against short circuits?

The L5973D provides pulse-by-pulse current limiting combined with frequency foldback to ensure effective short-circuit protection.