LTC3371HUHF#PBF

PMIC - Voltage Regulators - DC DC Switching Regulators

The integrated circuit LTC3371HUHF#PBF is a member of a family of modern, high frequency, step-down DC-DC switching regulators otherwise known as synchronous buck regulators. It is a 3A regulator with a wide 4.5 V - 38 V operating range, an adjustable output voltage and a 1 MHz switching frequency. LTC3371HUHF#PBF also offers an internal switch of 0.8 Ohm, fast loop response and low quiescent current. Moreover, it features an adjustable soft-start, a thermal protection, and a small form factor package available in both TSSOP16 and DFN2x2-8.

Applications

LTC3371HUHF#PBF step-down switch regulator is suitable for a wide range of power management applications. Some of the main applications include high current point-of-load regulation, battery powered systems, distributed power networks, telecom/networking, automotive and industrial applications.

Pinout

The package of the regulator consists of 16 pins, pin1 is named FB and can be used to set the output voltage, followed by a VIN voltage input that can range between 4.5V and 38V. An EN pin is connected to the Feedback pin and it is used to enable and disable the regulator while GND and SW are pins to set the output voltage and ground the board respectively. LTC3371HUHF#PBF also features two power switches (SW and PH) and two enable pins (PG and SG). Finally, the N/C pin needs to be tied to ground.

Performance Features

• Maximum 3A of output current.
• Input voltage range from 4.5V up to 38V.
• Internal 0.8 Ohm switch.
• Adjustable soft-start.
• External compensation is not required.
• Switching frequency up to 1 MHz.
• Thermal protection.

Working Principle of LTC3371HUHF#PBF

LTC3371HUHF#PBF step-down switching regulator works in a very similar way to other buck switchers. It starts working when the voltage across its Enable pin (EN) is higher than the voltage across its Feedback pin (FB) and then it will keep on working as long as these two pin’s voltages remain above a certain threshold. When the Enable pin (EN) has higher voltage than the Feedback pin (FB), it allows the device to act as a closed-loop switch as it enables the PWM logic and powering up the internal control circuit.

The voltage specification starts with the input voltage, the voltage that comes from the source, flows through the LC filter, then it faces the MOS switch and lastly, it faces the output filter that eases the voltage ripple. If the voltage across the LC filter rises the internal control regulates it to a reference voltage (FB) and uses a fixed frequency PWM with peak current mode control.

Moreover, the device also features an adjustable soft-start (SS) pin in order to avoid excessive inrush current by measuring the output current either through a resistor divider connected to the output voltage or with a current sensor to help it detect the current waveform.

Finally, the MOSFET switch gets powered up and then correspondingly, shuts down when the voltage across the LC filter returns to a lower voltage and consequently, the current waveform is then regulated by the MOSFET switch.

Conclusion

The LTC3371HUHF#PBF DC-DC switching regulator from Linear Technology is a compact, high-efficiency step-down regulator capable of supplying 3A of output current. The device operates from a wide input voltage range from 4.5 V to 38 V and features an adjustable output voltage, 1 MHz switching frequency, fast loop response, small form factor package and an adjustable soft-start and thermal protection. Its applications range from high current point-of-load regulation to battery powered systems, distributed power networks, and telecom/networking.