TPS54561DPRR Detailed explanation of pin function specifications and circuit principle instructions

The TPS54561DPRR is a product from Texas Instruments, a well-known manufacturer of semiconductor products. Specifically, the TPS54561DPRR is a step-down voltage regulator (buck converter) with integrated features.

1. Pin Function and Specification

The TPS54561DPRR comes in a 40-pin HTSSOP (Heat Sink Standard Small Outline Package) form factor. Below is the pinout and description of each pin:

Pin No. Pin Name Function Description 1 COMP Compensation node for the control loop. Connect an external capacitor and resistor here to set the control loop compensation. 2 FB Feedback pin used for regulating the output voltage. A voltage divider is typically used between the output and ground to set the desired output voltage. 3 EN Enable pin. A high voltage on this pin enables the device. A low voltage disables the device. 4 AGND Analog ground pin. Connect to the ground of the analog circuit. 5 PGOOD Power Good indicator. When the output voltage is within regulation, this pin is pulled high to indicate proper operation. 6 SW Switch pin, connected to the external MOSFET or inductor. 7 PGND Power ground pin. This pin is the ground for high current switching. 8 BOOT Bootstrapped voltage supply for the high-side MOSFET gate driver. 9 VIN Input voltage pin. Connect to the supply voltage that powers the step-down regulator. 10 VOS Output voltage sense pin, used to monitor the output voltage for feedback control. 11 VOUT Output voltage pin. Connect to the load or external filter components. 12 VDD Internal voltage regulator supply pin. 13 THERM Temperature sensing pin. Provides thermal feedback for the system. 14 TS Temperature sense input pin. 15 NC No connection pin, not used in the circuit. 16 NC No connection pin, not used in the circuit. 17 NC No connection pin, not used in the circuit. 18 NC No connection pin, not used in the circuit. 19 NC No connection pin, not used in the circuit. 20 NC No connection pin, not used in the circuit. 21 NC No connection pin, not used in the circuit. 22 NC No connection pin, not used in the circuit. 23 NC No connection pin, not used in the circuit. 24 NC No connection pin, not used in the circuit. 25 NC No connection pin, not used in the circuit. 26 NC No connection pin, not used in the circuit. 27 NC No connection pin, not used in the circuit. 28 NC No connection pin, not used in the circuit. 29 NC No connection pin, not used in the circuit. 30 NC No connection pin, not used in the circuit. 31 NC No connection pin, not used in the circuit. 32 NC No connection pin, not used in the circuit. 33 NC No connection pin, not used in the circuit. 34 NC No connection pin, not used in the circuit. 35 NC No connection pin, not used in the circuit. 36 NC No connection pin, not used in the circuit. 37 NC No connection pin, not used in the circuit. 38 NC No connection pin, not used in the circuit. 39 NC No connection pin, not used in the circuit. 40 NC No connection pin, not used in the circuit.

2. General Circuit Principle and Usage

Step-down Regulation: The TPS54561DPRR is designed for efficient step-down voltage conversion, with the ability to convert input voltages as high as 60V down to the desired output voltage with high efficiency. Inductor and Capacitors : The inductor and capacitors play a crucial role in energy storage and filtering within the power converter circuit. External components are needed to set the regulator's output voltage and stabilize the feedback loop. Thermal Management : Proper thermal management is important. A good PCB layout with adequate copper area for heat dissipation and proper grounding is recommended to avoid thermal shutdown. Compensation and Feedback: The compensation pin (COMP) is used to configure the control loop's bandwidth and stability. The feedback pin (FB) senses the output voltage and adjusts the duty cycle of the internal switches to maintain regulation.

3. Frequently Asked Questions (FAQ)

Q1: What is the maximum input voltage for the TPS54561DPRR? A1: The TPS54561DPRR can handle an input voltage up to 60V.

Q2: Can the TPS54561DPRR regulate down to 0V? A2: No, the TPS54561DPRR has a minimum output voltage of around 0.8V.

Q3: How do I calculate the output voltage of the TPS54561DPRR? A3: The output voltage can be set using a resistive divider between the output and ground, with feedback to the FB pin. The formula is: Vout = 0.8V × (1 + R1/R2).

Q4: Is there an external compensation network required for the TPS54561DPRR? A4: Yes, external components such as a resistor and capacitor are needed to set the compensation network for the control loop, connected to the COMP pin.

Q5: How does the TPS54561DPRR handle thermal shutdown? A5: If the junction temperature exceeds the threshold, the TPS54561DPRR will enter thermal shutdown to protect itself. The device will resume operation once the temperature drops to a safe level.

Q6: What is the Power Good (PGOOD) pin used for? A6: The PGOOD pin indicates the status of the output voltage. When the output is within the regulation window, PGOOD will be high; otherwise, it will be low.

Q7: How does the TPS54561DPRR protect against short circuits? A7: The device features overcurrent protection and will enter a protection mode if a short circuit is detected on the output.

Q8: What is the switching frequency of the TPS54561DPRR? A8: The switching frequency is typically set to 500 kHz, but it can be adjusted with external components.

Q9: Can the TPS54561DPRR be used for 12V to 5V step-down conversion? A9: Yes, the TPS54561DPRR can easily step down from 12V to 5V, as long as the input and output requirements are met.

Q10: How do I ensure the TPS54561DPRR operates efficiently? A10: Proper PCB layout with short and wide traces for high-current paths, along with a good ground plane, is essential for efficient operation.

Q11: What is the recommended inductor for use with the TPS54561DPRR? A11: The recommended inductor should have a low DC resistance and be sized for the desired output current, typically in the range of 10µH to 22µH.

Q12: Can the TPS54561DPRR be used for high power applications? A12: Yes, the TPS54561DPRR is suitable for high power applications, but ensure the thermal management and component ratings are adequate.

Q13: What is the output voltage range of the TPS54561DPRR? A13: The output voltage range typically spans from 0.8V to 15V, depending on the external resistor divider.

Q14: Is the TPS54561DPRR suitable for automotive applications? A14: Yes, the TPS54561DPRR is automotive-qualified and can handle the rugged conditions of automotive power systems.

Q15: Can I use the TPS54561DPRR for 5V USB charging circuits? A15: Yes, the TPS54561DPRR is suitable for USB charging circuits if the input voltage and current requirements align with the device’s specifications.

Q16: What is the efficiency of the TPS54561DPRR? A16: The efficiency can be as high as 95% depending on the input and output voltage conditions.

Q17: Does the TPS54561DPRR support soft start? A17: Yes, the TPS54561DPRR features an internal soft-start mechanism to reduce inrush current during startup.

Q18: What are the recommended decoupling capacitors for the TPS54561DPRR? A18: The TPS54561DPRR requires low ESR ceramic capacitors for stable operation; typically, 10µF to 22µF for input and output.

Q19: How can I adjust the switching frequency? A19: The switching frequency of the TPS54561DPRR can be adjusted by selecting appropriate external resistors at the SYNC pin.

Q20: Is there a design guide available for the TPS54561DPRR? A20: Yes, Texas Instruments provides a detailed application note and design guide for implementing the TPS54561DPRR.

If you need further details or specific guidelines, feel free to ask!