The TPS5450DDA R is a voltage regulator IC manufactured by Texas Instruments. It is a step-down (buck) converter designed to provide efficient Power conversion for a variety of applications. The device is available in the VQFN-20 (20-pin) package.
Pin Function Specifications and Circuit Principle
Pinout and Function List (for TPS5450DDAR, 20 pins)Below is the detailed pinout and function list for the TPS5450DDAR in its VQFN-20 package:
Pin Number Pin Name Pin Type Pin Function Description 1 EN Input Enable pin. When high, the device operates normally; when low, the device is disabled. 2 PGND Ground Power ground pin, provides the reference for the low-side MOSFET. 3 BOOT Input Bootstrapped voltage for the high-side MOSFET driver. Requires an external bootstrap capacitor . 4 SW Output Switch node for the external inductor connection; provides the switching output. 5 VIN Input Input voltage pin; provides the input voltage to the device (e.g., from a power supply). 6 PG Output Power good indicator pin. High indicates the output voltage is within tolerance. 7 COMP Input Compensation pin for adjusting the control loop. 8 FB Input Feedback pin for the voltage regulation loop; connects to the feedback resistor divider. 9 VOUT Output Output voltage, connected to the load (usually regulated by the feedback loop). 10 VDD Power Internal power supply for the IC, typically connected to the same supply as VIN. 11 SYNC Input External synchronization input, used for timing control. 12 GND Ground Ground pin for the IC's circuitry. 13 NC No Connection Not connected, not internally used by the IC. 14 NC No Connection Not connected, not internally used by the IC. 15 NC No Connection Not connected, not internally used by the IC. 16 NC No Connection Not connected, not internally used by the IC. 17 NC No Connection Not connected, not internally used by the IC. 18 NC No Connection Not connected, not internally used by the IC. 19 NC No Connection Not connected, not internally used by the IC. 20 NC No Connection Not connected, not internally used by the IC.Note: "NC" stands for "No Connection" and these pins are not internally connected to any circuitry in the chip.
General Circuit Principle of TPS5450DDAR
The TPS5450DDAR is a buck converter, meaning it steps down an input voltage to a lower output voltage efficiently. It uses a high-side MOSFET to switch the input voltage through an inductor, and the switching node (SW) allows this process to regulate the output. The feedback pin (FB) controls the regulation by comparing the output voltage to a reference voltage, adjusting the duty cycle of the switching MOSFET. The enable pin (EN) controls whether the converter is active, and the PG pin signals whether the output is within a specified tolerance.
Frequently Asked Questions (FAQ) for TPS5450DDAR
Q: What is the input voltage range of the TPS5450DDAR? A: The TPS5450DDAR accepts an input voltage range from 4.5V to 60V, making it suitable for a variety of power supply applications.
Q: What is the output voltage range of the TPS5450DDAR? A: The output voltage is adjustable from 0.8V to 15V, depending on the feedback resistor configuration.
Q: How do I enable the TPS5450DDAR? A: The device is enabled by applying a voltage greater than 2V to the EN pin. A voltage less than 0.5V will disable the IC.
Q: What is the switching frequency of the TPS5450DDAR? A: The switching frequency of the TPS5450DDAR is typically 1.2 MHz, but it can be synchronized to an external clock using the SYNC pin.
Q: What is the maximum output current of the TPS5450DDAR? A: The TPS5450DDAR can provide a maximum output current of 5A, making it suitable for medium-power applications.
Q: How should I choose the inductance for the TPS5450DDAR circuit? A: The choice of inductor depends on the output current and voltage ripple requirements. A typical value would be around 4.7 µH to 22 µH.
Q: Does the TPS5450DDAR have overcurrent protection? A: Yes, the TPS5450DDAR includes overcurrent protection to prevent damage during fault conditions.
Q: How do I set the output voltage of the TPS5450DDAR? A: The output voltage is set by a resistor divider connected to the FB pin. The ratio of resistors sets the desired output voltage according to the formula: ( V{OUT} = V{REF} \times (1 + R2/R1) ), where ( V_{REF} ) is typically 0.8V.
Q: What is the maximum input voltage of the TPS5450DDAR? A: The maximum input voltage is 60V. Exceeding this voltage can damage the device.
Q: Can I use the TPS5450DDAR in parallel for higher output current? A: Yes, the TPS5450DDAR can be used in parallel for higher output currents, but proper current sharing techniques must be used to ensure even current distribution.
Q: What are the thermal shutdown features of the TPS5450DDAR? A: The TPS5450DDAR has built-in thermal shutdown protection. If the junction temperature exceeds 150°C, the device will shut down to prevent overheating.
Q: How should I handle the ground connections for the TPS5450DDAR? A: Ensure that the ground (PGND) and signal ground (GND) are properly connected, with minimal noise between them, to ensure stable operation.
Q: Can I use a ceramic capacitor at the output of the TPS5450DDAR? A: Yes, ceramic capacitors are commonly used at the output for stability and low ESR performance, typically with values around 10 µF to 100 µF.
Q: How does the power good (PG) signal work? A: The PG pin outputs a high signal when the output voltage is within regulation. It indicates when the converter is delivering proper voltage to the load.
Q: What is the purpose of the BOOT pin in the TPS5450DDAR? A: The BOOT pin is used to provide a bootstrap capacitor to drive the high-side MOSFET, allowing for proper switching operation.
Q: What is the difference between VDD and VIN pins? A: VIN is the input voltage pin that supplies power to the buck converter, while VDD is the internal supply pin that powers the internal circuitry of the IC.
Q: How do I set the switching frequency of the TPS5450DDAR? A: The switching frequency can be externally adjusted via a resistor at the SYNC pin or by using the internal frequency of approximately 1.2 MHz.
Q: Is the TPS5450DDAR suitable for automotive applications? A: Yes, the TPS5450DDAR is suitable for automotive applications due to its wide input voltage range and robust features.
Q: Can the TPS5450DDAR be used in high-efficiency power supply designs? A: Yes, the TPS5450DDAR is designed for high efficiency, with typical efficiencies exceeding 90% depending on the application.
Q: How can I prevent noise in the output of the TPS5450DDAR? A: To minimize output noise, use low-ESR capacitors at the output and ensure a good layout design that minimizes parasitic inductances and capacitances.
This detailed explanation covers the pinout and function, as well as the relevant FAQs for the TPS5450DDAR. Let me know if you need more details!