TPS5450DDAR: High Performance Step-Down Switching Regulator
17 April 2024
Ⅱ. Technical parameters of TPS5450DDAR
Ⅲ. Simplified schematic of TPS5450DDAR
Ⅳ. Features and advantages of TPS5450DDAR
Ⅴ. How to configure the soft start function of TPS5450DDAR?
Ⅵ. Concrete applications of TPS5450DDAR
The TPS5450DDAR is a high-performance step-down switching regulator chip manufactured by Texas Instruments. With its high output current, high efficiency and built-in protection functions, it is widely used in power systems of various industrial and consumer electronic equipment. Its easy-to-use design enables engineers to quickly develop high-performance power solutions. In this article, we will discuss some key points related to the TPS5450DDAR, including its specifications, features, layout, and applications, so that you can have an in-depth understanding of this device. So, let’s get started!
The TPS5450DDAR is a high output current PWM converter that integrates a low resistance, high-side N-channel MOSFET. It has a high-performance voltage error amplifier that provides tight voltage regulation accuracy under transient conditions. In addition, it also has an undervoltage lockout circuit to prevent startup when the input voltage does not reach 5.5V. An internal slow-start circuit is used to limit inrush current, while a voltage feedforward circuit is used to improve transient response. By using the ENA pin, the current can be reduced to typically 18µA when the power is turned off. To reduce design complexity and reduce external component count, the TPS5450DDAR’s feedback loop is internally compensated.
Alternatives and equivalents:
• TPS5450DDAR belongs to the category of switching voltage regulators.
• Its quiescent current is 18uA.
• Its topology is buck.
• Its switching regulator has a frequency of 500 kHz.
• This converter is 90(typ) percent efficient.
• Its installation method is SMD or SMT.
• TPS5450DDAR has eight pins and one output interface.
• The converter has an output current up to 5A and a peak current up to 6A.
• The length of the TPS5450DDAR is 5 mm, the width is 4 mm, and the height is 1.55 mm.
• The converter has a minimum operating temperature of -40 °C and a maximum operating temperature of 125 °C.
• The converter is designed with a wide voltage input range and can operate within an input voltage range of 5.5V to 36V.
• The converter will be shipped in SO-PowerPad-8 package and tape and reel packaging for quick installation and safe delivery.
The chip has a high-precision output voltage adjustment function. The output voltage can be adjusted through an external resistor with an accuracy of up to ±1 percent. In normal working mode, its switching frequency reaches 500kHz. In addition, the chip also integrates a variety of protection functions, including input under-voltage protection, overheating protection, output under-voltage protection and short-circuit protection. At the same time, the chip complies with industry standards and has a wide temperature operating range (-40°C to +125°C) and input voltage range (5.5V to 36V). It is worth mentioning that the TPS5450DDAR also complies with environmental directives such as REACH, RoHS and WEEE. In addition to excelling in electrical performance and environmental friendliness, the TPS5450DDAR offers many other features. Among them are:
1. Thermal management: TPS5450DDAR has a variety of built-in thermal management protection measures, including overheating protection, overload protection, etc., which can ensure the safety and stability of the system.
2. Adjustable output voltage: The output voltage of TPS5450DDAR can be adjusted through external resistors to adapt to the needs of different application scenarios.
3. Wide input voltage range: The input voltage range of TPS5450DDAR is 5.5V to 36V, which can meet the needs of various application scenarios.
4. High integration: TPS5450DDAR integrates various protection and control circuits such as power MOSFET, reverse voltage protection circuit, and output current limiting circuit, which can reduce the number of external components and system costs.
5. High output current: TPS5450DDAR can provide an output current of up to 5A (6A peak current), which can meet application scenarios with high power requirements.
6. High efficiency: TPS5450DDAR adopts SWIFT™ (Switcher With Integrated FET Technology) technology, which can provide conversion efficiency of up to more than 90 percent, thereby reducing energy waste and heat loss.
7. SWIFT™ technology: TPS5450DDAR adopts Texas Instruments’ SWIFT™ (Step-Down Switching Regulator Integrated Frequency Technology) technology. This technology integrates the controller and high-side and low-side MOSFETs into a single chip, significantly improving efficiency and reducing costs. In addition, this technology helps designers simplify circuit layout, thereby improving system reliability and overall performance.
The main purpose of the soft-start function is to prevent the output voltage from generating excessive inrush current during startup. When the power supply is turned on, the output voltage will rise rapidly, and without proper control, this may cause excessive current in the circuit, thereby damaging components in the circuit or causing other adverse effects. Through the soft-start function, the TPS5450DDAR can gradually increase the output voltage during startup, thereby limiting the rate of rise of the current. This helps protect components in the circuit and ensures stable startup of the power supply. The following are the general steps to configure the TPS5450DDAR soft-start feature:
1. Determine the start-up time: First, determine how long we want the output voltage to stabilize from low to high. This will determine the time constant for soft start.
2. Connect SS/TR pins: We connect SS/TR pins to the required power or voltage source. If we wish to enable the soft-start feature, we need to connect the SS/TR pin to an external voltage source. If we want fast startup without soft start, we need to connect the SS/TR pin to ground (GND).
3. Adjust the soft start time: According to the needs, the soft start time can be controlled by adjusting the output of the external voltage source. Higher voltage will result in faster startup, while lower voltage will extend startup time. When adjusting, please ensure that the set value is within the allowable range to avoid possible unnecessary problems.
4. Verify function: Connect TPS5450DDAR to the input power supply and load, and observe the startup process of the output voltage. If everything is working properly, the output voltage should slowly rise to a steady state according to our configured soft-start time.
• Battery charger
• Power adapter
• High-density point-of-load regulators
• 12V and 24V distributed power systems
• LCD monitors, plasma monitors
1. Layout guidelines
Connect a low-ESR ceramic bypass capacitor to the VIN pin. Take care to minimize the loop area formed by the bypass capacitor connections, the VIN pin, and the TPS5450DDAR ground pin. The best way to do this is to extend the top-side ground area from under the device adjacent to the VIN trace, and place the bypass capacitor as close as possible to the VIN pin. The minimum recommended bypass capacitance is 4.7-μF ceramic with a X5R or X7R dielectric.
There should be a ground area on the top layer directly underneath the IC, with an exposed area for connection to the PowerPAD. Use vias to connect this ground area to any internal ground planes. Use additional vias at the ground side of the input and output filter capacitors as well. The GND pin should be tied to the PCB ground by connecting it to the ground area under the device as shown below.
The PH pin should be routed to the output inductor, catch diode and boot capacitor. Since the PH connection is the switching node, the inductor should be located very close to the PH pin and the area of the PCB conductor minimized to prevent excessive capacitive coupling . The catch diode should also be placed close to the device to minimize the output current loop area. Connect the boot capacitor between the phase node and the BOOT pin as shown. Keep the boot capacitor close to the IC and minimize the conductor trace lengths. The component placements and connections shown work well, but other connection routings may also be effective.
Connect the output filter capacitor(s) as shown between the VOUT trace and GND. It is important to keep the loop formed by the PH pin, Lout, Cout and GND as small as is practical.
Connect the VOUT trace to the VSENSE pin using the resistor divider network to set the output voltage. Do not route this trace too close to the PH trace. Due to the size of the IC package and the device pin-out, the trace may need to be routed under the output capacitor. Alternately, the routing may be done on an alternate layer if a trace under the output capacitor is not desired.
If using the grounding scheme shown in the following figure, use a via connection to a different layer to route to the ENA pin.
2. Layout example
When using TPS5450DDAR, we should pay attention to the following matters:
1. Line regulation and response
Reasonable adjustment of the line of TPS545ODDAR is an important means to improve the response speed and stability of the power supply system. By adjusting the parameters of the critical components in the circuit, precise control of the output voltage and current can be realized, thus improving the dynamic response of the system.
2. Built-in protection function use
TPS5450DDAR built-in overheating and overcurrent protection can effectively protect the device from damage. In the process of use, we should make full use of these built-in protection functions to ensure that the equipment in abnormal circumstances can be disconnected from the power supply in a timely manner to avoid further damage.
3. Temperature range and operating node
In the process of using TPS5450DDAR, we should pay attention to the temperature change of the device, avoid working for a long time in a high or low temperature environment, so as to avoid damage to the device or performance degradation.
4. Switching frequency adjustment
The switching frequency of TPS5450DDAR has a certain impact on the performance of the power supply system. Adjusting the switching frequency as needed can optimize the response speed and stability of the system. In practical applications, we should select the appropriate switching frequency according to the characteristics of the load and the system requirements.
5. Input voltage range setting
Ensuring that the input voltage of TPS5450DDAR is within the specified range can effectively avoid equipment damage or performance degradation caused by too high or too low voltage. When designing the circuit, we should consider the possible voltage fluctuation in the actual application and select the appropriate input voltage range accordingly.
6. Package and thermal considerations
TPS5450DDAR package and thermal design has an important impact on its performance and stability. In package selection, we should take into account the operating environment and temperature requirements of the device and select the appropriate package type. At the same time, reasonable heat dissipation design is also the key to ensure the stable operation of the device. In practical application, we can optimize the heat dissipation effect by increasing heat sinks and improving ventilation.
Frequently Asked Questions
1. What is the operating temperature range of TPS5450DDAR?
The operating temperature of TPS5450DDAR ranges from -40°C to 125°C.
2. What applications is the TPS5450DDAR suitable for?
It is suitable for a wide range of applications including industrial, automotive, and telecommunications.
3. What is the replacement and equivalent of TPS5450DDAR?
You can replace the TPS5450DDAR with TPS5450DDA, TPS5450QDDARQ1 or TPS5450DDARG4.
4. What features does the TPS5450DDAR offer for protection?
It offers protection features including overcurrent protection, thermal shutdown, and undervoltage lockout.
