TPS54531DDAR IC

Technical Specifications of TPS54531DDAR

Datasheet	TPS54531DDAR datasheet
Category	Integrated Circuits (ICs)
Family	PMIC – Voltage Regulators – DC DC Switching Regulators
Manufacturer	Texas Instruments
Series	SWIFT?, Eco-Mode?
Packaging	Tape & Reel (TR)
Part Status	Active
Function	Step-Down
Output Configuration	Positive
Topology	Buck
Output Type	Adjustable
Number of Outputs	1
Voltage – Input (Min)	3.5V
Voltage – Input (Max)	28V
Voltage – Output (Min/Fixed)	0.8V
Voltage – Output (Max)	26.04V
Current – Output	5A
Frequency – Switching	570kHz
Synchronous Rectifier	No
Operating Temperature	-40°C ~ 85°C (TA)
Mounting Type	Surface Mount
Package / Case	8-PowerSOIC (0.154″, 3.90mm Width)
Supplier Device Package	8-SO PowerPad

TPS54531DDAR Description

The TPS54531 is a buck converter that takes a 28 V input and gives out 5 A. It has a high-side n-channel MOSFET and uses constant-frequency, current-mode control to improve load and line performance. The converter has a switching frequency of 570 kHz and needs an input voltage of 3.5 V to work properly. With external resistors and the pullup current source on the EN pin, you can change the undervoltage lockup (UVLO). The built-in 80-m high-side MOSFET can be used in designs for power supplies that are always on and have peak currents of up to 5 A. The TPS54531 has a boot update diode built in, so you don’t need to buy any extra parts. The high-side MOSFET gets its bias voltage from the boot capacitor, which is attached to the PH pin. When the voltage on the boot capacitor goes below 2.1 V, the MOSFET is turned off by the UVLO circuit.

For different output filter choices, the output voltage can be lowered to the reference level, and the slow-start time of the device can be changed with the help of an extra capacitor. When the peak inductor current is less than 160 mA, the TPS54531 goes into “Eco” mode and skips pulses to improve economy. Frequency foldback is used to slow down the switching frequency when there is a lot of power in the inductor or when the motor starts up. The converter has a safety feature that shuts it down if it gets too hot.

TPS54531DDAR Features

• Voltage ranges from 3.5 V to 28 V.
• The output voltage can be changed down to 0.8 V.
• The switching frequency is fixed at 570 kHz.
• Typical 1A Quiescent Current at Shutdown
• Inrush currents are limited by a slow start that can be set.
• Overvoltage Transient Protection
• The UVLO threshold can be set.

TPS54531DDAR Feature Description

● Fixed-Frequency PWM Control

When peak-current regulation is in place, the TPS54531 works at a steady frequency. The TPS54531 changes at a rate of 570 kilohertz on the inside.

● Voltage Reference (Vref)

By scaling the output of a bandgap circuit that is stable over temperature, the voltage reference system makes a voltage reference that is accurate to within 2% at first (and within 3.5% as the temperature changes). The normal value for the voltage standard is 0.8 V.

● Bootstrap voltage (BOOT)

A 0.1-F ceramic capacitor placed between the BOOT and PH pins of the TPS54531 device, which has an integrated boot regulator, provides the gate-drive voltage for the high-side MOSFET. Ceramic capacitors with X7R or X5R-grade dielectric are strongly advised since they function consistently over a wide range of temperatures and voltages. As long as the voltage from the BOOT pin to the PH pin is more than 2.1 V (normal), the TPS54531 can operate at 100% duty cycle.

● Enable and Adjustable Input Undervoltage Lockout (VIN UVLO)

The TPS54531 device operates in the default state when the EN pin floats thanks to an inbuilt pullup current source on the EN pin.

Device Functional Modes

●  Eco-mode™

The TPS54531 is made to work in pulse-skipping Eco-mode at low loads to improve economy at low loads. When the highest inductor current is less than 160 mA (typically), the COMP pin voltage drops to 0.5 V (typically), and the device goes into Eco-mode. The COMP pin voltage is limited internally to 0.5 V in Eco-mode. This prevents high-side integrated MOSFET switching. For the COMP pin voltage to go above 0.5 V and get out of eco-mode, the peak inductor current must go above 160 mA. Because the built-in current comparator only measures the peak inductor current, the average load current entering Eco-mode depends on the application and external output filters.

● Operation with VIN  3.5 V

It is suggested that the device work with voltages above 3.5 V. No information is given about the usual VIN-UVLO threshold, and the device can work with input voltages as low as the UVLO voltage. When the input voltage is lower than the real UVLO voltage, the switch doesn’t happen. When the VIN pin crosses the UVLO barrier, the device turns on if the EN pin is pulled up from the outside or is left floating. When the slow-start process starts, switching starts.

● Operation with EN Control

Most of the time, the allowed threshold voltage is 1.25 V. If the EN pin is kept below that voltage, the device is turned off and switching is stopped, even if the VIN pin is above the UVLO threshold. In this state, the IC idle current is less than it was before. If the voltage on the EN pin goes above the threshold while the voltage on the VIN pin is above the threshold for UVLO, the device turns on. The switch is turned on, and the slow start process begins.

TPS54531DDAR Application Information

The TPS54531 is often used as a step-down converter, which means that it can take a voltage between 3.5 V and 28 V and turn it into a smaller voltage. The WEBENCH® software is easy to get, which makes it easier to build and analyse circuits.

Layout

● Layout Guidelines

To make sure the TPS54531 works right, the PCB plan needs to take a number of things into account. A low-ESR ceramic bypass capacitor with a suggested capacitance of 10 F and an X5R or X7R dielectric should be used to connect the VIN pin to ground. It is important to keep the area of the loop made by the links of the bypass capacitor, the VIN pin, and the anode of the catch diode as small as possible. Place the bypass capacitor as close as possible to the VIN pins and the source of the anode of the catch diode. At the device’s pin, the GND pin should be linked to the PCB ground plane.

Connecting the PH pin to the cathode of the catch diode and the output inductor makes the PH pin the switching node. To keep capacitive coupling from happening too much, the PH pins should be close to the catch diode and output inductor, and the PCB wire area should be small. To help the device get rid of heat as well as possible, solder the device’s exposed thermal pad straight to the top-side ground area underneath it. Thermal vias can be used to connect the top-side ground area to an interior or bottom-layer ground plane, which lets enough heat escape. You can use more vias close to the device to help heat move to the internal or bottom-layer ground plane. The layout’s suggested placement of components is a guideline, but good performance can be achieved with other layout methods as well.

Conclusion

With a voltage range of 3.5 V to 28 V, Texas Instruments’ TPS54531DDAR step-down converter is versatile and efficient. Even during rigorous line and load fluctuations, its integrated high-side MOSFET, constant-frequency current mode regulation, and 570 kHz switching frequency provide excellent performance. Overvoltage transient protection, thermal shutdown, and programmed undervoltage lockout protect the TPS54531DDAR. WEBENCH® simplifies circuit design and analysis, enabling efficient implementation.

Due to its versatility and durability, this device is used in consumer electronics, industrial power supplies, and distributed power systems. Following the layout rules optimises performance and heat dissipation. Contact ICRFQ to get the powerful TPS54531DDAR to inspire creativity and discovery. Exploit its potential.

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