TPS70918DBVT

The TPS70918DBVT is a low-voltage dropout (LDO) linear voltage regulator which is designed for low noise, low quiescent current and excellent power supply rejection ratio (PSRR). It belongs to the family of PMIC – Voltage Regulators – Linear, and has wide applications in a variety of applications, especially in audio and automotive applications. In this article, we explore the TPS70918DBVT application field and working principle in detail.

Overview of TPS70918DBVT

The TPS70918DBVT is a low-voltage linear voltage regulator with an input voltage range of 2.5V to 6V and an output voltage of 0.8V to 5.5V. It can provide up to 200mA of output current and features a low dropout voltage (Vdroop) of 105mV. Moreover, it has a low quiescent current of 19μA from 1.2V to 3.6V and a high PSRR of 76dB at 1kHz for eliminating power supply noise. It also offers an adjustable device to allow for the optimization of the output voltage. All of the above features make it suitable for use in applications that require low power consumption, reliable power supply and ultra-low noise.

Features of TPS70918DBVT

• Wide input voltage range: 2.5V to 6V.
• Wide output voltage range: 0.8V to 5.5V.
• High output current capacity; up to 200mA.
• Low dropout voltage: 105mV
• Low quiescent current: 19μA from 1.2V to 3.6V.
• High PSRR: 76dB at 1kHz.
• Adjustable device to allow for the optimization of the output voltage.

Application areas of TPS70918DBVT

Due to its low dropout voltage and high PSRR, the TPS70918DBVT is suitable for applications that require low power consumption, reliable power supply and low noise, especially when used with low voltage battery sources. It has wide applications in various areas, such as embedded systems, automotive, audio, and communications.

It can be used in embedded systems to provide the powering requirements for devices such as microprocessors, memories, ASICs, and digital signal processors. With its adjustable device, it can be used for post-production trimming used in factory calibration of electronic devices. In automotive applications, it can be used in radio frequency devices, such as GSM and CDMA for powering the components. In audio applications, it is suitable for use in language translation devices and portable multimedia players. It can also be used in communications devices, such as digital cameras, set-top boxes, BlueTooth headsets, and WiFi radios.

Working Principle

The TPS70918DBVT uses the PMOS pass element which is the transistor with the source connected to VIN (input voltage), and the drain connected to the load and output voltage, VOUT. The transistor turns on when the gate of the transistor is driven above the threshold voltage. The gate voltage is controlled by the internal error amplifier using the feedback voltage from the R1/R2 divider.

The internal error amplifier compares the output voltage against the reference voltage generated by the bandgap circuit. If the output voltage is lower than the reference voltage, the internal error amplifier will drive the PMOS gate, which will cause the PMOS current to increase, thus raising the output voltage. Similarly, if the output voltage is higher than the reference voltage, the internal error amplifier will drive the PMOS gate lower, which will cause the PMOS current to decrease, thus lowering the output voltage. This can be used to adjust the output voltage of the TPS70918DBVT to the desired voltage level.

Conclusion

The TPS70918DBVT is a low-voltage linear voltage regulator with a wide input voltage range, wide output voltage range, high current capacity, low dropout voltage, low quiescent current, and high PSRR. It is suitable for applications that require low power consumption, reliable power supply, and low noise. It has wide applications in various areas, such as embedded systems, automotive, audio, and communications. The TPS70918DBVT works by using a PMOS pass element, with the gate voltage controlled by the internal error amplifier using the feedback voltage from a R1/R2 divider.