TPS70938DBVR

Introduction

TPS70938DBVR is a low-dropout (LDO) linear regulator from Texas Instruments, which comes in the tiny SOT-23-5 package. It is designed to provide solutions for energy harvesting or battery backup power supplies. It is suitable for microprocessor, microcontroller and digital signal processor, and it can provide low-power embedded systems a low-noise and accurate power supply. TPS70938DBVR is stable when a minimum 1.0 µF ceramic input capacitor and a 0.22 µF ceramic output capacitor are used for bypassing.

Application field

TPS70938DBVR is used for trickle or battery backup power supplies with low output current. The discontinuous conduction mode switching frequency at 200 kHz and the 0.8 V reference voltage make TPS70938DBVR extremely suitable for low dropout applications. The nominal output voltage is 3.3V, and it has an output voltage that is adjustable up to 5.3V. TPS70938DBVR is ideal for low power applications such as RF, sensors, LAN, USB, and portable applications.

Working Principle

The power is supplied by an input voltage and is regulated to an output voltage by a linear regulator. The output voltage of the regulator is set by an internal reference voltage and an external resistor compared to the input voltage. A series of complicated control circuitry is needed to make sure the output voltage is maintained, and to ensure good regulation, stability, high efficiency and good ripple rejection for the output voltage of the regulator.

Input voltage is applied at the IN pin, and will be compared to the output (Vout) pin and regulated by the control circuitry. When the input voltage is higher than the reference voltage, the power transistor will conduct, limiting the amount of current flowing from the input voltage towards the output voltage, so that the output voltage stays at the programmed value.

The TPS70938DBVR features a low output current shutdown. When the output current becomes smaller than the triggering current the output will be disabled, and the output voltage will become equal to the input voltage. The output will be restarted when the input voltage is turned off and then on again, resetting the internal circuitry.

The TPS70938DBVR provides excellent regulation, as well as low drop out, making it an ideal choice for low dropout applications. It features low quiescent current and high efficiency. It is able to react quickly to short-term load transients and its low input capacitance minimizes its effect on the switch mode power supplies. It also offers protection against reverse current, thermal shutdown, and over voltage protection.