LP2985A-33DBVR Detailed explanation of pin function specifications and circuit principle instructions

The LP2985A-33DBVR is a low dropout (LDO) voltage regulator made by Texas Instruments. Specifically, it is a 33V version of the LP2985 series, packaged in a SOT-23-5 form factor, which contains 5 pins. This model is typically used for providing low-voltage regulation for sensitive electronic components that require a stable and regulated Power supply with low noise.

Pin Function Specifications

The LP2985A-33DBVR is a 5-pin SOT-23 package. Below is the detailed description of each pin:

Pin Number Pin Name Function 1 VOUT This is the output voltage pin. It provides the regulated output voltage. For the LP2985A-33DBVR, the output is 3.3V. The current available on this pin depends on the load and thermal conditions. 2 GND This is the ground pin. It is connected to the ground of the circuit. All reference voltages and signals are relative to this pin. This pin is typically tied to the negative terminal of the power supply. 3 VIN This is the input voltage pin. It connects to the power supply input, typically requiring a voltage between 3.5V and 40V to maintain proper regulation. The input voltage must always be higher than the output voltage by the dropout voltage, which is around 40mV for the LP2985 at low currents. 4 EN This is the enable pin. It is used to turn the regulator on or off. A high level on this pin enables the device, while a low level disables it. The typical threshold for enabling is 2V, and for disabling, it's 0.4V. 5 NC This is a no-connect pin. It is not internally connected to anything inside the chip, and it should be left floating or can be optionally tied to ground in a design, though it does not have any functional purpose in operation.

Packaging Information

Package Type: SOT-23-5 Total Pins: 5

Complete FAQ for the LP2985A-33DBVR

FAQ 1:

Q: What is the output voltage of the LP2985A-33DBVR? A: The output voltage of the LP2985A-33DBVR is 3.3V.

FAQ 2:

Q: What is the maximum input voltage for the LP2985A-33DBVR? A: The maximum input voltage for the LP2985A-33DBVR is 40V.

FAQ 3:

Q: What is the dropout voltage of the LP2985A-33DBVR? A: The dropout voltage is approximately 40mV at low load currents.

FAQ 4:

Q: What is the typical quiescent current of the LP2985A-33DBVR? A: The typical quiescent current is around 30µA.

FAQ 5:

Q: What is the enable pin voltage threshold for the LP2985A-33DBVR? A: The enable pin threshold is 2V for enabling the device and 0.4V for disabling it.

FAQ 6:

Q: Can I use the LP2985A-33DBVR without the enable pin connected? A: Yes, if the enable pin is left floating, the device will typically be enabled, but it is recommended to pull it high to ensure reliable operation.

FAQ 7:

Q: What is the typical load regulation of the LP2985A-33DBVR? A: The typical load regulation of the LP2985A-33DBVR is 0.05% over the full load range.

FAQ 8:

Q: What is the output noise voltage of the LP2985A-33DBVR? A: The output noise voltage is typically around 40µV RMS.

FAQ 9:

Q: How should I handle the no-connect (NC) pin on the LP2985A-33DBVR? A: The NC pin does not require any connection but can be optionally tied to ground if desired.

FAQ 10:

Q: What is the maximum output current of the LP2985A-33DBVR? A: The maximum output current of the LP2985A-33DBVR is 150mA.

FAQ 11:

Q: Can I use the LP2985A-33DBVR to regulate a voltage higher than 3.3V? A: No, the LP2985A-33DBVR is specifically designed for a 3.3V output. For other voltages, different versions of the LP2985 series can be used.

FAQ 12:

Q: Does the LP2985A-33DBVR have thermal shutdown protection? A: Yes, the LP2985A-33DBVR includes thermal shutdown protection to prevent damage from excessive temperatures.

FAQ 13:

Q: What is the package size of the LP2985A-33DBVR? A: The LP2985A-33DBVR is in a SOT-23-5 package.

FAQ 14:

Q: How do I calculate the power dissipation in the LP2985A-33DBVR? A: Power dissipation can be calculated using the formula: P = (Vin - Vout) * Iload, where Vin is the input voltage, Vout is the output voltage, and Iload is the current drawn by the load.

FAQ 15:

Q: Can the LP2985A-33DBVR be used for high-frequency applications? A: Yes, the LP2985A-33DBVR has a low output noise, making it suitable for sensitive analog and high-frequency applications.

FAQ 16:

Q: What type of capacitor s should be used with the LP2985A-33DBVR? A: It is recommended to use ceramic capacitors with low ESR for stable operation. A typical configuration is a 10µF ceramic capacitor on the input and a 1µF ceramic capacitor on the output.

FAQ 17:

Q: What is the output tolerance of the LP2985A-33DBVR? A: The output tolerance is typically within ±2% at full load.

FAQ 18:

Q: Can the LP2985A-33DBVR be used for battery-powered devices? A: Yes, the LP2985A-33DBVR is ideal for battery-powered devices due to its low quiescent current and low dropout voltage.

FAQ 19:

Q: What happens if the input voltage drops below the output voltage? A: If the input voltage drops below the output voltage, the regulator will not be able to maintain the output voltage, and the output will fall below the desired value.

FAQ 20:

Q: Is the LP2985A-33DBVR pinout the same for all versions of the LP2985? A: Yes, the pinout is the same across the LP2985 family, but the output voltage value may differ depending on the specific part number (e.g., LP2985A-33DBVR is a 3.3V version).

Conclusion

This detailed explanation provides the essential functions of each pin on the LP2985A-33DBVR, as well as frequently asked questions (FAQs) for better understanding and usage of this voltage regulator in various applications.