Details

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BUY LP3878SD-ADJ/NOPB https://www.utsource.net/itm/p/12605985.html

Parameter	Symbol	Test Conditions	Min	Typ	Max	Unit
Input Voltage	VIN		2.7		5.5	V
Output Voltage Range	VOUT	Adj. Mode	1.21		5.0	V
Quiescent Current	IQ	VOUT = 3.3V, IOUT = 0A		65		μA
Dropout Voltage	VDROPOUT	IOUT = 500mA		450		mV
Load Regulation		IOUT = 1mA to 500mA		±0.5		%
Line Regulation		VIN = 2.7V to 5.5V		±0.1		%
PSRR (Power Supply Rejection Ratio)		f = 120Hz		70		dB
Operating Temperature	TOPR		-40		85	°C

Instructions for Use:

1. Input Voltage (VIN):

   • Ensure the input voltage is within the range of 2.7V to 5.5V to avoid damage and ensure proper operation.

2. Output Voltage Adjustment:

   • The output voltage can be adjusted using external resistors. The formula to calculate the output voltage is: [ V_ = 1.21 times left(1 + fracright) ]
   • Choose R1 and R2 values to set the desired output voltage within the 1.21V to 5.0V range.

3. Quiescent Current:

   • Keep in mind that the quiescent current is typically 65μA at no load. This value should be considered when calculating overall system power consumption.

4. Dropout Voltage:

   • The dropout voltage is around 450mV at a load current of 500mA. Ensure the input voltage exceeds the sum of the output voltage and dropout voltage to maintain regulation.

5. Load and Line Regulation:

   • Both load and line regulation are critical for stable output. The device maintains ±0.5% load regulation from 1mA to 500mA and ±0.1% line regulation over the input voltage range.

6. PSRR (Power Supply Rejection Ratio):

   • For noise reduction, the device offers a PSRR of 70dB at 120Hz, which helps in filtering out ripple and noise from the power supply.

7. Operating Temperature:

   • Operate the device within the temperature range of -40°C to +85°C to ensure reliability and performance.

8. PCB Layout Considerations:

   • Place the input capacitor as close as possible to the LP3878SD-ADJ/NOPB input pin.
   • Use a low ESR ceramic capacitor for the input to improve transient response and stability.
   • Ensure adequate heat sinking if operating at high currents or in high ambient temperatures.

9. Capacitors:

   • Use appropriate capacitors for both input and output to stabilize the regulator and reduce noise. Typical values are 1μF for the input and 1μF for the output.

(For reference only)