Features

• Operating Voltages Range：+2.5V to +18.0V
• Output Voltages Range：+1.5V to +5.0V with 100mV Increment
• Low Dropout: 800mV @ 50mA
• High Output Voltage Accuracy

???????? ±2%：VOUT≧2.7V

??????? ±2.4%：VOUT≦2.6V

• Thermal Overload Shutdown Protection
• Low ESR Capacitor Compatible
• SOT-23, SOT-89 & TO-92 Packages
• RoHS Compliant and **** Lead (Pb)-Free and Green (Halogen Free with Commercial Standard)

Applications

• Battery powered Equipments
• Portable Communication Devices
• Precision Voltage References
• Hand-Held Electronics
• Wireless Communication Systems?

General Description

?? The AP8841 series is a positive voltage regulator with high accuracy output voltage and ultra-low quiescent current which is typically 1.0μA. The device is ideal for battery powered handheld equipments which require low quiescent current.
The AP8841 contains a bandgap voltage reference,an error amplifier, a P-channel pass transistor, and a resistor-divider for setting output voltage. The output voltage is fixed with high accuracy by advanced trimming technology.
??? The AP8841 has been designed to be used with low cost ceramic capacitors and requires a minimum output capacitor of 1.0μF. The devices are available in SOT-23, SOT-89, and TO-92 packages

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Simplified Application Circuit

APPLICATION CIRCUITS
? Current Boost Circuit

The figure below shows a boost circuit for increasing the output current. Output current 60mA or more can be obtained by this circuit.

Short-Circuit protection of Tr1 can be implemented by adding the sense resistor RS and the PNP transistor Tr2 as shown below.

The current limit of the protection circuit is:

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Voltage Boost Circuit

?? If the output voltage you need is greater than 5.0V, the circuit in the figure below will increase output voltages easily

The output voltage is obtained by:
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Where VSET is the preset output voltage of AP8841 and ISS is the quiescent current. Because of the low quiescent current, the resistor values, R1 and R2,can be set as large as several hundreds kΩ to lower the power consumption of the whole
system.

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Constant Current Source
????? The AP8841 Series can be used as a constant
current source within allowable current limit.

The output current is obtained by:

Dual Supply
???? A dual supply can be constructed with two AP8841 series as show in the figure below. This circuit provides two outputs (5V and 8V) with the AP8841 -30Px and the AP8841-50Px. As the resistance R lets the quiescent current of IC1 pass. R is unnecessary if the minimum output current of IC2 is more than the IC1 quiescent current. D is a protection diode in case VOUT2 becomes larger than VOUT1.