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High Speed, Extremely Low Noise LDO Regulator

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The AP2121 series are positive voltage regulator ICs fabricated by CMOS process. Each of these ICs consists of a voltage reference, an error amplifier, a resistor network for setting output voltage, a current limit circuit for current protection and a chip-enable circuit (5-pin products only). The AP2121 series feature high supply voltage ripple rejection, low dropout voltage, low noise, high output voltage accuracy, and low current consumption which make them ideal for use in various battery-powered devices. The AP2121 series have 1.2V, 1.3V, 1.5V, 1.8V, 2.5V, 2.8V, 2.85V, 3.0V, 3.2V and 3.3V versions.


· Low Dropout Voltage at IOUT=100mA: 150mV Typical (Except 1.2V, 1.3V and 1.5V Versions) · Low Standby Current: 0.1μA Typical · Low Quiescent Current: 25μA Typical · High Ripple Rejection: 70dB Typical (F=1kHz) · Output Current: More Than 200mA (300mA Limit) · Extremely Low Noise: 30μVrms (10Hz to 100kHz) · Excellent Line Regulation: 4mV Typical · Excellent Load Regulation: 12mV Typical · High Output Voltage Accuracy: ±2% · Excellent Line Transient Response and Load Transient Response · Compatible with Low ESR Ceramic Capacitor (as Low as 1μF)


· Mobile Phones, Cordless Phones · Wireless Communication Equipment · Portable Games · Cameras, Video Recorders · Sub-board Power Supplies for Telecom Equipment · Battery Powered Equipment

Product Specifications

Product Parameters

Compliance (Only Automotive supports PPAP) Standard
Output options Fixed
Iout (A) 0.2
Vin (Max) (V) 6
Vin (Min) (V) 2
Vout (min) 1.2
Vout (max) 3.3
Fixed Vout (V) 1.2, 1.3, 1.5, 1.8, 2.5, 2.8, 3.0, 3.2, 3.3
Iq (typ) (µA) 25
Accuracy 25C 2%
Noise uV RMS 10-100 kHz 30
VDROPOUT (Max) (V) at Max Current and Max Ouput Voltage 0.5
PSRR (dB) 1kHz 70
Operating Temperature (Ambient) (°C) -40 to 85 (°C)
Enable Active H
Channels 1
Output Discharge no
Iq (max)(µA) 50
VCTL function no

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Product Change Notices (PCNs)

A PCN may only apply to specific orderable part numbers in this datasheet. Please refer to the corresponding PCN to see the exact orderable part number(s) affected.

PCN # Issue Date Implementation Date Subject
PCN-2575 2022-04-05 2022-07-05 Qualified Additional Bill of Material (BOM) - Lead Frame Raw Material (C19400 FH)
PCN-2343 2018-05-15 2018-08-15 Qualification of Additional Bill of Materials (BOM), Fab Source for Select Products with Top Marking Change on Select Product