Data Sheet
HIGH SPEED, EXTREMELY LOW NOISE LDO REGULATOR AP2121
General Description Features
The AP2121 series are positive voltage regulator ICs
Low Dropout Voltage at I =100mA: 150mV
OUT
fabricated by CMOS process. Each of these ICs con-
Typical (Except 1.2V, 1.3V and 1.5V Versions)
sists of a voltage reference, an error amplifier, a resis-
Low Standby Current: 0.1A Typical
tor network for setting output voltage, a current limit
Low Quiescent Current: 25A Typical
circuit for current protection and a chip-enable circuit
High Ripple Rejection: 70dB Typicalf=1kHz
(5-pin products only).
Output Current: More Than 200mA (300mA
Limit)
The AP2121 series feature high supply voltage ripple
Extremely Low Noise: 30Vrms (10Hz to
rejection, low dropout voltage, low noise, high output
100kHz)
voltage accuracy, and low current consumption which
make them ideal for use in various battery-powered Excellent Line Regulation: 4mV Typical
devices.
Excellent Load Regulation: 12mV Typical
High Output Voltage Accuracy: 2%
The AP2121 series have 1.2V, 1.3V, 1.5V, 1.8V, 2.5V,
Excellent Line Transient Response and Load
2.8V, 2.85V, 3.0V, 3.2V and 3.3V versions.
Transient Response
Compatible with Low ESR Ceramic Capacitor (as
The AP2121 are available in standard SOT-23-3, SOT-
Low as 1F)
23-5 and CSP-4 packages.
Applications
Mobile Phones, Cordless Phones
Wireless Communication Equipment
Portable Games
Cameras, Video Recorders
Sub-board Power Supplies for Telecom Equip-
ment
Battery Powered Equipment
SOT-23-3 SOT-23-5 CSP-4
Figure 1. Package Types of AP2121
Dec. 2012 Rev. 2. 6 BCD Semiconductor Manufacturing Limited
1 Data Sheet
HIGH SPEED, EXTREMELY LOW NOISE LDO REGULATOR AP2121
Pin Configuration
N Package K Package
(SOT-23-3) (SOT-23-5)
V
IN
3
V 1 5 V
IN OUT
GND 2
NC
CE34
1 2
V
GND
OUT
J4/J4A Package
J4C/J4B Package
(CSP-4 (P 0.5)/CSP-4 (P 0.4))
(CSP-4 (P 0.5)/CSP-4 (P 0.4))
Pin 1 Mark Pin 1 Mark
CE V
IN V V
IN OUT
A1 A2 A1 A2
B1 B2 B1 B2
GND V
OUT CE GND
Figure 2. Pin Configuration of AP2121 (Top View)
Pin Description
Pin Number
Pin Name Function
SOT-23-3 SOT-23-5 CSP-4 CSP-4
(J4/J4A) (J4C/J4B)
3 1 A2 A1 V Input voltage
IN
1 2 B1 B2 GND Ground
3 A1 B1 CE Active high enable input pin. Logic high=enable,
logic low=shutdown
4 NC No connection
25 B2 A2 V Regulated output voltage
OUT
Dec. 2012 Rev. 2. 6 BCD Semiconductor Manufacturing Limited
2