AAT3125
USB OTG 5V Charge Pump
3125.2005.12.1.4 1
General Description
The AAT3125 USB On-the-Go (OTG) charge pump
is a member of AnalogicTech's Total Power
Management IC™ (TPMIC™) product family. The
device integrates a high efficiency 1.5X fractional
100mA regulated charge pump for supplying V
BUS
with the additional functions required for OTG
devices (formerly known as dual role devices).
Four voltage detectors monitor V
BUS
, and a current
source dedicated for V
BUS
pulsing is provided for
compliance with Session Request Protocol (SRP)
as defined by the USB OTG Supplement.
The charge pump section uses a high efficiency
fractional topology, with a high frequency 750kHz
switching speed which enables the use of small
capacitors (less than 3.3µF). The AAT3125 fea-
tures extremely low quiescent current to extend
battery run time. Additionally, the device integrates
protection features such as under-voltage lockout,
and output short circuit and thermal protection.
The AAT3125 is available in a Pb-free, surface
mount QFN44-16 package and is rated over the
-40°C to +85°C temperature range.
Features
•V
IN
Range: 2.7V to 5.5V
• Regulated Fractional Charge Pump
• 100mA Output Current
• Reverse Load Protection
• Power Good Flag
• SRP Detection Flag
• SRP Ready Flag
• Output Short-Circuit and Thermal Protection
• Under-Voltage Protection
• Less than 1µA Consumed While Disabled
• Designed to Allow Operation with Output
Capacitance as Low as 3.3µF
• 16-pin QFN44 Package
• -40°C to +85°C Temperature Range
Applications
• Cell Phones
• Hand-Held Computers
• PDAs
Typical Application
IN
POK1
GND
SR
OUT
C
OUT
C
IN
1µF
1µF
1µF
1µF
3.3µF to 6.5µF
SR POK2
SESDET
SRRDY
ENEN
R1 R2 R3 R4
POK1
VBUS
POK2
SESDET
SRRDY
AAT3125
1 Cell
Li-Ion
C1
C2
C1+
C1-
C2+
C2-
80kΩ
C
CP
OUTCP
R
CS
0.2Ω
ChargePump
™