FEATURES
n Seamless Transition Between Power Sources:
Li-Ion Battery, USB, and 6V to 36V Supply (60V Max)
n 2A Output High Voltage Buck Regulator with
Bat-Track™ Adaptive Output Control (LTC4090)
n Internal 215mW Ideal Diode Plus Optional
External Ideal Diode Controller Provides Low Loss
PowerPath™ When External Supply/ USB Not Present
n Load Dependent Charging from USB Input
Guarantees Current Compliance
n Full Featured Li-Ion Battery Charger
n 1.5A Maximum Charge Current with Thermal Limiting
n NTC Thermistor Input for Temperature Qualified
Charging
n Tiny (3mm × 6mm × 0.75mm) 22-Pin DFN Package
APPLICATIONS
n HDD-Based Media Players
n Personal Navigation Devices
n Other USB-Based Handheld Products
n Automotive Accessories
LTC4090/LTC4090-5
USB Power Manager with
2A High Voltage Bat-Track
Buck Regulator
DESCRIPTION
The LTC®4090/LTC4090-5 are USB power managers plus
high voltage Li-Ion/Polymer battery chargers. The devices
control the total current used by the USB peripheral for
operation and battery charging. Battery charge current
is automatically reduced such that the sum of the load
current and the charge current does not exceed the pro-
grammed input current limit. The LTC4090/LTC4090-5
also accommodate high voltage power supplies, such as
12V AC/DC wall adapters, Firewire, or automotive power.
The LTC4090 provides a Bat-Track adaptive output that
tracks the battery voltage for high efficiency charging from
the high voltage input. The LTC4090-5 provides a fixed 5V
output from the high voltage input to charge single-cell
Li-Ion batteries. The charge current is programmable and an
end-of-charge status output (CHRG) indicates full charge.
Also featured are programmable total charge time, an NTC
thermistor input used to monitor battery temperature while
charging and automatic recharging of the battery.
L, LT, LTC, LTM, Linear Technology, the Linear logo and Burst Mode are registered trademarks
and Bat-Track, PowerPath and ThinSOT are trademarks of Linear Technology Corporation. All
other trademarks are the property of their respective owners.
TYPICAL APPLICATION
HIGH (7.5V-36V)
VOLTAGE INPUT
5V WALL
ADAPTER
USB
59k
270pF
HVIN
1µF
IN
4.7µF
VC
TIMER
BOOST
LTC4090
0.47µF
SW
HVOUT
HVPR
OUT
BAT
6.8µH
22µF
1k
LOAD
4.7µF
0.1µF
RT CLPROG
40.2k
2k
GND PROG
100k +
Li-Ion BATTERY
VOUT (TYP)
VBAT + 0.3V
5V
5V
VBAT
AVAILABLE INPUT
HV INPUT (LTC4090)
HV INPUT (LTC4090-5)
USB ONLY
BAT ONLY
4090 TAO1
For more information www.linear.com/LTC4090
LTC4090/LTC4090-5 High Voltage
Battery Charger Efficiency
90 FIGURE 12 SCHEMATIC
80
WITH RPROG = 52k
NO OUTPUT LOAD
LTC4090
70
LTC4090-5
60
50
40
HVIN = 8V
30
HVIN = 12V
HVIN = 24V
HVIN = 36V
20
2.0 2.5 3.0 3.5 4.0 4.5
VBAT (V)
4090 TA01b
4090fd
1
