LTC4098-3.6_15 Datasheet, PDF (1/32 Pages) Linear Technology – USB Compatible Switching Power Manager/LiFePO4 Charger with Overvoltage Protection

LTC4098-3.6
FEATURES
USB Compatible Switching
Power Manager/LiFePO₄ Charger
with Overvoltage Protection
DESCRIPTION
n _{Switching Regulator with Bat-Track}^TM _Adaptive
Output Control Makes Optimal Use of Limited
Power Available from USB Port to Charge Battery
and Power Application
n _{Charge Control Algorithm Specifically Designed}
for LiFePO₄ (Lithium Iron Phosphate)
n _{Overvoltage Protection Guards Against Damage}
n _{Bat-Track External Step-Down Switching Regulator}
Control Maximizes Efficiency from Automotive,
Firewire and Other High Voltage Input Sources
n _{180mΩ Internal Ideal Diode Plus External Ideal Diode}
Controller Seamlessly Provide Low Loss PowerPath^TM
When Input Power Is Limited or Unavailable
n _{Preset 3.6V Charge Voltage with 0.5% Accuracy}
n _{Instant-On Operation with Discharged Battery}
n _{700mA Maximum Load Current from USB Port}
n _{2A Maximum Input Current from Internal Switching}
Regulator
n _{1.5A Maximum Charge Current with Thermal Limiting}
n _{20-Lead 3mm × 4mm × 0.75mm QFN Package}
APPLICATIONS
n _{High Peak Power Battery-Powered Equipment}
n _{Backup Applications}
n _{High Reliability Handhelds}
The LTC^®4098-3.6 is a high efficiency USB PowerPath
controller and full-featured LiFePO₄ battery charger. It seam-
lessly manages power distribution from multiple sources
including USB, wall adapter, automotive, Firewire or other
high voltage DC/DC converters, and a LiFePO₄ battery.
The LTC4098-3.6 charge algorithm is optimized for LiFePO₄
by implementing a 1-hour float voltage termination timer
and a 0°C to 60°C NTC-based charge qualification range.
Furthermore, completely discharged batteries are charged
at the full programmed charge current.
The LTC4098-3.6’s switching regulator can automatically
limit its input current for USB compatibility. For automo-
tive and other high voltage applications, the LTC4098‑3.6
interfaces with an external switching regulator. Both the
USB input and the auxiliary input controller feature Bat-
Track optimized charging to provide maximum power to
the application and reduced heat in high power density ap-
plications with input supplies from 5V to as high as 38V.
An overvoltage protection circuit guards the LTC4098-3.6
from high voltage damage on the VBUS pin with just two
external components.
The LTC4098-3.6 is available in a 20-lead 3mm × 4mm ×
0.75mm QFN surface mount package.
L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks and
Bat Track and PowerPath are trademarks of Linear Technology Corporation. All other trademarks
are the property of their respective owners.
TYPICAL APPLICATION
High Efficiency USB Compatible LiFePO₄ Battery Charger with Overvoltage Protection
5V/USB
V_BUS
10µF
3.3µH
SW
SYSTEM
LOAD
TO µC
OVGATE ^LTC4098-3.6
6.04k
OVSENS
3
D0-D2
V_OUT
BAT
CLPROG PROG GND BATSENS
10µF
0.1µF 3.01k 500Ω
+
LiFePO₄
409836 TA01a
Reduced Power Dissipation
vs Linear Battery Charger
3.0
V_IN = 5V
2.5
LINEAR BATTERY
CHARGER
PROG = 500Ω
I_CHRG = 1.1A
10x MODE
2.0
ADDITIONAL POWER
1.5
AVAILABLE FOR CHARGING
1.0
SWITCHING
0.5
BATTERY
CHARGER
0
2.70
2.85 3.00 3.15 3.30 3.45 3.60
BATTERY VOLTAGE (V)
409836 TA01b _409836f
1