LTC4098 Datasheet, PDF (1/32 Pages) Linear Technology – USB Compatible Switching Power Managers/Li-Ion Chargers with Overvoltage Protection

LTC4098/LTC4098-1
FEATURES
USB Compatible Switching
Power Managers/Li-Ion Chargers
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 _{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 4.2V Charge Voltage with 0.5% Accuracy}
(4.1V for LTC4098-1)
n _{4.1V Float Voltage (LTC4098-1) Improves Battery Life}
and High Temperature Safety Margin
n _{Instant-On Operation with Discharged Battery}
n _{700mA Maximum Load Current from USB Port}
n _{1.5A Maximum Charge Current with Thermal Limiting}
n _{Ultra-Thin (0.55mm) 20-Lead 3mm × 4mm QFN}
APPLICATIONS
n _{Media Players}
n _GPS
n _PDAs
n _{Smart Phones}
The LTC^®4098/LTC4098-1 are high efficiency USB Power-
Path controllers and full-featured Li-Ion/Polymer battery
chargers. They seamlessly manage power distribution from
multiple sources including USB, wall adapter, automotive,
Firewire or other high voltage DC/DC converters, and a
Li-Ion/Polymer battery.
The LTC4098/LTC4098-1’s internal switching regulator
automatically limits its input current for USB compatibility.
For automotive and other high voltage applications, the
LTC4098/LTC4098-1 interface with a Linear Technology
external switching regulator to provide a high efficiency
high voltage power path. Both the USB and the optional
high voltage inputs feature Bat-Track optimized charging
to provide maximum power to the application and ease
thermal issues in high power density applications with
input supplies from 5V to as high as 38V.
An overvoltage circuit protects the LTC4098/LTC4098-1
from high voltage damage on the USB/wall adaptor inputs
with an N-channel FET and a resistor.
The LTC4098/LTC4098-1 are available in the ultra-thin
(0.55mm) 20-lead 3mm × 4mm QFN surface mount
package.
, LT, LTC and LTM are registered trademarks of Linear Technology Corporation.
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/Automotive Battery Charger with Overvoltage Protection
INPUT
AUTOMOTIVE,
FIREWIRE, ETC.
INPUT
USB
TO μC
LT3653
3.3μH
V_BUS
10μF
V_C WALL
SW
6.04k
OVGATE
LTC4098/LTC4098-1
OVSENS
3
D0-D2
V_OUT
BAT
CLPROG PROG GND BATSENS
SYSTEM
LOAD
10μF
0.1μF 3.01k 1k
+
Li-Ion
40981 TA01a
USB Switching Regulator Efficiency
to System Load (P_VOUT/P_VBUS)
100
90
80
70 BAT = 4.2V
60
BAT = 3.3V
50
40
30
20 _{VBUS = 5V}
10 IBAT = 0mA
10x MODE
0
0.01
0.1
I_VOUT (A)
1
40981 TA01b
40981fb
1