LTC4081
4
4081fa
For more information www.linear.com/LTC4081
Note 1: Stresses beyond those listed under Absolute Maximum Ratings
may cause permanent damage to the device. Exposure to any Absolute
Maximum Rating condition for extended periods may affect device
reliability and lifetime.
Note 2: The LTC4081 is guaranteed to meet performance specifications
from 0°C to 85°C. Specifications over the –40°C to 85°C operating
temperature range are assured by design, characterization and correlation
with statistical process controls.
Note 3: Failure to solder the exposed backside of the package to the PC
board ground plane will result in a thermal resistance much higher than
43°C/W.
Note 4: Although the LTC4081 charger functions properly at 3.75V, full
charge current requires an input voltage greater than the desired final
battery voltage per
DV
UVCL1
specification.
Note 5: The 2.8V maximum buck undervoltage lockout (V
UVLO_BUCK
) exit
threshold must first be exceeded before the minimum V
BAT
specification
applies.
Note 6: I
C/10
is expressed as a fraction of measured full charge current
with indicated PROG resistor.
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
Buck Converter
V
FB
FB Servo Voltage
l
0.78 0.80 0.82 V
I
FB
FB Pin Input Current V
FB
= 0.85V –50 50 nA
f
OSC
Switching Frequency
l
1.8 2.25 2.75 MHz
I
BAT_NL_CF
No-Load Battery Current (Continuous
Frequency Mode)
No-Load for Regulator, V
EN_CHRG
= 5V,
L = 10µH, C = 4.7µF
1.9 mA
I
BAT_NL_BM
No-Load Battery Current (Burst Mode
Operation)
No-Load for Regulator, V
EN_CHRG
= 5V,
MODE = V
BAT
, L = 10µH, C = 4.7µF
23 µA
I
BAT_SLP
Battery Current in SLEEP Mode V
EN_CHRG
= 5V, MODE = V
BAT
,
V
OUT
> Regulation Voltage
l
10 15 20 µA
V
UVLO_BUCK
Buck Undervoltage Lockout Voltage V
BAT
Rising
V
BAT
Falling
l
l
2.6
2.4
2.7
2.5
2.8
2.6
V
V
R
ON_P
PMOS Switch On-Resistance 0.95
W
R
ON_N
NMOS Switch On-Resistance 0.85
W
I
LIM_P
PMOS Switch Current Limit
375 520 700 mA
I
LIM_N
NMOS Switch Current Limit 700 mA
I
ZERO_CF
NMOS Zero Current in Normal Mode 15 mA
I
PEAK
Peak Current in Burst Mode Operation MODE = V
BAT
50 100 150 mA
I
ZERO_BM
Zero Current in Burst Mode Operation MODE = V
BAT
20 35 50 mA
t
SS_BUCK
Buck Soft-Start Time From the Rising Edge of EN_BUCK to 90%
of Buck Regulated Output
400 µs
Logic
V
IH
Input High Voltage EN_CHRG, EN_BUCK, MODE Pin Low to High
l
1.2 V
V
IL
Input Low Voltage EN_CHRG, EN_BUCK, MODE Pin High to Low
l
0.4 V
V
OL
Output Low Voltage (CHRG) I
SINK
= 5mA
l
60 105 mV
I
IH
Input Current High EN_BUCK, MODE Pins at 5.5V, V
BAT
= 5V
l
–1 1 µA
I
IL
Input Current Low EN_CHRG, EN_BUCK, MODE Pins at GND
l
–1 1 µA
R
EN_CHRG
EN_CHRG Pin Input Resistance V
EN_CHRG
= 5V
1 1.45 3.3 MW
I
CHRG
CHRG Pin Leakage Current V
BAT
= 4.5V, V
EN_CHRG
= 5V
l
1 µA
ELECTRICAL CHARACTERISTICS
The l denotes specifications which apply over the full operating temperature
range, otherwise specifications are at T
A
= 25°C, V
CC
= 5V, V
BAT
= 3.8V, V
EN_CHRG
= 0V, V
NTC
= 0V, V
EN_BUCK
= V
BAT
, V
MODE
=0V. (Note 2)
