LTC4076EDD#TR Linear Technology, LTC4076EDD#TR Datasheet - Page 9

• Manufacturer Part Number: LTC4076EDD#TR
• Description: IC CHARG BATT LI-ON USB 10DFN
• Manufacturer: Linear Technology

Specifications of LTC4076EDD#TR

• Function: Charge Management
• Battery Type: Lithium-Ion (Li-Ion)
• Voltage - Supply: 4.3 V ~ 8 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 10-WFDFN Exposed Pad
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

OPERATIO
The LTC4076 is designed to efficiently manage charging of
a single-cell lithium-ion battery from two separate power
sources: a wall adapter and USB power bus. Using the
constant-current/constant-voltage algorithm, the charger
can deliver up to 950mA of charge current from the wall
adapter supply or up to 650mA of charge current from the
USB supply with a final float voltage accuracy of ±0.6%.
The LTC4076 has two internal P-channel power MOSFETs
and thermal regulation circuitry. No blocking diodes or
external sense resistors are required.
Power Source Selection
The LTC4076 can charge a battery from either the wall
adapter input or the USB port input. The LTC4076 automati-
cally senses the presence of voltage at each input. If both
power sources are present, the LTC4076 defaults to the
wall adapter source provided sufficient power is present
at the DCIN input. “Sufficient power” is defined as:
The open drain power status output (  P  W  R ) indicates that
sufficient power is available. Table 1 describes the behavior
of this status output.
Table 1. Power Source Selection
V
V
V
V
Programming and Monitoring Charge Current
The charge current delivered to the battery from the wall
adapter supply is programmed using a single resistor from
the IDC pin to ground.
DCIN
DCIN
DCIN
DCIN
• Supply voltage is greater than the UVLO threshold.
• Supply voltage is greater than the battery voltage by
R
50mV (180mV rising, 50mV falling).
IDC
> 4.15V and
> BAT + 50mV
< 4.15V or
< BAT + 50mV
=
I
CHRG DC
1000
(
U
V
V
V
Device powered from
wall adapter source;
USBIN current < 25µA
 P  W  R : LOW
Device powered from
USB source;
 P  W  R : LOW
)
USBIN
USBIN
,
I
CHRG DC
> 3.95V and
> BAT + 50mV
(
)
=
1000
R
IDC
V
V
Device powered from
wall adapter source
 P  W  R : LOW
No charging
 P  W  R : Hi-Z
USBIN
USBIN
V
< 3.95V or
< BAT + 50mV
Similarly, the charge current from the USB supply is
programmed using a single resistor from the IUSB pin
to ground. Setting HPWR pin to its high state will select
100% of the programmed charge current, while setting
HPWR to its low state will select 20% of the programmed
charge current.
Charge current out of the BAT pin can be determined at
any time by monitoring the IDC or IUSB pin voltage and
using the following equations:
Programming Charge Termination
The charge cycle terminates when the charge current falls
below the programmed termination threshold during con-
stant-voltage mode. This threshold is set by connecting an
external resistor, R
The charge termination current threshold (I
set by the following equation:
I
I
I
I
R
R
BAT
BAT
BAT
CHRG USB
I
CHRG USB
ITERM
IUSB
=
=
=
(
(
=
R
R
R
V
V
V
=
IDC
IUSB
IUSB
I
IDC
IUSB
IUSB
CHRG USB
)
I
1000
)
TERMINATE
=
= =
•
100
R
200
•
•
1000
(
1000
R
IUS
1000
200
ITERM
V
IUSB
V
V
B B
)
, ( arg
, ( arg
V
HPWR LOW
(
(
, ( arg
ch
HPWR HIGH
HPWR LOW
ch
, from the ITERM pin to ground.
HPWR HIGH
,
(
ch
I
HPWR HIGH
TERMINATE
in
ing from wall adapter
=
=
=
ing from USB
=
g g from USB
=
=
)
)
)
LTC4076
)
R
100
)
ITERM
TERMINATE
V
sup
sup
ply
p
l l y
,
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