LTM8062EVPBF LINER [Linear Technology], LTM8062EVPBF Datasheet - Page 7

• Manufacturer Part Number: LTM8062EVPBF
• Description: 32VIN, 2A ?Module Power Tracking Battery Charger
• Manufacturer: LINER [Linear Technology]

PIN FUNCTIONS
the CHRG pin becomes high impedance. If the internal timer
is used for termination, the pin stays low during the charg-
ing cycle until the charge current drops below a C/10 rate,
approximately 200mA, even though the charger will continue
to top off the battery until the end-of-charge timer terminates
the charge cycle. A temperature fault also causes this pin to
be pulled low (see the Applications Information section).
NTC (Pin H6): Battery Temperature Monitor Pin. This pin
is the input to the NTC (negative temperature coefficient)
thermistor temperature monitoring circuit. This function is
enabled by connecting a 10kΩ, B = 3380 NTC thermistor
from the NTC pin to ground. The pin sources 50μA, and
monitors the voltage across the 10kΩ thermistor. When the
voltage on this pin is above 1.36V (T < 0°C) or below 0.29V
(T > 40°C), charging is disabled and the CHRG and FAULT
pins are both pulled low. If the internal timer termination is
being used, the timer is paused, suspending the charging
cycle. Charging resumes when the voltage on NTC returns to
within the 0.29V to 1.36V active region. There is approximately
5°C of temperature hysteresis associated with each of the
temperature thresholds. The temperature monitoring func-
tion remains enabled while thermistor resistance to ground
is less than 250kΩ. If this function is not desired, leave the
NTC pin unconnected.
ADJ (Pin H7): Battery Float Voltage Feedback Input. The charge
function operates to achieve a final float voltage of 3.3V on this
pin. The output battery float voltage (V
using a resistor divider. V
14.4V. The auto-restart feature initiates a new charging cycle
when the voltage at the ADJ pin falls 2.5% below the float
voltage reference. The ADJ pin input bias current is 110nA.
Using a resistor divider with an equivalent input resistance
at the ADJ pin of 250k compensates for input bias current
error. Required resistor values to program desired V
follow the equations:
R1 is connected from BAT to ADJ, and R2 is connected from
ADJ to ground.
FAULT (Pin J7): Open-Collector Fault Status Output; typically
pulled up through a resistor to a reference voltage. This status
R1=
R2 =
V
R1− (2.5 • 10
BAT(FLT)
R1• 2.5 • 10
3.3
• 2.5 • 10
5
5
)
BAT(FLT)
(Ω)
5
(Ω)
can be programmed up to
BAT(FLT)
) is programmed
BAT(FLT)
pin can be pulled up to voltages as high as V
currents up to 10mA. This pin indicates charge cycle fault
conditions during a battery charging cycle. A temperature
fault causes this pin to be pulled low. If the internal timer is
used for termination, a bad battery fault also causes this pin
to be pulled low. If no fault conditions exist, the FAULT pin
remains high impedance (see the Applications Information
section).
TMR (Pin J6): End-Of-Cycle Timer Programming Pin. If a timer-
based charge termination is desired, connect a capacitor from
this pin to ground. Full charge end-of cycle time (in hours) is
programmed with this capacitor following the equation:
A bad battery fault is generated if the battery does not reach
the precondition threshold voltage within one-eighth of t
or:
A 0.68μF capacitor is often used, which generates a timer EOC
at three hours, and a precondition limit time of 22.5 minutes.
If a timer-based termination is not desired, the timer function
can be disabled by connecting the TMR pin to ground. With the
timer function disabled, charging terminates when the charge
current drops below a C/10 rate, approximately 200mA.
V
maximum charge current is reduced when this pin is below
2.7V. Connecting a resistor divider from V
minimum operational V
program the peak power voltage for a solar panel. The LTM8062
servos the maximum charge current required to maintain the
programmed operational V
voltage on V
feature is not used, connect the pin to V
RUN (Pin K6): Precision Threshold Enable Input Pin. The
RUN threshold is 1.25V (rising), with 120mV of input hys-
teresis. When in shutdown mode, all charging functions are
disabled. The precision threshold allows use of the RUN pin
to incorporate UVLO functions. If the RUN pin is pulled below
0.4V, the IC enters a low current shutdown mode where the
V
bias current is 10nA. If the shutdown function is not desired,
connect the pin to the V
INREG
IN
t
t
EOC
PRE
pin current is reduced to 15μA. Typical RUN pin input
= C
= C
(Pin L6): Input Voltage Regulation Reference. The
TIMER
TIMER
INREG
• 4.4 • 10
• 5.5 • 10
at or above 2.7V. If the voltage regulation
IN
IN
IN
6
5
pin.
voltage. This is typically used to
voltage, through maintaining the
IN
LTM8062
.
IN
IN
to this sets the
and can sink
EOC
7
8062f
,