ltc4007eufd-1-trpbf Linear Technology Corporation, ltc4007eufd-1-trpbf Datasheet - Page 7

• Manufacturer Part Number: ltc4007eufd-1-trpbf
• Description: 4a, High Efficiency, Standalone Li-ion Battery Charger
• Manufacturer: Linear Technology Corporation

PI FU CTIO S
ITH (Pin 10): Control Signal of the Inner Loop of the
Current Mode PWM. Higher ITH voltage corresponds to
higher charging current in normal operation. A 6k resistor,
in series with a capacitor of at least 0.1µF to GND provides
loop compensation. Typical full-scale output current is
40µA. Nominal voltage range for this pin is 0V to 3V.
PROG (Pin 11): Current Programming/Monitoring Input/
Output. An external resistor to GND programs the peak
charging current in conjunction with the current sensing
resistor. The voltage at this pin provides a linear indication
of charging current. Peak current is equivalent to 1.19V.
Zero current is approximately 0.3V. A capacitor from
PROG to ground is required to filter higher frequency
components. The maximum resistance to ground is 100k.
Values higher than 100k can cause the charger to shut
down.
NC (Pin 12): No Connect.
I
digital output. Internal 10µA pull-up to 3.5V. Pulled low if
the charger current is being reduced by the input current
limiting function. The pin is capable of sinking at least
100µA. If V
pull-up.
CSP (Pin 14): Current Amplifier CA1 Input. The CSP and
BAT pins measure the voltage across the sense resistor,
R
quired for both peak and average current mode operation.
BAT (Pin 15): Battery Sense Input and the Negative
Reference for the Current Sense Resistor. A precision
internal resistor divider sets the final float potential on this
pin. The resistor divider is disconnected during shutdown.
CL
SENSE
U
(Pin 13): Input Current Limit Indicator. Active low
, to provide the instantaneous current signals re-
U
LOGIC
is greater than 3.3V, add an external
U
CHEM (Pin 16):Select 4.1V or 4.2V cell chemistry by
connecting the pin to GND or open, respectively. Internal
14µA pull-up to 5.3V. Can also be driven with open-
collector/drain logic levels.
FLAG (Pin 17): Active low open-drain output that indi-
cates when charging current has declined to 10% of
maximum programmed current. A pull-up resistor is
required if this function is used. The pin is capable of
sinking at least 100µA.
CLP (Pin 18): Positive input to the supply current limiting
amplifier, CL1. The threshold is set at 100mV above the
voltage at the CLN pin. When used to limit supply current,
a filter is needed to filter out the switching noise. If no
current limit function is desired, connect this pin to CLN.
CLN (Pin 19): Negative Reference for the Input Current
Limit Amplifier, CL1. This pin also serves as the power
supply for the IC. A 10µF to 22µF bypass capacitor should
be connected as close as possible to this pin.
TGATE (Pin 20): Drives the top external P-channel MOS-
FET of the battery charger buck converter.
PGND (Pin 21): High Current Ground Return for the BGATE
Driver.
BGATE (Pin 22): Drives the bottom external N-channel
MOSFET of the battery charger buck converter.
INFET (Pin 23): Drives the Gate of the External Input PFET.
SHDN (Pin 24): Charger is shut down and timer is reset
when this pin is HIGH. Internal 10µA pull-up to 3.5V. This
pin can also be used to reset the charger by applying a
positive pulse that is a minimum of 0.1µs long.
LTC4007
4007fa
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