Datasheet LTC4007 (Analog Devices) - 7

LTC4007
PIN FUNCTIONS ITH (Pin 10):
Control Signal of the Inner Loop of the
CHEM (Pin 16):
Select 4.1V or 4.2V cell chemistry by Current Mode PWM. Higher ITH voltage corresponds to connecting the pin to GND or open, respectively. Internal higher charging current in normal operation. A 6k resistor, 14µA pull-up to 5.3V. Can also be driven with open- in series with a capacitor of at least 0.1µF to GND provides collector/drain logic levels. loop compensation. Typical full-scale output current is
FLAG (Pin 17):
Active low open-drain output that indicates 40µA. Nominal voltage range for this pin is 0V to 3V. when charging current has declined to 10% of maximum
PROG (Pin 11):
Current Programming/Monitoring Input/ programmed current. A pull-up resistor is required if this Output. An external resistor to GND programs the peak function is used. The pin is capable of sinking at least charging current in conjunction with the current sensing 100µA. resistor. The voltage at this pin provides a linear indication
CLP (Pin 18):
Positive input to the supply current limiting of charging current. Peak current is equivalent to 1.19V. amplifier, CL1. The threshold is set at 100mV above the Zero current is approximately 0.3V. A capacitor from voltage at the CLN pin. When used to limit supply current, PROG to ground is required to filter higher frequency a filter is needed to filter out the switching noise. If no components. The maximum resistance to ground is 100k. current limit function is desired, connect this pin to CLN. Values higher than 100k can cause the charger to shut down.
CLN (Pin 19):
Negative Reference for the Input Current Limit Amplifier, CL1. This pin also serves as the power
NC (Pin 12):
No Connect. supply for the IC. A 10µF to 22µF bypass capacitor should
ICL (Pin 13):
Input Current Limit Indicator. Active low be connected as close as possible to this pin. digital output. Internal 10µA pull-up to 3.5V. Pulled low if
TGATE (Pin 20):
Drives the top external P-channel the charger current is being reduced by the input current MOSFET of the battery charger buck converter. limiting function. The pin is capable of sinking at least 100µA. If VLOGIC is greater than 3.3V, add an external
PGND (Pin 21):
High Current Ground Return for the pull-up. BGATE Driver.
CSP (Pin 14):
Current Amplifier CA1 Input. The CSP and
BGATE (Pin 22):
Drives the bottom external N-channel BAT pins measure the voltage across the sense resistor, MOSFET of the battery charger buck converter. RSENSE, to provide the instantaneous current signals
INFET (Pin 23):
Drives the Gate of the External Input PFET. required for both peak and average current mode operation.
SHDN (Pin 24):
Charger is shut down and timer is reset when this pin is
BAT (Pin 15):
Battery Sense Input and the Negative HIGH. Internal 10µA pull-up to 3.5V. This pin can also be Reference for the Current Sense Resistor. A precision used to reset the charger by applying a positive pulse that internal resistor divider sets the final float potential on this is a minimum of 0.1µs long. pin. The resistor divider is disconnected during shutdown. Rev D For more information www.analog.com 7 Document Outline Description Typical Application Absolute Maximum Ratings Electrical Characteristics Typical Performance Characteristics Pin Functions Block Diagram Operation Applications Information Package Description Typical Application Related Parts Features Applications Typical Application Description Absolute Maximum Ratings Order Information Electrical Characteristics Pin Configuration Electrical Characteristics Typical Performance Characteristics Pin Functions Block Diagram Test Circuit Operation Applications Information Package Description Revision History Typical Application Related Parts