Datasheet LTM8062, LTM8062A (Analog Devices) - 7

LTM8062/LTM8062A
pin FuncTions GND (Bank 1, Pin L7):
Power and Signal Ground Return. of the temperature thresholds. The temperature monitoring
BAT (Bank 2):
Battery Charge Current Output Bus. The function remains enabled while thermistor resistance to charge function operates to achieve the final float voltage ground is less than 250kΩ. If this function is not desired, at this pin. The auto-restart feature initiates a new charging leave the NTC pin unconnected. cycle when the voltage at the ADJ pin falls 2.5% below
ADJ (Pin H7):
Battery Float Voltage Feedback Input. The the float voltage. Once the charge cycle is terminated, the charge function operates to achieve a final float voltage of input bias current of the BAT pin is reduced to minimize 3.3V on this pin. The output battery float voltage (VBAT(FLT)) battery discharge while the charger remains connected. is programmed using a resistor divider. VBAT(FLT) can be
V
programmed up to 14.4V. The auto-restart feature initi-
INA (Bank 3):
Anode of input reverse protection Schottky diode. Connect the input power here if input reverse volt- ates a new charging cycle when the voltage at the ADJ age protection is desired. pin falls 2.5% below the float voltage reference. The ADJ pin input bias current is 110nA. Using a resistor divider
VIN (Bank 4):
Charger Input Supply. Decouple with at least with an equivalent input resistance at the ADJ pin of 250k 4.7µF to GND. Connect the input power here if no input compensates for input bias current error. Required resistor reverse voltage protection is needed. values to program desired VBAT(FLT) follow the equations:
BIAS (Pin G7):
The BIAS pin connects to the internal power bus. In most cases connect to V V BAT. If this is not R1= BAT(FLT) • 2.5 • 105 (Ω) desirable, connect to a power source greater than 2.8V 3.3 and less than 10V. R1• 2.5 • 105
CHRG (Pin K7):
Open-Collector Charger Status Output; R2 = (Ω) R1−(2.5 • 105) typically pulled up through a resistor to a reference voltage. This status pin can be pulled up to voltages as R1 is connected from BAT to ADJ, and R2 is connected high as VIN and can sink currents up to 10mA. During from ADJ to ground. a battery charging cycle, CHRG is pulled low. When the charge current falls below C/10, the CHRG pin becomes
FAULT (Pin J7):
Open-Collector Fault Status Output; typi- high impedance. If the internal timer is used for termina- cally pulled up through a resistor to a reference voltage. tion, the pin stays low during the charging cycle until the This status pin can be pulled up to voltages as high as charge current drops below a C/10 rate, approximately VIN and can sink currents up to 10mA. This pin indicates 200mA, even though the charger will continue to top off charge cycle fault conditions during a battery charging the battery until the end-of-charge timer terminates the cycle. A temperature fault causes this pin to be pulled charge cycle. A temperature fault also causes this pin to low. If the internal timer is used for termination, a bad bat- be pulled low (see the Applications Information section). tery fault also causes this pin to be pulled low. If no fault conditions exist, the FAULT pin remains high impedance
NTC (Pin H6):
Battery Temperature Monitor Pin. This pin (see the Applications Information section). is the input to the NTC (negative temperature coefficient) thermistor temperature monitoring circuit. This function is
TMR (Pin J6):
End-Of-Cycle Timer Programming Pin. enabled by connecting a 10kΩ, B = 3380 NTC thermistor If a timer-based charge termination is desired, connect from the NTC pin to ground. The pin sources 50μA, and a capacitor from this pin to ground. Full charge end-of monitors the voltage across the 10kΩ thermistor. When the cycle time (in hours) is programmed with this capacitor voltage on this pin is above 1.36V (T < 0°C) or below 0.29V following the equation: (T > 40°C), charging is disabled and the CHRG and FAULT tEOC = CTIMER • 4.4 • 106 pins are both pulled low. If the internal timer termination is being used, the timer is paused, suspending the charging A bad battery fault is generated if the battery does not cycle. Charging resumes when the voltage on NTC returns reach the precondition threshold voltage within one-eighth to within the 0.29V to 1.36V active region. There is approxi- of tEOC, or: mately 5°C of temperature hysteresis associated with each tPRE = CTIMER • 5.5 • 105 8062fd For more information www.linear.com/LTM8062 7 Document Outline Features Applications Description Typical Application Absolute Maximum Ratings Pin Configuration Order Information Electrical Characteristics Typical Performance Characteristics Pin Functions Applications Information Typical Application Related Parts