ZHCSDK7 April 2015
PRODUCTION DATA.
PIN | TYPE | DESCRIPTION | |
---|---|---|---|
NAME | NUMBER | ||
VBUS | 1,24 | P | Charger Input Voltage. The internal n-channel reverse block MOSFET (RBFET) is connected between VBUS and PMID with VBUS on source. Place a 1-µF ceramic capacitor from VBUS to PGND and place it as close as possible to IC. |
PSEL | 2 | I | Power source selection input. High indicates a USB host source and Low indicates an adapter source. |
PG | 3 | O | Open drain active low power good indicator. Connect to the pull up rail via 10-kΩ resistor. LOW indicates a good input source if the input voltage is between UVLO and ACOV, above SLEEP mode threshold, and current limit is above 30 mA. |
STAT | 4 | O | Open drain charge status output to indicate various charger operation. Connect to the pull up rail via 10-kΩ resistor. LOW indicates charge in progress. HIGH indicates charge complete or charge disabled. When any fault condition occurs, STAT pin in the charge blinks at 1 Hz. |
SCL | 5 | I | I2C Interface clock. Connect SCL to the logic rail through a 10-kΩ resistor. |
SDA | 6 | I/O | I2C Interface data. Connect SDA to the logic rail through a 10-kΩ resistor. |
INT | 7 | O | Open-drain Interrupt Output. Connect the INT to a logic rail via 10kΩ resistor. The INT pin sends active low, 256-µs pulse to host to report charger device status and fault. |
OTG | 8 | I Digital |
USB current limit selection pin during buck mode, and active high enable pin during boost mode. |
For bq24298, when in buck mode with USB host (PSEL = High), when OTG = High, IIN limit = 500 mA and when OTG = Low, IIN limit = 100 mA. | |||
The boost mode is activated when the REG01[5] = 1 and OTG pin is High. | |||
CE | 9 | I | Active low Charge Enable pin. Battery charging is enabled when REG01[5:4] = 01 and CE pin = Low. CE pin must be pulled high or low. |
ILIM | 10 | I | ILIM pin sets the maximum input current limit by regulating the ILIM voltage at 1 V. A resistor is connected from ILIM pin to ground to set the maximum limit as IINMAX = (1V/RILIM) × KILIM. The actual input current limit is the lower one set by ILIM and by I2C REG00[2:0]. The minimum input current programmed on ILIM pin is 500 mA. |
TS | 11 | I Analog |
Temperature qualification voltage input. Connect a negative temperature coefficient thermistor. Program temperature window with a resistor divider from REGN to TS to GND. Charge suspends or Boost disable when TS pin is out of range. A 103AT-2 thermistor is recommended. |
QON | 12 | I | BATFET enables control in shipping mode and BATFET reset function. Logic high to low transition on this pin with at least tQON_ON_1 deglitch turns on BATFET to exit shipping mode. It has internal pull up to maintain default high logic. When VBUS is not plugged-in, a logic low of at least tQON_RST will reset SYS power by turning BATFET off for tBATFET_RST and then re-enable BATFET after tBATFET_RST duration. The pin integrates a pull-up resistor of typical 187 kΩ. |
BAT | 13,14 | P | Battery connection point to the positive pin of the battery pack. The internal BATFET is connected between BAT and SYS. Connect a 10 µF closely to the BAT pin. |
SYS | 15,16 | I | System connection point. The internal BATFET is connected between BAT and SYS. When the battery falls below the minimum system voltage, switch-mode converter keeps SYS above the minimum system voltage. The SYS pin has a built-in load to ground which may discharge 330-µF load to less than 0.3 V within 250 ms typically. |
PGND | 17,18 | P | Power ground connection for high-current power converter node. Internally, PGND is connected to the source of the n-channel LSFET. On PCB layout, connect directly to ground connection of input and output capacitors of the charger. A single point connection is recommended between power PGND and the analog GND near the IC PGND pin. |
SW | 19,20 | O | Switching node connecting to output inductor. Internally SW is connected to the source of the n-channel HSFET and the drain of the n-channel LSFET. Connect the 0.047-µF bootstrap capacitor from SW to BTST. |
BTST | 21 | P | PWM high side driver positive supply. Internally, the BTST is connected to the anode of the boost-strap diode. Connect the 0.047-µF bootstrap capacitor from SW to BTST. |
REGN | 22 | P | PWM low side driver positive supply output. Internally, REGN is connected to the cathode of the boost-strap diode. Connect a 4.7-µF (10-V rating) ceramic capacitor from REGN to analog GND. The capacitor should be placed close to the IC. REGN also serves as bias rail of TS pin. |
Thermal Pad | P | Exposed pad beneath the IC for heat dissipation. Always solder thermal pad to the board, and have vias on the thermal pad plane star-connecting to PGND and ground plane for high-current power converter. |