LTC4100 Typical perForMance characTerisTicsCharging Current ErrorCharging Voltage Error 0.4 0.150 VDD = 5V VDD = 5V 0.125 0.3 TEMP = 27°C TEMP = 27°C VLOAD = 12V 0.100 ILOAD = 0.120A 0.2 0.075 0.050 DCIN = 20V 0.1 0.025 DCIN = 15V 0 TAGE ERROR (V) 0 –0.025 –0.1 –0.050 –0.2 –0.075 OUTPUT CURRENT ERROR (A) DCIN = 15V, NoLowI OUTPUT VOL DCIN = 20V, NoLowI –0.100 –0.3 DCIN = 15V, LowI –0.125 DCIN = 20V, LowI –0.4 –0.150 0 1 2 3 4 0 2 4 6 8 10 12 14 16 18 20 22 CHARGING CURRENT (A) CHARGING VOLTAGE (V) 4100 G10 4100 G11 pin FuncTions TGATE (Pin 1): Drives the Top External P-MOSFET of the change of status in the charger registers and that the host Battery Charger Buck Converter. should read the LTC4100 status registers to determine if PGND (Pin 2): High Current Ground Return for BGATE any action on its part is required. This signal can be con- Driver. nected to the optional SMBALERT# line of the SMBus. Open drain with weak current source pull-up to VDD (with BGATE (Pin 3): Drives the Bottom External N-MOSFET of Schottky to allow it to be pulled to 5V externally). the Battery Charger Buck Converter. SDA (Pin 8): SMBus Data Signal from Main (host- INFET (Pin 4): Drives the Gate of the External Input controlled) SMBus. External pull-up resistor is required. P-MOSFET. SCL (Pin 9): SMBus Clock Signal from Main (host- DCIN (Pin 5): External DC Power Source Input. Bypass to controlled) SMBus. External pull-up resistor is required. ground with a 0.1µF capacitor. ACP (Pin 10): This Output Indicates the Value of the CHGEN (Pin 6): Digital Bidirectional Pin to Enable Charger DCDIV Comparator. It can be used to indicate whether Function. This pin is connected as a wired AND bus. AC is present or not. The following events will cause the POWER_FAIL bit in DCDIV (Pin 11): Supply Divider Input. This is a high im- the ChargerStatus register to become set: pedance comparator input with a 1.2V threshold (rising 1. An external device pulling the CHGEN signal to within edge) and hysteresis. 0.9V to GND; GND (Pin 12): Ground for Digital and Analog Circuitry. 2. The AC adapter voltage is not above the battery voltage. ILIM (Pin 13): An external resistor is connected between this SMBALERT (Pin 7): Active Low Interrupt Output to Host pin and GND. The value of the external resistor programs (referred to as the SMBALERT# signal in the SMBus Revi- the range and resolution of the programmed charger cur- sion 1.1 specification). Signals host that there has been a rent. This is a digital, not an analog, function. 4100fc For more information www.linear.com/LTC4100 7