LTC2946 PIN FUNCTIONS ADIN: ADC Input. The onboard ADC measures voltages GPIO3: General Purpose Input/Output (Open Drain). between 0V and 2.048V with respect to GND or INTVCC. Configurable to general purpose output, input or ALERT. Tie to ground if unused. See Table 3 in the Applications As ALERT, it is pulled to ground when a fault occurs to Information section for details. alert the host controller. A fault alert is enabled by setting ADR1, ADR0: I2C Device Address Inputs. Connecting these the corresponding bit in the ALERT registers, as shown pins to INTV in Tables 5 and 8. Tie to ground if unused. See Table 9 in CC, GND, or leaving the pins open configures one of nine possible addresses. See Table 1 in the Ap- the Applications Information section for details. plications Information section for details. INTVCC: Internal Low Voltage Supply Input/Output. This pin CLKIN: Clock Input. Connect to ground to use the internal is used to power internal circuitry. It can be configured as ±5% clock. For improved accuracy, connect to an external a direct input for a low voltage supply, as a linear regula- crystal oscillator circuit or drive with an external clock. tor from a higher voltage supply connected to VDD, or as a shunt regulator. Connect this pin directly to a 2.7V to CLKOUT: Clock Output. Connect to an external crystal 5.8V supply if available. When INTVCC is powered from oscillator circuit. Leave open if unused. an external supply, short the VDD pin to INTVCC. If VDD is EXPOSED PAD: Exposed Pad may be left open or con- connected to a 4V to 100V supply, INTVCC becomes the nected to device ground. For best thermal performance, 5V output of an internal series regulator that can supply connect to a large PCB area. up to 10mA to external circuitry. For even higher supply voltages, or if a floating topology is desired, INTV GND: Device Ground. CC can be used as a 6.3V shunt regulator. Connect the supply to GPIO1: General Purpose Input/Output (Open Drain). Con- INTVCC through a resistor or current source that limits the figurable to general purpose output or input. Tie to ground shunt regulator current to less than 35mA. An undervolt- if unused. See Table 9 in the Applications Information age lockout circuit disables the ADC when the voltage at section for details. this pin drops below 2.5V. Connect a bypass capacitor of 0.1μF or greater from this pin to ground. If an external GPIO2: General Purpose Input/Output (Open Drain). Con- load is present, for loop stability use a bypass capacitor figurable to general purpose output, input or accumulation of 0.22μF or greater. enable (ACC) to gate internal accumulators. Tie to ground if unused. See Table 9 in the Applications Information SCL: I2C Bus Clock Input. Data at the SDAI pin is shifted section for details. in or out on rising edges of SCL. This pin is driven by an open-collector output from a master controller. An external pull-up resistor or current source is required and can be placed between SCL and VDD or INTVCC. The voltage at SCL is internally clamped to 6.4V typically. 2946fa 8 For more information www.linear.com/LTC2946 Document Outline Features Applications Description Typical Application Absolute Maximum Ratings Pin Configuration Order Information Electrical Characteristics Typical Performance Characteristics Pin Functions Block Diagram Timing Diagram Operation Applications Information Typical Applications Package Description Typical Application Related Parts
