Datasheet LTC2945 (Analog Devices) - 8

LTC2945
PIN FUNCTIONS ADIN:
ADC Input. The onboard ADC measures voltages
SCL:
I2C Bus Clock Input. Data at the SDAI pin is shifted between 0V and 2.048V. Tie to ground if unused. in or out on rising edges of SCL. This pin is driven by an
ADR1, ADR0:
I2C Device Address Inputs. Connecting these open-col ector output from a master control er. An external pins to INTV pull-up resistor or current source is required and can be CC, GND or leaving the pins open configures one of nine possible addresses. See Table 1 in Applications placed between SCL and VDD or INTVCC. The voltage at Information section for details. SCL is internally clamped to 6.4V (5.9V minimum)
ALERT:
Fault Alert Output. Open drain logic output that
SDAI:
I2C Bus Data Input. Used for shifting in address, is pulled to ground after an ADC conversion resulted in command or data bits. This pin is driven by an open- a fault to alert the host controller. A fault alert is enabled collector output from a master controller. An external by setting the corresponding bit in the ALERT register pull-up resistor or current source is required and can be as shown in Table 4. This device is compatible with the placed between SDAI and VDD or INTVCC. The voltage at SMBus alert protocol. See Applications Information. Tie SDAI is internally clamped to 6.4V (5.9V minimum) to ground if unused.
SDAO:
I2C Bus Data Output. Open-drain output used for
EXPOSED PAD (Pin 13, DD Package Only):
Exposed pad sending data back to the master controller or acknowledging may be left open or connected to device ground. For best a write operation. An external pull-up resistor or current thermal performance, connect to a large PCB area. source is required.
GND:
Device Ground.
SDAO:
Inverted I2C Bus Data Output. Open-drain output used for sending data back to the master controller or
INTVCC:
Internal Low Voltage Supply Input/Output. This acknowledging a write operation. Data is inverted for pin is used to power internal circuitry. It can be config- convenience of opto-isolation. An external pull-up resistor ured as a direct input for a low voltage supply, as linear or current source is required. regulator from higher voltage supply connected to VDD, or as a shunt regulator. Connect this pin directly to a 2.7V
SENSE+:
Supply Voltage and Current Sense Input. Used as to 5.9V supply if available. When INTV a supply and current sense input for the internal current CC is powered from an external supply, short the V sense amplifier. The voltage at this pin is monitored by the DD pin to INTVCC. If VDD is connected to a 4V to 80V supply, INTV onboard ADC with a full-scale input range of 102.4V. See CC becomes the 5V output of an internal series regulator that can supply Figure 16 for recommended Kelvin connection. up to 10mA to external circuitry. For even higher supply
SENSE–:
Current Sense Input. Connect an external sense voltages or if a floating topology is desired, INTVCC can resistor between SENSE+ and SENSE–. The differential be used as a 6.3V shunt regulator. Connect the supply to voltage between SENSE+ and SENSE– is monitored by the INTVCC through a shunt resistor that limits the current to onboard ADC with a full-scale sense voltage of 102.4mV. less than 35mA. An undervoltage lockout circuit disables
V
the ADC when the voltage at this pin drops below 2.5V.
DD:
High Voltage Supply Input. This pin powers an internal series regulator with input voltages ranging from 4V to Connect a bypass capacitor between 0.1µF and 1µF from 80V and produces 5V at INTV this pin to ground. CC when the input voltage is above 7V. Connect a bypass capacitor between 0.1µF and 1µF from this pin to ground if external load is pres- ent on the INTVCC pin. The onboard 12-bit ADC can be configured to monitor the voltage at VDD with a full-scale input range of 102.4V. 2945fb 8 For more information www.linear.com/LTC2945