Features

• Rail-to-Rail Input Range: 0V to 80V
• Wide Input Supply Range: 2.7V to 80V
• Shunt Regulator for Supplies >80V
• ΔΣ ADC with less than ±0.75% Total Unadjusted Error
• 12-Bit Resolution for Current and Voltages
• Internal Multiplier Calculates 24-Bit Power Value
• Stores Minimum and Maximum Values
• Alerts When Limits Exceeded
• Additional ADC Input Monitors an External Voltage
• Continuous Scan and Snapshot Modes
• Shutdown Mode with I_Q < 80μA
• Split SDA for Opto-Isolation
• Available in 12-Lead 3mm × 3mm QFN and MSOP Packages

Typical Application

Description

The LTC®2945 is a rail-to-rail system monitor that measures current, voltage, and power. It features an operating range of 2.7V to 80V and includes a shunt regulator for supplies above 80V to allow flexibility in the selection of input supply. The current measurement range of 0V to 80V is independent of the input supply. An onboard 0.75% accurate 12-bit ADC measures load current, input voltage and an auxiliary external voltage. A 24-bit power value is generated by digitally multiplying the measured 12-bit load current and input voltage data. Minimum and maximum values are stored and an overrange alert with programmable thresholds minimizes the need for software polling. Data is reported via a standard I²C interface. Shutdown mode reduces power consumption to 20μA.

The LTC2945 I²C interface includes separate data input and output pins for use with standard or opto-isolated I²C connections. The LTC2945-1 has an inverted data output for use with inverting opto-isolator configurations.