- Buyers Guide
Linear's new rail-to-rail 80 V monitor measures current & voltage with +/-0.75% accuracy
Linear Technology Corp. introduces the LTC2945, a wide range I²C system monitor that monitors the current, voltage and power of any 0 to 80 V rail. In many cases, prior power monitoring solutions are limited to 3 to 5 V supplies and monitor voltages less than 36 V, requiring additional circuitry to monitor higher voltages. The LTC2945 has flexible power supply options, deriving power from a 4 to 80 V monitored supply, a 2.7 to 80 V secondary supply, or from the onboard shunt regulator. These supply options eliminate the need for a separate buck regulator, shunt regulator or inefficient resistive divider while monitoring any 0 to 80 V rail. The LTC2945 is a simple, single-IC solution that uses an internal Delta Sigma ADC and multiplier to provide 12-bit current and voltage measurements and 24-bit power readings.
The LTC2945’s wide operating range is ideal for many applications, especially for 48 V telecom equipment, advanced mezzanine cards (AMC) and blade servers. The onboard shunt regulator provides support for supplies greater than 80 V and negative supply monitoring. The LTC2945 measures current and voltage either continuously or on-demand, calculates power and stores all of this information along with minimum and maximum values in I²C accessible registers. Measurements are made with only ±0.75% of total unadjusted error (TUE) over the entire temperature range. If any parameter exceeds the user-programmable limits, the LTC2945 flags an alert register and pin per the SMBus alert response protocol. The 400kHz I²C interface features nine device addresses, a stuck bus reset timer and a split SDA pin that simplifies I²C opto-isolation. The LTC2945-1 version offers an inverted data output I²C pin for use with inverting opto-isolator configurations.
The LTC2945 and LTC2945-1 are offered in commercial and industrial versions, supporting operating temperature ranges from 0° to 70°C and -40° to 85°C, respectively. Both versions are available today in RoHS compliant, 12-pin 3 x 3 mm QFN and 12-lead MSOP packages. Pricing starts at $3.57 each in 1,000 piece quantities. Please visit www.linear.com/products/power_monitors for more product selection and information.