November 8, 2012 – Linear Technology Korea (CEO Hong Sa-gwak) announced the launch of an I2C system monitoring solution (product name: LTC2945) that monitors current, voltage, and power across a wide range of 0V to 80V rails. In many cases, previous power monitoring solution products have power supply limitations of 3V to 5V and monitor voltages below 36V, requiring additional circuitry to monitor higher voltages. The LTC2945 provides flexible power supply options, receiving power from 4V to 80V monitored at the power source, and receiving power from a 2.7V to 80V secondary power supply or from an onboard shunt regulator. These power supply options eliminate the need for individual buck regulators, shunt regulators, or inefficient resistor dividers while monitoring any rail from 0V to 80V. The LTC2945 is a simple, straightforward IC solution that uses an internal delta-sigma ADC and multiplier to provide 12-bit current and voltage measurement and 24-bit power reading capabilities.

The LTC2945's wide operating range is suitable for numerous applications, and is particularly ideal for 48V telecom equipment, AMC (advanced mezzanine card), and blade servers. The onboard shunt regulator supports power supplies above 80V and provides negative power supply monitoring capability. The LTC2945 measures current and voltage either continuously or on demand, calculates power, and stores all information as minimum and maximum values in registers accessible via I2C. Once measurement is performed, the total unadjusted error (TUE) across the full temperature range is only ±0.75%. When parameters exceed user-programmable thresholds, the LTC2945 indicates alert registers and pins for 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 provides inverted data output I2C pins for conversion to opto-isolator configuration.

The LTC2945 and LTC2945-1 are available in commercial and industrial versions, operating at temperature ranges of 0°C to 70°C and -40°C to 85°C, respectively. Both versions comply with RoHS specifications and are supplied in 12-pin 3mm x 3mm QFN and 12-pin MSOP packages. Pricing is set at $3.57 per unit based on a quantity of 1,000 units. For detailed information on product selection and specifications, refer to www.linear.com/products/power_monitors.

Photo Caption: Wide-range power monitor with onboard ADC I2C & shunt regulator

Product Features: LTC2945

• Rail-to-rail input range: 0V to 80V
• Wide input power range: 2.7V to 80V
• Shunt regulator for power supplies >80V
• I2C interface
• Δ∑ ADC with TUE below ±0.75%
• 12-bit resolution for current & voltage
• Internal multiplier calculating power value at 24-bit
• Additional ADC input for monitoring external voltage
• Minimum & maximum value storage
• Continuous scan & snapshot mode
• Shutdown mode with IQ < 80µA
• Split SDA suitable for opto-isolation
• Available in 12-pin 3mm x 3mm QFN & 12-pin MSOP packages