Energy monitor enables measurement accuracy

24th September 2014

Siobhan O'Gorman

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Datasheet

Designed for DC supply rails in the 0 to 100V range, a high or low side charge, power and energy monitor has been released by Linear Technology. The LTC2946 monitor features a ±0.4% accurate, 12-bit ADC and external precision time base (crystal or clock), enabling measurement accuracy of more than ±0.6% for current and charge, and ±1% for power and energy.

In the absence of an external time base, a ±5% accurate internal time base is provided. Digital readings, including minimums and maximums of voltage, current and power, are stored in registers accessible by an I²C/SMBus interface. When measurements exceed configurable warning thresholds, an alert output signals which relieves the host of polling for data. To accurately assess and manage board level energy consumption, the LTC2946 provides access to all the necessary parameters.

The monitor can be powered from 2.7-5V directly, 4-100V through an internal linear regulator, or beyond 100V through an internal shunt regulator. Due to this wide operating range, the LTC2946 is suitable for monitoring board energy consumption in blade servers, telecomms, solar and industrial equipment, and AMC. The monitor features three general purpose I/O pins, two of which are configurable as an accumulator enable and alert output. An internal ADC is also featured and operates in either a continuous scan mode or a snapshot mode. In shutdown mode, the device current consumption drops from 900 to 15µA.

The LTC2946 is available in two options: the LTC2946 I²C and the LTC2946-1. The former has separate SDA input and output pins for standard or opto-isolated I²C, whereas the latter has an inverted SDA output for inverting opto-isolator configurations. Offered in 16-pin MSOP and 4x3mm DFN packages, the LTC2946 is specified over the commercial, industrial, automotive and military temperature ranges. The LTC2946 is sold in 1,000-piece quantities and priced at $3.95 each.