CS5461 datasheet(5/46 Pages) CIRRUS

5 / 46 page

CS5461

DS546PP2

1. GENERAL DESCRIPTION

The CS5461 is a CMOS monolithic power measurement device with a real power/energy computation en-

gine. The CS5461 combines two programmable gain amplifiers, two

∆Σ modulators, two high rate filters,

system calibration, and calculation functions to provide instantaneous voltage and current data samples

and to calculate average (real) power, VRMS, IRMS, and instantaneous power data samples.

The CS5461 functionality is optimized for power measurement applications and is optimized to interface

to a shunt or current transformer for current measurement, and to a resistive divider or potential transform-

er for voltage measurement. To accommodate various input voltage levels from a multitude of current sen-

sors, the CS5461’s current channel has a front-end programmable gain amplifier (PGA), which allow for

two available full-scale differential input signal ranges on the current channel: 100 mVP-P and 500 mVP-P,

while the voltage channel has a set input range of 500 mVP-P. With single +5 V (common-mode) supply

across VA+/VA-, both of the CS5461’s input channels can accommodate (common-mode + signal) levels

between -0.25 V and VA+. This allows for a completely bipolar differential input configuration. The com-

mon-mode voltage level of the differential input signals can be anywhere between the supply voltage levels

on the VA+/VA- pins, as long as enough voltage margin is left over so that the addition of the differential

signals will not cause the total swing to go below -0.25 V or above +5 V.

The CS5461 includes two high-rate digital filters, which decimate the output from the two

∆Σ modulators.

These filters integrate the output of the

∆Σ modulators for both channels to yield instantaneous voltage and

current waveform output data at a (MCLK/K)/1024 output word rate (OWR).

To facilitate communication to a microcontroller, the CS5461 includes a simple three-wire serial interface

which is SPI™ and Microwire™ compatible.

CS5461 Datasheet(PDF) 5 Page - Cirrus Logic