Cirrus Logic CS5461A - Manual (Page 5)

CS5461A
DS661F3 5
1. OVERVIEW
The CS5461A is a CMOS monolithic power measurement device with a computation engine and an en-
ergy-to-frequency pulse output. The CS5461A combines a programmable-gain amplifier, two
 ana-
log-to-digital converters (ADCs), system calibration and a computation engine on a single chip.
The CS5461A is designed for power measurement applications and is optimized to interface to a cur-
rent-sense resistor or transformer for current measurement, and to a resistive divider or potential trans-
former for voltage measurement. The voltage and current channels provide programmable gains to
accommodate various input levels from a wide variety of sensing elements. With single +5 V supply on
VA+/AGND, both of the CS5461A’s input channels can accommodate common mode as well as signal
levels between (AGND - 0.25 V) and VA+.
Additionally, the CS5461A is equipped with a computation engine that calculates I
RMS
, V
RMS
, apparent
power and active (real) power. To facilitate communication to a microprocessor, the CS5461A includes a
simple three-wire serial interface which is SPI™ and Microwire™ compatible. The CS5461A provides
three outputs for energy registration. E1 and E2 are designed to directly drive a mechanical counter or
stepper motor, or interface to a microprocessor. The pulse output E3 is designed to assist with meter cal-
ibration.