CS5451A

DS635PP1

9

3. GENERAL DESCRIPTION

The CS5451A is designed for 3-phase power meter

applications and interfaces to a current transform-

ers or shunt to measure current, and a resistive di-

vider or transformer to measure voltage.

The CS5451A combines six

∆Σ modulators and

decimation filters, three channels assigned for cur-

rent input that have programmable input gain am-

plifiers, and three channels assigned for voltage

input.

The CS5451A includes six decimation filters that

output data at a 2000 Hz or 4000 Hz output word

rate (OWR) when the input frequency at XIN =

4.096 MHz.

The device outputs data on a serial output port.

3.1

Theory of Operation

The CS5451A is designed to operate from a single

range for the voltage channels. These voltages rep-

resent the maximum zero-to-peak voltage levels

that can be presented to the inputs. The CS5451A

is designed to accommodate common mode + sig-

nal levels from VA- to VA+. Figure 2 illustrates the

VA +

VD +

VIN 1+, VIN2 +, or VIN 3+

V IN 1 -, VIN2 -, o r V IN3-

IIN1 +, IIN 2 +, o r IIN 3+

IIN 1 -, I IN2 - , o r II N3 -

AG N D

DG N D

RE FIN

RE FO UT

O ption al

Exte rn al

Re fe ren ce

V

PHA S E

+

I

-2 V

PHA S E

VA -

+3 V

1.2 V

NOTE: Current input channels

actually measure voltage.

Figure 2. Typical Connection Diagram