71M6533 Datasheet, PDF (68/132 Pages) Teridian Semiconductor Corporation – Energy Meter IC

71M6533/G/H and 71M6534/H Data Sheet
FDS_6533_6534_004
3 Application Information
3.1 Connection of Sensors (CT, Resistive Shunt)
Figure 31 through Figure 33 show how resistive dividers, current transformers, Rogowski coils and resistive
shunts are connected to the voltage and current inputs of the 71M6533/71M6534.
The analog input pins of the 71M65XX are designed for sensors with low source impedance. RC
filters with components differing from the components used in the Teridian Demo Boards should be
avoided. See Application Note AN5292 for details on filter implementation.
VA = Vin * R_out/(R_out + R_in)
VA
V_in
R_in
R_out
Figure 31: Resistive Voltage Divider
I_in
I_out
R
IA
V_out
I_IN
I_OUT
V_OUT
R
V_DIFF
InP
V3P3A
V3P3
1/N
Filter
1/N
InN
Figure 32: CT with Single Ended (Left) and Differential Input (Right) Connection
I_in
IA
I_{in 1/N} ^{Vout = dI}in ^/dt
IA
R
V_out
R
V_out
V_C
V3P3
V3P3
Figure 33: Resistive Shunt (Left), Rogowski Sensor (Right)
Note: Ferrites or other inductive components must not be connected directly to the sensor input pins (InP,
InN Vn).
3.2 Distinction between 71M6533/71M6534 and 71M6533G/H/71M6534H Parts
The 71M6533G, 71M6533H, and 71M6534H (high-accuracy) parts go through an additional process of
characterization during production which makes them suitable to high-accuracy performance over
temperature.
The first process, applied to all parts is the trimming of the reference voltage to the target value of 1.195
V.
The second process, which is applied only to the high-accuracy parts, is the characterization of the re-
ference voltage over temperature. The coefficients for the reference voltage are stored in trim fuses (I/O
RAM registers TRIMBGA, TRIMBGB, TRIMM[2:0]. The MPU can read these trim fuses and calculate the
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