71M6513/71M6513H
3-Phase Energy Meter IC
A Maxim Integrated Products Brand
DATA SHEET
SEPTEMBER 2011
APPLICATION INFORMATION
Connection of Sensors (CT, Resistive Shunt, Rogowski Coil)
Figures 27 through 30 show how resistive dividers, current transformers, restive shunts, and Rogowski coils are connected to
the voltage and current inputs of the 71M6513.
The analog input pins of the 71M6511 are designed for sensors with low source impedance. RC filters with resistance
values higher than those implemented in the Teridian Demo Boards should be avoided.
VA = Vin * Rout/(Rout + Rin)
VA
Rin
Vin
Rout
Figure 27: Resistive Voltage Divider (left), Current Transformer (right)
Vout = dIin /dt
R
I
i
n
1/N
Vout
=
dI
R
i
n
I
A
V
out
V
C
V3P3
Vout
Figure 28: Resistive Shunt (left), Rogowski Coil (right)
Distinction between 71M6513 and 71M6513H Parts
71M6513H parts go through a process of trimming and characterization during production that make them suitable to high-
accuracy applications.
The first process applied to the 71M6513H is the trimming of the reference voltage, which is guaranteed to have accuracy over
temperature of better that ±10PPM/°C.
The second process applied to the 71M6513H is the characterization of the reference voltage over temperature. The
coefficients for the reference voltage are stored in so-called trim fuses (I/O RAM registers TRIMBGA, TRIMBGB, TRIMM[2:0].
The MPU program can read these trim fuses and calculate the correction coefficients PPM1 and PPM2 per the formulae given
in the Performance Specifications section (VREF, VBIAS). See the Temperature Compensation section for details.
The fuse TRIMBGB is non-zero for the 71M6513H part and zero for the 71M6513 part.
Trim fuse information is not available for non-H parts. Thus, the standard settings are to be applied. These settings are:
•
•
PPMC = TC1 * 22.46 = –149
PPMC2 = TC2 * 1150.1 = –392
© 2005-2011 Teridian Semiconductor Corporation
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