71M6513-IGTR/F Maxim Integrated Products, 71M6513-IGTR/F Datasheet - Page 81

• Manufacturer Part Number: 71M6513-IGTR/F
• Description: IC ENERGY METER 3PH 100-LQFP
• Manufacturer: Maxim Integrated Products

Specifications of 71M6513-IGTR/F

• Mounting Style: SMD/SMT
• Package / Case: LQFP-100
• Program Memory Size: 64 KB
• Program Memory Type: Flash
• Supply Current (max): 6.4 mA
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

When applying the inverted coefficients, a curve (see Figure 30) will result that effectively neutralizes the original crystal
characteristics. The frequencies were calculated using the fit coefficients as follows:
The MPU Demo Code supplied with the Teridian Demo Kits has a direct interface for these coefficients and it directly controls
the RTC_DEC_SEC or RTC_INC_SEC registers. The Demo Code uses the coefficients in the following form:
Note that the coefficients are scaled by 10, 100, and 1000 to provide more resolution. For our example case, the coefficients
would then become (after rounding, since the Demo Code accepts only integers):
Alternatively, the mains frequency may be used to stabilize or check the function of the RTC. For this purpose, the CE
provides a count of the zero crossings detected for the selected line voltage in the MAIN_EDGE_X address. This count is
equivalent to twice the line frequency, and can be used to synchronize and/or correct the RTC.
In a production electricity meter, the 71M6513 or 71M6513H is not the only component contributing to temperature de-
pendency. In fact, a whole range of components (e.g. current transformers, resistor dividers, power sources, filter capacitors)
will exhibit slight or pronounced temperature effects. Since the output of the on-chip temperature sensor is accessible to the
MPU, temperature-compensation mechanisms with great flexibility, i.e. beyond the capabilities implemented in the CE, are
possible.
Temperature measurement can be implemented with the following steps:
CORRECTION
1)
2)
3)
Y_CAL = 109, Y_CALC = 12, Y_CALC2 = 7
At a known temperature T
Read the TEMP_X register at the known temperature. The obtained value should be <±0.1°C.
The temperature T (in °C) at any environment can be obtained by reading TEMP_X and applying the following
formula:
A Maxim Integrated Products Brand
T
f
=
=
T
f
N
nom
+
(
ppm
TEMP
⋅



1
+
10
)
=
10
_ X
a
Y
6
+
32768.5
32768.4
32768.3
32768.2
32768.1
32767.9
32767.8
32767.7
32767.6
32767.5
_
10
32768
T
CAL
10
b
N
6
-50
, read the TEMP_RAW register of the CE and write the value into TEMP_NOM.
+
+
T
T
⋅
External Temperature Compensation
2
Y
© 2005-2011 Teridian Semiconductor Corporation
10
_
c
100
6
Figure 30: Crystal Compensation
CALC



Temperature Measurement
-25
+
T
2
⋅
Y
_
crystal
curve fit
inverse curve
1000
CALC
0
3-Phase Energy Meter IC
2
71M6513/71M6513H
25
DATA SHEET
50
SEPTEMBER 2011
Page: 81 of 104