71M6531F-IM/F Maxim Integrated Products, 71M6531F-IM/F Datasheet - Page 64

• Manufacturer Part Number: 71M6531F-IM/F
• Description: IC ENERGY METER 256KB 68-QFN
• Manufacturer: Maxim Integrated Products

Specifications of 71M6531F-IM/F

• Mounting Style: SMD/SMT
• Package / Case: QFN-68
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

It is recommended that temperature measurements be based on TEMP_RAW_X which is the sum of two
consecutive temperature readings, thus being higher by a factor of two than the raw sensor readings.
PPM/°C.
T > 62°C) or for which T-22 < -40 (i.e. T < -18°C), the data sheet states ±40 PPM/°C. For temperatures
between -18°C and +62°C, the error should be considered constant at ±1,600 PPM, or ±0.16%.
tical to measure the temperature coefficient of high-quality references at small temperature excursions.
For example, at +25°C, the expected error would be ±3°C * 40 PPM/°C, or just 0.012%.
The maximum deviation of ±2520 PPM (or 0.252%) is reached at the temperature extremes. If the refer-
ence voltage is used to measure both voltage and current, the identical errors of ±0.252% add up to a
maximum Wh registration error of ±0.504%.
Data Sheet 71M6531D/F-71M6532D/F
3.3
Measurement of absolute temperature uses the on-chip temperature sensor and applying the following
formula:
In the above formula, T is the temperature in °C, N(T) is the ADC count at temperature T, N
count at 25°C, S
3.4
3.4.1
The internal voltage reference VREF is calibrated during device manufacture.
The temperature coefficient TC2 is given as a constant that represents typical component behavior (in
µV/°C
RAM register. TC1 and TC2 allow compensation for variations of the reference voltage to within ± 40
Close examination of the electrical specification (see Table 53) reveals that the achievable deviation is
not strictly ±40 PPM/°C over the whole temperature range: Only for temperatures for which T-22 > 40 (i.e.
Figure 31 shows this concept graphically. The “box” from -18°C to +62°C reflects the fact that it is imprac-
64
Parameter
VREF(T) deviation from VNOM(T)
VREF
2
). TC1 (µV/°C) can be calculated for the individual chip from the contents of the TRIMT[7:0] I/O
VNOM
(
Since TC1 and TC2 are given in µV/°C and µV/°C
(1.195V) has to be taken into account when transitioning to PPM/°C and PPM/°C
that PPMC = 26.84*TC1/1.195 and PPMC2 = 1374*TC2/1.195).
T
Temperature Measurement
Temperature Compensation
Temperature Coefficients:
)
−
VNOM
(
T
)
n
is the sensitivity in LSB/°C as stated in the Electrical Specifications and T
(
T
)
max(
© 2005-2010 TERIDIAN Semiconductor Corporation
T
10
−
6
22
,
Table 53: VREF Definition for 6513H
40
)
T
=
(
N
Condition
(
T
S
)
n
−
N
n
2
, respectively, the value of the VREF voltage
)
+
T
n
-40
Min
FDS 6531/6532 005
2
. This means
+40
n
n
is the ADC
is +25 °C.
PPM/ºC
Typ
v1.3