71M6521FE-IGT/F Maxim Integrated Products, 71M6521FE-IGT/F Datasheet - Page 61

• Manufacturer Part Number: 71M6521FE-IGT/F
• Description: IC ENERGY METER 32K FLASH 64LQFP
• Manufacturer: Maxim Integrated Products

Specifications of 71M6521FE-IGT/F

• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

71M6521DE/DH/FE Data Sheet
Measurement of absolute temperature uses the on-chip temperature sensor while applying the following formula:
In the above formula T is the temperature in °C, N(T) is the ADC count at temperature T, N
25°C, S
Example: At 25°C a temperature sensor value of 518,203,584 (N
LQFP package. At an unknown temperature T the value 449.648.000 is read at (N(T)). The absolute temperature is
then determined by dividing both N
the results into the above formula, using –2220 for LSB/°C:
It is recommended to base temperature measurements 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.
Temperature Coefficients: The internal voltage reference is calibrated during device manufacture.
For the 71M6521DE/FE, the temperature coefficients TC1 and TC2 are given as constants that represent typical
component behavior (in µV/°C and µV/°C
For the 71M6521DH, the temperature characteristics of the chip are measured during production and then stored in
the fuse registers TRIMBGA, TRIMBGB, TRIMT and TRIMM[2:0]. TC1 and TC2 can be derived from the fuses by
using the relations given in the Electrical Specifications section.
Close examination of the electrical specification (see Table 61) for the parts with regular accuracy 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. 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%.
Similar considerations apply to the high-accuracy parts (see Table 62), where the error around the calibration
temperature should be considered constant at ±800 PPM, or ±0.08%.
Rev 2
Parameter
VREF(T) deviation from VNOM(T)
VREF
VNOM
n
(
Since TC1 and TC2 are given in µV/°C and µV/°C
to be taken into account when transitioning to PPM/°C and PPM/°C
26.84*TC1/1.195, and PPMC2 = 1374*TC2/1.195.
T
is the sensitivity in LSB/°C as stated in the Electrical Specifications, and T
)
−
VNOM
(
T
)
(
T
)
max(
Table 61: VREF Definition for the Regular Accuracy Parts
T
10
T
−
6
=
22
n
and N(T) by 512 to account for the 9-bit shift of the ADC value and then inserting
449.648.00
,
40
Temperature Compensation
Temperature Measurement
)
2
, respectively).
512
Condition
T
⋅
- 0
(
−
=
2220
518,203,58
(
N
(
T
2
)
, respectively, the value of the VREF voltage (1.195 V) has
S
)
n
−
N
n
4
n
) is read by the ADC by a 71M6521FE in the 64-pin
)
+
+
25
T
n
C
=
Min
85
-40
3 .
°
n
C
is +25°C.
2
. This means that PPMC =
n
is the ADC count at
+40
Typ
PPM/ºC
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