78M6612 Maxim, 78M6612 Datasheet - Page 22

• Manufacturer Part Number: 78M6612
• Description: The Teridian™ 78M6612 is a highly integrated, single-phase, power and energy measurement and monitoring system-on-chip (SoC) that includes a 32-bit compute engine (CE), an MPU core, RTC, and flash
• Manufacturer: Maxim

78M6612 Data Sheet
3.2 Connecting 5 V Devices
All digital input pins of the 78M6612 are compatible with external 5 V devices. I/O pins configured as
inputs do not require current-limiting resistors when they are connected to external 5 V devices.
3.3 Temperature Measurement
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 Temperature Compensation
Temperature Coefficients: The internal voltage reference is calibrated during device manufacture.
The temperature coefficients TC1 and TC2 are given as constants that represent typical component
behavior (in
Temperature Compensation: The CE provides the bandgap temperature to the MPU, which then may
digitally compensate the power outputs for the temperature dependence of VREF.
The MPU, not the CE, is entirely in charge of providing temperature compensation. The MPU applies the
following formula to determine GAIN_ADJ (address 0x12). In this formula TEMP_X is the deviation from
nominal or calibration temperature expressed in multiples of 0.1°C:
22
Since TC1 and TC2 are given in
(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).
In a power and energy measurement unit, the 78M6612 is not the only component contributing to
temperature dependency. A whole range of components (e.g. current transformers, resistor
dividers, power sources, filter capacitors) will contribute temperature effects. Since the output of
the on-chip temperature sensor is accessible to the MPU, temperature-compensation mechanisms
with great flexibility are possible
local to the chip)
µ
V/°C and
GAIN
n
is the sensitivity in LSB/°C and T
.
µ
_
V/°C
ADJ
2
, respectively).
=
16385
(e.g. system-wide temperature correction over the entire unit rather than
µ
+
V/°C and
T
TEMP
=
(
N
(
_
T
n
µ
2
S
X
)
V/°C
is +25 °C.
14
n
−
⋅
N
PPMC
2
n
, respectively, the value of the VREF voltage
)
+
T
n
+
TEMP
_
X
2
23
2
⋅
PPMC
2
2
. This means
n
DS_6612_001
is the ADC
Rev 2