78M6612 Maxim, 78M6612 Datasheet - Page 9

• 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

DS_6612_001
78M6612 Data Sheet
1.2.2
A/D Converter (ADC)
A single delta-sigma A/D converter digitizes the voltage and current inputs to the 78M6612. The
resolution of the ADC is configurable to either 21 or 22 bit. At the end of each ADC conversion, the FIR
filter output data is stored into the CE RAM location.
1.2.3 FIR Filter
The finite impulse response filter is an integral part of the ADC and it is optimized for use with the
multiplexer. The purpose of the FIR filter is to decimate the ADC output to the desired resolution. At the
end of each ADC conversion, the output data is stored into the CE RAM location determined by the
multiplexer selection. FIR data is stored LSB justified, but shifted left by nine bits.
1.2.4 Voltage References
The device includes an on-chip precision bandgap voltage reference that incorporates auto-zero
techniques. The reference is trimmed to minimize errors caused by component mismatch and drift. The
result is a voltage output with a predictable temperature coefficient.
1.2.5 Temperature Sensor
The 78M6612 includes an on-chip temperature sensor implemented as a bandgap reference. It is used
to determine the die temperature The MPU reads the temperature sensor output during alternate
multiplexer cycles. The primary use of the temperature data is to determine the magnitude of
compensation required to offset the thermal drift in the system (see
Section 3.4 Temperature
Compensation).
1.2.6 Battery Monitor
The 78M6618 also has the ability to measure battery voltage by the ADC during alternative multiplexer
frames. When set, an on-chip 45 kΩ load resistor is applied to the battery and a scaled fraction of the
battery voltage is applied to the ADC input. Battery operating modes are not supported in all firmware
libraries. Contact Maxim support for more information.
Rev 2
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