78M6610+LMU Data Sheet
Analog Front-End and Conversion
The Analog Front-End (AFE) includes an input multiplexer, optional pre-amplifier gain stage, Delta-Sigma
A/D Converter, bias current references, voltage references, temperature sensor, and several voltage fault
comparators.
Analog Inputs
Up to four external sensors can be connected to the 78M6610+LMU. Two single-ended inputs are
available for voltage sensors and two differential pairs are available for connecting current sensors.
Although the current inputs are differential inputs, a common-mode voltage of less than V3P3A ±25 mV is
recommended in order to utilize the available dynamic range. The full-scale signal level that can be
applied to the analog input pins is V3P3A ±250mVpk. Considering a sinusoidal AC waveform, the maximum
RMS voltage applied to the inputs pins is:
250푚푉푝푘
rmsMAX =
= 176.78mVrms
√2
Delta-Sigma A/D Converter
A second-order Delta-Sigma converter digitizes the analog inputs. The converted data is then processed
through a FIR filter.
Voltage Reference
The device includes an on-chip precision bandgap voltage reference that incorporates auto-zero
techniques as well as production trims to minimize errors caused by component mismatch and drift. The
voltage reference is digitally compensated over temperature.
Die Temperature Measurement
The device includes an on-chip die temperature sensor used for digital compensation of the voltage
reference. It is also used to report temperature information to the user.
24-Bit Energy Measurement Processor (EMP)
The 78M6610+LMU integrates a dedicated 24-bit signal processor that performs the entire digital signal
processing necessary for energy measurement, alarm generation, calibration, compensation, etc. Refer
to Section 2 for a description of functionality and operations.
Flash and RAM
The 78M6610+LMU includes 8KB of on-chip flash memory. The flash memory primarily contains program
code, but also stores calibration data and defaults for select nonvolatile configuration registers. The
device also includes 1.5KB of on-chip RAM which contains the values of input and output registers and is
utilized by the processor for its operations.
Multipurpose DIOs
There are a total of eleven digital input/outputs (DIOs) on the 78M6610+LMU device. Some are dedicated
to serial interface communications and configuration. Others are multipurpose I/O that can be used as a
simple output under user control or routed to special purpose internal signals like alarm signaling and
relay control.
Communication Interface
The 78M6610+LMU includes three communication interfaces: UART, SPI, and I2C. Since the I/O pins are
shared, only one mode is supported at a time. Interface configuration and address pins are sampled at
power-on or reset to determine which interface will be active and to set device addresses.
15
Rev 0
MAXIM [ MAXIM INTEGRATED PRODUCTS ]
