78M6610+LMU
Energy Measurement Processor
for Load Monitoring Units
GENERAL DESCRIPTION
The 78M6610+LMU is an energy measurement processor
(EMP) for load monitoring and control of any 2-wire single-
phase or 3-wire split-phase (120/180°) AC circuit. It
provides flexible sensor configuration of four analog inputs
and numerous host interface options for easy integration
into any system architecture.
The internal 24-bit processor and field upgradeable
firmware performs all the necessary signal processing,
compensation, and data formatting for accurate real-time
measurement. Energy accumulation, alarm monitoring, and
fault detection schemes minimize the overhead
requirements of the host interface and/or network. The
integrated flash memory also provides for nonvolatile
storage of input configurations and calibration coefficients.
FEATURES
•
Four Configurable Analog Inputs for
Monitoring Any Single-Phase Circuit
(2/3-Wire)
•
Supports Current Transformers (CT) and
Resistive Shunts
•
Flexible SPI, I C, or UART Interface Options
with Configurable I/O Pins for Alarm
Signaling, Address Pins, or User Control
•
Nonvolatile Storage of Calibration and
Configuration Parameters
•
Small 24-TQFN Package and Reduced Bill of
Materials
•
Internal or External Oscillator Timing
References
•
Quick Calibration Routines Minimize
Manufacturing (System) Cost
2
APPLICATIONS
•
•
•
•
Building Automation Systems (Commercial, Industrial)
Inverters and Renewable Energy Systems
Level 1 and 2 EV Charging Systems
Grid-Friendly Appliances and Smart Plugs
Single Converter
Front End
Voltage
Sensor(s)
Current
Sensor(s)
Measurement
Processor
UART
Host
Interface
Load
Relay(s)
MUX
ADC
RAM
SPI
Digital
I/O
FLASH
I
2
C
78M6610+LMU
For pricing, delivery, and ordering information, please contact Maxim Direct at
1-888-629-4642, or visit Maxim Integrated’s website at www.maximintegrated.com.
19-6573; Rev 0; 1/13
78M6610+LMU Data Sheet
Table
of Contents
Electrical Specifications ............................................................................................................................. 5
Absolute Maximum Ratings .................................................................................................................. 5
Recommended External Components .................................................................................................. 5
Recommended Operating Conditions ................................................................................................... 5
Performance Specifications .................................................................................................................. 6
Input Logic Levels ....................................................................................................................... 6
Output Logic Levels .................................................................................................................... 6
Supply Current ............................................................................................................................ 6
Crystal Oscillator ......................................................................................................................... 6
Internal RC Oscillator .................................................................................................................. 6
ADC Converter, V
3P3
Referenced................................................................................................ 7
Timing Specifications ............................................................................................................................ 8
Reset ........................................................................................................................................... 8
SPI Slave Port ............................................................................................................................. 8
2
I C Slave Port (Note 1) ................................................................................................................ 9
Pin Configuration ...................................................................................................................................... 10
Package Information ........................................................................................................................... 11
On-Chip Resources Overview ................................................................................................................. 12
IC Block Diagram ................................................................................................................................ 12
Clock Management ............................................................................................................................. 13
Power-On and Reset Circuitry ............................................................................................................ 14
Watchdog Timer .................................................................................................................................. 14
Analog Front-End and Conversion ..................................................................................................... 15
24-Bit Energy Measurement Processor (EMP) ................................................................................... 15
Flash and RAM.......................................................................................................................... 15
Multipurpose DIOs .............................................................................................................................. 15
Communication Interface .......................................................................................................... 15
Functional Description and Operation .................................................................................................... 16
Measurement Interface ....................................................................................................................... 16
AFE Input Multiplexer ................................................................................................................ 16
High Pass Filters and Offset Removal ...................................................................................... 17
Gain Correction ......................................................................................................................... 18
Die Temperature Compensation ............................................................................................... 18
Phase Compensation ................................................................................................................ 19
Voltage Input Configuration....................................................................................................... 20
Current Input Configuration ....................................................................................................... 23
Data Refresh Rates ............................................................................................................................ 26
Scaling Registers ................................................................................................................................ 26
Calibration ........................................................................................................................................... 27
Voltage and Current Gain Calibration ....................................................................................... 27
Offset Calibration ...................................................................................................................... 27
Die Temperature Calibration ..................................................................................................... 27
Voltage Channel Measurements ........................................................................................................ 28
Quadrature Voltage ................................................................................................................... 28
Voltage Frequency .................................................................................................................... 28
Peak Voltage ............................................................................................................................. 28
RMS Voltage ............................................................................................................................. 28
Current Channel Measurements ......................................................................................................... 29
Peak Current ............................................................................................................................. 29
RMS Current ............................................................................................................................. 30
Crest Factor............................................................................................................................... 30
Power Calculations ............................................................................................................................. 31
Active Power (P) ....................................................................................................................... 31
2
Rev 0
78M6610+LMU Data Sheet
Reactive Power (Q) ................................................................................................................... 32
Apparent Power (S) ................................................................................................................... 32
Power Factor (PF) ..................................................................................................................... 32
Fundamental and Harmonic Calculations ........................................................................................... 33
Energy Calculations ............................................................................................................................ 34
Bucket Size for Energy Counters .............................................................................................. 34
Min/Max Tracking ................................................................................................................................ 36
Alarm Monitoring ................................................................................................................................. 37
Status Registers .................................................................................................................................. 39
Digital IO Functionality ........................................................................................................................ 40
DIO Polarity ............................................................................................................................... 40
Multipurpose (MP) Pins ............................................................................................................. 41
Command Register ............................................................................................................................. 42
Normal Operation ...................................................................................................................... 42
Calibration Command ............................................................................................................... 42
Save to Flash Command........................................................................................................... 43
Control Register .................................................................................................................................. 43
Configuration Register ........................................................................................................................ 43
Register Access ........................................................................................................................................ 44
Data Types .......................................................................................................................................... 44
Register Locations .............................................................................................................................. 45
Serial Interfaces ........................................................................................................................................ 49
UART Interface ................................................................................................................................... 49
RS-485 Support ........................................................................................................................ 49
Device Address Configuration................................................................................................... 50
SSI Protocol Description ........................................................................................................... 51
SPI Interface ....................................................................................................................................... 55
2
I C Interface ........................................................................................................................................ 58
Device Address Configuration................................................................................................... 58
Bus Characteristics ................................................................................................................... 59
Device Addressing .................................................................................................................... 59
Write Operations ....................................................................................................................... 60
Read Operations ....................................................................................................................... 61
Ordering Information ................................................................................................................................ 62
Contact Information .................................................................................................................................. 62
Revision History ........................................................................................................................................ 63
3
Rev 0
78M6610+LMU Data Sheet
Figure 1. SPI Timing ..................................................................................................................................... 8
2
Figure 2. I C Timing ...................................................................................................................................... 9
Figure 4. Package Outline........................................................................................................................... 11
Figure 5. Block Diagram .............................................................................................................................. 12
Figure 6. Crystal Connections ..................................................................................................................... 13
Figure 7. Reset Connections ...................................................................................................................... 14
Figure 8. AFE Input Multiplexer .................................................................................................................. 16
Figure 9. Voltage Input Configuration ......................................................................................................... 20
Figure 10. Voltage Computation ................................................................................................................. 20
Figure 12. Voltage Input Flowchart ............................................................................................................. 22
Figure 13. Current Input Configuration ....................................................................................................... 23
Figure 14. Current Computation ................................................................................................................. 23
Figure 15. Current Configuration Examples ................................................................................................ 24
Figure 16. Current Input Flowchart ............................................................................................................. 25
Figure 17. Peak Voltage Computation ........................................................................................................ 28
Figure 18. RMS Voltage Computation ........................................................................................................ 28
Figure 19. Peak Current Computation ........................................................................................................ 29
Figure 20. RMS Current Computation ........................................................................................................ 30
Figure 21. Active Power Computation ........................................................................................................ 31
Figure 22. Reactive Power Computation .................................................................................................... 32
Figure 23. Apparent Power Computation.................................................................................................... 32
Figure 24. Min/Max Tracking....................................................................................................................... 36
Figure 25. Voltage Sag ............................................................................................................................... 38
Figure 26. Relay Timing .............................................................................................................................. 41
Figure 27. RS-485 Interface ........................................................................................................................ 49
Figure 28. Device Address Configuration ................................................................................................... 50
Figure 29. SSI Protocol ............................................................................................................................... 51
Figure 30. Master Packet Structure ............................................................................................................ 51
Figure 31. SPI Interface .............................................................................................................................. 55
Figure 32. SPI Timing Continuous Clock .................................................................................................... 57
Figure 33. SPI Timing Gapped Clock ......................................................................................................... 57
2
Figure 34. I C Interface ............................................................................................................................... 58
2
Figure 35. I C Device Address .................................................................................................................... 58
2
Figure 36. I C Bus Characteristics .............................................................................................................. 59
2
Figure 37. I C Device Addressing ............................................................................................................... 59
Figure 38. Write Operation⎯Single Register .............................................................................................. 60
Figure 39. Write Operation⎯Multiple Registers .......................................................................................... 60
Figure 40. Read Operation.......................................................................................................................... 61
Figure 41. Setting Read Address ................................................................................................................ 61
Figure 42. Reading Multiple Registers ........................................................................................................ 61
Table of Figures
4
Rev 0
78M6610+LMU Data Sheet
Electrical Specifications
ABSOLUTE MAXIMUM RATINGS
(All voltages with respect to ground.)
Supplies and Ground Pins:
V
3P3D
, V
3P3A
GNDD, GNDA
Analog Input Pins:
A0, A1, A2, A3, A4, A5
Oscillator Pins:
XIN, XOUT
Digital Pins:
IFC0, IFC1, SSB/DIR/SCL, SDO/TX/SDAO, SDI/RX/SDAI,
RESET,
SPCK/ADDR0, MP10, MP0, MP4, MP6/ADDR1, MP7
Digital Pins Configured as Inputs
Temperatures:
Operating Junction Temperature)
Peak, 100ms
Continuous
Storage Temperature Range
Lead Temperature (soldering, 10s)
Soldering Temperature (reflow)
ESD Stress on All Pins
+140°C
+125°C
-45°C to +165°C
+260°C
0°C
±4kV
-30mA to +30mA,
-0.5V to (V
3P3D
+ 0.5V)
-10mA to +10mA,
-0.5V to +6V
-10mA to +10mA
-0.5V to +3.0V
-10mA to +10mA
-0.5V to (V
3P3
+ 0.5V)
-0.5V to +4.6V
-0.5V to +0.5V
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress
ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational
sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect
device reliability.
Recommended External Components
NAME
XTAL
CXS
CXL
FROM
XIN
XIN
XOUT
TO
XOUT
GNDD
GNDD
20.000MHz
Load capacitor for crystal (exact value
depends on crystal specifications and
parasitic capacitance of board)
FUNCTION
VALUE
20.000
18
±10%
18
±10%
UNITS
MHz
pF
pF
Recommended Operating Conditions
PARAMETER
3.3V Supply Voltage (V
3P3
)
Operating Temperature
CONDITIONS
Normal operation
MIN
3.0
-40
TYP
3.3
–
MAX
3.6
+85
UNITS
V
°C
5
Rev 0
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