71M6541D Datasheet, PDF (95/166 Pages) Maxim Integrated Products – 0.1% Accuracy Over 2000:1 Current Range Energy Meter ICs

71M6541D/F/G and 71M6542F/G Data Sheet
4.5 71M6542F/G Using Local Sensors
Figure 38 shows a 71M6542F/G configuration using locally connected current sensors. The IAP-IAN
current channel may be directly connected to either a shunt resistor or a CT, while the IBP-IBN channel is
connected to a CT and is therefore isolated. This configuration implements a dual-phase measurement
utilizing Equation 2. For best performance, both the IAP-IAN and IBP-IBN current sensor inputs are
configured for differential mode (i.e., DIFFA_E = 1 and DIFFB_E = 1, I/O RAM 0x210C[4] and 0x210C[5]).
The IBP-IBN input must be configured as an analog differential input disabling the remote sensor
interface (i.e., RMT_E = 0, I/O RAM 0x2709[3]). See Figure 4 for the AFE configuration corresponding to
Figure 38.
CT or
PHASE A
Shunt
NEUTRAL
Shunt
PHASE B
LOAD
LOAD
Note:
This system is referenced to PHASE A
NEUTRAL
PHASE A
POWER SUPPLY
AMR
IR
HOST
MUX and ADC V3P3A V3P3SYS _{GNDA GNDD}
IAP
PWR MODE
IAN
CONTROL
TERIDIAN ^WAKE-UP
71M6542F ^REGULATOR
VB
VBAT
VA
VBAT_RTC
IBP
TEMPERATURE ^BATTERY
IBN
SENSOR
MONITOR
VREF
SERIAL PORTS
TX
RX
MODUL- _RX
ATOR _TX
POWER FAULT
COMPARATOR
SPI INTERFACE
RAM
COMPUTE
ENGINE
FLASH
MEMORY
MPU
RTC
TIMERS
ICE
COM0...5
SEG
SEG/DIO
LCD DRIVER
DIO, PULSES
DIO
V3P3D
OSCILLATOR/
PLL _XIN
XOUT
11/5/2010
Figure 37: 71M6542F/G with Local Sensors
BATTERY
RTC
BATTERY
LCD DISPLAY
8888.8888
PULSES,
DIO
I²C or µWire
EEPROM
32 kHz