71M6545 MAXIM [Maxim Integrated Products], 71M6545 Datasheet - Page 12

• Manufacturer Part Number: 71M6545
• Description: Four-Quadrant Metering, Phase Metrology Processors Flash/RAM Size
• Manufacturer: MAXIM [Maxim Integrated Products]

One of the two internal UARTs is adapted to support an Infrared LED with internal drive and sense
configuration and can also function as a standard UART. This flexibility makes it possible to implement
AMR meters with an IR interface. A block diagram of the IC is shown in
filter and stored in CE RAM where it can be accessed and processed by the CE.
Shunt current sensors that are isolated by using a 71M6xx3 device, are sampled by a second-order
Data Sheet 71M6545/H
correction factors can be programmed to produce electricity meters with exceptional accuracy over the
industrial temperature range.
2.2
The AFE functions as a data acquisition system, controlled by the MPU or by the host processor over the
SPI interface. The 71M6545/H AFE may also be augmented by isolated 71M6xx3 sensors in order to
support low-cost current shunt sensors.
configurations; other configurations are possible. Sensors that are connected directly to the 71M6545/H
(i.e., IADC0-IADC1, VADC8, VADC9 and VADC10) are multiplexed into the single second-order sigma-
delta ADC input for sampling in the 71M6545/H. The 71M6545/H ADC output is decimated by the FIR
sigma delta ADC in the 71M6xx3 and the signal samples are transferred over the digital isolation interface
through the low-cost isolation pulse transformer.
Figure 2
Figure 2
plus three remote (isolated) shunt sensors. As seen in
connected via the 71M6xx3, the samples associated with this current channel are not routed to the
multiplexer, and are instead transferred digitally to the 71M6545/H via the isolation interface and are
directly stored in CE RAM. The MUX_SELn[3:0] I/O RAM control fields allow the MPU to configure the
AFE for the desired multiplexer sampling sequence. Refer to
code and the corresponding AFE settings.
See
12
Figure 27
Analog Front End (AFE)
shows the 71M6545/H using shunt current sensors and the 71M6xx3 isolated sensor devices.
supports neutral current measurement with a local shunt connected to the IADC0-IADC1 input
for the meter wiring configuration corresponding to
Remote
Remote
Remote
Shunt
Shunt
Shunt
Figure 2: AFE Block Diagram (Shunts: One-Local, Three-Remotes)
IB
IC
IA
INN
INN
INN
INP
INP
INP
71M6xx3
71M6xx3
71M6xx3
© 2008–2011 Teridian Semiconductor Corporation
Local
Shunt
IN*
SP
SP
SN
SN
SP
SN
VADC10 (VC)
VADC9 (VB)
VADC8 (VA)
Figure 2
IADC2
IADC3
IADC4
IADC5
IADC7
IADC0
IADC1
IADC6
*IN = Neutral Current
and
Interface
Isolation
MUX
Digital
Figure 3
Figure
VREF
Table 1
VADC
2, when a remote isolated shunt sensor is
show two of the most common
71M6545/H
VREF
Figure
and
VREF
CONVERTER
22
22
22
∆Σ ADC
Figure
2.
FIR
Table 2
22
1.
CE RAM
10/7/2010
for the appropriate CE
PDS_6545_009
v1.0