71M6542F MAXIM [Maxim Integrated Products], 71M6542F Datasheet - Page 12

• Manufacturer Part Number: 71M6542F
• Description: 0.1% Accuracy Over 2000:1 Current Range Energy Meter ICs
• Manufacturer: MAXIM [Maxim Integrated Products]

71M6541D/F/G and 71M6542F/G Data Sheet
standards. Temperature-dependent external components such as crystal oscillator, resistive shunts, current
transformers (CTs) and their corresponding signal conditioning circuits can be characterized and their
correction factors can be programmed to produce electricity meters with exceptional accuracy over the
industrial temperature range.
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. The optical output can be modulated at 38 kHz. This flexibility
makes it possible to implement AMR meters with an IR interface. A block diagram of the IC is shown in
Figure
2.2
The AFE functions as a data acquisition system, controlled by the MPU. When used with locally
connected sensors, as seen in
multiplexed to the ADC input and sampled by the ADC. The ADC output is decimated by the FIR filter
and stored in CE RAM where it can be accessed and processed by the CE.
See
configuration corresponding to
Figure 6
I
LINE
CT
1.
Analog Front End (AFE)
or
CT
for the multiplexer sequence corresponding to
IN*
Shunt
Local
I
LINE
VADC10 (VA)
Figure 2. 71M6541D/F/G AFE Block Diagram (Local Sensors)
IBP
IBN
IAN
IAP
Figure
Figure
*IN = Optional Neutral Current
2.
2, the analog input signals (IAP-IAN, VA and IBP-IBN) are
MUX
VREF
VADC
Figure
VREF
71M6541D/F
2. See
VREF
CONVERTER
∆Σ ADC
Figure 35
FIR
22
for the meter
CE RAM
11/5/2010