71M6531F-IM/F Maxim Integrated Products, 71M6531F-IM/F Datasheet - Page 10

• Manufacturer Part Number: 71M6531F-IM/F
• Description: IC ENERGY METER 256KB 68-QFN
• Manufacturer: Maxim Integrated Products

Specifications of 71M6531F-IM/F

• Mounting Style: SMD/SMT
• Package / Case: QFN-68
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

blocks required to implement a solid-state electricity meter. Included on the chips are:
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Various current sensor technologies are supported including Current Transformers (CT), Resistive Shunts
and Rogowski coils.
In a typical application, the 32-bit compute engine (CE) of the 71M6531D/F and 71M6532D/F sequentially
process the samples from the voltage inputs on pins IA, VA, IB, VB and performs calculations to measure
active energy (Wh) and reactive energy (VARh), as well as A
environments. Flexible mapping of LCD display segments facilitate integration of existing custom LCDs.
Design trade-off between the number of LCD segments and DIO pins can be implemented in software to
accommodate various requirements.
In addition to the temperature-trimmed ultra-precision voltage reference, the on-chip digital temperature
compensation mechanism includes a temperature sensor and associated controls for correction of unwanted
temperature effects on measurement and RTC accuracy, e.g. to meet the requirements of ANSI and IEC
standards. Temperature-dependent external components such as a crystal oscillator, 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
71M6531D/F IC is shown in
IA and IB pins are single-ended. In the 71M6532D/F, the IAP/IAN and IBP/IBN pins can be programmed
individually to be differential (see I/O RAM bit SEL_IAN and SEL_IBN) or single-ended. The differential signal
is applied between the IAP and IAN input pins and between the IBP and IBN input pins. Single-ended
signals are applied to the IAP and IBP input pins whereas the common signal, return, is the V3P3A pin.
When using the differential mode, inputs can be chopped, i.e. a connection from V3P3A to IAP or IAN (or
IBP an IBN, respectively) alternates in each multiplexer cycle.
Data Sheet 71M6531D/F-71M6532D/F
1
1.1
The Teridian 71M6531D/F and 71M6532D/F single-chip energy meters integrates all primary functional
These measurements are then accessed by the MPU, processed further and output using the peripheral
devices available to the MPU.
In addition to advanced measurement functions, the real time clock function allows the 71M6531D/F and
71M6532D/F to record time of use (TOU) metering information for multi-rate applications and to time-stamp
tamper events. Measurements can be displayed on 3.3 V LCDs commonly used in low-temperature
1.2
The AFE consists of an input multiplexer, a delta-sigma A/D converter and a voltage reference.
1.2.1
All analog signal input pins are sensitive to voltage. In the 71M6531D/F, the VA and VB pins, as well as the
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An analog front end (AFE)
An Independent digital computation engine (CE)
An 8051-compatible microprocessor (MPU) which executes one instruction per clock cycle (80515)
A voltage reference
A temperature sensor
LCD drivers
RAM and Flash memory
A real time clock (RTC)
A variety of I/O pins
Hardware Description
Hardware Overview
Analog Front End (AFE)
Signal Input Pins
© 2005-2010 TERIDIAN Semiconductor Corporation
Figure
1. A block diagram of the 71M6532D/F IC is shown in
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h and V
2
h for four-quadrant metering.
FDS 6531/6532 005
Figure 2.
v1.3