ADE7757*

Features:

On Chip Oscillator as clock source
High Accuracy, Supports 50 Hz/60 Hz IEC 521/1036 Less than 0.1% Error Over a Dynamic Range of 500 to 1
The ADE7757 Supplies Average Real Power on the Frequency Outputs F1 and F2
The High Frequency Output CF Is Intended for Calibration and Supplies  Instantaneous Real Power
Direct Drive for Electromechanical Counters and Two Phase Stepper Motors (F1 and F2)
Proprietary ADCs and DSP Provide High Accuracy over Large Variations in Environmental Conditions and Time
On-Chip Power Supply Monitoring
On-Chip Creep Protection (No Load Threshold)
Single 5 V Supply, Low Power (15 mW Typical)
Low Cost CMOS Process
AC Input only


Pinout




Specifications

V_DD to AGND  . . . . . . . . . . . . . . . . . . . . . . . .  0.3 V to +7 V
V_DD to DGND  . . . . . . . . . . . . . . . . . . . . . . .   0.3 V to +7 V
Analog Input Voltage to AGND
V1P, V1N, V2P and V2N  . . . . . . . . . . . . . . .     6 V to +6 V
Reference Input Voltage to AGND  . . 0.3 V to V_DD + 0.3 V
Digital Input Voltage to DGND  . . . . . 0.3 V to V_DD + 0.3 V
Digital Output Voltage to DGND . . . . 0.3 V to V_DD + 0.3 V
Operating Temperature Range
Industrial (A, B Versions)  . . . . . . . . . . . .  40°C to +85°C
Storage Temperature Range  . . . . . . . .  65°C to +150°C
Junction Temperature  . . . . . . . . . . . . . . . . . . . . . .+150°C


Description

The ADE7757 is a high accuracy electrical energy measurement IC. It is a pin reduction version of AD7755 with an enhancement of a precise oscillator circuit that serves as a clock source to the chip. The ADE7757 eliminates the cost of an external crystal or resonator, thus reducing the overall cost of a meter built with this IC. The chip directly interfaces with shunt resistor and only operates with AC input.

The ADE7757 specifications surpass the accuracy requirements as quoted in the IEC1036 standard. Due to the similarity between the ADE7757 and AD7755, the Application Note AN-559 can be used as a basis for a description of an IEC1036 low cost watt-hour meter reference design. The only analog circuitry used in the ADE7757 is in the sigma-delta ADCs and reference circuit. All other signal processing (e.g., multiplication and filtering) is carried out in the digital domain. This approach provides superior stability and accuracy over time and extreme environmental conditions. It supplies average real power information on the low frequency outputs F1 and F2. These outputs may be used to directly drive an electromechanical counter or interface  with an  MCU. The high frequency CF logic output, ideal for calibration purposes, provides instantaneous real power information.