ATT7030A Application Note（260-CS-105）
ATT7030A’s package is QFP44. The external hardware circuitry includes power supply, voltage
and current analog signal input, pulse output and electromechanical counter.
Analog input circuitry
ATT7030A incorporates 6 second-order 16-bits ADCs. The voltage sampling data is 0.2V ~ 0.6V.
The current sampling data is 2mV ~ 1V. The energy linear error is less than 0.1%.
Every ADC’s AC signal is input from VxP and VxN. At the same time the VxP and VxN need be
added 2.4V direct current bias voltage, which could be obtained from ATT7030A’s reference voltage
output ‘REFOUT’ or external benchmark voltage.
ATT7030A’s sampling input voltage can adopt resistance divided-voltage method (as diagram 1
and diagram 2), or switching voltage to current, then through current mutual inductance implement
switching current to voltage (as diagram 3). The latter method adopt mutual inductance implement,
which can segregate chip and electric power net, thereby can get favorable anti-jamming capability. In
diagram 1, the neutral line Vn is connected to reference voltage output ‘REFO’, which achieves adding
AC sampling signal to 2.4V direct current bias voltage expediently. In diagram 2, the neutral line Vn is
connected to chip’s ground, which is applied to power supply using autotransformer.
Diagram 1: Vn is connected to REFO
Diagram 2: Vn is connected to ground
Diagram 3: current mutual inductance
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