Datasheet ADE7755 (Analog Devices) - 6

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ADE7755 Data Sheet PIN CONFIGURATION AND FUNCTION DESCRIPTIONS DVDD 1 24 F1 AC/DC 2 23 F2 AVDD 3 22 CF NC 4 21 DGND V1P 5 20 REVP ADE7755 V1N 6 TOP VIEW 19 NC V2N 7 (Not to Scale) 18 CLKOUT V2P 8 17 CLKIN RESET 9 16 G0 REFIN/OUT 10 15 G1 AGND 11 14 S0 SCF 12 13 S1
003 6-
NC = NO CONNECT
89 02 Figure 3. Pin Configuration
Table 4. Pin Function Descriptions Pin No. Mnemonic Description
1 DVDD Digital Power Supply. This pin provides the supply voltage for the digital circuitry in the ADE7755. The supply voltage should be maintained at 5 V ± 5% for specified operation. This pin should be decoupled with a 10 μF capacitor in parallel with a ceramic 100 nF capacitor. 2 AC/DC High-Pass Filter Select. This logic input is used to enable the HPF in Channel 1 (current channel). A Logic 1 on this pin enables the HPF. The associated phase response of this filter is internally compensated over a frequency range of 45 Hz to 1 kHz. The HPF should be enabled in power metering applications. 3 AVDD Analog Power Supply. This pin provides the supply voltage for the analog circuitry in the ADE7755. The supply should be maintained at 5 V ± 5% for specified operation. Every effort should be made to minimize power supply ripple and noise at this pin by the use of proper decoupling. This pin should be decoupled to AGND with a 10 μF capacitor in parallel with a ceramic 100 nF capacitor. 4, 19 NC No Connect. 5, 6 V1P, V1N Analog Inputs for Channel 1 (Current Channel). These inputs are fully differential voltage inputs with a maximum differential signal level of ±470 mV for specified operation. Channel 1 also has a PGA, and the gain selections are outlined in Table 5. The maximum signal level at these pins is ±1 V with respect to AGND. Both inputs have internal ESD protection circuitry. An overvoltage of ±6 V can be sustained on these inputs without risk of permanent damage. 7, 8 V2N, V2P Negative and Positive Inputs for Channel 2 (Voltage Channel). These inputs provide a fully differential input pair with a maximum differential input voltage of ±660 mV for specified operation. The maximum signal level at these pins is ±1 V with respect to AGND. Both inputs have internal ESD protection circuitry, and an overvoltage of ±6 V can be sustained on these inputs without risk of permanent damage. 9 RESET Reset Pin. A logic low on this pin holds the ADCs and digital circuitry in a reset condition. Bringing this pin logic low clears the ADE7755 internal registers. 10 REFIN/OUT This pin provides access to the on-chip voltage reference. The on-chip reference has a nominal value of 2.5 V ± 8% and a typical temperature coefficient of 30 ppm/°C. An external reference source may also be connected at this pin. In either case, this pin should be decoupled to AGND with a 1 μF ceramic capacitor and a 100 nF ceramic capacitor. 11 AGND This pin provides the ground reference for the analog circuitry in the ADE7755, that is, the ADCs and reference. This pin should be tied to the analog ground plane of the PCB. The analog ground plane is the ground reference for all analog circuitry, for example, antialiasing filters and current and voltage transducers. For good noise suppression, the analog ground plane should be connected to the digital ground plane at one point only. A star ground configuration helps to keep noisy digital currents away from the analog circuits. 12 SCF Select Calibration Frequency. This logic input is used to select the frequency on the calibration output, CF. Table 8 shows how the calibration frequencies are selected. 13, 14 S1, S0 These logic inputs are used to select one of four possible frequencies for the digital-to-frequency conversion. This offers the designer greater flexibility when designing the energy meter. See the Selecting a Frequency for an Energy Meter Application section. 15, 16 G1, G0 These logic inputs are used to select one of four possible gains for Channel 1, that is, V1. The possible gains are 1, 2, 8, and 16. See the Analog Inputs section. Rev. B | Page 6 of 20 Document Outline Features General Description Functional Block Diagram Revision History Specifications Timing Characteristics Absolute Maximum Ratings ESD Caution Pin Configuration and Function Descriptions Typical Performance Characteristics Terminology Theory of Operation Power Factor Considerations Nonsinusoidal Voltage and Current Analog Inputs Channel 1 (Current Channel) Channel 2 (Voltage Channel) Typical Connection Diagrams Power Supply Monitor HPF and Offset Effects Digital-to-Frequency Conversion Interfacing the ADE7755 to a Microcontroller for Energy Measurement Power Measurement Considerations Transfer Function Frequency Outputs F1 and F2 Example 1 Example 2 Frequency Output CF Selecting a Frequency for an Energy Meter Application Frequency Outputs No Load Threshold Outline Dimensions Ordering Guide