SSP1851
The SSP1851 is a high-accuracy, fault-tolerant electrical energy measurement IC that is intended for use with 2-wire distribution systems. The part specifications surpass the accuracy requirements as quoted in the IEC1036 standard.
The only analog circuitry used in the SSP1851 is in the 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 extremes in environmental conditions and over time.
The SSP1851 incorporates a novel fault detection scheme that warns of fault conditions and allows the SSP1851 to continue accurate billing during a fault event. The SSP1851 does this by continuously monitoring both the phase and neutral (return) currents. A fault is indicated when these currents differ by more than 12.5%. Billing is continued using the larger of the two currents.
The SSP1851 supplies average real power information on the low-frequency outputs F1 and F2. These logic outputs may be used to directly drive an electromechanical counter or interface to
an MCU. The CF logic output gives instantaneous real power information. This output is intended to be used for calibration purposes.
The SSP1851 includes a power supply monitoring circuit on the AVDD supply pin. The SSP1851 will remain in a reset condition until the supply voltage on AVDD reaches 4 V. If the supply falls below 4 V, the SSP1851 will also be reset and no pulses will be issued on F1, F2, and CF. Internal phase matching circuitry ensures that the voltage and current channels are matched whether the HPF in Channel 1 is on or off. The SSP1851 also has anticreep protection.
The SSP1851 is available in 24-lead SSOP packages.
SSP1855
The SSP1855 is a high accuracy electrical energy measurement integrated circuit with technical specifications that meet the accuracy requirements specified in IEC1036. The SSP1855 uses analogue circuitry only for the ADC and reference source, and digital circuitry for all other signal processing (such as multiplication and filtering), which allows the SSP1855 to maintain extremely high accuracy and long-term stability in harsh environmental conditions.The SSP1855 pins F1 and F2 output the average value of active power at a lower frequency and can be used to directly drive electromechanical meters or to interface with microcontrollers (MCUs). Pin CF outputs an instantaneous value of active power at a higher frequency for calibration or interfacing with an MCU.The SSP1855 contains an internal monitoring circuit for the VDD power supply pin. The SSP1855 remains in reset until VDD rises to 4V. When VDD falls below 4V, the SSP1855 is also reset, at which point there are no outputs from F1, F2, or CF.Internal phase matching circuitry allows the voltage and current channels to always be phase matched, regardless of whether the high pass filter (HPF) within channel 1 is on or off. An internal no-load threshold feature ensures that the SSP1855 has no latency at no load.The SSP1855 is available in a 24-pin SSOP package.
