STPMS1 st Dual-channel 1-bit, 2 MHz, 1 order sigma-delta modulator with embedded PGA Features V supply range: 3.2 V - 5.5 V CC st Two 1 order sigma-delta modulators Programmable chopper-stabilized low noise and low offset amplifier Supports 50-60 Hz AC watt meters Internal low-drop regulator at 3 V (typ.) Precision voltage reference: 1.23 V and 30 QFN16 (3 x 3 mm.) ppm/C (typ.) Applications measurement applications when single or double inputs must be monitored at the same time. Power metering Motor control Industrial process control Weight scale Pressure transducers Description The STPMS1, also called a smart-sensor device, is an ASSP designed for effective measurement in power line systems utilizing the Rogowski coil, current transformer, or shunt principle. It is used in combination with the STPMC1 programmable poly-phase energy calculator IC, as a building block for single-phase or poly-phase energy meters. The STPMS1 is a mixed signal IC consisting of an analog and a digital section. The analog section consists of a pre-amplifier and two st 1 order modulator blocks, band-gap voltage reference, a low-drop voltage regulator, and DC buffers, while the digital section consists of a clock generator and output multiplexer. This device is designed for use in medium resolution Table 1. Device summary Order code Package Packaging STPMS1BPQR QFN16 (3 x 3 mm) 2500 parts per reel October 2010 Doc ID 16524 Rev 2 1/23 www.st.com 23Contents STPMS1 Contents 1 Schematic diagram 3 2 Pin configuration 4 3 Electrical characteristics . 5 4 General operating conditions . 6 5 Application . 9 6 Terminology . 12 6.1 Conventions . 12 6.2 Notation 12 7 Typical performance characteristics . 13 8 Theory of operation 15 8.1 General operation description . 15 8.2 Function description of the analog part 15 8.3 Functional description of the digital part 17 9 Package mechanical data 18 10 Revision history . 22 2/23 Doc ID 16524 Rev 2