STPM34TR

Overview

The STPM34TR is a specialized application-specific standard product (ASSP) designed for high-accuracy power and energy measurement in power line systems. It features four independent 24-bit second-order sigma-delta analog-to-digital converters (ADCs) and two embedded programmable gain low-noise amplifiers (PGLNA). The device supports supply voltages between 2.95 V and 3.65 V with a maximum operating current of 5.9 mA. It achieves an active power accuracy error of less than 0.1% over a 5000:1 dynamic range and less than 0.5% over a 10000:1 dynamic range. The component operates within a temperature range of -40°C to +105°C and utilizes a QFN-32 surface-mount package.

Feature Summary

• Integrates four independent 24-bit second-order sigma-delta ADCs for precise signal acquisition.
• Includes two programmable gain chopper-stabilized low-noise amplifiers with low offset characteristics.
• Features a hardwired digital signal processor for calculating RMS, active, reactive, and apparent power.
• Supports configurable serial communication interfaces including UART and SPI with CRC verification.

Applications

• High-accuracy AC watt meters compliant with EN 50470-x standards
• Smart metering systems utilizing Rogowski coils or current transformers
• Power quality monitoring devices requiring sag and swell detection
• Industrial energy management systems using shunt current sensors

Procurement Notes

Verify the specific suffix 'TR' indicates tape-and-reel packaging configuration when sourcing. Confirm that the QFN-32 package matches your PCB footprint requirements. Ensure compatibility with the 3.3 V ± 10% supply voltage range specified for the STPM3x family. Check moisture sensitivity levels and reflow soldering profiles against your manufacturing capabilities. Validate that the firmware supports the required calibration points for your specific sensor interface.

Selection Notes

Select this component when four independent measurement channels are required for single or split-phase applications. Choose the STPM34TR over lower-channel variants if multi-point monitoring is necessary. Consider the 3.6 kHz bandwidth limitation for applications involving higher frequency harmonics. Verify that the external clock source meets the 16 MHz requirement for optimal performance. Evaluate the need for the integrated low-dropout regulator versus external power solutions.

Part Context

The STPM34TR belongs to the STPM3x family of mixed-signal ICs designed for electricity metering. This family shares a common architecture featuring analog front-ends and digital processing cores. Variants within the series differ primarily in the number of available measurement channels. The STPM34 specifically provides four channels, distinguishing it from the two-channel STPM32 and three-channel STPM33 models.

Replacement Considerations

STPM32 and STPM33 are pin-compatible members of the same family but offer fewer measurement channels. Substitution requires verifying that the reduced channel count meets system requirements. Firmware adjustments may be necessary to accommodate different channel configurations. Ensure that the power consumption and thermal characteristics remain within acceptable limits for the target application.

FAQ

What types of current sensors does the STPM34 support?

The STPM34 supports current sampling using Rogowski coils, current transformers, or shunt current sensors.

Does the device include internal voltage references?

Yes, the analog section includes two bandgap voltage references with independent temperature compensation.

How is the device calibrated?

The STPM34 is fully configurable and allows fast digital system calibration at a single point across the entire current dynamic range.