Fraunhofer Institute for Electronic Microsystems and Solid State Technologies EMFTFrom IoT devices to high-performance computing, reliable reference circuits are essential for every System-on-Chip. As modern semiconductor technologies scale, designing robust references becomes increasingly challenging due to shrinking supply voltages, changing device characteristics, and rising digital noise. At Fraunhofer EMFT, we develop specialized reference solutions tailored to demanding SoC environments – from classical bandgap architectures to innovative MOS-based concepts for ultra-low supply voltages that ensure stable operation even under challenging conditions.
Precision Current and Voltage References for SoC Design
Integrated Circuit with System on Chip (SoC) combining processor and memory
Reference Circuits for Advanced SoC Technologies
Modern SoCs often operate at supply voltages below 1 V, where conventional reference circuits reach their limits and new design concepts are required. Fraunhofer EMFT develops innovative reference architectures that overcome these challenges.
One example is a Buffered Voltage Reference based on the threshold-voltage difference of MOS transistors, presented at the IEEE Custom Integrated Circuits Conference 2025 by Matthias Eberlein.
- Supply Ultra-Compact Voltage Reference Exploiting MOS Threshold Correlations (publica.fraunhofer.de)
Cryogenic Reference Circuits for Quantum Technologies
Our research also explores reference architectures for cryogenic electronics. Based on a similar design concept, Fraunhofer EMFT has developed a reference circuit capable of operating at temperatures as low as 4 K. The design delivers a 300 mV reference output at a supply voltage of only 0.66 V, while maintaining a temperature coefficient of 82 ppm/K. Such circuits are highly relevant for quantum computing and other cryogenic electronic systems, where reliable reference signals are essential but only very few suitable reference architectures have been reported so far.
A New Approach: Oven-Controlled References
High-precision references span far beyond traditional voltage and current sources. They are critical across multiple domains in analog and mixed-signal circuits:
- Voltage and current references for biasing and signal conditioning
- Frequency and timing references for synchronization
- Temperature sensors for thermal management
- Performance parameters (gain, sensitivity, etc.) for system calibration
Achieving stability and accuracy across these diverse reference types remains a central challenge. Instead of relying solely on classical compensation techniques, Fraunhofer EMFT is exploring a novel concept: fully integrated oven-controlled references. In this approach, a miniaturized on-chip micro-oven stabilizes the temperature of the reference circuitry locally. A tiny control loop consisting of heater and temperature sensing electronics maintains a constant operating point. This method can enable ppm-level stability of critical reference signals without complex multi-point calibration.
The micro-oven concept is currently an active research topic at Fraunhofer EMFT and represents a promising new direction for ultra-stable integrated references.
On-chip thermal control system for high-precision references