This paper presents a 0.36-mm2I2C-to-SPI converter chip with on-the-fly conversion for E-textile applications. The on-the-fly operation eliminates the need for on-chip data buffers and clock generation, improving the area and power efficiency versus prior works. The die area is 7.33× smaller than commercially-available off-the-shelf (COTS) I2Cto-SPI converters, enabling it to integrate unobtrusively into E-textile applications. The chip supports conversion at ultra-fast I2C operating frequency up to 5 MHz while consuming only 0.379 mW of power. At the standard I2C speed of 400 kHz, it consumes 0.145 mW, which is 48× more power-efficient than commercially available I2C-to-SPI converters.

Traditionally, both reference circuits and the components they supply are designed independently to be as immune to temperature change as practical, but this requires power and area overhead to achieve. These overheads can compound in complex systems or consume excessive portions of a low power budget. In contrast, we propose a sub-μwatt digital temperature compensation architecture that generates voltage and current references with a user-defined temperature response rather than a fixed, near-ideal response. This flexible approach allows a single programmable design to be reused easily to produce different profiles over temperature, reducing design time. It also can reduce the temperature non-linearity in the components it supports by providing an input temperature profile that effectively cancels that non-linear response to allow components to operate at their target spec and eliminate excess power consumption. This approach allows designers to prioritize power consumption in their designs and use this compensation strategy to manage performance across temperature.

This paper presents a 0.36-mm2I2C-to-SPI converter chip designed for electronic textile (E-textile) applications, featuring an on-the-fly conversion scheme that eliminates the need for on-chip data buffers and internal clock generation. By leveraging the synchronous nature of both I2C and SPI protocols, the proposed design forwards each incoming I2C data bit, SDA (Serial Data Line) directly to the SPI output using the I2C serial clock line (SCL), thereby reducing both area and power consumption. Two versions of the chip are proposed: a ‘full’ die and a ‘compact’ die. The converter enables seamless integration into distributed in-textile architectures by minimizing silicon overhead. The ‘full’ die implementation achieves a$7.33\times $area reduction compared to commercially available I2C-to-SPI converters, while the ‘compact’ version further reduces the footprint by$14.73\times $through the use of a small corner seal-ring and a linear pad ring layout. Measurement results confirm robust operation at ultra-fast I2C frequency (5 MHz), consuming only 0.379 mW for the ‘full’ die and 0.333 mW for the ‘compact’ variant. At standard I2C speeds (400 kHz), the converter demonstrates a$48\times $improvement (‘full’ die) in power efficiency over commercial off-the-shelf (COTS) solutions, making it an effective and unobtrusive solution for next-generation E-textile systems.