SCEA141A May   2024  – September 2025 LSF0102 , PCA9306 , SN74AXC8T245 , TXU0304 , TXV0106 , TXV0106-Q1 , TXV0108 , TXV0108-Q1

 

  1.   1
  2.   2

Introduction

Several of today’s electronic end equipment applications are adding artificial intelligence (AI) capabilities to help bring new functionality and user experiences to end applications enabling users to harness the power of AI in their day to day work flows. To bring AI capabilities to their end application, electronic system designers need to leverage large language models (LLM) such as Generative Pre-trained Transformers (GPT) which requires high performance compute capabilities on both the cloud side as well as the client side of applications. Enabling AI capabilities on device or by leveraging cloud-based compute infrastructure requires client systems and cloud infrastructure designers to leverage the latest processor technologies.

GPT based AI implementations require system designers to not only use the latest high-performance processors and FPGAs (CPU based devices) but also use the latest high-performance GPU (Graphic Processing Units) that are better suited for AI given their ability to parallel process large amounts of data as well as higher memory bandwidths needed for high speed data transfer. Using the latest CPUs and GPUs to support AI functionality does present systems designer with multiple design challenges.

One of these design challenges is overcoming the control and low speed data I/O level mismatches that results from operating CPUs and GPUs at very low core voltages. Operating high performance CPUs and GPUs at low core voltages is often an absolute requirement for achieving target performance levels given the thermal and power limitations of a specific processor. Operating CPUs and GPUs at low core voltages limits the I/O voltage levels that these processors can support.

System designers often need a simple, efficient and scalable way to connect the numerous I/O and control buses of their GPU processors to peripheral devices and sub-systems. One design approach that enables system designers to maintain the CPU’s or GPU’s lower core voltage and still resolve I/O level mismatches is to use simple voltage level translator devices. Level translation devices provide system designers an easy and cost-effective solution for resolving their system’s I/O level mismatch challenges without having to compromise on performance, power, or size. See Figure 1.

 AI Accelerator Card Block DiagramFigure 1 AI Accelerator Card Block Diagram

Voltage Level Translation

Integrated level shifting designs are available in a wide assortment of I/O types, bit widths, data rate ranges, current drive capabilities, and package options. Texas Instruments’ portfolio of level shifter devices contains many different types of level translation functions that collectively is able to address almost any interface requirement likely needed for high performance compute use cases for AI applications. TI’s level translation portfolio includes Auto Directional, Direction Controlled, and Fixed Direction level translators in Industrial, Automotive and Enhanced ratings. Table 1 shows common control interfaces found on high-performance CPU and GPU families and recommended level translation devices for each interface supporting voltage ranges from < 0.8V to 5.5V. For more information on all of TI’s level translation devices, please visit TI’s Level Translation Landing Page.

Table 1 Recommended Translator by Interface
Translation Level
Interface Up to 3.6V Up to 5.5V
FET Replacement 2N7001T SN74LXC1T45/TXU0101
1 Bit GPIO/Clock Signal SN74AXC1T45 SN74LXC1T45/TXU0101
2 Bit GPIO SN74AXC2T245 SN74LXC2T45 / TXU0x02
2-Pin JTAG/UART SN74AXC2T45 SN74LXC2T45 / TXU0x02
I2C/MDIO/SMBus TXS0102 / LSF0102

/ PCA9306

TXS0102 / LSF0102

/ PCA9306

I3C TCA39306

TCA39306

4 Bit GPIO SN74AXC4T245 TXB0104 / TXU0104
UART SN74AXC4T245 TXB0104 / TXU0204
SPI SN74AXC4T774 / TXB0104 TXB0104 / TXU0304
JTAG SN74AXC4T774/ TXB0104 TXB0104 / TXU0204
I2S/PCM SN74AXC4T774 / TXB0104 TXB0104 / TXU0204
Quad-SPI TXB0106 TXB0106
SDIO/SD/MMC TXS0206 / TWL1200 NA
8 Bit GPIO/RGMII TXV0106/TXV0108 SN74LXC8T245

Analog Multiplexers

Analog multiplexers allow the selection and routing of multiple data lines to a single output, optimizing resource utilization and improving overall performance within the accelerator architecture. Switching is involved in many components including hardware accelerator baseboards, GPU cards, and Smart NICs to aid in processing large amounts of data in a small space.

Low voltage multiplexing is prevalent in AI accelerators for a variety of needs. TI offers devices for many applications including SPI interface, isolation and power sequencing for digital bus switching, GPIO expansion, clock signal muxing, and I2C/I3C protocol switching. Table 2 shows common control interfaces found in accelerators along with the recommended multiplexers for each interface supporting a wide range of supply voltages ranging from 1V to 5.5V. For more information, please visit TI’s Analog Switches and Multiplexers page.

Table 2 Recommended Multiplexer by Interface

Interface

Configuration

Multiplexer Supply Voltage

1.8V

3.3V

5V

Quad-SPI

2:1

TS3A27518E

TS3A27518E

-

SPI

2:1

TMUX1575

SN74CB3Q3257

TMUX1574

I2C

GPIO Controlled

2:1

TMUX1574

TMUX121

TMUX1072

3:1, 4:1

TMUX1309A

TS3A5017

SN74LV4052A

I2C Controlled

4:1

TCA9546A

TCA9546A

TCA9546A

8:1

TCA9548A

TCA9548A

TCA9548A

I3C Controlled

2:1

TMUX1574

TMUX136

TMUX1574

3:1, 4:1

SN74CB3Q3253

TMUX131

-

USB

2:1

TMUXHS221F

TS3USB221A

TS5USBC412

GPIO

1:1, 1-bit

SN74LVC1G66

SN74CBTLV1G125

SN74CBT1G125

1:1, 2-bit

SN74LVC2G66

SN74CBQ3306A

SN74CBTD3306C

1:1, 4-bit

TMUX1511

SN74CBTLV3126

SN74CBT3126

1:1, 8-bit

-

SN7CBTLV3245A

SN74CBT3245C