TMUX1308QDYYRQ1 is an 8-channel bidirectional multiplexer (1:8) from TI, enabling signal routing from 8 inputs to 1 output or signal distribution from 1 input to 8 outputs. The device supports bidirectional signal transmission, allowing signals to pass through the switch in both directions without any direction control pin (true bidirectional switch). This feature makes it ideal for bus applications requiring bidirectional signal transmission such as UART, SPI, and I2C.

The device operates over a wide voltage range (1.65V to 5.5V), compatible with multiple voltage domains (1.8V, 3.3V, 5V systems), featuring low on-resistance (typical 4 Ohms) and low leakage current (less than 10nA at room temperature). Integrated latch-up suppression and over-temperature protection ensure reliable operation in harsh environments. The QFN-20 package offers a compact 3mm x 3mm footprint with bottom thermal pad, suitable for space-constrained portable and handheld device designs.

Typical applications include: industrial sensor multiplexing (8 sensors sharing one ADC channel), test equipment channel switching (ATE channel boards), communication system signal routing (baseband board signal distribution), and consumer electronics button/interface expansion.

Note: For detailed electrical parameters, refer to the official TI TMUX1308 datasheet. Specifications subject to change without notice. Design engineers should verify all parameters before final design.

TMUX1308QDYYRQ1 uses a compact QFN-20 (Quad Flat No-Lead, 5x4 pin array) package, typical dimensions 3mm x 3mm x 0.75mm. The bottom features an exposed thermal pad (EP) connected to chip ground, improving thermal performance and providing better ground shielding. Pin pitch is 0.5mm.

PCB layout recommendations: The thermal pad should be well-soldered to the PCB ground plane. In thermally critical applications, use thermal vias connecting to back-side ground copper for enhanced heat dissipation. Since this is an analog switch, switch node traces should be kept short and away from noise sources. Input/output traces should maintain consistent impedance to reduce signal reflection. For high-frequency applications (>10MHz), use microstrip line design.

TMUX1308QDYYRQ1 QFN-20 package has 20 pins (including thermal pad), key pin functions:

• Pin 1-8 - S1-S8 (Channel I/O): 8 independent channel signal ports. Each channel is a bidirectional switch - signals can flow into or out of the COM port, supporting bidirectional signals such as UART TX/RX and SPI MISO/MOSI. Keep traces short to minimize parasitic inductance.
• Pin 9 - COM (Common Port): The common port of the multiplexer - all 8 channels connect to this pin. Channel selection via SEL pins determines which S connects to COM. Can serve as the collection point for multiple inputs (8:1 mode) or the distribution origin for a single signal (1:8 mode).
• Pin 10-12 - SEL0-SEL2 (Channel Select): 3-bit binary channel select inputs, selecting one of 8 channels via binary encoding (000=S1, 001=S2, ... 111=S8). Internal pull-up or pull-down resistors prevent undefined states.
• Pin 13 - VCC (Power): Main power supply pin (1.65V to 5.5V). Recommend placing a 0.1uF decoupling capacitor near the pin to filter power noise impact on analog switch characteristics.
• Pin 14 - GND (Ground): Chip ground pin, connected to the internal substrate. Should be well-connected to the PCB ground plane to provide a clean reference ground and thermal path.
• Bottom Pad - EP (Thermal Pad): Exposed thermal pad on the bottom, electrically connected to GND. Must be well-soldered to the PCB ground plane for enhanced thermal dissipation and EMI shielding.

The following alternative parts are listed for reference. Before selecting an alternative, verify communication interface, supply voltage, security algorithm compatibility, and software API differences.

Selection Tips: Key considerations for multiplexer selection: number of channels (8 vs 16); true bidirectional requirement (required for UART/SPI applications); on-resistance impact on signal (more critical for analog signals); switching speed (ns-level required for high-speed SPI buses); package type (QFN vs TSSOP vs LFCSP).

Texas Instruments (NASDAQ: TXN), headquartered in Dallas, Texas, USA, is one of the world's largest analog semiconductor companies. TI has the industry's most comprehensive analog switch and multiplexer product line, covering from single/dual channel to 32-channel multiplexers, supporting analog signal, digital signal, and bidirectional bus applications. TI's analog switches feature ultra-low on-resistance, fast switching, and low power consumption, widely used in industrial automation, medical equipment, communication systems, and consumer electronics.

TMUX1308 belongs to TI's analog switch/multiplexer product line, using a compact QFN package suitable for space-constrained portable and industrial applications. TI provides complete simulation models (SPICE) and reference designs to help engineers quickly complete signal routing and channel switching designs.