8.2.2 Detailed Design Procedure

The TMUX1119 can be operated without any external components except for the supply decoupling capacitors.

All inputs passing through the switch must fall within the recommend operating conditions of the TMUX1119,

including signal range and continuous current. For this design with a supply of 5V the signal range can be 0V to

5V, and the maximum continuous current can be 30mA.

The TMUX1119 device is a bidirectional, single-pole double-throw (SPDT) switch that offers low on-resistance,

low leakage, and low power. These features make this device suitable for portable and power sensitive

applications such as ultrasonic gas metering systems. The two TMUX1119 devices are used to switch the

transmission and reception signals from the MCU to the two transceivers in an efficient manner without

distortion. Exceptional on-resistance flatness, leakage performance, and charge injection allows the TMUX1119

to be utilized in place of the TS5A9411 in Ultrasonic Gas Meter Front-End With MSP430™ Reference Design.

For a more detailed analysis of the entire system refer to the reference design.

8.2.3 Application Curve

The TMUX1119 is capable of switching signals with minimal distortion because of the ultra-low leakage currents

and excellent On-resistance flatness. Figure 8-2 shows how the on-resistance of the TMUX1119 varies with

different supply voltages.

VS or VD - Source or Drain Voltage (V)

0

1

2

3

4

5

5.5

0

1

2

3

4

5

6

VDD = 5.5 V

VDD = 4.5 V

VDD = 3.63 V

VDD = 3 V

D001

TA = 25°C

Figure 8-2. On-Leakage vs Source or Drain Voltage

8.3 Power Supply Recommendations

The TMUX1119 operates across a wide supply range of 1.08V to 5.5V. Do not exceed the absolute maximum

ratings because stresses beyond the listed ratings can cause permanent damage to the devices.

Power-supply bypassing improves noise margin and prevents switching noise propagation from the VDD

supply to other components. Good power-supply decoupling is important to achieve optimum performance.

For improved supply noise immunity, use a supply decoupling capacitor ranging from 0.1μF to 10μF from VDD

to ground. Place the bypass capacitors as close to the power supply pins of the device as possible using

low-impedance connections. TI recommends using multi-layer ceramic chip capacitors (MLCCs) that offer low

equivalent series resistance (ESR) and inductance (ESL) characteristics for power-supply decoupling purposes.

For very sensitive systems, or for systems in harsh noise environments, avoiding the use of vias for connecting

the capacitors to the device pins may offer superior noise immunity. The use of multiple vias in parallel lowers

the overall inductance and is beneficial for connections to ground planes.

8.4 Layout

8.4.1 Layout Guidelines

When a PCB trace turns a corner at a 90° angle, a reflection can occur. A reflection occurs primarily because of

the change of width of the trace. At the apex of the turn, the trace width increases to 1.414 times the width. This

TMUX1119

SCDS401C – DECEMBER 2018 – REVISED FEBRUARY 2024

www.ti.com

22

Submit Document Feedback

Copyright © 2024 Texas Instruments Incorporated

Product Folder Links: TMUX1119