TMUX7219 datasheet(32/51 Pages) TI2

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8.2.1.2 Detailed Design Procedure

The application shown in Figure 8-1 demonstrates how to toggle between the DAC output and low signal voltage

for control of a GaN power amplifier using a single control input. The DAC output is utilized to bias the gate of

the power amplifier and can be disconnected from the circuit using the select pin of the switch. The TMUX7219

can support 1.8 V logic signals on the control input, allowing the device to interface with low logic controls of an

FPGA or MCU. The TMUX7219 can operate without any external components except for the supply decoupling

capacitors. The select pin has an internal pull-down resistor to prevent floating input logic. All inputs to the switch

must fall within the recommended operating conditions of the TMUX7219 including signal range and continuous

current. For this design with a positive supply of 8 V on VDD and negative supply of −12 V on VSS, the signal

range can be 8 V to −12 V. The maximum continuous current (IDC) can be up to 440 mA for a wide-range current

measurement (for more information, refer to Recommended Operating Conditions).

8.2.1.3 Application Curve

The low on and off leakage currents of TMUX7219 and ultra-low charge injection performance make this device

ideal for implementing high precision industrial systems. The TMUX7219 contains specialized architecture to

reduce charge injection on the source (Sx) (see Section 7.3.7 for more details). Figure 8-2 shows the plot for the

charge injection versus source voltage for the TMUX7219.

Figure 8-2. Charge Injection vs Source Voltage

8.2.2 Ultrasonic Sensing Gas Meter

Another application of the TMUX7219 is in the ultrasonic sensing gas meter. Ultrasonic sensing of gas flow

uses the time of flight (ToF) of an ultrasonic wave and its dependency and behavior in the medium using

two transducer pairs for upstream and downstream paths. Figure 8-3 shows a circuit example utilizing the

MSP430FR6043 MCU, high voltage low distortion operational amplifiers (THS3091), along with TMUX7219, 2:1

precision switches. The TMUX7219 are needed to select the Rx and Tx path of the transducer. The TMUX7219

offers low on-state resistance and causes a very low signal distortion. The break-before-make feature allows

transferring of a signal from one port to another, with a minimal signal distortion. This device also offers a low

charge injection which makes this device suitable for high-performance audio and data acquisition systems.

TMUX7219

SCDS407F – NOVEMBER 2020 – REVISED JULY 2024

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TMUX7219 Datasheet(PDF) 32 Page - Texas Instruments