RF Output

TMUX1219

SEL

1.8 V

DAC

0 V

5 V

RF Input

Source or Drain Voltage (V)

0

0.5

1

1.5

2

2.5

3

3.5

4

4.5

5

0

20

40

60

80

VDD = 1.08V

VDD = 1.62 V

VDD = 3 V

VDD = 4.5 V

D001

21

TMUX1219

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SCDS409A – MAY 2019 – REVISED JUNE 2020

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9.2.1.2 Detailed Design Procedure

The application shown in Figure 17 demonstrates how to use a single control input and toggle between gain

settings of -1 and +1. If switching between inverting and unity gain is not required, the TMUX1219 can be utilized

in the feedback path to select different feedback resistors and provide scalable gain settings for configurable

signal conditioning.

The TMUX1219 can be operated without any external components except for the supply decoupling capacitors.

The select pin is recommended to have a weak pull-down or pull-up resistor to ensure the input is in a known

state. All inputs to the switch must fall within the recommend operating conditions of the TMUX1219 including

signal range and continuous current. For this design with a supply of 2.75 V the signal range can be 0 V to 2.75

V and the max continuous current can be 30 mA.

9.2.1.3 Application Curve

TA = 25°C

Figure 18. On-Resistance vs Source or Drain Voltage

9.2.2 Input Control for Power Amplifier

Another application of the TMUX1219 is for input control of a power amplifier. Utilizing a switch allows a system

to control when the DAC is connected to the power amplifier, and can stop biasing the power amplifier by

switching the gate to GND. Figure 19 shows the TMUX1219 configured for control of the power amplifier.

Figure 19. Input Control of Power Amplifier