SCDA050 July   2024 TMUX9832 , TX7516

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1Introduction
  5. 2Front-End Architecture Comparison
  6. 3Routing Topologies for Transmitters With Multiplexer Switches
  7. 4Layout Example – Interwoven Input With TMUX9832 BGA Package
  8. 5Extending the Architecture to Implement Higher Channel Count Systems
  9. 6Summary
  10. 7References

2 Front-End Architecture Comparison

This section looks at two different ultrasound transmitter front-end architectures for creating a 64-CH system (Figure 2-1). Both of the architectures employ the TX7516 (±100V, five-level, 16-channel transmitter with transmit/receive switch and on-chip beamformer). The latter employs the TMUX9832, which is a 5V Supply, 220V High Voltage 1:1, 32-Channel Switch with Latch-Up Immunity.

The first architecture is composed of four TX7516 transmitters in parallel. In this configuration all 64 channels can be driven simultaneously. Each TX7516 dissipates 77mW/channel in transmit receive mode and up to 197mW/channel in continuous wave (CW) mode. For four transmitters this equates to a power range of 4.93W to 12.6W. Each transmitter IC is 100mm^2 for a total IC area of 400mm^2.

The second architecture consists of two TX7516 transmitters connected to two TMUX9832 multiplexers. In this configuration, only 32 of the channels are driven at a time from both transmitters. The switches route the signals to the appropriate transducer elements, alternating between each set of 32 to make up the whole 64 channels. TMUX9832 has a typical dynamic power consumption of 9.5mW when switching all 32 channels at 50kHz. Altogether, the two transmitters and two switches can take anywhere from 2.47W to 6.31W. This corresponds to a power reduction of nearly 50% compared to the design with all transmitters. Each multiplexer IC (in BGA package) is 56.25mm^2 for a total IC area of 312.5mm^2, corresponding to a 22% size reduction.

Example Front-End Architectures for 64-CH Ultrasound Systems Figure 2-1 Example Front-End Architectures for 64-CH Ultrasound Systems

Table 2-1 summarizes the power and size comparison between the two architectures outlined previously.

Table 2-1 Power and Size Comparison Of Ultrasound Front-End Architectures
Four 16-CH transmitters

Two 16-CH transmitters,
Two 32-CH switches

 % Reduction with multiplexers
Power - B mode (W) 4.93 2.47 49.7%
Power - CW mode (W) 12.6 6.31 49.8%
IC area (mm^2) 400 312.5 21.9%

Another potential option is to use four TX7516 devices (and no multiplexers), but only operate two of the TX7516 ICs for a total of 32CH transmitting at a time. In this case for B Mode, the total power for this design can be 2.496W, with the transmitting channels having 77mW/CH ×32, and the two TX7516 ICs not transmitting can consume 16mW/IC ×2. For this configuration, the two 16CH TX7516 transmitters plus two 32CH TMUX9832 switch architecture power improvement is only 1% better. However, if four transmitters are still on the board, the IC Area can still be larger by the same amount, and the customer can also need to consider the price difference of having four TX7516 ICs versus two TX7516 ICs and two TMUX9832 ICs.