MP4864A

– 64-CHANNEL, HIGH-VOLTAGE, SPST ANALOG SWITCH

MP4864A Rev. 1.0

MonolithicPower.com

19

10/20/2021

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© 2021 MPS. All Rights Reserved.

Figure 17 shows the advantage of placing

analog switches inside the probe head, which is

called an active probe. Typically, the probe head

is severely space-limited and thermally limited.

The housing is waterproof so that it can be

submersed

in

alcohol

for

sterilization.

By

employing analog switches inside the probe

head, the number of coaxial cables can be

reduced. Instead of 192 coaxial cables, only 64

coaxial cables are required for the PZT, plus 10

or less additional coaxial cables for the supply

lines and logic interface.

The reduced number of coaxial cables provides

significant cost savings for the probe head. The

coaxial cable is by far the most expensive item.

Aside from the material cost, the labor to connect

the coaxial cables is also quite costly. An added

user benefit is the increased maneuverability of

the probe head. The sonographer undergoes

less fatigue using an active probe. Because it

does not require high-voltage supplies, the

MP4864A eliminates concerns about running

high-voltage DC lines on the coaxial cables. The

minimal power dissipation design also minimizes

thermal constraints inside the probe head, and

the higher clock speed helps reduce the number

of data lines.

SWIN-0

PZT-0

SWIN-1

PZT-64

SWIN-2

PZT-128

SWIN-189

PZT- 63

SWIN-190

PZT-127

SWIN-191

PZT-191

Tx

Rx

T/R

SW

Tx-0

Tx

Rx

T/R

SW

Tx-63

Ultrasound Probe

Ultrasound Console

64 Coaxial Cables

Figure 17: MP4864A Inside the Ultrasound Probe Head