MAX14805 Datasheet, PDF(10/14 Page) Maxim Integrated Products – 16-Channel (Two Banks of 8-Channel), High-Voltage Analog Switches

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16-Channel (Two Banks of 8-Channel),

High-Voltage Analog Switches

Detailed Description

The MAX14805/MAX14806 provide high-voltage switch-

ing on 16 channels for ultrasonic imaging. Both devices

are ideal for the following applications: bank selection in

biplane or triplane ultrasound probes and relays replace-

ment in medical ultrasound systems. The devices utilize

200V process technology to provide 16 high-voltage,

low-charge injection SPST switches, controlled by a

digital interface.

The MAX14805/MAX14806âs output switches are con-

figured as two sets of eight SPST analog switches. The

switches are controlled by two input logic controls, DIN1

and DIN2 (respectively for switch 0 to 7 and switch 8

to 15). The MAX14806 features integrated 40kI bleed

resistors on each switch terminal that help to reduce

voltage buildup in capacitive loads such as piezoelectric

elements.

The MAX14805/MAX14806 operate with a wide range of

high-voltage supplies, including VPP/VNN = +100V/-100V,

+200V/0V and +40V/-160V. The digital interface oper-

ates from a separate VDD supply from +2.7V to +5.5V.

Digital inputs DIN1, DIN2, and LE operate on the VDD

supply voltage.

The MAX14805CCM+ is a drop-in replacement for the

Supertex HV2631. The MAX14806CCM+ is a drop-in

replacement for the Supertex HV2731.

Analog Switch

The MAX14805/MAX14806 allow a peak-to-peak analog

signal range from VNN to (VPP - 10V). During power-up

and power-down, all analog switch inputs (SW_) must be

unconnected or satisfy VNN P VSW_ P VPP.

High-Voltage Supplies

The MAX14805/MAX14806 allow a wide range of high-

voltage supplies. The devices operate with VNN from

-160V to 0V and VPP from +40V to (VNN + 220V). When

VNN is connected to GND (single-supply applications),

the devices operate with VPP up to +200V. The VPP and

VNN high-voltage supplies are not required to be sym-

metrical, but the voltage difference (VPP - VNN) must not

exceed 230V.

Bleed Resistors (MAX14806)

The MAX14806 features integrated 40kI bleed resis-

tors to discharge capacitive loads such as piezoelectric

transducers. Each analog switch terminal is connected

to GND with a bleed resistor.

Data Input (DIN1/DIN2)

DIN1/DIN2 control the on/off state of the analog switches.

DIN1 controls SW0âSW7 and DIN2 controls SW8âSW15

(see Table 1 and Figure 2). DIN1 and DIN2 operate on

the VDD supply voltage.

Latch Enable (LE)

Drive LE logic-low to latch DIN1/DIN2 data input (see

Figure 2). Drive LE logic-high to hold data. The LE input

operates on the VDD supply voltage.

Applications Information

For medical ultrasound applications, see Figures 3 and 4.

Supply Sequencing and Bypassing

The MAX14805/MAX14806 do not require special

sequencing of the VDD, VPP, and VNN supply voltages;

however, analog switch inputs must be unconnected or

satisfy VNN P VSW_ P VPP during power-up and power-

down. Bypass VDD, VPP, and VNN to GND with a 0.1FF

ceramic capacitor as close as possible to the device.

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