Supertex inc. - Microchip Technologyww1.microchip.com/downloads/en/DeviceDoc/HV7355DB1...TP26 TP3...

Supertex inc.

Supertex inc. www.supertex.com

HV7355DB1

Doc.# DSDB-HV7355DB1B070314

General DescriptionThe HV7355 is a monolithic eight-channel, high-speed, high voltage, unipolar ultrasound transmitter pulser. This integrated, high performance circuit is in a single, 8x8x0.9mm, 56-lead QFN package.

The HV7355 can deliver guaranteed ±1.5A source and sink current to a capacitive transducer with 0 to +150V peak voltage. It is designed for medical ultrasound imaging and ultrasound material NDT applications. It can also be used as a high voltage driver for other piezoelectric or capacitive MEMS transducers, or for ATE systems and pulse signal generators as a signal source.

The HV7355’s circuitry consists of controller logic circuits, level translators, gate driving buffers and a high current and high voltage MOSFET output stage. The output stages of each channel are designed to provide peak output currents typically over ±1.5A for pulsing, with up to 150V swings. The upper limit frequency of the pulser waveform is dependent upon the load capacitance. With different capacitance load conditions the maximum output frequency is about 20MHz.

This demoboard datasheet describes how to use the HV7355DB1 to generate the basic high voltage pulse waveform as an ultrasound transmitting pulser.

The HV7355 circuit uses DC-coupling from a 3.3V logic input to output TX0~7 internally, therefore the chip needs three sets of voltage supply rails: VLL (+3.3V), VDD/VSS (+/-5.0V) and VPP (up to +150V). The VPP high voltage supply can be changed rather quickly, compared to the capacitor gate-coupled driving pulsers. This direct coupling topology of the gate drivers not only saves two high voltage capacitors per channel, but also makes the PCB layout easier.

The control signal logic-high voltage should be the same as the VLL voltage of the IC, and the logic-low should be referenced to GND.

The HV7355DB1 output waveforms can be displayed using an oscilloscope by connecting the scope probe to the test points TX0~7 and GND. The soldering jumper can select whether or not to connect the on-board dummy load, a 330pF capacitor paralleling with a 2.5kΩ resistor. The test points can be used to connect the user’s transducer to easily evaluate the pulser.

Block Diagram

150V, 1.5A, Unipolar Ultrasound Pulser Demoboard

LTIN0

IN7

VLL

GND

MC

VSS

VSS

+5.0 to 150V+3.3V

CPF VPPVDDVPF

CWD

Q[7:0]

LT

LT

LT

-5.0V

D0SDI

Q7SDO

SCK

SETLE

CS

ENPWR

RGND

RGND

RGND

SUB

Q7

Q0

AVDD

VSUB

TX0

R32.5k

C4330pF

GND

DummyLoad

R2WaveformGenerator

CPLD

+3.3V

OSC

JTAG

EXCLK

EN

CLKIN

WAVEFREQ

SELEN

CW/RTZ

CWLRRTZPWREN

40MHz

6

TX7

LR

DataLatch

ShiftRegister

VDD

VDD VPP

VDD

VDD

VDDVDD

VPF

VPF

VPP

TX7

VPP

+5.0V

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HV7355DB1



The PCB Layout TechniquesThe large thermal pad at the bottom of the HV7355 package is internally connected to the IC’s substrate (VSUB). This thermal pad should be connected to 0V or GND externally on the PCB. The designer needs to pay attention to the con-necting traces on the outputs TX0~7, as the high-voltage and high-speed traces. In particular, controlled-impedance to the ground plane and more trace spacing needs to be ap-plied in this situation.

High-speed PCB trace design practices that are compatible with about 50 to 100MHz operating speeds are used for the demo board PCB layout. The internal circuitry of the HV7355 can operate at quite a high frequency, with the primary speed limitation being load capacitance. Because of this high speed and the high transient currents that result when driv-ing capacitive loads, the supply voltage bypass capacitors and the driver to the FET’s gate-coupling capacitors should be as close to the pins as possible. The GND pin should have low inductance feed-through via connections that are connected directly to a solid ground plane. The VDD, VSS, VPP and CPP voltage-supply and/or bypass capacitor pins can draw fast transient currents of up to 2.0A, so they should be provided with a low-impedance bypass capacitor at the chip's pins. A ceramic capacitor of 1.0 to 2.0µF may be used. Only VPP to GND capacitors need be high voltage. CPF to VPP capacitors only need be low voltage. Minimize the trace length to the ground plane, and insert a ferrite bead in the power supply lead to the capacitor to prevent resonance in the power supply lines. For applications that are sensitive to jitter and noise when using multiple HV7355 ICs, insert another ferrite bead between each chips supply line.

Pay particular attention to minimizing trace lengths and using sufficient trace width to reduce inductance. Surface mount components are highly recommended. Since the out-put impedance of the HV7355’s high voltage power stages is very low, to obtain better waveform integrity at the load terminals after long cables, in some cases it may be desir-able to add a small value resistor in series with the outputs TX0~7. This will, of course, reduce the output voltage slew rate at the terminals of a capacitive load. Be aware of the parasitic coupling from the outputs to the input signal termi-nals of the HV7355.

This feedback may cause oscillations or spurious waveform shapes on the edges of signal transitions. Since the input operates with signals down to 3.3V, even small coupling voltages may cause problems. Use of a solid ground plane and good power and signal layout practices will prevent this problem. Also ensure that the circulating ground return cur-rent from a capacitive load cannot react with common induc-tance to create noise voltages in the input logic circuitry.

Testing the Integrated PulserThe HV7355 pulser demoboard should be powered up with a DC power supplie that has current limiting functions.

To meet the typical loading conditions, the on-board dummy load 330pF//2.5kΩ should be connected to the high voltage pulser output through the solder jumper when using an oscil-loscope’s high impedance probe. To evaluate different load-ing conditions, the values of the RC within the current and power limit of the device may be changed. In order to drive the user’s piezo transducers with a cable, one should match the output load impendence properly to avoid cable and transducer reflections. A 70 to 75Ω coaxial cable is recommended. The coaxial cable end should be sol-dered to TX0~7 and GND directly with very short leads. If a user’s load is being used, the on-board dummy load should be disconnected by cutting the small shorting copper trace in between the zeroΩ resistor’s (R2, R12 etc.) pads. They are shorted by factory default.

All of the on-board test points are designed to work with the high impedance probe of the oscilloscope. Some probes may have limited input voltage. When using the probe on these high voltage test-points, make sure that VPP voltages do not exceed the probe limit. Using the high impendence oscilloscope probe for the on-board test points, it is impor-tant to have short ground leads to the circuit board ground plane.

3

HV7355DB1



HV7355DB1 Schematic

6

24

11

11

2

33 4

6

VZ2

VZ5

EN

VZ8

VZ4

VZ3

VZ9

VZ6

VZ7

LE MC

SE

T

CS

SD

IS

CK

VP

PV

CC

VD

D

VP

P

VS

S

VP

P

VD

D

VC

C

VC

C

VS

SV

CC

VD

D

VC

C

VC

C =

+3.

3VV

DD/V

SS =

+/-5

.0V

VP

P =

+5.

0 to

+15

0V

J2E

XC

LKEX

=0

D7 R

ED

TP37

TP34

C9

1µF

160V

TP11

BAT54DW-7

BAT54DW-7D

22B

TP26

TP3

TP14

EN

1

GN

D2

OU

T3

VC

C4

40M

Hz

X1

EN

56

IN0

IN1

IN2

IN3

IN4

IN5

IN6

IN7

MC

LE SE

TC

SS

CK

SD

I

SD

O

TX0

TX0

TX1

TX1

TX2

TX2

TX3

TX3

TX4

TX4

TX5

TX5

TX6

TX6

TX7

TX7

VLL

AVDD

VDD

VDD

CPF

CPFVPPVPPVPPVPPVPPVPPVPPVPP

GND

GND

VSS

RGND

RGND

RGND

RGND

RGND

RGND

RGND

RGND

JX9577

TP9

TP31

TP17

R14

1.0k

D4 Y

LW

TP12

JTA

G J

3

TP40

C31

0.22

TP1

R9

1.0k

TP18

SW2

TP4

TP21

D6 G

RN

41725

23567

109

2411

SET

LE

MC

CS

EN

VCC

VCC

VCC

32

31

30

29

28

35

26

15

SD

O39

SC

K40

CLK

43

38 37 22 21 19 18 14 13

W4

ZE;794ZNaXS66

TP13

13

TP36

D22

A

TP38

B1100-13

D17

TP2

R34

2.55

k1W

TP39

TP10

C22

0.22

C37

330p

F25

0V

12

J1

R17

50

R21

50

R22

50

R23

50

R36

50

R39

50

R45

50

R46

50

R4

1.0k

BAT54DW-7

D20

B

D3 R

ED

TP6

R2 0

TP24

TP7

R25

33k

TP15

TP23

BAT54DW-7

D20

A

D5 Y

LW

R15

50

TP30

D15

B1100-13

R20

50

TP32

TP33

R47

50

R48

50

R49

50

R50

50

R51

50

R32

2.55

k1WR

542.

55k

1WR11

2.55

k1WR

242.

55k

1WR19

2.55

k1WR

132.

55k

1WR3

2.55

k1W

R12 0 R18 0 R23 0 R10 0 R37 0 R52 0 R53 0

C23

330p

F25

0VC24

330p

F25

0VC7

330p

F25

0VC29

330p

F25

0VC21

330p

F25

0VC20

330p

F25

0VC4

330p

F25

0V

C27

1µF

160V

C6

1µF

160V

C28

1µF

160V

C8

1µF

C5

1µF

C14

1µC

121µ

C13

1µ

C19

0.22

TP8

TP5

C1

022

C2

022

C3

022

VC

C

R5

1.0k

R6

1.0k

R7

1.0k

R8

1.0k

C18

0.22

VC

C

2

IN0

IN1

IN2

IN3

IN4

IN5

IN6

IN7

TP16

TP20

TP19

TP22

TP25

TP27

TP6

TP28

TP29

C36 1µ

R20 50

VC

CV

DD

VS

SV

PP

MH

3M

H2

MH

1

12

34

56

12

34

56

HE

AD

ER

6 J

4

MH

4

R35

1.0

R38

1.0

R31 1.0

R30 1.0

C32

0.22

C33

0.22

C34

0.22

C35

0.22

SW1

SW3

SW4

SW5

R26

33k

R27

33k

R28

33k

R29

33k

R40

200

R41

200

R42

200

R43

200

R45

200

VC

C

C30

0.22

GNDGNDGND

WAVFRESELENAMOD

TMSTDITDOTCK

57

54

17

44

25

46

47

26

27

24

45

42 43 41 40 39 38 37 36 35 34 33 32 31 30 29 28

1 2 3 4 5 6 7 8 15 11 14 9 12 10 13

MC LE

SE

TC

SS

CK

SD

I

16

55

23

48

53

184921205251501922

TP35

VD

D

4

HV7355DB1



HV7355DB1 PCB and Board Layout

Actual Board Size: 72.4mm x 68.4mm

Power Connector Description1 VCC +3.3V Logic voltage input for VLL and CPLD. (100mA)

2 GND 0V, Ground

3 VDD +5.0V HV7355 positive VDD supply. (25mA)

4 VSS -5.0V HV7355 negative VSS supply. (-25mA)

5 GND 0V, Ground

6 VPP +10 to +150V positive high voltage supply. (5mA)

Voltage Supply Power-Up and Operation Sequence1 +VCC +3.3V positive logic supply voltage for HV7355’s VLL and CPLD VCC.

2 +VDD / -VSS ±5.0V positive and negative VDD and VSS power supply.

3 +VPP +10 to +150V positive high voltage.Note:

Power-down in reverse order

Push Button OperationsWAV Toggle select pulse B-mode waveforms: None, 1-cycle, 3-cycles, 7-cycles.

FREQ Toggle select frequency: 20, 10, 5, 2.5, 1.25 and 0.625MHz when X1 oscillator is 40MHz.

SEL Toggle select. Increases the off-time between 2 consecutive pulses.

EN Toggle ON or OFF HV7355 chip enable

MODE Toggle select between B-mode and CW.

LED IndicatorSET Set the latch registers of serial interface, when high, all latches are set to logic high.

LE Latch enable when low, data can be latched into the registers of serial interface.

MC Mode control, high indicates B-mode and low indicates CW.

PWR HV7355 VLL 3.3V and CPLD chip VCC power supply indicator.

EN HV7355 chip enable signal indicator. Power state initially is OFF until EN is pushed.

5

HV7355DB1



Typical Waveforms

Figure 1. Input logic and TX output waveforms of 5.0MHz (0 to +150V with 330pF//2.5kΩ load)

Figure 2. Rise and fall time at 0 to +150V (with 330pF//2.5kΩ load)

6

HV7355DB1



Typical Waveforms (cont.)

Figure 3. Multiple channel at 5.0MHz (0 to +150V with 330pF//2.5kΩ load)

Figure 4. FFT Plot of Second Harmonic Distortion (HD2) -36dB at 5.0MHz, VPP = 150V (with 330pF//2.5kΩ load)

7

HV7355DB1




Figure 5. Output Waveform at 10MHz and VPP = 120V (with 330pF//2.5kΩ load)

Figure 6. Output Waveform at 2.5MHz and VPP = 120V (with 330pF//2.5kΩ load)

8

HV7355DB1




Figure 7. Output Waveform at 20MHz at VPP = 75V (with 330pF//2.5kΩ load)

Figure 8. Power on EN chip enable to VPF setting time

Supertex inc. does not recommend the use of its products in life support applications, and will not knowingly sell them for use in such applications unless it receivesan adequate “product liability indemnification insurance agreement.” Supertex inc. does not assume responsibility for use of devices described, and limits its liabilityto the replacement of the devices determined defective due to workmanship. No responsibility is assumed for possible omissions and inaccuracies. Circuitry andspecifications are subject to change without notice. For the latest product specifications refer to the Supertex inc. (website: http//www.supertex.com)

©2014 Supertex inc. All rights reserved. Unauthorized use or reproduction is prohibited. Supertex inc.1235 Bordeaux Drive, Sunnyvale, CA 94089

Tel: 408-222-8888www.supertex.com9

HV7355DB1


Bill of MaterialsComponent Description Manufacturer Part Number

C1 - C3, C18, C19, C22, C30 - C35 CAP CER 0.22µF 16V X7R 10% 0603 TDK C1608X7R1C224K

C4, C7, C20 - C24, C29, C37 CAP CER 330pF 200V X7R 0603 Panasonic ECJ-1VB2D331K

C5, C8, C12, C13, C14, C36 CAP CER 1.0µF 16V X7R 0603 TDK C1608X7R1C105M

C6, C9, C27, C28 CAP CER 1µF 100V X7R 20% 1210 TDK C3225X7R2A105M

D3, D7 LED THIN 635NM RED DIFF 0805 SMD Lumex SML-LXT0805IW-TR

D4, D5 LED THIN 585NM YEL DIFF 0805 SMD Lumex SML-LXT0805YW-TR

D6 LED THIN 565NM GRN DIFF 0805 SMD Lumex SML-LXT0805GW-TR

D15, D17 DIODE SCHOTTKY 100V 1A SMA Diodes Inc. B1100-13

D20, D22 DIODE SCHOTTKY DUAL 30V SOT-363 Diodes Inc. BAT54DW-7

J1 CONN HEADER 2POS .100 VERT GOLD Molex 22-28-4023

J2 CONN JACK END LAUNCH PCB GOLD SMA Johnson 142-0711-821

J3 CONN HEADER 6POS .100 VERT GOLD Molex 22-28-4063

J4 CONN HEADER 10POS .100 VERT GOLD Tyco 1-640454-0

R2, R10, R12, R18, R23, R37, R52, R53 Solder Gap (SHORT) NA NA

R3, R11, R13, R19, R24, R32, R34, R54 RES 2.55kΩ 1W 1% 2512 SMD Panasonic ERJ-1TNF2551U

R4, R5, R6, R7, R8, R9, R14 RES 1.00kΩ 1/16W 1% 0603 SMD Panasonic ERJ-3EKF1001V

R15 - R17, R20 - R22, R33, R36, R39,

R45 - R51RES 49.9Ω 1/16W 1% 0603 SMD Panasonic ERJ-3EKF49R9V

R25, R26, R27, R28, R29 RES 33.2kΩ 1/16W 1% 0603 SMD Panasonic ERJ-3EKF3322V

R30, R31, R35, R38 RES 1.00Ω 1/10W 1% 0603 SMD Rohm MCR03EZPFL1R00

R40, R41, R42, R43, R44 RES 200Ω 1/16W 1% 0603 SMD Panasonic ERJ-3EKF2000V

SW1, SW2, SW3, SW4, SW5 SWITCH LT 4.7MMX3.5MM 100GF SMD Panasonic EVQ-P2002M

TP3, TP15 TEST POINT PC MULTI PURPOSE BLK Keystone 5011

U2 IC CPLD 72 MCELL C-TEMP 44-VQFP Xilinx XC9572XL-5VQ44C

U3 IC HV7355K6-G 4-ch RTZ Supertex Inc. HV7355K6-G

X1 OSC CLOCK 40.000MHz 3.3V SMD CTS CB3LV-3C-40.0000-T

Supertex inc. - Microchip Technologyww1.microchip.com/downloads/en/DeviceDoc/HV7355DB1...TP26 TP3...

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