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Supertex inc.

Supertex inc. www.supertex.com

MD2134DB1

Doc.# DSDB-MD2134DB1A070114

IntroductionThe MD2134 is a high-speed, arbitrary waveform, push-pull source-driver. It is designed for medical ultrasound imaging and HIFU beam forming applications. It also can be used in NDT, sonar and other ultrasound phase-array focusing beam-forming applications.

The integrated circuit (IC) consists of the CMOS digital logic input circuits, an 8-bit current DAC for the waveform amplitude control, and four pre-stored Sine waveforms with pulse-amplitude-modulation (PAM) current sources. These current sources are constructed with the high-speed current-switch array and SPI programmable LV[15:1] PAM level registers. The PAM level resolution of the waveform is 7-bit, 128-step plus sign. There are four logic inputs M[3:0] as fast control signals. They control the push-pull current-source’s output timing, frequency, cycle in the burst, as well as the current-level output. The 15 level registers, along with the DAC value, together can be written and read-back via a SPI serial interface. The MD2134’s output stage is designed to drive two depletion mode high voltage Supertex DN2625 N-type MOSFETs as the source drivers. The MOSFET drains are connected to a center-tap ultrasound frequency pulse transformer. The secondary winding of the transformer can connect to the ultrasound piezo or capacitive transducer via cable and with a good impedance match. MD2134 has a high-speed 120MHz serial data interface that can quickly update the beam forming apodization between scans.

General DescriptionThis demoboard datasheet describes how to use the MD-2134DB1 to generate the ultrasound transmit beam forming waveform with the Gaussian profile, and the adjustable fre-quency, amplitude and phase angle. It also provides informa-tion about how to design a user application circuit and PCB using the MD2134K7 and DN2625DK6 devices. The MD2134DB1 circuit uses a pair of depletion mode, high voltage, DN2625 MOSFETs in the push-pull mode to drive the center-tap wide band ultrasound output transformer. The MOSFETs are in one 8-Lead DFN surface mount pack-age. The sources of the MOSFETs are directly driven by the MD2134’s two outputs, whose maximum peak sinking current is up to 3.3A. These current-source outputs are controlled by the MD1234’s internal current source switch array and the in-put signals M[3:0]. All of the MD2134’s logic control signals are generated by two small CPLD-programmable logic circuits clocked by an on-board 160MHz crystal oscillator. The on-board CPLD circuits not only generate accurate timing for the high-speed PAM level control waveforms, but also the serial data and clock to set and change the waveform amplitude DAC and waveform selection registers. The external clock input can be used if the on-board oscillator is disabled. The external trigger input can be used to synchronize the burst waveforms’ launch timing.

There are five push buttons for enabling and selecting the out-put waveform selection (PAM), amplitude (DAC) and chip en-

MD2134 UltrasoundBeamforming Transmitter Demoboard

Demoboard Block Diagram

T11:1:1

+70 to 100V VPP

C7 220pF

XDCX

+2.5V+3.3V

OSC

EXTRG

EXCLK

DIS

WaveFreq

PhaseAmplENA

PhaseDACPWREN

160MHz

JTAG

DN2625

1k

LOAD

JUMPDN2625

+5.0V +3.3V

CPLD

VCCIO

EXTRG

CLKIN

ENM1M3M0M2

SDISDOSCK

CSLD

MD2134

PA

PBRFB

VDD

GND

+5.0V +3.3V

+5.0V

VLL

+2.5V

VCC

2

MD2134DB1



able (EN). The FREQ button is not being used for this revision of firmware. Four color LEDs indicate the power, chip enable, waveform selection, and DAC states. The MD2134DB1 output waveform can be displayed by using an oscilloscope and the high impedance probe at the TP13 test point. It also can use an SMA to BNC 50Ω coaxial cable connected directly to an os-cilloscope, with an attenuation of 5:1 if R10 is 200Ω. A cable can also be used to drive the user’s transducer directly. Jumper J4 can be used to select whether or not to connect the on-board equivalent-load, which is formed by a 220pF capacitor in paral-lel with a 1.0kΩ resistor.

Circuit Design & PCB LayoutThe thermal pad at the bottom of the MD2134 package must be connected to the VSUB pin on the PCB. The VSUB is con-nected to the IC’s substrate. It is important to make sure that the VSUB is well grounded. A proper supply voltage power-up sequence is needed to test the circuit. To prevent any sup-ply voltage polarity reversing, the circuit also has protection Schottky diodes (D7, D8 and D9). Due to the high current and high current slew rate nature of this common gate, source-driven and push-pull circuit topol-ogy, the two cascading N-channel MOSFETs need to have very low lead inductance of the connections. The Supertex DN2625DK6 is designed for this application and works with the MD2134K7 seamlessly. In particular, a good PCB layout design needs to shorten the traces between the MD2134K7 output pins and the DN2625DK6 source pins. It is also neces-sary to connect all three pairs of pins between them for the high current carrying capacity. Furthermore, because of the high di/dt current in MD2134’s outputs, it is also necessary to connect the Schottky diodes D5 and D6 from the driver output pins connected to the +5.0V power supply line, as the clamp-ing diodes. Note that the diodes must have enough speed and peak current capability. The RC snubber circuits of R8-C5 and R15-C28 at the output pins can dump the current pulse edge ringing effectively. PCB designers need to pay attention to some of the connect-ing traces as high-voltage and high-speed traces. In particular, low capacitance to the ground plane and more trace spacing needs to be applied in this situation.

High-speed PCB trace design practices that are compatible with about 100 to 200 MHz operating speed are used for the demoboard PCB layout. The internal circuitry of the MD2134 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 driving even

very small inductive loads, ringing and even oscillations are possible. The supply voltage bypass capacitors and the MOSFET gate de-coupling capacitors should be as close to the pins as possible. The capacitor’s ground pin pads should have low inductance, feed-through connections that are con-nected directly to a solid ground plane. The VDD and VPP supplies can draw fast transient currents of up to 3.5A, so they should be provided with a low-impedance bypass capacitor at the chip’s pins. A ceramic capacitor of 0.1 to 1.0µF may be used. Minimize the trace length to the ground plane, and in-sert 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 and when using multiple MD2134 ICs, insert another ferrite bead between VDD and decouple each chip supply separately. Pay particular attention to minimizing trace lengths and using sufficient trace width to reduce inductance not only on the supply pins but also on the CA/B and KA/B compensation pins. Very closely placed sur-face mount components are highly recommended. Be aware of the parasitic coupling from the high voltage outputs to the input signal terminals of MD2134. This feedback may cause oscillations or spurious waveform shapes on the edges of signal transitions. Since the input operates with signals down to 2.5V, 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 cir-culating ground return current from a capacitive load cannot react with common inductance to create noise voltages in the input logic circuitry.

This MD2134DB1 demoboard should be powered up with multiple DC power supplies with current limiting functions. The power supply voltages and current limits used in the testing are listed on page 7. There are examples of the MD2134DB1 demoboard input and output waveform and measurements shown in Figures 1 to 7 below.

Output Transformer DesignThe center tap, wide band, ultrasound transformer for push- pull output circuit serves three functions: a balanced-differen-tial to single-end output transformer; an isolation barrier to the ultrasound probe; and an impedance matching or low-pass network combined with the cable and transducer element. The MD2134 PAM clock may operate at a 80 to 160MHz frequen-cy range, however the wide band transformer needs only to work in the frequency band of the dummy load (220pF//1.0k). Besides the bandwidth consideration, the small transformer should be designed using a ferrite magnetic core selected to give high enough saturation current and low leakage induc-tance.

3

MD2134DB1



OU

T1

IN3

OU

T1O

UT2

2 4

3 41

C27 0.

1

WAV 2FRE 3

GND 4

PAM 5

AMPL 6

TDI19TMS 10

TCK 11

VCC

GND 17

M2

20

M1

19

M3

21

M0

18

TDO124

GND 25

VCC

F29

NC1130NC1231

Z22

Y16

VCC

EXTRG39

D40

CLKIN43

X23

V14

U13

ENA 7

EN

12NC1027

L1

A44

K42

M41

J38

B37

N34

C36

G28

E32

H33

I8

U2

XC95

72XL

_VQ

44TP

11

B2

R2

50

PW

R

B3

12345

J7

D1

R27 0

TP5

VG

G

B4

PB

VD

D

PH0

MH

2

MH

3

MH

4

MH

1

B5

VD

D2

3U

4LM

4040

VD

D

B6

EN

VC

C

TP4

123456

J6JT

AG

VC

C

B7

PA

C15

27nF

B8

C24 0.1

B9

C1

0.1

1 2

4 3D6B

43D5B

35 14

67910

2

1

2

7 8 9 10 11 12

M1B

DN

2625

DK

6O

UTP

UT

R15

1.0

1W

R9

100

1W

R14 200

VP

P

B11

SD

I

CS

SC

KS

DO

LD

(+3.

3V)

VG

G

C23

0.1

VD

D

C28

3.3n

F

+

1 2

D4

YLW

R3

1k

DAC

1 2(+

3.3V

)V

GG

VLL

C21

27nF

12J2

EX

= 0

1

23

1 2

VD

D

R1 1k

KA1

GND 2

C1A3

GND 4VDD5

C3A6

GND7

VLL8

DG

ND

9

SC

K10

SD

I11

M3

12

M2

13

M1

14

M0

15

VDD16

AGND 17

SD

O18

CS

19

LD20

EN

21

VREF 22

RFB 23

GND24

C3B25

VDD26

GN

D27

C1B28G

ND

29

KB 30

C2B 31

PB

32P

B33

PB

34

VS

UB

35V

SU

B36

PA37

PA38

PA39

C2A40

VSUB

U1

MD

2134

K7

TP3

(+70

to 1

00V

)V

PP

+C

32 1016

V

1

23J5 X

DC

R- A

16

D8A

C6

0.1

TP13

1

23

R7

50

C2

0.1

J3E

XTR

GJ1E

XC

LK

TP1

R10 200

VC

C

R17 33k

(+3.

3V)

VC

C

C19

220p

250V

EN

PH

0

R13

1k 1W

VC

C

C36

1µ 100V

3

4

5613141516

EN

1

GN

D2

OU

T3

VC

C4

X1

FXO

-HC

73-1

60

43D7B

SD

I

(+5.

0V)

VD

D

16D7A

C12 0.1

21

D9

B11

00-1

3

TP19

SD

O

R16

49.9

k

TP2

TP15

PWR

R11 0

SC

K

1 6

D6A

16

D5A

NC1 2

NC2 3

GND 4

NC3 5

NC4 6

TDI2 9TMS10

TCK 11

VCCIO26

GND 17

NC

820

NC

719

NC

621

NC

918

TDO2 24

GND 25

VCC15

FF29

LED230LED131

SD

I22

SD

O16

VCC

35

EXTRG39

DD

40

CLKIN43

SC

K23

CS

14

LD13

NC5 7

EN

12

PWR27

LL1

AA44

KK

42

MM

41

JJ38

BB37

NN

34

CC

36

GG

28

EE

32

HH

33

II8

U3

XC95

72XL

_VQ

44

CS

EN

DA

C

TP17

B0

R8

1.0

1W

C22 0.

1

D2

C39 0.1

LD

12

34

J4

B1

R18 33k

R19 33k

R20 33k

R21 33k

R22 200

R23 200

R24 200

R25 200

R26 200

SW1

SW2

SW3

SW4

SW5

C30 0.1

C35 0.1

C38 0.1

C37 0.1

C31 0.1

R4

1kR

51k

R6

1k

D1

YLW

D1

RE

DD

3G

RN

TP20

C33

10 16V

C18 1µ

100V

R12

100

1WM

1AD

N26

25D

K6

C5

3.3n

F

C17

0.1

C16 0.1

41

1

C3

0.1

C4

0.1

C14

27nF

C13

27nF

C26

27nF

C25

27nF

TP10

TP14

TP18

TP16

TP6

TP12

TP7

TP9

TP8

B10

B2

B3

B4

B5

B6

B7

B8

B9

B11

B0

B1

B10

C8

0.1

C7

0.1

VC

C

C9

0.1

152635

C11 0.1

C10 0.1

C29 0.1

VLL

T1E

P10

_EP

13

C20

0.1

U5

AD

P333

9AK

C-2

.5R

L7

VC

C(+

2.5V

)V

LL

C34 10

16V

+

R28 0

D8B

TP1

Circuit Schematic

4

MD2134DB1



PCB Layout

Actual Dimensions: 10.2cm x 7.6cm (4.00” x 3.00”)

MD2134DB1 Demoboard

5

MD2134DB1



Figure 1: Output waveform of 16-sample/cycle fS = 160MHz, VPP = 75V, 220pF//1.0kΩ load.LV = (0, -12, -12, -45, -45, -12, -12, 0, 0, 14, 14, 45, 45, 14, 14, 0, . . .) 5 cycles

MD2134DB1 Input and Output Waveforms

DAC

A

B

DGND AGND

C3A KA C1A

C3B C2B C1BVREF

+VREF

M0

M1

M2

M3

EN

SDI

SDO

SCK

CS

LD

VLL

SUB DataLatch

&ControlLogic

Beamform Switch Matrix

VDD

+5.0V+2.5V

PA

PB

+3.3V

+3.3V

+70 to 100VVPP GND

KB

C2A

RFB

D2

D1

+5.0V

M1

M2

+5.0V

LevelTranslator

PAMLevelSelect TP

1kΩ220pFLeakage

2µH

Test Load

(WE750340727-02)

DN2625

DN2625

6

MD2134DB1



The level-registers in MD2134 store 7 positive and 8 negative numbers and control the M[3:0] to trans-mit these levels. Use the sequence below and its reverse order. Including zeros, there are a total of 45 transmitted data samples.

LV = (0, 0, 2, 2, 2, 0, 0, -6, -12, -20, -29, -38, -45, -48, -45, -32, -12, 14, 45, 76, 103, 121, 127, . . )

Figure 3: Example of Gauss-Sine waveform for LV1~LV15 SPI register values and transmit se-quence.

130

112

94

76

58

40

22

4

-14

-32

-500 10 20 30 40

Figure 2: Output waveform of 16-sample/cycle of 7.46MHz DAC = 255, VPP = 75V, 220pF//1.0kΩ load.

7

MD2134DB1



Figure 4: Output waveform and polarity reversed Gauss-Sine waveform at 16-sample/cycle of 7.46MHz DAC = 255, VPP = 75V, 220pF//1.0kΩ load.

0 40 80 120 160 200 240 280 320 360 400

200

100

0

-100

-200

Time (ns)

Volta

ge (V

)

Figure 5: Gauss-Sine waveform at 16-sample/cycle of 7.46MHz DAC = 255, VPP = 75V, 220pF//1.0kΩ load.

8

MD2134DB1



Current Level Control Pin DescriptionInput Control Pin Name PAM

Current Level DescriptionM3 M2 M1 M00 0 0 0 LV0 PA & PB both off, zero current.0 0 0 1 LV1 Select LV1 current magnitude to PA.0 0 1 0 LV2 Select LV2 current magnitude to PA.0 0 1 1 LV3 Select LV3 current magnitude to PA.0 1 0 0 LV4 Select LV4 current magnitude to PA.0 1 0 1 LV5 Select LV5 current magnitude to PA.0 1 1 0 LV6 Select LV6 current magnitude to PA.0 1 1 1 LV7 Select LV7 current magnitude to PA.1 0 0 0 LV8 Select LV8 current magnitude to PB.1 0 0 1 LV9 Select LV9 current magnitude to PB.1 0 1 0 LV10 Select LV10 current magnitude to PB.1 0 1 1 LV11 Select LV11 current magnitude to PB.1 1 0 0 LV12 Select LV12 current magnitude to PB.1 1 0 1 LV13 Select LV13 current magnitude to PB.1 1 1 0 LV14 Select LV14 current magnitude to PB.1 1 1 1 LV15 Select LV15 current magnitude to PB.

Note:Turning on PA & PB simultaneously can cause over-current and permanent damage to the IC, high voltage MOSFETs, or to the transformer.

Figure 6: MD2134DB1 6.5MHz Gauss-Sine waveforms and frequency spectrum.

9

MD2134DB1



CPLD Pin # Signal Name Description

U2, 3 - 15, 26, 35 VCC CPLD logic power supply +3.3V

U2, 3 - 26 VLL CPLD, VCCIO and MD2134 logic power supply +2.5V

U2, 3 - 4, 17, 25 GND Logic power ground 0V

U2 - 2 WAV Run or stop demo waveform phase

U2 - 3 FRE Selecting frequency: 8,10 and 13.3MHz

U2 - 5 PHASE Single step phase change, angle stepping:0, 7.5, 15…360

U2 - 6 AMPL Single step amplitude change, DAC stepping: 15, 31…255

U2 - 7 ENA Control MD2134 EN pin

U2 - 18 M1 Output signal to MD2134 M1




U3 - 31 LED1 Output signal yellow, PH0 LED is on when phase = 0

U3 - 30 LED2 Output signal yellow, DAC LED is on when DAC = 127

U3 - 27 PWR Output signal LED green, indicates +3.3V power supply on

U2, 3 - 10 TMS Test mode select of JTAG

U2, 3 - 9 TDI Test data in of JTAG, two CPLD in daisy chain

U2, 3 - 24 TDO Test data out of JTAG, two CPLD in daisy chain

U2, 3 - 11 TCK Test clock of JTAG

U2, 3 - 43 CLK CPLD clock input

U2, 3 - 39 EXTRG External trigger signal input to control waveform timing

U2, 3 - 12 EN Output signal LED red, indicates MD2134 is enabled

U3 - 22 SDI Output signal to MD2134 SDI

U3 - 16 SDO Input signal from MD2134 SDO

U3 - 23 SCK Output signal to MD2134 SCK

U3 - 14 CS Output signal to MD2134 CS

U3 - 13 LD Output signal to MD2134 LD

All remaining pins NC or Reserved

Board Connector and Test Pin Description

10

MD2134DB1



Voltage Supply Power-Up SequenceStep Signal Name Description

1 VDD +5.0, MD2134 positive supply voltages2 VCC +3.3V, MOSFET gate biasing and CPLD control logic supply voltage3 VPP +70V to 100V, the high voltage supply

4 ENLogic Active Enable logic control, active-high signal to MD2134

Voltage Supply Power-Down Sequence

1 ENLogic Active Disable logic control, active-high signal to MD2134

2 VPP +70V to 100V, the high voltage supply, off3 VDD +5.0V, MD2134 positive supply voltages with all input signals LOW, off4 VCC +3.3, CPLD control logic supply voltage with EN = 0, off

JTAG Connector

Pin #

Signal Name Description

J6-1 TMS Test Mode Select of CPLD.J6-2 TDI Test Data In of CPLD.J6-3 TDO Test Data Out of CPLD.J6-4 TCK Test Clock of CPLD.J6-5 GND Logic power supply ground 0V for programming only.J6-6 VCC Logic power supply +3.3V for programming only.

Signal and Jumper

Pin #

Signal Name Description

J1 EXCLK External clock input when on-board oscillator is disabled, or output of the clock when it is enabled.

J2 OSC_EN Jumper for on-board oscillator, short = disabled, open = enabled.J3 EXTRG External trigger signal input.J4 Load JP Jumper for on-board RC load to MD2134DB1 high voltage output and XDCR connector.

J5 XDCR MD2134DB1 waveform output, for SMA-cable to oscilloscope, high voltage! 0 to +/-350VP-P max.

Power Supply ConnectorJ7-1 VCC +3.3V, MOSFET gate biasing and CPLD supply voltage with current limit from 120 to

150mA.J7-2 GND Ground reference, 0V.J7-3 VDD +5.0V MD2134 positive supply voltages with current limit to 50mAJ7-4 GND Ground reference, 0V.J7-5 VPP +70 to100V, the high voltage supply with current limit to 30mA.

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.com11

MD2134DB1


MD2134DB1 Bill of MaterialsReference Description Manufacturer’s

Part Number Manufacturer

C1 - C12, C16, C17, C20,

C22 - C24, C27, C29 - C31, C35,

C37 - C39

CAP .1µF 25V CERAMIC X7R 0603 ECJ-1VB1E104K Panasonic

C5, C28 CAP CER 3300PF 10% 100V X7R 0603 06031C332KAT2A AVXC13, C14, C15, C21, C25, C26 CAP .027µF 50V CERAMIC X7R 0603 ECJ-1VB1H273K Panasonic

C18,C36 CAP CER 1µF 100V X7R 20% 1210 C3225X7R2A105M TDK

C19 CAP CERAMIC 220PF 200V NP0 0805 ECJ-2YC2D221J Panasonic

C32, C33, C34 CAP 10µF 16V ELECT WT SMD UWT1C100MCL1GB Nichicon

D1, D4 LED THIN 585NM YEL DIFF 0805 SMD SML-LXT0805YW-TR Lumex

D2 LED THIN 635NM RED DIFF 0805 SMD SML-LXT0805IW-TR Lumex

D3 LED THIN 565NM GRN DIFF 0805 SMD SML-LXT0805GW-TR Lumex

D9 Diode Schottky, 100V, 1.0A, SMA B1100-13 Diodes Inc.

D5 - D8 Diode Schottky, dual, 30V, SOT-363 BAT54DW-7 Diodes Inc.

M1 250V 3.0A dual depletion N-MOSFET, 5x5mm, DFN-8 DN2625DK6-G Supertex Inc.

R1 RES 1.00kΩ 1/16W 1% 0603 SMD ERJ-3EKF1001V Panasonic

R2, R7 RES 49.9Ω 1/16W 1% 0603 SMD ERJ-3EKF49R9V PanasonicR3 - R6, R10,

R14, R22 - R26 RES 200Ω 1/16W 1% 0603 SMD ERJ-3EKF2000V Panasonic

R8,R15 RES 1.0Ω 1W 1% 2512 SMD ERJ-1TRQF1R0U Panasonic

R9,R12 RES 100Ω 1W 1% 2512 SMD ERJ-1TNF1000U Panasonic

R11,R27 PCB copper short NA NA

R13 RES 1kΩ 1W 1% 2512 SMD ERJ-1TYF102U Panasonic

R16 RES 49.9kΩ 1/16W 1% 0603 SMD ERJ-3EKF4992V PanasonicR17, R18, R19,

R20, R21 RES 33.2kΩ 1/16W 1% 0603 SMD ERJ-3EKF3322V Panasonic

R28 PCB copper short NA NA

T1 22µH, 1:1:1 wideband ultrasound pulse transformer 750340727 Würth Electronics

U1 IC ultrasound beamforming source driver 40-Lead QFN MD2134K7-G Supertex Inc.

U2, U3 IC CPLD, 72 MCELL, C-Temp, 44-VQFP XC9572XL-5VQ44C Xilinx

U4 IC precision reference micropower ref, SOT-23 LM4040DEM3-2.5 National

U5 IC voltage regulator, 1.5A, 2.5V, SOT-223 ADP3339AKC-2.5 ADI

X1 Oscillator clock, 160.000MHz, 3.3V, SMD JITO-2-DC3AE-160 FOX Electronics

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