Texas Instruments DRV2700EVM User manual

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DRV2700EVM High Voltage Piezo Driver Evaluation Kit
User's Guide
SLOU403C–March 2015–Revised June 2018
DRV2700EVM High Voltage Piezo Driver Evaluation Kit
The DRV2700 is a single-chip, high-voltage piezo driver with an integrated 105-V boost switch, integrated
power diode, and integrated fully differential amplifier. This evaluation kit demonstrates:
• Multiple input modes including: 0- to 10-V single ended, PWM, and AC input modes
• Multiple output modes including: 0- to 200-Vpp differential, 0- to 105-V single and multiple ended
• 2 power supply inputs to isolate power consumption on DRV2700
• 8 convenient boost voltage settings and 4 different gain settings
• Small footprint (9 mm x 13 mm)
• Breakout for usage as a boost converter
The evaluation kit is designed for all-around use and can be used not only for evaluation but can also be
used for prototyping into systems. The EVM also contains a microcontroller, LDO (3.3 V) and LEDs for
status and input settings.
Evaluation Kit Contents:
• DRV2700EVM evaluation board
• Demonstration mode firmware preloaded onto microcontroller
• Downloadable software to control EVM
• Mini-B USB cable
Needed for programming and advanced configuration:
• Code Composer Studio™ (CCS) or IAR Embedded Workbench IDE for MSP430
• MSP430 LaunchPad™ (MSP-EXP430G2) or MSP430-FET430UIF hardware programming tool
• DRV2700EVM firmware available on the DRV2700EVM tool folder
• MSP-JTAG2SBW JTAG to Spy-Bi-Wire adapter

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Contents
1 Getting Started............................................................................................................... 6
1.1 Evaluation Module Operating Parameters....................................................................... 6
1.2 Quick Start Board Setup........................................................................................... 7
1.3 Connecting a Load.................................................................................................. 7
2 Overview of EVM ............................................................................................................ 8
2.1 DRV2700............................................................................................................. 8
2.2 Microcontroller (MSP430).......................................................................................... 8
2.3 Power Supply Inputs and Path.................................................................................... 8
2.4 EN and Gain Configuration........................................................................................ 9
2.5 Inputs ............................................................................................................... 10
2.6 Outputs ............................................................................................................. 10
2.7 BST/PVDD Disconnect ........................................................................................... 10
2.8 TRIG Button........................................................................................................ 10
3 EVM Control Software (GUI).............................................................................................. 11
4 Boost Converter ............................................................................................................ 12
4.1 Boost Voltage Setting Resistors................................................................................. 13
4.2 Disconnecting BST/PVDD........................................................................................ 14
4.3 Programming the Boost Current Limit.......................................................................... 14
4.4 Boost Inductor Selection ......................................................................................... 14
4.5 Boost Capacitor Selection........................................................................................ 14
5 PWM, Analog, and Single-Ended Inputs................................................................................ 15
5.1 PWM (AC Coupled) Input Using MSP430 ..................................................................... 15
5.2 PWM (AC Coupled) Input Using AIN ........................................................................... 15
5.3 External Analog (AC Coupled) Input............................................................................ 16
5.4 Single-Ended (DC Coupled) Input .............................................................................. 16
6 Output........................................................................................................................ 19
6.1 Two Terminal Differential Output Configuration (OUT+ – OUT–)........................................... 19
6.2 Two Terminal Single Ended Output Configuration (OUT± to BST/GND) .................................. 19
6.3 Three Terminal Single Ended Output Configuration (BST to OUT± to GND)............................. 20
7 Load Selection.............................................................................................................. 20
8 Filtering and Adapting PWM Waveforms................................................................................ 21
8.1 PWM Input ......................................................................................................... 21
8.2 Filter Selection Criteria ........................................................................................... 22
9 Reference ................................................................................................................... 25
9.1 Schematic .......................................................................................................... 25
9.2 PCB Layout ........................................................................................................ 26
9.3 Bill of Materials .................................................................................................... 28
List of Figures
1 Board Diagram............................................................................................................... 6
2 Power Path Diagram ........................................................................................................ 8
3 Gain = 40.7 dB............................................................................................................... 9
4 Gain = 38.4 dB............................................................................................................... 9
5 Gain = 34.8 dB............................................................................................................... 9
6 Gain = 28.8 dB............................................................................................................... 9
7 GUI Interface................................................................................................................ 11
8 BST Network JP2, JP3, and JP4......................................................................................... 13
9 PWM Signal................................................................................................................. 15
10 Set Reference to External 2.5 V ......................................................................................... 17
11 Floating Reference at 3 Hz and No Load............................................................................... 17
12 Floating Reference at 1 Hz and No Load............................................................................... 17
13 DC Coupled Input Diagram ............................................................................................... 18

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14 Two Terminal Differential Output......................................................................................... 19
15 Two Terminal Single Ended Output ..................................................................................... 19
16 Three Terminal Single Ended Output ................................................................................... 20
17 DRV2700EVM First- and Second-Order Filters........................................................................ 21
18 Differential, First-Order Filter ............................................................................................. 22
19 Frequency Response of the First-Order Filter.......................................................................... 22
20 Differential, Second-Order Filter ......................................................................................... 23
21 Frequency Response of the Second-Order Filter...................................................................... 23
22 DRV2700EVM Schematic................................................................................................. 25
23 All Layers.................................................................................................................... 26
24 Top Layer ................................................................................................................... 26
25 Mid Layer 1 ................................................................................................................. 27
26 Mid Layer 2 ................................................................................................................. 27
27 Bottom Layer................................................................................................................ 28
WARNING
EXPORT NOTICE
Recipient agrees to not knowingly export or re-export, directly or
indirectly, any product or technical data (as defined by the U.S.,
EU, and other Export Administration Regulations) including
software, or any controlled product restricted by other applicable
national regulations, received from Disclosing party under this
Agreement, or any direct product of such technology, to any
destination to which such export or re-export is restricted or
prohibited by U.S. or other applicable laws, without obtaining prior
authorization from U.S. Department of Commerce and other
competent Government authorities to the extent required by those
laws. This provision shall survive termination or expiration of this
Agreement. According to our best knowledge of the state and end-
use of this product or technology, and in compliance with the
export control regulations of dual-use goods in force in the origin
and exporting countries, this technology is classified as follows:
US ECCN: 3E991
EU ECCN: EAR99
And may require export or re-export license for shipping it in
compliance with the applicable regulations of certain countries.

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Cautions and Warnings
CAUTION:
Warning! Do not leave EVM powered when unattended.
HOT SURFACE:
Warning Hot Surface! Contact may cause burns. Do not touch. Please take the proper
precautions when operating.
HIGH VOLTAGE:
Danger High Voltage! Electric shock possible when connecting board to live wire. Board should
be handled with care by a professional. For safety, use of isolated test equipment with
overvoltage/overcurrent protection is highly recommended.

WARNING
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General Texas Instruments High Voltage Evaluation (TI HV EVM) User Safety Guidelines
Always follow TI’s setup and application instructions, including use of all interface components within their
recommended electrical rated voltage and power limits. Always use electrical safety precautions to help
ensure your personal safety and those working around you. Contact TI's Product Information Center
http://support/ti./com for further information.
Save all warnings and instructions for future reference.
Failure to follow warnings and instructions may result in personal injury, property damage, or
death due to electrical shock and burn hazards.
The term TI HV EVM refers to an electronic device typically provided as an open framed, unenclosed
printed circuit board assembly. It is intended strictly for use in development laboratory environments,
solely for qualified professional users having training, expertise and knowledge of electrical safety
risks in development and application of high voltage electrical circuits. Any other use and/or
application are strictly prohibited by Texas Instruments. If you are not suitable qualified, you should
immediately stop from further use of the HV EVM.
1. Work Area Safety
1. Keep work area clean and orderly.
2. Qualified observer(s) must be present anytime circuits are energized.
3. Effective barriers and signage must be present in the area where the TI HV EVM and its interface
electronics are energized, indicating operation of accessible high voltages may be present, for the
purpose of protecting inadvertent access.
4. All interface circuits, power supplies, evaluation modules, instruments, meters, scopes and other
related apparatus used in a development environment exceeding 50Vrms/75VDC must be
electrically located within a protected Emergency Power Off EPO protected power strip.
5. Use stable and nonconductive work surface.
6. Use adequately insulated clamps and wires to attach measurement probes and instruments. No
freehand testing whenever possible.
2. Electrical Safety
As a precautionary measure, it is always a good engineering practice to assume that the entire EVM
may have fully accessible and active high voltages.
1. De-energize the TI HV EVM and all its inputs, outputs and electrical loads before performing any
electrical or other diagnostic measurements. Revalidate that TI HV EVM power has been safely
de-energized.
2. With the EVM confirmed de-energized, proceed with required electrical circuit configurations,
wiring, measurement equipment connection, and other application needs, while still assuming the
EVM circuit and measuring instruments are electrically live.
3. After EVM readiness is complete, energize the EVM as intended.
WARNING: WHILE THE EVM IS ENERGIZED, NEVER TOUCH THE EVM OR ITS ELECTRICAL
CIRCUITS AS THEY COULD BE AT HIGH VOLTAGES CAPABLE OF CAUSING ELECTRICAL
SHOCK HAZARD.
3. Personal Safety
1. Wear personal protective equipment (for example, latex gloves or safety glasses with side shields)
or protect EVM in an adequate lucent plastic box with interlocks to protect from accidental touch.
Limitation for safe use:
EVMs are not to be used as all or part of a production unit.

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1 Getting Started
The DRV2700EVM is designed for flexible use for prototyping as well as evaluation. Figure 1 shows the
names and locations of the various elements on the EVM. To power the board, connect the DRV2700EVM
to an available USB port on your computer using a mini-B USB cable. The default board settings cause
the microcontroller (MSP430) to control the inputs of the DRV2700 at power up. The MSP430 has each of
these control settings low which disables the DRV2700, by default. Figure 1 shows the basic board
diagram of the DRV2700EVM. Table 2 shows the original configuration of the jumpers, as shipped.
Figure 1. Board Diagram
1.1 Evaluation Module Operating Parameters
Table 1 lists the operating conditions for the DRV2700 on the evaluation module.
Table 1. Typical Operating Conditions
Parameter Specification
Supply voltage range 3.6 V to 5.5 V
Power-supply current rating 500 mA
Input Voltage 0 V to VDD
Max Output Voltage 200 Vpp

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1.2 Quick Start Board Setup
The DRV2700EVM comes with preprogrammed firmware to provide a 0- to 200-Vpp signal between OUT+
and OUT–.
1. Out of the box, the jumpers are set to begin demo mode using USB power. The default jumper settings
are found in Table 2.
2. Connect a mini-USB cable to the USB connector on the DRV2700EVM board.
3. Connect the other end of the USB cable to an available USB port on a computer, USB charger, or USB
battery pack.
4. If the board is powered correctly, the 5-V LED is on.
5. Enable the output using the GUI or programmatically through the computer, see GUI Interface for
additional assistance. If using an external input signal, EN the output by changing the jumper (JP9) or
equivalent control signal.
6. Once the output is EN, the device allows for the high-voltage output.
(1) In the table, (top) or (bottom) means the (top) or (bottom) is connected to the middle of the 3-terminal header. For questions,
refer to Figure 1.
Table 2. Default Jumper Settings
Parameter Jumper Setting Default Specification
JP10 MSP
Open MSP not connected to either power supply
USB (top)(1) X MSP connected to USB power supply
VIN (bottom)(1) MSP connected to VIN power supply
JP11 DRV
Open DRV2700 not connected to either power supply
VIN (top)(1) DRV2700 connected to VIN power supply
USB (bottom)(1) X DRV2700 connected to USB power supply
JP5 and JP6 Open Disconnected PWM± and I/O of MSP430
Connected X Connected PWM± and I/O of MSP430
JP9-EN
JP8-G1
JP7-G0
Open EN/G1/G0 pulled internally to GND through DRV2700 internal resistance
MSP (top)(1) X EN/G1/G0 tied to I/O of MSP430
PU (bottom)(1) EN/G1/G0 pulled up to MSP power supply through external pull up resistor
JP13-DCIN Open X DC input not connected (PWM and AC input mode)
Connected DC input connected (single-ended input mode)
JP12-VBST Open PVDD disconnected to BST (boost only mode)
Connected X PVDD connected to BST (normal operation)
I2C Open Always leave open. Never jumper together.
J2, J3, J4 Open Disconnects particular FB resistor (lowers BST)
Connected X Connects particular FB resistor (raises BST)
1.3 Connecting a Load
1. With the power supply off, connect the negative terminal of the load to OUT– and connect the positive
terminal of the load to OUT+
2. Ensure the terminals are connected correctly, then enable the supply
WARNING
Before connecting the load, ensure that the load is rated for the
selected output voltage. If not, see the Boost Voltage Setting
Resistors section to adjust the DRV2700 maximum output voltage.
See Figure 13 for a diagram of the input configuration.

USB
Power
VIN
External
MSP HeaderDRV Header
Power to Rest of Board
Power to DRV2700
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2 Overview of EVM
The following sections provide a description of each of the blocks identified in Figure 1.
2.1 DRV2700
The DRV2700 is a single-chip, high-voltage piezo driver with an integrated 105-V boost switch, integrated
power diode, and integrated fully-differential amplifier. This EVM allows the designer to evaluate this
device and appropriately prototype it into their design. See the DRV2700 (SLOS861) datasheet for more
in-depth information.
2.2 Microcontroller (MSP430)
An onboard MSP430F5510 is used to control the various input signals as well as communicate through
the USB to the GUI. See the Quick Start Board Setup section for how to setup and run with the GUI.
2.3 Power Supply Inputs and Path
Two power supply inputs are available to power the EVM: USB power and VEXTERNAL (Ext VIN on the EVM).
Each of these inputs can be used to power the entire board or parts of the board.
2.3.1 USB Power Input
The USB power input can be supplied from a standard USB port on a computer, USB charger, or USB
battery pack. This input is intended for ease-of-use and can be routed to power all circuitry on the EVM.
Additionally, this input has a 5-V LED indicator showing that power is being supplied to the EVM. If the
GUI is going to be used, the USB must be connected to the computer and JP10 routed to USB
connection.
2.3.2 VIN/External Power Input
Provide the VIN power input with an external 3.6- to 5.5-V power supply. Additionally, this input can power
the entire board.
2.3.3 Power Path Selection
Each of the two power supply inputs can be routed to the DRV2700 or the rest of the IC. The positions of
the jumpers are described in Table 2 or can be read from the silkscreen of the EVM. Figure 2 shows the
basic diagram of the power paths.
Figure 2. Power Path Diagram
If a power measurement of the DRV2700 circuitry is desired, it is best to provide the MSP jumper (JP10)
with USB power and the DRV jumper (JP11) with VIN. With this configuration, measuring the provided
voltage and current into VIN gives the power consumption of the DRV2700.

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2.4 EN and Gain Configuration
The EN, GAIN0, and GAIN1 inputs into the DRV2700 have 4 different driving configurations:
• Driven through the MSP430. This is done by connecting the configuration jumper to the “MSP” state
(default).
• Pulled to a logic level high through pullup resistor. This is done by connecting the configuration jumper
to the “PU” state.
• Pulled to a logic level low through internal pulldown resistor. This is done by removing the configuration
jumper.
• Driven externally. This is done by connecting the external control signal to the center 100-mil header.
Each of these signals have an LED to indicate when the signal is at a logic-level high.
Additionally, the GAIN pins control the internal gain of the high voltage amplifier. Table 3 shows the 4 gain
settings
Table 3. Gain Settings
GAIN1 GAIN0 Gain (dB)
Low Low 28.8
Low High 34.8
High Low 38.4
High High 40.7
Figure 3 through Figure 6 showcase all 4 gain settings with BST set to max of 105 V (JP2, JP3, and JP4
closed). C3 = BST, C1 = VOUT(+), C2 = VOUT(–), and MATH = OUT(+) – OUT (–). PWM input from
MSP430 of 0–3.3 V, 300 Hz and 50% duty cycle.
Figure 3. Gain = 40.7 dB Figure 4. Gain = 38.4 dB

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Figure 5. Gain = 34.8 dB Figure 6. Gain = 28.8 dB
2.5 Inputs
The analog input (AIN) is used for PWM and analog inputs. The single-ended (DC) input test point is used
when a DC input is desired. See PWM, Analog, and Single-Ended Inputs, for more information.
2.6 Outputs
The DRV2700EVM has 4 referenced outputs (BST, OUT–, OUT+, and GND). They are output from a
terminal block to mitigate touching between two high voltage lines. See the Output section for additional
information.
2.7 BST/PVDD Disconnect
The BST jumper (JP12) is provided to allow disconnecting between PVDD and BST. This enables the
DRV2700EVM to be configured purely as a boost converter. See Disconnecting BST/PVDD, for additional
information.
2.8 TRIG Button
The DRV2700EVM has a built-in trigger button for user prototyping. If different modes of operation are
desired without using the GUI, the MSP430 can be programmed such that the trigger button can cycle
through different modes. Additionally, there are 3 test point pads that be can be used in a similar manner
through MSP430 firmware programming.
See Figure 13 for a diagram of the input configuration.

Gain Settings
and Boost Chart
EN Output
Output
Timing
Output
Status
Standard Drive
vs Audio Drive
Frequency
Control
Duty Cycle
Control
Note
and/or
Frequency
Generator
Simple
Piano
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3 EVM Control Software (GUI)
By default, the DRV2700EVM can be controlled programmatically through the GUI Interface. Figure 7 is a
screenshot of the GUI.
Run the GUI by downloading it from the DRV2700 product page, installing the GUI and then running it.
When prompted, connect to the USBHID setting.
Figure 7. GUI Interface

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The GUI is broken up into two sections: Standard Drive and Audio Drive. The Standard Drive utilizes
changing the frequency and duty cycle of the PWM signal and is intended for easy prototyping. The Audio
Drive tab is for showcasing the DRV2700 as a Piezo buzzer/speaker. On both tabs, the sections are
intuitive, however, the following sections are worth describing:
•Gain Settings and Boost Chart: After changing the gain and clicking the Set button, the MSP430
changes the G0 and G1 GPIO therefore changing the gain of the DRV2700. The chart then updates to
reflect the recommended voltage ranges by not highlighting them.
•Output Timing: This button has 3 different modes: Continuous,Pulsed, and Single. These modes help
with a timed EN signal.
•Duty Cycle: This allows control of the power that gets through the DC blocking input filter. Duty Cycle
can be thought of as an amplitude control. Additionally, the PWM signal can be connected through
external wires using JP5 and JP6 headers to IN+ and IN–, in order to control the output.
•Note Generator and Simple Piano: The DRV2700 is capable of also driving piezo loads used in
many alarms and buzzers. To sample this, the simple piano sends the corresponding frequency of the
notes when pressed. If a series of notes and/or frequencies with specific timing is desired, the note
generator can be used in the format of “[Note],[TimeOn],[TimeOff]” as shown in Figure 7. The note
format is A–G (including sharps “#” but not flats “b”) followed by the octave, and the frequency is in Hz
rounded to the nearest integer. Some examples include: A4, C#5, E5 (or 659), and so forth. All time
inputs are based in milliseconds.
See Figure 13 for a diagram of the input configuration.
4 Boost Converter
The DRV2700 device creates a boosted supply rail with an integrated DC-DC converter that can go up to
105 V. The switch-mode power supplies have a few different sources of losses. When boosting to very
high voltages, the efficiency begins to degrade because of these losses. The DRV2700 device has a
hysteretic boost design to minimize switching losses and therefore increase efficiency. A hysteretic
controller is a self-oscillation circuit that regulates the output voltage by keeping the output voltage within a
hysteresis window set by a reference voltage regulator and, in this case, the current-limit comparator.
Hysteretic converters typically have a larger ripple as a trade off because of the minimized switching. This
ripple is a function of the output capacitor, internal delays, and the hysteresis of the control loop. The
power FET and power diode of the boost converter are both integrated within the device to provide the
required switching while minimizing external components. Additionally, the boost voltage output (BST) can
be easily fed into the high-voltage amplifier through the adjacent pin (PVDD) to help minimize routing
inductance and resistance on the board.
Before connecting the load, ensure the load is rated for the current boost voltage setting.
See Boost Voltage Setting Resistors for more information on how to set the boost voltage.

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BST FB
EQ
R
V V 1
R
R5
806 lQ
R4
80.6 lQ
R3
49.9 lQ
R2
23.3 lQ
R1
49.9 lQ
JP2JP3JP4
FB
BST
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4.1 Boost Voltage Setting Resistors
The boost voltage (BST) is set through a resistor network and through the use of jumpers JP2, JP3, and
JP4 as shown in Figure 8.
Figure 8. BST Network JP2, JP3, and JP4
The boost output voltage is given by Equation 1
(1)
where VFB = 1.32 V and REQ is the equivalent resistor between all the connected resistors in parallel. Refer
to Table 4 for BST setting based on the jumper configuration.
WARNING
Be sure not to hot switch the JP2, JP3, or JP4 connection. This can
be accomplished by only removing or connecting the JP2, JP3, or
JP4 jumpers while the board is unpowered.
Table 4. BST Setting Based on the Jumper Configuration
BST REQ JP2 JP3 JP4
23 V 50 kΩOpen Open Open
37 V 30.8 kΩOpen Open Closed
45 V 25 kΩOpen Closed Open
58 V 19.0 kΩOpen Closed Closed
70 V 15.7 kΩClosed Open Open
83 V 13.2 kΩClosed Open Closed
91 V 12 kΩClosed Closed Open
105 V 10.4 kΩClosed Closed Closed
If another voltage is desired, replace R1 and R5 using Equation 1 and leave JP2–4 disconnected.

REF
EXT INT
LIM
V
R  K R
I
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= -
ç ÷
è ø
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4.2 Disconnecting BST/PVDD
The DRV2700 has two essential blocks: the boost converter and the amplifier. If only using the
DRV2700’s boost converter, JP_VBST allows the user to disconnect PVDD from BST to shut down the
amplifier to save power.
WARNING
Be sure not to hot switch the BST and PVDD connection. This can
only be accomplished by removing or connecting the JP_VBST
jumper while the board is unpowered.
4.3 Programming the Boost Current Limit
The peak inductor current is set with resistor R3 (REXT). The current limit is not a safety mechanism, but
the highest value current the inductor will see each cycle. The inductor must be capable of handling this
programmed limit during normal operation. The relationship of REXT to ILIM is approximated with
Equation 2 where ILIM is the current limit set by REXT, K = 10500, VREF = 1.35 V and RINT = 60 Ω.
(2)
4.4 Boost Inductor Selection
Inductor selection plays a critical role in the performance of the DRV2700. The range of recommended
inductor values is 3.3 µH to 22 µH. When a larger inductance is chosen, the DRV2700 boost converter
automatically runs at a lower switching frequency and incurs less switching losses; however, the larger
inductors may also have a higher equivalent series resistance (ESR), which will increase the parasitic
inductor losses. Smaller inductances generally have higher saturation currents; therefore, they are better
suited for maximizing the output current of the boost converter. Table 5 lists several sample inductors that
provide adequate performance.
Table 5. Sample Inductors
Manufacturer Part Number DCR (Ω) Inductance (µH) ISAT (A) REXT (Ω) ILIM (A)
Coilcraft LPS4018-332MLB 0.080 3.3 1.9 7.32k 1.9
Coilcraft LPS4018-472MLB 0.125 4.7 1.8 7.5k 1.8
TDK VLS3012T-3R3M1R3 0.100 3.3 1.5 9.31k 1.5
4.5 Boost Capacitor Selection
The boost output voltage may be programmed as high as 105 V. A capacitor must have a voltage rating
equivalent to the boost output voltage or higher. A 250-V rated 100-nF capacitor of X5R or X7R type is
recommended for a boost converter voltage of 105 V. The selected capacitor should have a minimum
derated capacitance of 50 nF.
See Figure 13 for a diagram of the input configuration.

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5 PWM, Analog, and Single-Ended Inputs
The DRV2700 requires a low-pass filtered PWM waveform, an analog signal or a single-ended input to
drive capacitive loads. By default, the DRV2700EVM uses the MSP430 PWM input mode with a low-pass
filter. This section describes each input mode in detail and the modifications necessary for operation of
each. See Filtering and Adapting PWM Waveforms for more details on adapting the PWM waveform using
a low-pass filter.
The DRV2700EVM supports four input modes for driving the DRV2700:
•PWM (AC coupled) input using MSP430: In this mode, the onboard MSP430 generates a PWM
waveform that is sent through the low-pass input filter to the DRV2700.
•PWM (AC coupled) input using AIN: An external source supplies a PWM waveform to the EXTIN
header which is sent through the low-pass input filter to the DRV2700.
•External analog (AC coupled) input: An external source supplies an analog waveform (sine wave) to
the IN+ and IN– header. The low-pass input filter can be removed in this case.
•Single-ended (DC coupled) input: A DC input signal can be used to drive the output in a steady
state.
5.1 PWM (AC Coupled) Input Using MSP430
Figure 9. PWM Signal
When using the DRV2700EVM in MSP430 PWM input mode, the onboard MSP430 generates a
differential PWM signal that is sent through a low-pass filter to the DRV2700. The DRV2700EVM is setup
to use this mode by default. Set to default settings to use this input mode.
If specific waveforms (other than those already on the MSP430) are needed, the firmware can be updated.
To update the firmware, download Code Composer Studio (or a third-party MSP430 IDE) and connect the
DRV2700EVM SpyBiWire to the computer. The TI website offers an MSP430 USB-to-JTAG hardware
interface (MSP-FET430UIF) for updating and debugging MSP430 code.
NOTE: Sample code is also available on the DRV2700 product web page.
5.2 PWM (AC Coupled) Input Using AIN
The PWM input mode can be used with an external processor or PWM source. The PWM signal is a
carrier wave (duty-cycle modulated) at a frequency much higher than the analog signal it represents. The
PWM input mode can be used with an external processor or PWM source.
To use an external PWM source to drive the DRV2700, follow these instructions to modify the board:
1. Disconnect the MSP430 output pins from the DRV2700 input pins by removing jumpers JP5 and JP6
2. Depending on the input source, follow the instructions in the Filtering and Adapting PWM Waveforms
section to adjust the input filter.
3. Connect DRV2700 control signals:
a. Use the onboard MSP430 and GUI to control the EN, GAIN0, and GAIN1 pins.
b. Use an external controller or jumpers to control the EN, GAIN0, and GAIN1 pins.
4. Connect the positive terminal of the input signal source to AIN+ and the negative terminal to AIN–
5. Enable the power supply

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5.3 External Analog (AC Coupled) Input
The following instructions are provided to use an external analog source (sine wave) to drive the
DRV2700:
1. Disconnect the MSP430 output pins from the DRV2700 input pins by removing jumpers JP6 and JP5
2. Modify the input filter according to the Filtering and Adapting PWM Waveforms section. The default
PWM filter is no longer necessary.
3. Connect the DRV2700 control signals:
a. Use the onboard MSP430 and GUI to control the EN, GAIN0, and GAIN1 pins
b. Use an external controller or jumpers to control the EN, GAIN0, and GAIN1 pins
4. Connect the positive terminal of the input signal source to AIN+ and the negative terminal to AIN–
5. Enable the power supply
5.4 Single-Ended (DC Coupled) Input
The DRV2700EVM can be operated with a DC input. There are two configurations available in this EVM
that show:
• Set reference
• Floating reference
In some applications, it is critical that the output does not go above or below a certain threshold. To help
mitigate this, landing pads for a zener diode on the DC input have been provided. Installing a properly-
selected zener can help assure the input does not go above the set voltage and therefore not allow the
output to swing above or below the undesired voltage.
5.4.1 Set Reference
The set reference configuration is used when the output needs to be controlled linearly. Just like a normal
amplifier, the output will be amplified based on the difference of the inputs. The DRV2700EVM has the
inputs connected to TP7 (IN+) and TP8 (IN–).
To use the DC input with a set reference to drive the DRV2700, follow these instructions:
1. Disconnect the MSP430 output pins from the DRV2700 input pins by removing jumpers JP6 and JP5
2. Connect JP_DC
3. Connect DRV2700 control signals:
a. Use the onboard MSP430 and GUI to control the EN, GAIN0, and GAIN1 pins
b. Use an external controller or jumpers to control the EN, GAIN0, and GAIN1 pins
4. DC reference input:
Connect the DC reference to TP8 (IN–)
5. Amplifying signal:
a. For 0–10 V range, connect jumper JP_DC and apply 0–10 V on DC_IN
b. For 0–5 V range, disconnect jumper JP_DC and apply 0–5 V on TP7 (IN+)
6. Enable the power supply
Figure 10 is with the EVM powered through USB (5 V).

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Figure 10. Set Reference to External 2.5 V
See Figure 13 for a diagram of the input configuration.
5.4.2 Floating Reference
If the application is to create a high voltage square wave where the output goes from ±VBST, this floating
reference configuration is beneficial. Unlike most amplifiers where both input terminals need to be biased
to control the output, the DRV2700 has an internal compensated common mode to try and keep the inputs
near VDD / 2. This allows the application to eliminate the need of a reference voltage, by instead applying a
capacitor to ground on one of the input terminals. Because there is compensation between the two inputs,
the common mode will have some drift based on the other input signal. If the DRV2700 is going to be
operated in the linear region, the set reference configuration should be used.
Use the DC input with a floating reference to drive the DRV2700 with the following instructions:
1. Disconnect the MSP430 output pins from the DRV2700 input pins by removing jumpers JP6 and JP5
2. Connect DRV2700 control signals:
a. Use the onboard MSP430 and GUI to control the EN, GAIN0, and GAIN1 pins
b. Use an external controller or jumpers to control the EN, GAIN0, and GAIN1 pins
3. Amplifying signal:
a. For 0–10 V range, connect jumper JP_DC and apply 0–10 V on DC_IN
b. For 0–5 V range, disconnect jumper JP_DC and apply 0–5 V on TP7 (IN+)
4. Enable the power supply
Figure 11 and Figure 12 show this mode at 3 Hz and 1 KHz. Notice that the floating reference (IN-) will
vary based on the IN+ signal. This drift can be minimized by increasing the frequency. This configuration
should only be used as long as the application can handle this drift. Each application should be properly
evaluated to verify if this configuration will be acceptable per its system requirements. Figure 11 and
Figure 12 are with the EVM powered through USB (5 V).
See Figure 13 for a diagram of the input configuration.

IN+
INí
R16
10.0 NŸ
R16
10.0 NŸ
Filter
Network
Filter
Network
PWM+
PWMí
DC_IN
TP7
TP8
JP13
Signal
Generator
Reference
Voltage
Not Used in Floating
Reference Config
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Figure 11. Floating Reference at 3 Hz and No Load Figure 12. Floating Reference at 1 Hz and No Load
Figure 13. DC Coupled Input Diagram

DRV2700
Piezo
Element
BST
OUT>
OUT+
GND
DRV2700
BST
OUT>
OUT+
GND
100 Vp
Piezo
Element
100 Vp
Piezo
Element
Piezo
Element
100 Vp
100 Vp
DRV2700 Piezo
Element
BST
OUT-
OUT+
GND
200 Vpp
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6 Output
The DRV2700 has 3 main outputs and GND on the 4-terminal output:
1. The output of the boost converter (BST)
2. The positive output of the amplifier (OUT+)
3. The negative output of the amplifier (VOUT–)
These outputs can be configured in a variety of ways and are described in more detail in this section.
6.1 Two Terminal Differential Output Configuration (OUT+ – OUT–)
The typical output configuration is a 2 terminal differential output with one terminal connected to OUT+
and the other connected to OUT–. This configuration can achieve 200 Vpp.
Figure 14. Two Terminal Differential Output
6.2 Two Terminal Single Ended Output Configuration (OUT± to BST/GND)
This output configuration allows for 2 outputs that are 180 degrees out of phase. This is configured with
OUT+ and/or OUT– referenced to GND with a voltage that can swing up to 100 V. Additionally, they can
be referenced to BST.
Figure 15. Two Terminal Single Ended Output

Piezo
Element
DRV2700 Piezo
Element
BST
OUT>
OUT+
GND
100 Vp
100 Vp
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6.3 Three Terminal Single Ended Output Configuration (BST to OUT± to GND)
The output configuration is very similar to the two terminal, however, only one output pin is used. This
ensures that the two voltage potentials (BST to OUTx and OUTx to GND) always add up to BST.
Figure 16. Three Terminal Single Ended Output
7 Load Selection
The DRV2700 is intended to drive Piezo (capacitive) loads, however, an improper load driven at certain
levels can cause the device to heat up and hit thermal shutdown. Therefore, there are several key
specifications to consider when choosing a Piezo load; such as dimensions, blocking force, and
displacement. However, the key electrical specifications from the driver perspective are voltage rating and
capacitance. At the maximum frequency of 500 Hz, the DRV2700 is optimized to drive up to 50 nF at 200
VPP, which is the highest voltage swing capability. The DRV2700 will drive larger capacitances if the
programmed boost voltage is lowered or the user limits the input frequency range to lower frequencies (for
example, 300 Hz). For more information, see the Piezo Load Selection section of the DRV2700 data sheet
(SLOS861).
See Figure 13 for a diagram of the input configuration.