PDu150 V5Three Channel, Ultra-low Noise
Miniature 150V Piezo DriverSpecifications

The PDu150 is a complete miniaturized power
supply and ultra-low noise driver for up to three
100V, 120V or 150V piezoelectric stack actuators.
Output currents up to 100mA per channel aredeveloped at frequencies up to 80 kHz with very lownoise. The three channels can be connected inparallel to produce an output current of 300mA.

+In1+
In2+-30V to +150V

Peak Current

100 mA per channel
300 mA single channel

RMS Current

78 mA per channel
235 mA single channel

Power Bandwidth

80 kHz (150 Vp-p)

Signal Bandwidth

180 kHz

Slew Rate

38 V/usGain

20 V/V

Load
Output Noise9.16 𝑘Ω (Input),
3.3 𝑘Ω (Offset)±5 mV
Unlimited
26 uV RMS,
1uF Load, 10Hz to 1MHz

Protection

Short-circuit, average current,
and under-voltage protection

Quiescent Current

100 mA (10 mA in Shutdown)

Dimensions

76 x 40 x 44 mm (L x W x H)

Environment

0 to 60C (-32 to 140F)
Non-condensing humidity

Weight80 g

Piezo 3G30V
0V3+
20V2+0V1-0V1+0VG 0V

INTEXTIn3Output Voltage

Input Offset

Offset+24VVSG0V EN0V R+0V R- 0V
V10V V20V V30V G 0V
OS0V 0V -+24V, Ground

Input Impedance

The PDu150 is protected against short-circuit,average current overload, and excessive
temperature. Passive cooling is available for low
power applications or the integrated fan can beused for power dissipations above 5W. The PDu150
can be mounted with four M2.5 screws. The PCB
mounting version (PDu150-PCB) is supplied withheaders for direct mounting onto a hostmotherboard.

+Power Supply

Piezo 2+GEN
OSRR+Figure 1. Basic Connection diagram. Offset jumper in EXT position.

PDu150 Datasheet

1Piezo 1++Ground
EnableOffset-2V Reference+10V Reference

Modified 20/01/2021

Operation

varying the potentiometer until the desired offset isobtained.

As shown in Figure 2, the amplifiers have differential
inputs where the negative input can be connected to an
external reference or the internal offset generator. A
precision +10V and -2V reference voltage (R+ and R-) areprovided to allow external potentiometers to generate
the amplifier inputs.

In the external offset mode, the offset voltage isdetermined by the voltage applied to the OS pin. The
offset voltage can be set to zero by grounding the OS pin.

Using the Reference Voltages

The amplifier outputs use a novel low-noise differentialarchitecture and cannot be connected to ground.
Enable+24V
SupplyR+

R-A precision +10V and -2V reference voltage (R+ and R-) isprovided to allow an external potentiometer to generate
the amplifier input, as shown below. Multiple
potentiometers can be used for multiple channels. The10uF capacitor reduces the noise bandwidth but is notstrictly necessary. The capacitor should preferably be afilm type but ceramic is acceptable in most applications.

OSOffset
Voltage

Boost
Converter

1+

V1+

20
V-

10k Pot

Piezo 1V-

1-

10uF

V2+

20
V-

Piezo 2

Figure 3. Circuit to create a variable DC input to channel 223+

V3+

20
V-

Output Current

Piezo 3The peak output current is 100mA per channel or 300mA
for three channels in parallel. In addition, the maximum
average current is 35mA per amplifier. The average
current is useful for calculating the power dissipation
and average supply current. For a sine wave, the average
positive output current is equal to3-Figure 2. PDu150 Block DiagramSingle Channel Mode
The power bandwidth and output current can be tripled
by connecting three amplifiers in parallel as shown
below. A third configuration with two parallel channels
and one single channel is also possible.
++
In1

INT

EXTVS
G
0V EN0V R+0V R- 0V
V1 0V
V20V V30V G0V OS0V 0V -Offset+24VG30V
0V3+
20V2+0V1-0V1+0VG 0V

INT2+EXT

VSG0V EN
0V R+0V R- 0V
V1 0V
V20V V30V G0V OS
0V 0V -External

OffsetInternal

G
30V
0V3+
20V2+0V1-0V1+0VG 0V

𝐼𝑎𝑣 =1√2𝐼= 𝐼 .
𝜋 𝑟𝑚𝑠 𝜋 𝑝𝑘

Supply Current

Piezo

The quiescent power for the amplifier is approximately
2 W or 85 mA. This can be reduced to <10 mA by pulling
the Enable pin low with an open collector circuit. If thefan is used, the quiescent power is increased by 0.5W,+The supply current is related to the total average output
current by
𝐼𝑠 =200 × (𝐼𝑎𝑣 + 0.010).
24

where 𝐼𝑎𝑣 is the total average output current. Themaximum supply current is 0.9 A at full power.

Offset Voltage Configuration
The offset voltage can be set from either the internalpotentiometer or by an external source by configuring
the jumper to either “Internal” or “External”.
When using the internal offset source, the offset voltage
is set by connecting a multimeter across the output andPDu150 Datasheet

2

Modified 20/01/2021

Power Bandwidth

Signal Bandwidth

The nominal slew-rate of the PDu150 is 38 V/us.
Therefore, the maximum frequency sine-wave is

The small-signal bandwidth for a range of capacitive
loads is listed in Table 2. The small-signal frequency
responses are plotted in Figure 5.

𝑓𝑚𝑎𝑥 =38 × 106
𝜋𝑉𝐿(𝑝−𝑝)LoadCapacitance
No Load
10 nF
30 nF
100 nF
300 nF
1 uF
3 uF
10 uF
30 uF

The power bandwidth for a 150 Vp-p sine-wave is80 kHz.
With a capacitive load, the power bandwidth is limitedby the output current. The maximum frequency sine
wave is𝑓𝑝𝑤𝑟 =𝐼 𝑝𝑘
𝜋𝑉𝐿(𝑝−𝑝) 𝐶𝐿

where 𝐼𝑝𝑘 is the peak current limit, 𝑉𝐿(𝑝−𝑝) is the peakto-peak output voltage, and 𝐶𝐿 is the effective load
capacitance. The power bandwidth for a range of load
capacitance values is listed in Table 1.

Table 2. Small signal bandwidth (-3 dB)

Voltage Range
50 V
100 V
150 V
64000
32000
21000
21000
11000
7100
6400
3200
2100
2100
1100
710
640
320
210
210
110
7164
32
2121
11740
Magnitude (dB)

Load(uF)
0.01
0.03
0.1
0.3131030Phase (deg.)

180

3uF

1uF

300nF 100nF

1u

300n

100n

30n 10n20102341010345100-50-10030nF-150

Peak to Peak Voltage (V)

3u

10u

10The maximum peak-to-peak voltage is plotted below.

10uF

300Table 1. Power bandwidth (in Hz) with a capacitive load

160

SignalBandwidth
180 kHz
105 kHz
40 kHz
11 kHz3.8 kHz
1.0 kHz320 Hz
62 Hz
24 Hz

140

210120100

1010Frequency (Hz)510Figure 5. Small signal frequency response

8060Noise40

The output noise contains a low frequency component(0.03 Hz to 10 Hz) that is independent of the load
capacitance; and a high frequency component (10 Hz to1 MHz) that is inversely related to the load capacitance.

200110210

310Frequency (Hz)410

Optimal noise performance is achieved with passive
cooling as magnetic fields from the fan can induce mVlevel interference in the outputs. In low noiseapplications, where the fan is removed, some external
air-flow is required if the power dissipation is above 5W,
refer to Heat Dissipation for further details.

Figure 4. Power Bandwidth (150 Vp-p)

PDu150 Datasheet

3

Modified 20/01/2021

Heat Dissipation

The noise is measured with an SR560 low-noise amplifier(Gain = 1000), oscilloscope, and an Agilent 34461A
Voltmeter. The low-frequency noise is plotted in Figure
6. The RMS value is 15 uV with a peak-to-peak voltage of
100 uV.

The heat dissipation is approximately
𝑃𝑑 = 200 × (𝐼𝑎𝑣 + 0.010).
For example, with a sinusoidal output, the power is60

𝑃𝑑 = 200 × (𝑉𝐿(𝑝−𝑝) 𝐶𝐿 𝑓 + 0.010).
For low-current applications that dissipate less than5W, the heatsink fan may be removed. If the power
dissipation is above 5W, forced air or the included fan isrequired.

LF Noise (uV)40
200Safety-20

This device produces hazardous potentials and should beused by suitably qualified personnel. Do not operate thedevice when there are exposed conductors.

-40-6005

10t (s)

15

Parts of the circuit may store charge
so precautions must also be taken
when the device is not powered.

20Figure 6. Low frequency output noise (0.03 Hz to 10 Hz)

The high frequency noise (10 Hz to 1 MHz) is listed in thetable below versus load capacitance. The total noisefrom 0.03 Hz to 1 MHz is found by summing the RMS
22values, that is 𝜎 = √𝜎𝐿𝐹
+ 𝜎𝐻𝐹.

LoadCapacitance
10 nF
30 nF
100 nF
300 nF
1 uF
3 uF
10 uF
30 uF

HF
Noise
450 uV
170 uV
60 uV
34 uV
21 uV
16 uV
16 uV
18 uV

Dimensions
The mounting posts accept M2.5 screws. For the PCB
mounting version (PDu150-PCB), a schematic andfootprint library are available for Altium Designer athttps://www.piezodrive.com/resources/Total
Noise
450 uV
170 uV
62 uV
37 uV
26 uV
23 uV
22 uV
23 uV

Table 3. HF Noise (10 Hz to 1 MHz) and total noiseOverload Protection / Shutdown
The PDu150 is protected against short-circuit andaverage current overload.
The amplifier can be shutdown manually by pulling theEnable pin low with an open-collector, or open-drain
circuit. The Enable pin normally floats at 5V and should
not be driven directly.
Figure 7. Dimensions (mm)PDu150 Datasheet

4Modified 20/01/2021

Test Procedure

Trouble Shooting Notes

To test the PDu150, follow these instructions:
1. Move the OFFSET jumper to EXT
2. Connect a 24V supply between VS and ground.
3. Connect a +1V DC signal to V1, V2, and V3
4. Connect the OS pin to ground
5. Check that the circuit connections match thediagram below.

The most common perceived issues with the PDu150 are
due to incorrect measurement of the output voltages.
The PDu150 output is differential, and the negative
outputs (1-, 2-, and 3-) cannot be connected to ground.
To measure the output voltage use a battery powered
multimeter to measure the voltage between 1+ and 1-,
for example.

+24V

In1

Offset+To measure the output voltage with an oscilloscope,connect the oscilloscope ground to the PDu150 ground(any G pin), and connect the probe to either the 1+, 2+,
or 3+ output. The actual voltage across the load is double
what is being measured, which can be accounted for
manually, or by doubling the probe sensitivity in theoscilloscope settings, e.g. change the probe sensitivity
from 10x to 20x. Do not connect the oscilloscope groundto the 1-, 2-, or 3- terminals.

G30V
0V3+
20V2+0V1-0V1+0VG 0V

INTEXTVSG
0V EN
0V R+0V R- 0V
V1 0V
V20V V30V G
0V OS
0V 0V -+Figure 8. Test Configuration

Contact / Support

Turn the power on and use a battery powered
multimeter to measure the voltage between thefollowing positive and negative positions. The measured
voltages should be within the minimum and maximum
values stated below.
Positive
VS
V1
V2
V3
OS
1+2+3+

Negative
GGGGG
123-Min
23V
0.95V
0.95V
0.95V
-0.01V+19.5V+19.5V+19.5V

info@piezodrive.com

Revision History
Date
20/01/21
20/01/21
16/01/21

Max
25V
1.05V
1.05V
1.05V
+0.01V+20.5V+20.5V+20.5V

Rev
R5
R4R3

By
KB
KB
KB

Changes
Updated test proceedure
Test procedure added
Temp range updated

Table 4. First test points and expected voltages

After this test is successful, increase the input voltage to7.5V and repeat the test points. The measured voltages
should be within the stated minimum and maximum
values stated below.
PositiveVSV1
V2
V3OS
1+2+3+NegativeGGGG
G
123-Min
23V
7.45V
7.45V
7.45V
-0.01V
+148V
+148V
+148V

Max
25V
7.55V
7.55V
7.55V
+0.01V
+152V
+152V
+152V

Table 5. Second test points and expected voltages

PDu150 Datasheet

5Modified 20/01/2021