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Data Sheet



  • Deformable mirror drive 
  • MEMS/NEMS device drive & test

The AmpArray[32]™ is a simple 32-channel amplifier unit capable of driving adaptive mirrors with actuator load capacitances in the 10pF – 10nF range, at the frequencies typically required to correct atmospheric turbulence. It contains no internal digital-to-
analogue converters, and is intended to be
driven by an external source of analogue control signals.

This analogue in–analogue out configuration was created to allow a deformable mirror to be controlled directly from high-level data acquisition and instrument control software, without requiring additional device driver software. The AmpArray[32] would typically be driven by a PC multi-channel DAC card supported by the user's preferred high-level software. The input specification matches the output characteristics of many popular DAC cards offered with the leading instrument control software packages.

This simple yet versatile device comes in a compact enclosure and requires only a single +5V dc power supply input. It offers a convenient and economical way to control a variety of modern MEMS-based and bimorph deformable mirrors. A variety of output options can be offered as semi-custom drive solutions.

System Specification

System Characteristics
Number of amplifier channels 32
Amplifier Gain +19 ± 5%
Input Characteristics
Input Voltage Range 0V to +10V
Input Impedance 10kΩ
Output Characteristics
Output Voltage Range 0V to +190V
Output Drive Current Limit 45μA ± 40%
Small Signal Bandwidth 4kHz @ -3dB corner
Slew Time with Capacitive Load
(2.2nF load, 100V step)
3.9ms typ. (10% to 90% of step)
Physical Characteristics
Enclosure Dimensions 126mm(D) × 106mm(W) × 34mm(H)
Power In +5V dc regulated, @ 0.2A


The AmpArray[32] has a unipolar output range, but it can also be used to drive mirrors requiring a bipolar drive signal. Application Note 1 explains how.

The 32-channel AmpArray[32] is matched to the channel count of popular DAC cards, and can be used to drive a wide range of deformable mirror sizes.

Several of the compact AmpArray[32] units can be combined to form higher channel-count drive systems. The image to the left shows a 128-channel configuration formed from four AmpArray[32] units. The maximum channel count is typically limited by the DAC I/O capacity of the host computer.

Current Limited Behaviour

Each amplifier channel's current limit is set to a nominal 50µA. There is a ± 40% spread in this value. The current limit is a safety feature of the amplifier, it is not the normal operating mode. The amplifier should be operated in the linear regime, not the current-limited regime.

The plot below shows the large signal step response for a low capacitance load (15pF) and for a high capacitance load (2.2nF). These values are typical of MEMS mirrors and bimorph mirrors, respectively. A 100V pk–pk square wave is applied, the voltage swing is between +20V and +120V.

For the 15pF load, the rise and fall times are about 80µs, determined by the 4kHz low pass filter. For the 2.2nF load, the large signal step response is quasi-linear, with a 3.4ms rise time and a 2.5ms fall time, determined by the current limit. There is a 2V overshoot on exit from the current limited mode.

Connector Pin Assignment

System Connectors:
Signal Input Connector: 44-way HD22 (density-and-a-half) 'D'-type socket.
HV Output Connector: 37-way HD20 'D'-type socket.
Power Supply Connector: 0.1" pin miniature power jack. (Power supply is included).

Pin assignment on the input (44-way) and output (37-way) 'D'-type connectors:

Input Connector: 44-way Output Connector: 37-way
Pin No. Signal Pin No. Signal
1 IN31 1 GND
2 GND 2 HV1
3 IN26 3 HV3
4 IN24 4 HV5
5 IN22 5 HV7
6 GND 6 HV8
7 IN17 7 HV10
8 IN15 8 HV12
9 IN13 9 HV14
10 GND 10 GND
11 IN8 11 HV17
12 IN6 12 HV19
13 IN4 13 HV21
14 GND 14 HV23
15 GND 15 HV24
16 GND 16 HV26
17 IN29 17 HV28
18 IN27 18 HV30
19 IN25 19 GND
20 GND 20 HV0
21 IN20 21 HV2
22 IN18 22 HV4
23 IN16 23 HV6
24 GND 24 GND
25 IN11 25 HV9
26 IN9 26 HV11
27 IN7 27 HV13
28 GND 28 HV15
29 IN2 29 HV16
30 IN0 30 HV18
31 IN30 31 HV20
32 IN28 32 HV22
33 GND 33 GND
34 IN23 34 HV25
35 IN21 35 HV27
36 IN19 36 HV29
37 GND 37 HV31
38 IN14
39 IN12
40 IN10
41 GND
42 IN5
43 IN3
44 IN1
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