Data Sheet

AD45335

APPLICATIONS INFORMATION

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Rev. 0 | 13 of 16

MEMS MIRROR CONTROL APPLICATION

The AD45335 is targeted to all optical switching control systems

based on MEMS technology. The AD45335 is a 32-channel, 14-bit

DAC with integrated high voltage amplifiers. The output amplifiers

are capable of generating an output range of 0 V to 200 V when us-

ing a 4 V reference. The full-scale output voltage is programmable

from 50 V to 200 V using reference voltages from 1 V to 4 V. Each

amplifier can output 150 µA sourcing current and directly drives the

control actuators, which determine the position of MEMS mirrors in

optical switch applications.

The AD45335 is generally used in a closed-loop feedback system,

as shown in Figure 17, with a high resolution analog-to-digital

converter (ADC) and DSP. The exact position of each mirror is

measured using capacitive sensors. The sensor outputs are multi-

plexed using an ADG739 4-to-1 multiplexer (MUX) to an 8-channel,

14-bit ADC (AD7856). An alternative solution is to multiplex using a

32-to-1 multiplexer (ADG732) into a single-channel ADC (AD7671).

With 14-bit monotonic behavior and a 0 V to 200 V output range,

coupled with its fast serial interface, the AD45335 is ideally suited

for controlling a cluster of MEMS-based mirrors.

Figure 17. AD45335 in a MEMS-Based Optical Switch