AD5382 Analog Devices, AD5382 Datasheet - Page 35

• Manufacturer Part Number: AD5382
• Description: 32-Channel 14-Bit 3 V/5 V Single-Supply Voltage-Output DAC
• Manufacturer: Analog Devices

Specifications of AD5382

• Resolution (bits): 14bit
• Dac Update Rate: 125kSPS
• Dac Settling Time: 8µs
• Max Pos Supply (v): +5.5V
• Single-supply: Yes
• Dac Type: Voltage Out
• Dac Input Format: Par,Ser,SPI

THERMAL MONITOR FUNCTION
The AD5382 contains a temperature shutdown function to
protect the chip if multiple outputs are shorted. The short-
circuit current of each output amplifier is typically 40 mA.
Operating the AD5382 at 5 V leads to a power dissipation of
200 mW per shorted amplifier. With five channels shorted, this
leads to an extra watt of power dissipation. For the 100-lead
LQFP, the θ
The thermal monitor is enabled by the user via CR8 in the
control register. The output amplifiers on the AD5382 are
automatically powered down if the die temperature exceeds
approximately 130°C. After a thermal shutdown occurs, the
user can re-enable the part by executing a soft power-up if the
temperature drops below 130°C or by turning off the thermal
monitor function via the control register.
JA
is typically 44°C/W.
0.01μF
REFOUT/REFIN
INPUT
A/B
DATA
14-BIT DAC
14-BIT DAC
AD5382
REGISTER
INPUT
AVDD
+5V
VOUT1
VOUT31
Figure 43. AD5382 in a MEMS Based Optical Switch
OUTPUT RANGE
REGISTER
REGISTER
0V TO 200V
DATA
DATA
G = 50
G = 50
A
B
Figure 42. Toggle Mode Function
Rev. B | Page 35 of 40
ACTUATORS
FOR MEMS
MIRROR
ARRAY
ADSP-21065L
REGISTER
DAC
AD5382 IN A MEMS-BASED OPTICAL SWITCH
In their feed-forward control paths, MEMS-based optical
switches require high resolution DACs that offer high channel
density with 14-bit monotonic behavior. The 32-channel, 14-bit
AD5382 DAC satisfies these requirements. In the circuit in
Figure 43, the 0 V to 5 V outputs of the AD5382 are amplified
to achieve an output range of 0 V to 200 V, which is used to
control actuators that determine the position of MEMS mirrors
in an optical switch. The exact position of each mirror is meas-
ured using sensors. The sensor outputs are multiplexed into a
high resolution ADC in determining the mirror position. The
control loop is closed and driven by an ADSP-21065L, a 32-bit
SHARC® DSP with an SPI-compatible SPORT interface. The
ADSP-21065L writes data to the DAC, controls the multiplexer,
and reads data from the ADC via the serial interface.
14-BIT DAC
MULTIPLEXER
SENSOR
AND
VOUT
LDAC
CONTROL INPUT
SINGLE CHANNEL
8-CHANNEL ADC
ADC (AD7671)
(AD7856)
OR
AD5382