AD5380 Analog Devices, AD5380 Datasheet - Page 37

• Manufacturer Part Number: AD5380
• Description: 40-Channel 14-Bit 3 V/5 V Single-Supply Voltage-Output DAC
• Manufacturer: Analog Devices

Specifications of AD5380

• 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

UTILIZING THE AD5380 FIFO
The AD5380 FIFO mode optimizes total system update rates
in applications where a large number of channels need to be
updated. FIFO mode is only available when parallel interface
mode is selected. The FIFO EN pin is used to enable the FIFO.
The status of FIFO EN is sampled during the initialization
sequence. Therefore, the FIFO status can only be changed by
resetting the device. In a telescope that provides for the cancella-
tion of atmospheric distortion, for example, a large number of
channels need to be updated in a short period of time.
FIFO DATA LOAD
CHNLS 0–39
GROUP A
GROUP A
1.6μs
14.4μs
CHNLS 40–79
GROUP B
1.6μs
14.4μs
FIFO DATA LOAD
TIME FOR GROUP A
OUTPUT UPDATE
GROUP C
CHNLS
80–119
GROUP B
Figure 45. Using FIFO Mode 400 Channels Updated in Under 30 μs
TIME FOR GROUP B
OUTPUT UPDATE
GROUP D
120–159
CHNLS
TIME TO UPDATE 400 CHANNELS = 28.8μs
GROUP E
160–199
CHNLS
Rev. A | Page 37 of 40
GROUP F
200–239
CHNLS
In such systems, as many as 400 channels need to be updated
within 40 μs. Four-hundred channels requires the use of 10
AD5380s. With FIFO mode enabled, the data write cycle time
is 40 ns; therefore, each group consisting of 40 channels can be
fully loaded in 1.6 μs. In FIFO mode, a complete group of 40
channels will update in 14.4 μs. The time taken to update all
400 channels is 14.4 μs + 9 × 1.6 μs = 28.8 μs. Figure 45 shows
the FIFO operation scheme.
GROUP G
240–279
CHNLS
GROUP H
280–319
CHNLS
TIME FOR GROUP J
OUTPUT UPDATE
FIFO DATA LOAD
GROUP J
GROUP I
320–359
CHNLS
GROUP J
360–399
CHNLS
1.6μs
14.4μs
AD5380