AD5611 Analog Devices, AD5611 Datasheet - Page 16

• Manufacturer Part Number: AD5611
• Description: 2.7 V to 5.5 V,
• Manufacturer: Analog Devices

Specifications of AD5611

• Resolution (bits): 10bit
• Dac Update Rate: 1.7MSPS
• Dac Settling Time: 6µs
• Max Pos Supply (v): +5.5V
• Single-supply: Yes
• Dac Type: Voltage Out
• Dac Input Format: Ser,SPI

AD5601/AD5611/AD5621
POWER-ON RESET
The AD5601/AD5611/AD5621 contain a power-on reset circuit
that controls the output voltage during power-up. The DAC
register is filled with 0s and the output voltage is 0 V. It remains
there until a valid write sequence is made to the DAC. This is
useful in applications in which it is important to know the state
of the DAC output while it is in the process of powering up.
POWER-DOWN MODES
The AD5601/AD5611/AD5621 have four separate modes of
operation. These modes are software-programmable by setting
two bits (DB15 and DB14) in the control register. Table 6 shows
how the state of the bits corresponds to the operating mode of
the device.
Table 6. Operating Modes of the AD5601/AD5611/AD5621
DB15
0
0
1
1
When both bits are set to 0, the part has normal power
consumption of 100 µA maximum at 5 V. However, for the
three power-down modes, the supply current falls to typically
0.2 µA at 3 V.
Not only does the supply current fall, but the output stage is
also internally switched from the output of the amplifier to a
resistor network of known values. This has the advantage that
the output impedance of the part is known while the part is in
power-down mode.
There are three different options: the output is connected
internally to GND through a 1 kΩ resistor or a 100 kΩ resistor,
or the output is left open-circuited (three-stated). Figure 45
shows the output stage.
The bias generator, output amplifier, resistor string, and other
associated linear circuitry are all shut down when power-down
mode is activated. However, the contents of the DAC register
are unaffected when in power-down. The time to exit power-
down is typically 13 µs for V
See Figure 21 for a plot.
STRING DAC
RESISTOR
Figure 45. Output Stage During Power-Down
DB14
0
1
0
1
POWER-DOWN
AMPLIFIER
CIRCUITRY
DD
Operating Mode
Normal operation
Power-down modes:
1 kΩ to GND
100 kΩ to GND
Three-state
= 5 V and 16 µs for V
RESISTOR
NETWORK
V
DD
OUT
= 3 V.
Rev. F | Page 16 of 24
MICROPROCESSOR INTERFACING
AD5601/AD5611/AD5621 to ADSP-2101 Interface
Figure 46 shows a serial interface between the AD5601/
AD5611/AD5621 and the ADSP-2101. The
be set up to operate in SPORT transmit alternate framing mode.
The
control register and should be configured as follows: internal
clock operation, active low framing, and 16-bit word length.
Transmission is initiated by writing a word to the Tx register
after the SPORT is enabled.
AD5601/AD5611/AD5621 to 68HC11/68L11 Interface
Figure 47 shows a serial interface between the AD5601/AD5611/
AD5621 and the 68HC11/68L11 microcontroller. SCK of the
68HC11/68L11 drives the SCLK of the AD5601/AD5611/
AD5621, while the MOSI output drives the serial data line of
the DAC. The SYNC signal is derived from a port line (PC7).
The setup conditions for correct operation of this interface are
as follows: the 68HC11/68L11 should be configured so that the
CPOL bit is 0 and the CPHA bit is 1. When data is being trans-
mitted to the DAC, the SYNC line is taken low (PC7). When the
68HC11/68L11 are configured as indicated, data appearing on
the MOSI output is valid on the falling edge of SCK. Serial data
from the 68HC11/68L11 is transmitted in 8-bit bytes with only
eight falling clock edges occurring in the transmit cycle. Data is
transmitted MSB first. To load data to the AD5601/AD5611/
AD5621, PC7 is left low after the first eight bits are transferred
and a second serial write operation is performed to the DAC.
PC7 is taken high at the end of this procedure.
*ADDITIONAL PINS OMITTED FOR CLARITY
*ADDITIONAL PINS OMITTED FOR CLARITY
ADSP-2101
Figure 47. AD5601/AD5611/AD5621 to 68HC11/68L11 Interface
Figure 46. AD5601/AD5611/AD5621 to
ADSP-2101*
68HC11/
68L11*
SCLK
SPORT is programmed through the SPORT
MOSI
TFS
SCK
DT
PC7
ADSP-2101
AD5601/AD5611/
AD5621*
SYNC
SDIN
SCLK
AD5601/AD5611/
AD5621*
SYNC
SCLK
SDIN
ADSP-2101
Data Sheet
Interface
should