AD5384 Analog Devices, AD5384 Datasheet - Page 23

• Manufacturer Part Number: AD5384
• Description: 40-Channel, 3 V/5 V Single Supply,14-Bit, Serial Voltage-Output DAC
• Manufacturer: Analog Devices

Specifications of AD5384

• 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: I2C/Ser 2-wire,Ser,SPI

Table 17. Control Register Contents
MSB
CR13
Control Register Write/Read
REG1 = REG0 = 0, A5–A0 = 001100, R/ W status determines if
the operation is a write (R/ W = 0) or a read (R/ W = 1). DB13 to
DB0 contain the control register data.
Control Register Contents
CR13: Power-Down Status. This bit is used to configure the
output amplifier state in power-down.
CR12: REF Select. This bit selects the operating internal
reference for the AD5384. CR12 is programmed as follows:
CR11: Current Boost Control. This bit is used to boost the
current in the output amplifier, thereby altering its slew rate.
This bit is configured as follows:
CR10: Internal/External Reference. This bit determines if the
DAC uses its internal reference or an externally applied
reference.
CR9: Channel Monitor Enable (see Channel Monitor Function).
CR13 = 1: Amplifier output is high impedance (default on
power-up).
CR13 = 0: Amplifier output is 100 kΩ to ground.
CR12 = 1: Internal reference is 2.5 V (AD5384-5 default), the
recommended operating reference for AD5384-5.
CR12 = 0: Internal reference is 1.25 V (AD5384-3 default),
the recommended operating reference for AD5384-3.
CR11 = 1: Boost Mode On. This maximizes the bias current
in the output amplifier, optimizing its slew rate but increasing
the power dissipation.
CR11 = 0: Boost Mode Off (default on power-up). This
reduces the bias current in the output amplifier and reduces
the overall power consumption.
CR10 = 1: Internal Reference Enabled. The reference output
depends on data loaded to CR12.
CR10 = 0: External Reference Selected (default on power-up).
CR9 = 1: Monitor Enabled. This enables the channel monitor
function. After a write to the monitor channel in the SFR
register, the selected channel output is routed to the
MON_OUT pin. VOUT39 operates as the MON_OUT pin.
CR9 = 0: Monitor Disabled (default on power-up). When the
monitor is disabled, the MON_OUT pin assumes its normal
DAC output function.
CR12
CR11
CR10
CR9
CR8
Rev. A | Page 23 of 36
CR7
CR8: Thermal Monitor Function. This function is used to
monitor the AD5384 internal die temperature, when enabled.
The thermal monitor powers down the output amplifiers when
the temperature exceeds 130°C. This function can be used to
protect the device when power dissipation might be exceeded if
a number of output channels are simultaneously short-circuited.
A soft power-up re-enables the output amplifiers if the die
temperature drops below 130°C.
CR7: Don’t Care.
CR6 to CR2: Toggle Function Enable. This function allows the
user to toggle the output between two codes loaded to the A
and B register for each DAC. Control register bits CR6 to CR2
are used to enable individual groups of eight channels for
operation in toggle mode. A Logic 1 written to any bit enables a
group of channels; a Logic 0 disables a group. LDAC is used to
toggle between the two registers. Table 18 shows the decoding
for toggle mode operation. For example, CR6 controls group w,
which contains Channels 32 to 39, CR6 = 1 enables these
channels.
CR1 and CR0: Don’t Care.
Table 18.
CR Bit
CR6
CR5
CR4
CR3
CR2
Channel Monitor Function
REG1 = REG0 = 0, A5–A0 = 001010
DB13–DB8 = Contain data to address the monitored channel.
A channel monitor function is provided on the AD5384. This
feature, which consists of a multiplexer addressed via the
interface, allows any channel output to be routed to the
MON_OUT pin for monitoring using an external ADC. In
channel monitor mode, VOUT39 becomes the MON_OUT pin,
to which all monitored pins are routed. The channel monitor
function must be enabled in the control register before any
channels are routed to MON_OUT. On the AD5384, DB13 to
DB8 contain the channel address for the monitored channel.
Selecting Channel Address 63 three-states MON_OUT.
CR6
CR8 = 1: Thermal Monitor Enabled.
CR8 = 0: Thermal Monitor Disabled (default on power-up).
CR5
CR4
Group
4
3
2
1
0
CR3
CR2
Channels
32–39
24–31
16–23
8–15
0–7
CR1
AD5384
LSB
CR0