Datasheet

Data Sheet AD5382
Rev. C | Page 23 of 40
Table 15. Control Register Contents
MSB LSB
CR13 CR12 CR11 CR10 CR9 CR8 CR7 CR6 CR5 CR4 CR3 CR2 CR1 CR0
Control Register Write/Read
REG1 = REG0 = 0, A4–A0 = 01100, 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.
CR13 = 1. Amplifier output is high impedance (default on
power-up).
CR13 = 0. Amplifier output is 100 kΩ to ground.
CR12: REF Select. This bit selects the operating internal
reference for the AD5382.
CR12 = 1: Internal reference is 2.5 V (AD5382-5 default), the
recommended operating reference for AD5382-5.
CR12 = 0: Internal reference is 1.25 V (AD5382-3 default),
the recommended operating reference for AD5382-3.
CR11: Current Boost Control. This bit is used to boost the
current in the output amplifier, thereby altering its slew rate.
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: Internal/External Reference. This bit determines
if the DAC uses its internal reference or an externally
applied reference.
CR10 = 1: Internal Reference Enabled. The reference output
depends on data loaded to CR12.
CR10 = 0: External Reference Selected (default on power-up).
CR9: Channel Monitor Enable (see Channel Monitor Function)
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.
CR9 = 0: Monitor Disabled (default on power-up). When the
monitor is disabled, MON_OUT is three-stated.
CR8: Thermal Monitor Function. This function is used to
monitor the AD5382’s 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 may 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.
CR8 = 1: Thermal Monitor Enabled.
CR8 = 0: Thermal Monitor Disabled (default on power-up).
CR7 and CR6: Don’t Care.
CR5 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 CR5 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 16 shows the decoding
for toggle contains Channels 24 to 31, CR5 = 1 enables these
channels.
Table 16.
CR Bit Group Channels
CR5 3 24–31
CR4 2 16–23
CR3 1 8–15
CR2 0 0–7
CR1 and CR0: Don’t Care.
Channel Monitor Function
REG1 = REG0 = 0, A4–A0 = 01010
DB13–DB8 = Contain data to address the monitored channel
A channel monitor function is provided on the AD5382.
This feature, which consists of a multiplexer addressed via the
interface, allows any channel output or the signals connected
to the MON_IN inputs to be routed to the MON_OUT pin for
monitoring using an external ADC. The channel monitor func-
tion must be enabled in the control register before any channels
are routed to MON_OUT. On the AD5382, DB13 to DB8
contain the channel address for the monitored channel.
Selecting channel address 63 three-states MON_OUT.