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Data Sheet
AD5380
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, A5 to A0 = 001100, R/W status determines
if the operation is a write (R/W = 0) or a read (R/W = 1). DB13
to DB0 contains 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 k to ground.
CR12: REF Select. This bit selects the operating internal
reference for the AD5380. CR12 is programmed as follows:
CR12 = 1: Internal reference is 2.5 V (AD5380-5 default),
the recommended operating reference for AD5380-5.
CR12 = 0: Internal reference is 1.25 V (AD5380-3 default),
the recommended operating reference for AD5380-3.
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:
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 = 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.
CR8: Thermal Monitor Function. This function is used to
monitor the AD5380’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 in cases where power dissipation may be
exceeded if a number of output channels are simultaneously
short-circuited. A soft power-up will re-enable the output
amplifiers if the die temperature has dropped below 130°C.
CR8 = 1: Thermal Monitor Enabled.
CR8 = 0: Thermal Monitor Disabled (default on power-up).
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 registers 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 16 shows the decoding
for toggle mode operation. For example, CR6 controls Group w,
which contains Channel 32 to Channel 39, CR6 = 1 enables
these channels.
CR1 and CR0: Don’t Care.
Table 16.
CR Bit
Group
Channels
CR6
4
32–39
CR5
3
24–31
CR4
2
16–23
CR3
1
8–15
CR2
0
0–7
Channel Monitor Function
REG1 = REG0 = 0, A5 to A0 = 001010
DB13 to DB8 = Contain data to address the monitored channel.
A channel monitor function is provided on the AD5380. This
feature, which consists of a multiplexer addressed via the inter-
face, 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 AD5380, DB13 to DB8 contain the
channel address for the monitored channel. Selecting Channel
Address 63 three-states MON_OUT.