PRELIMINARY TECHNICAL DATA

REV. PrF 09/2003

AD5380

–19–

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-DB0 contains the control register data.

AD5380 Control Register Contents

MSB

LSB

CR13

CR12

CR11

CR10

CR9

CR8

CR7

CR6

CR5

CR4

CR3

CR2

CR1

CR0

Table VI: AD5380 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 .

CR13=0 amplifier output is 100k to ground (default on power up).

CR12: REF Select. This bit selects the operating internal reference for the AD5380. CR12 is programmed as follows:

CR12=1: Internal reference is 2.5V (AD5380-5 default). Recommended operating reference for

AD5380-5.

CR12=0: Internal reference is 1.25V (AD5380-3 default). Recommended operating reference for AD5380-3.

CR11: Current Boost Control. This bit is used to boost the current in the output amplifier therby 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 bits determines if the DAC uses its internal reference or an externally applied

reference.

CR10=1: Internal Reference enabled. 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.

Following a write to the monitor

channel in the SFR register the selected channel output is routed to the MON_OUT pin. VOUT 39 operates

as the MON-OUT pin on the AD5380.

CR9=0: Monitor Disabled (default on power-up). When monitor is disabled the MON_OUT pin assumes its

normal DAC output function on the AD5380.

CR8: Thermal Monitor Function. This function is used to monitor the internal die temperature of the AD5380 when

enabled. The thermal monitor powers down the output amplifiers when the temperature exceeds 130 degree C. This

function can be used to protect the device in cases where the power dissipation of the device may be exceeded if a number

of output channels are simultaneously short circuited. A soft power-up will re-enable the output amplifiers id the die

temperature has dropped below 130C.

CR8=1: Thermal monitor enabled.

CR8=0 Thermal monitor disabled (default on power-up).

CR7: Dont 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 8-chan-

nels for operation in toggle mode. A logic 1 written to any bit enables a group of channels and a logic zero disables a

group.

LDAC is used to toggle between the two registers. Logic 1 enables a group of channels and a logic zero disables

a group.

CR Bit

CR6

CR5

CR4

CR3

CR2

Group

4

3210

Channels

32-39

24-31

16-23

8-15

0-7

CR1 and CR0 are dont cares.