Datasheet

AD5735 Data Sheet

Rev. C | Page 30 of 48

REGISTERS

Table 8, Table 9, and Table 10 provide an overview of the registers for the AD5735.

Table 8. Data Registers for the AD5735

DAC Data Registers The four DAC data registers (one register per DAC channel) are used to write a DAC code to each DAC

channel. The DAC data bits are D15 to D4.

Gain Registers The four gain registers (one register per DAC channel) are used to program the gain trim on a per-channel

basis. The gain data bits are D15 to D4.

Offset Registers The four offset registers (one register per DAC channel) are used to program the offset trim on a per-channel

basis. The offset data bits are D15 to D4.

Clear Code Registers The four clear code registers (one register per DAC channel) are used to program the clear code on a per-

channel basis. The clear code data bits are D15 to D4.

Table 9. Control Registers for the AD5735

Main Control Register The main control register is used to configure functions for the entire part. These functions include the

following: enabling status readback during a write; enabling the output on all four DAC channels simulta-

neously; power-on of the dc-to-dc converter on all four DAC channels simultaneously; and enabling and

configuring the watchdog timer. For more information, see the Main Control Register section.

DAC Control Registers The four DAC control registers (one register per DAC channel) are used to configure the following functions

on a per-channel basis: output range (for example, 4 mA to 20 mA or 0 V to 10 V); selection of the internal

current sense resistor or an external current sense resistor; enabling/disabling the use of a clear code;

enabling/disabling overrange on a voltage channel; enabling/disabling the internal circuitry (dc-to-dc

converter, DAC, and internal amplifiers); power-on/power-off of the dc-to-dc converter; and enabling/

disabling the output channel.

Software Register The software register is used to perform a reset, to toggle the user bit in the status register, and, as part of

the watchdog timer feature, to verify correct data communication operation.

DC-to-DC Control Register The dc-to-dc control register is used to set the control parameters for the dc-to-dc converter: maximum

output voltage, phase, and switching frequency. This register is also used to select the internal compensa-

tion resistor or an external compensation resistor for the dc-to-dc converter.

Slew Rate Control Registers The four slew rate control registers (one register per DAC channel) are used to program the slew rate of

the DAC output.

Table 10. Readback Register for the AD5735

Status Register The status register contains any fault information, as well as a user toggle bit.