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AD5697RBRUZ-RL7

Dual, 12-Bit nanoDAC+ with 2 ppm/°C Reference, I2C Interface

Analog Devices 

Data Sheet

APPLICATIONS INFORMATION

MICROPROCESSOR INTERFACING

Microprocessor interfacing to the AD5697R is via a serial bus that

uses a standard protocol that is compatible with DSP processors

and microcontrollers. The communications channel requires a

2-wire interface consisting of a clock signal and a data signal.

AD5697R-TO-ADSP-BF531 INTERFACE

The I2C interface of the AD5697R is designed to be easily

connected to industry-standard DSPs and microcontrollers.

Figure 50 shows the AD5697R connected to the Analog Devices

Blackfin® DSP (ADSP-BF531). The Blackfin has an integrated I2C

port that can be connected directly to the I2C pins of the AD5697R.

AD5697R

ADSP-BF531

GPIO1

GPIO2

PF9

PF8

SCL

SDA

LDAC

RESET

Figure 50. ADSP-BF531 Interface to the AD5338R

LAYOUT GUIDELINES

In any circuit where accuracy is important, careful consideration of

the power supply and ground return layout helps to ensure the

rated performance. Design the printed circuit board (PCB) on

which the AD5697R is mounted so that the AD5697R lies on

the analog plane.

The AD5697R must have ample supply bypassing of 10 µF in

parallel with 0.1 µF on each supply, located as close to the package

as possible, ideally right up against the device. The 10 µF capacitor

is the tantalum bead type. The 0.1 µF capacitor must have low

effective series resistance (ESR) and low effective series inductance

(ESI), such as the common ceramic types that provide a low

impedance path to ground at high frequencies to handle transient

currents due to internal logic switching.

In systems where there are many devices on one board, it is often

useful to provide some heat sinking capability to allow the power

to dissipate easily.

The AD5697R LFCSP model has an exposed paddle beneath

the device. Connect this paddle to the GND supply for the part.

For optimum performance, use special considerations to design

the motherboard and to mount the package. For enhanced thermal,

electrical, and board level performance, solder the exposed paddle

AD5697R

on the bottom of the package to the corresponding thermal land

paddle on the PCB. Design thermal vias into the PCB land paddle

area to further improve heat dissipation.

The GND plane on the device can be increased (as shown in

Figure 51) to provide a natural heat sinking effect.

AD5697R

GND

PLANE

BOARD

Figure 51. Paddle Connection to Board

GALVANICALLY ISOLATED INTERFACE

In many process control applications, it is necessary to provide

an isolation barrier between the controller and the unit being

controlled to protect and isolate the controlling circuitry from

any hazardous common-mode voltages that may occur. iCoupler®

products from Analog Devices provide voltage isolation in

excess of 2.5 kV. The serial loading structure of the AD5697R

makes the part ideal for isolated interfaces because the number of

interface lines is kept to a minimum. Figure 52 shows a 4-channel

isolated interface to the AD5697R using the ADuM1400. For

further information, visit http://www.analog.com/icouplers.

CONTROLLER

SERIAL VIA

CLOCK IN

ADuM14001

ENCODE

DECODE

VOA TO

SCLK

SERIAL VIB

DATA OUT

ENCODE

DECODE

VOB TO

SDIN

VIC

RESET OUT

ENCODE

DECODE

VOC TO

RESET

LOAD DAC VID

OUT

ENCODE

DECODE

VOD TO

LDAC

1ADDITIONAL PINS OMITTED FOR CLARITY.

Figure 52. Isolated Interface

Rev. B | Page 25 of 27

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