AD5686R datasheet(27/32 Pages) AD

27 / 32 page

Data Sheet

AD5696R/AD5695R/AD5694R

Rev. 0 | Page 27 of 32

APPLICATIONS INFORMATION

MICROPROCESSOR INTERFACING

Microprocessor interfacing to the AD5696R/AD5695R/

AD5694R 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.

AD5696R/AD5695R/AD5694R TO ADSP-BF531

INTERFACE

The I2C interface of the AD5696R/AD5695R/AD5694R is

designed to be easily connected to industry-standard DSPs and

microcontrollers. Figure 58 shows the AD5696R/AD5695R/

AD5694R connected to the Analog Devices Blackfin® DSP. The

Blackfin has an integrated I2C port that can be connected

directly to the I2C pins of the AD5696R/AD5695R/AD5694R.

Figure 58. ADSP-BF531 Interface

LAYOUT GUIDELINES

In any circuit where accuracy is important, careful consider-

ation of the power supply and ground return layout helps

to ensure the rated performance. The PCB on which the

AD5696R/AD5695R/AD5694R are mounted should be

designed so that the AD5696R/AD5695R/AD5694R lie

on the analog plane.

The AD5696R/AD5695R/AD5694R should 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 capacitors are the tantalum bead type. The

0.1 μF capacitor should have low effective series resistance

(ESR) and low effective series inductance (ESI) such as the

common ceramic types, which 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 AD5696R/AD5695R/AD5694R LFCSP models have 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 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 59) to provide a natural heat sinking effect.

Figure 59. 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 struc-

ture of the AD5696R/AD5695R/AD5694R makes the part ideal

for isolated interfaces because the number of interface lines is

kept to a minimum. Figure 60 shows a 4-channel isolated

interface to the AD5696R/AD5695R/AD5694R using an

ADuM1400. For further information, visit

http://www.analog.com/icouplers.

Figure 60. Isolated Interface

ADSP-BF531

SCL

GPIO1

SDA

GPIO2

LDAC

PF9

RESET

PF8

AD5696R/

AD5695R/

AD5694R

AD5696R/

AD5695R/

AD5694R

GND

PLANE

BOARD

ENCODE

SERIAL

CLOCK IN

CONTROLLER

ADuM14001

SERIAL

DATA OUT

RESET OUT

LOAD DAC

OUT

DECODE

SCL

SDA

RESET

LDAC

VIA

VOA

ENCODE

DECODE

VIB

VOB

ENCODE

DECODE

VIC

VOC

ENCODE

DECODE

VID

VOD

ADDITIONAL PINS OMITTED FOR CLARITY.

AD5686R Datasheet(PDF) 27 Page - Analog Devices

AD5686R Datasheet(HTML) 27 Page - Analog Devices

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32

Datasheet Download

Link URL