Datasheet

AD5750/AD5750-1
Rev. C | Page 32 of 36
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. The iCoupler®
family of products from Analog Devices, Inc., provides voltage
isolation in excess of 5.0 kV. The serial loading structure of the
AD5750/AD5750-1 makes it ideal for isolated interfaces because
the number of interface lines is kept to a minimum. Figure 58
shows a 4-channel isolated interface using an ADuM1400. For
further information, visit www.analog.com/icouplers.
DECODE ENCODE
V
IA
V
OA
TO
SCLK
V
IB
V
OB
TO
SDIN
V
IC
V
OC
TO
SYNC
V
ID
V
OD
TO
CLEAR
SERIAL
CLOCK OUT
SERIAL
DATA OUT
SYNC OUT
CONTROL OUT
CONTROLLER ADuM1400
1
1
ADDITIONAL PINS OMITTED FOR CLARITY.
DECODE ENCODE
DECODE ENCODE
DECODE ENCODE
07268-052
Figure 58. Isolated Interface
MICROPROCESSOR INTERFACING
Microprocessor interfacing to the AD5750/AD5750-1 is via a
serial bus that uses a protocol compatible with microcontrollers
and DSP processors. The communication channel is a 3-wire
(minimum) interface consisting of a clock signal, a data signal,
and a
SYNC
signal. The AD5750/AD5750-1 require a 16-bit
data-word with data valid on the falling edge of SCLK.