AD5757 Analog Devices, AD5757 Datasheet - Page 42

• Manufacturer Part Number: AD5757
• Description: Quad Channel, 16-Bit, Serial Input, 4-20mA Output DAC, Dynamic Power Control, HART Connectivity
• Manufacturer: Analog Devices

Specifications of AD5757

• Resolution (bits): 16bit
• Dac Update Rate: 60kSPS
• Dac Settling Time: 15µs
• Max Pos Supply (v): +33V
• Single-supply: No
• Dac Type: Current Out
• Dac Input Format: SPI

AD5757
DC-to-DC Converters
To achieve high efficiency, good regulation, and stability, a well-
designed printed circuit board layout is required.
Follow these guidelines when designing printed circuit boards
(see Figure 56):
•
•
•
•
•
•
Keep the low ESR input capacitor, C
and PGND.
Keep the high current path from C
L
Keep the high current path from C
rectifier, D
possible.
Keep high current traces as short and as wide as possible.
The path from C
PGND should be able to handle a minimum of 1 A.
Place the compensation components as close as possible to
COMP
Avoid routing high impedance traces near any node
connected to SW
noise injection.
DCDC
, to SW
DCDC_x
DCDC
.
X
and PGND as short as possible.
, to the output capacitor, C
IN
x
or near the inductor to prevent radiated
through the inductor, L
IN
IN
IN
through the inductor,
through L
, close to AV
DCDC
DCDC
, as short as
, to SW
DCDC
CC
and the
X
and
Rev. B | Page 42 of 44
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. Analog
Devices i Coupler® products can provide voltage isolation in
excess of 2.5 kV. The serial loading structure of the AD5757
makes it ideal for isolated interfaces because the number of
interface lines is kept to a minimum. Figure 65 shows a 4-channel
isolated interface to the AD5757 using an ADuM1400. For
more information, visit www.analog.com.
*ADDITIONAL PINS OMITTED FOR CLARITY.
MICROCONTROLLER
SERIAL CLOCK
CONTROL OUT
SERIAL DATA
SYNC OUT
OUT
OUT
V
V
V
V
ADuM1400*
IA
IB
IC
ID
Figure 65. Isolated Interface
ENCODE
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Data Sheet
V
V
V
V
OA
OB
OC
OD
TO SCLK
TO SDIN
TO SYNC
TO LDAC