Datasheet

Data Sheet ADM2486
Rev. E | Page 17 of 20
ISOLATED POWER SUPPLY CIRCUIT
The ADM2486 requires isolated power capable of 5 V at up to
approximately 75 mA (this current is dependent on the data
rate and termination resistors used) to be supplied between the
V
DD2
and the GND
2
pins.
A transformer driver circuit with a center-tapped transformer
and LDO can be used to generate the isolated 5 V supply, as
shown in Figure 32. The center-tapped transformer provides
electrical isolation of the 5 V isolated power supply. The primary
winding of the transformer is excited with a pair of square
waveforms that are 180° out of phase with each other. A pair
of Schottky diodes and a smoothing capacitor are used to create
a rectified signal from the secondary winding. The ADP667
linear voltage regulator provides a regulated 5 V power supply
to the ADM2486’s bus-side circuitry (V
DD2
).
V
CC
V
CC
V
CC
ISO 5V
ADP667
IN
10µF
100nF
OUT
GND
5V
SET
SD103C
SD103C
SHDN
V
DD1
GND
1
V
DD2
GND
2
ADM2486
22µF
78253
ISOLATION BARRIER
TRANSFORMER
DRIVER
04604-035
100nF
Figure 32. Isolated Power Supply Circuit
Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.