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