ADUM5200 Datasheet, PDF (21/23 Pages) Analog Devices – Dual-Channel Isolators with Integrated DC/DC Converter

ADuM5200/5201/5202
POWER CONSIDERATIONS
The ADuM520x Converter Primary side, Data input channels
on the Primary side and Data input channels on the Secondary
side are all protected from premature operation by Under
Voltage Lock Out (UVLO) circuitry. Below the minimum
operating voltage, the power converter holds its oscillator
inactive and all input channel drivers and refresh circuits are
idle. Outputs are held in their default low state. This is to
prevent transmission of undefined states during power up and
power down operations.
During application of power to VDD1, the primary side circuitry
is held idle until the UVLO preset voltage is reached. At that
time the data channels initialize to their default low output state
until they receive data pulses from the secondary side.
The primary side input channels sample the input and send
pulse to the inactive secondary output. The secondary side
converter begins to accept power from the primary and the VISO
voltage starts to rise. When the secondary side UVLO is
reached, the secondary side outputs are initialized to their
default low state until data, either a transition or a DC refresh
pulse, is received from the corresponding primary side input. It
could take up to 1μS after the secondary side is initialized for
the state of the output to correlate with the primary side input.
Secondary side inputs sample their state and transmit it to the
Primary side. Outputs are valid one propagation delay after the
secondary side becomes active.
Because the rate of charge of the secondary side is dependant on
loading conditions, input voltage and output voltage level
selected, care should be taken in the design to allow the
converter to stabilize before valid data is required.
When power is removed from VDD1, the primary side converter
and coupler shut down when UVLO is reached. The secondary
side stops receiving power and starts to discharge. The outputs
on the secondary side will hold the last state that they received
from the primary until either the UVLO level is reached and the
outputs are put in their default low state or the output detects a
lack of activity from the input and the outputs are set to default
before secondary power reaches UVLO.
INCREASING AVAILABLE POWER
The ADuM5200 devices are designed with capability of running
in combination with other compatible isoPower devices. The
RCIN and RCSEL pins allow the ADuM5200 to receive a PWM
signal from another device through the RCIN pin and act as a
slave to that control signal. The RCSEL pin chooses whether the
part will act as a stand alone self regulated device or slave
device. When the ADuM5200 is acting as a slave, its power is
regulated by the master device allowing multiple isoPower parts
to be combined in parallel while sharing the load equally.
When the ADuM5000 is configured as a Stand alone unit, it
generates its own PWM feedback signal to regulate itself and
slave devices.
The ADuM5000 can act as a master or a slave deice, the
ADuM5400 can only be a master/stand alone device, and the
ADuM5200 can only be a slave/Stand alone device. This means
that the ADuM5000, ADuM5200, and ADuM5400 can only be
used in certain master slave combinations as listed in Table 15.
Master
Slave
ADuM5000 ADuM5200 ADuM5400
ADuM5000
Y
Y
N
ADuM5200
N
N
N
ADuM5400
Y
Y
N
Table 15 Allowed combinations of isoPower Parts
The allowed combinations of master and slave configured parts
listed in Table 15 is sufficient to make any combination of
power and channel count. Table 16 illustrates how isoPower
devices can provide many combinations of data channel count
and multiples of the single unit power.
1 Unit
Power
0
ADuM5000
Master
Number of Data Channels
2
ADuM520x
Master
4
ADuM540x
Master
6
ADuM540x
Master
ADuM12xx
2 Unit
Power
ADuM5000
Master
ADuM5000
Slave
ADuM500x
Master
ADuM5200
Slave
ADuM540x
Master
ADuM5200
Slave
ADuM540x
Master
ADuM520x
Slave
3 Unit
Power
ADuM5000
Master
ADuM5000
Slave
ADuM5000
Slave
ADuM5000
Master
ADuM5000
Slave
ADuM520x
Slave
ADuM540x
Master
ADuM5000
Slave
ADuM5000
Slave
ADuM540x
Master
ADuM520x
Slave
ADuM5000
Slave
Table 16 Configurations for Power and Data Channels
INSULATION LIFETIME
All insulation structures will eventually break down when
subjected to voltage stress over a sufficiently long period. The
rate of insulation degradation is dependant on the
characteristics of the voltage waveform applied across the
insulation. In addition to the testing performed by the
regulatory agencies, Analog Devices carries out an extensive set
of evaluations to determine the lifetime of the insulation
structure within the ADuM520x.
ADI performs accelerated life testing using voltage levels higher
than the rated continuous working voltage. Acceleration factors
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