ADUM3160BRWZ-RL Analog Devices Inc, ADUM3160BRWZ-RL Datasheet - Page 10

• Manufacturer Part Number: ADUM3160BRWZ-RL
• Description: 2.5kVFull/Low Speed USB Digital Isolator
• Manufacturer: Analog Devices Inc
• Series: iCoupler®r

Specifications of ADUM3160BRWZ-RL

• Operating Temperature: -40°C ~ 105°C
• Inputs - Side 1/side 2: 2/2
• Number Of Channels: 4
• Isolation Rating: 2500Vrms
• Voltage - Supply: 3 V ~ 5.5 V
• Data Rate: 12Mbps
• Propagation Delay: 70ns
• Output Type: Logic
• Package / Case: 16-SOIC (0.300", 7.50mm Width)
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

ADuM3160
APPLICATIONS INFORMATION
FUNCTIONAL DESCRIPTION
USB isolation in the D+/D− lines is challenging for several
reasons. First, access to the output enable signals is normally
required to control the transceiver. Some level of intelligence
must be built into the isolator to interpret the data stream and
determine when to enable and disable its upstream and down-
stream output buffers. Second, the signal must be faithfully
reconstructed on the output side of the coupler while retaining
precise timing and not passing transient states such as invalid
SE0 and SE1 states. In addition, the part must meet the low
power requirements of the suspend mode.
The iCoupler technology is based on edge detection and,
therefore, lends itself well to the USB application. The flow of
data through the device is accomplished by monitoring the
inputs for activity and setting the direction for data transfer
based on a transition from the idle state. After data directionality
is established, data is transferred until either an end of packet
(EOP) or a sufficiently long idle state is encountered. At this
point, the coupler disables its output buffers and monitors its
inputs for the next activity.
During the data transfers, the input side of the coupler holds its
output buffers disabled. The output side enables its output buffers
and disables edge detection from the input buffers. This allows
the data to flow in one direction without wrapping back through
the coupler causing the iCoupler to latch. Timing is based on
the differential input signal transition. Logic is included to
eliminate any artifacts due to different input thresholds of the
differential and single-ended buffers. The input state is trans-
ferred across the isolation barrier as one of three valid states,
J, K, or SE0. The signal is reconstructed at the output side with a
fixed time delay from the input side differential input.
The iCoupler does not have a special suspend mode, nor does it
need one because its power supply current is below the suspend
current limit of 2.5 mA when the USB bus is idle.
The ADuM3160 is designed to interface with an upstream-
facing low/full speed USB port by isolating the D+/D− lines.
An upstream-facing port supports only one speed of operation;
therefore, the speed-related parameters, J/K logic level, and
D+/D− slew rate are set to match the speed of the upstream-
facing peripheral port (see Table 10).
A control line on the downstream side of the ADuM3160
activates the idle state pull-up resistor. This allows the
downstream port to control when the upstream port attaches
to the USB bus. The pin can be tied to the peripheral pull-up,
a control line, or the peripheral power supply depending on
when the initial bus connect is performed.
Rev. A | Page 10 of 16
PRODUCT USAGE
The ADuM3160 is designed to be integrated into a USB
peripheral with an upstream-facing USB port as shown in
Figure 4. The key design points are as follows:
•
•
•
•
•
•
Other than the delayed application of pull-up resistors, the
ADuM3160 is transparent to USB traffic, and no modifications
to the peripheral design are required to provide isolation. The
isolator adds propagation delay to the signals comparable to a
hub and cable. Isolated peripherals must be treated as if there
were a built-in hub when determining the maximum number of
hubs in a data chain.
Hubs can be isolated like any other peripheral. Isolated hubs
can be created by placing an ADuM3160 on the upstream port
of a hub chip. This configuration can be made compliant if
counted as two hub delays. The hub chip allows the ADuM3160
to operate at full speed yet maintains compatibility with low
speed devices.
HOST
USB
The USB host provides power for the upstream side of the
ADuM3160 through the cable.
The peripheral supply provides power to the downstream
side of the ADuM3160.
The DD+/DD− lines of the isolator interface with the
peripheral controller, and the UD+/UD− lines of the
isolator connect to the cable or host.
Peripheral devices have a fixed data rate that is set at design
time. The ADuM3160 has configuration pins, SPU and
SPD, that are set by the user to match this speed on the
upstream and downstream sides of the coupler.
USB enumeration begins when either the D+ or D−line is
pulled high at the peripheral end of the USB cable. Control
of the timing of this event is provided by the PIN input on
the downstream side of the coupler.
Pull-up and pull-down resistors are implemented inside
the coupler. Only external series resistors and bypass
capacitors are required for operation.
GND
V
D+
D–
BUS
BUS
Figure 4. Typical ADuM3160 Application
ADuM3160
3.3V
D+
D–
PERIPHERAL
µCPU
POWER
SUPPLY