AD8191ASTZ-RL Analog Devices Inc, AD8191ASTZ-RL Datasheet - Page 28

• Manufacturer Part Number: AD8191ASTZ-RL
• Description: IC,Telecom Switching Circuit,QFP,100PIN,PLASTIC
• Manufacturer: Analog Devices Inc

Specifications of AD8191ASTZ-RL

• Function: Switch
• Circuit: 1 x 4:1
• On-state Resistance: 100 Ohm
• Voltage Supply Source: Single Supply
• Voltage - Supply, Single/dual (±): 3 V ~ 3.6 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 100-LQFP
• Operating Supply Voltage (typ): 3.3/5V
• Operating Supply Voltage (min): 3V
• Operating Supply Voltage (max): 3.6V
• Operating Temp Range: -40C to 85C
• Operating Temperature Classification: Industrial
• Package Type: LQFP
• Mounting: Surface Mount
• Pin Count: 100
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

AD8191
HPD is a dc signal presented by a sink to a source to indicate
that the source EDID is available for reading. The placement
of this signal is not critical, but it should be routed as directly
as possible.
When the AD8191 is powered up, one set of the auxiliary in-
puts is passively routed to the outputs. In this state, the AD8191
looks like a 100 Ω resistor between the selected auxiliary inputs
and the corresponding outputs as illustrated in Figure 27. The
AD8191 does not buffer the auxiliary signals, therefore, the
input traces, output traces, and the connection through the
AD8191 all must be considered when designing a PCB to meet
HDMI/DVI specifications. The unselected auxiliary inputs of the
AD8191 are placed into a high impedance mode when the device
is powered up. To ensure that all of the auxiliary inputs of the
AD8191 are in a high impedance mode when the device is powered
off, it is necessary to power the AMUXVCC supply as illustrated
in Figure 28.
In contrast to the auxiliary signals, the AD8191 buffers the
TMDS signals, allowing a PCB designer to layout the TMDS
inputs independently of the outputs.
SILKSCREEN
LAYER 1: SIGNAL (MICROSTRIP)
PCB DIELECTRIC
LAYER 2: GND (REFERENCE PLANE)
PCB DIELECTRIC
LAYER 3: PWR (REFERENCE PLANE)
PCB DIELECTRIC
LAYER 4: SIGNAL (MICROSTRIP)
SILKSCREEN
Figure 32. Example Board Stackup
3W
RELIEVED UNDERNEATH
REFERENCE LAYER
MICROSTRIP
W
3W
Rev. 0 | Page 28 of 32
Power Supplies
The AD8191 has five separate power supplies referenced to
two separate grounds. The supply/ground pairs are:
•
•
•
•
•
The AVCC/AVEE (3.3 V) and DVCC/DVEE (3.3 V) supplies
power the core of the AD8191. The VTTI/AVEE supply (3.3 V)
powers the input termination (see Figure 25). Similarly, the
VTTO/AVEE supply (3.3 V) powers the output termination
(see Figure 26). The AMUXVCC/DVEE supply (3.3 V to 5 V)
powers the auxiliary multiplexer core and determines the
maximum allowed voltage on the auxiliary lines. For example,
if the DDC bus is using 5 V I
connected to +5 V relative to DVEE.
In a typical application, all pins labeled AVEE or DVEE should
be connected directly to ground. All pins labeled AVCC,
DVCC, VTTI, or VTTO should be connected to 3.3 V, and
Pin AMUXVCC tied to 5 V. The supplies can also be powered
individually, but care must be taken to ensure that each stage of
the AD8191 is powered correctly.
Power Supply Bypassing
The AD8191 requires minimal supply bypassing. When
powering the supplies individually, place a 0.01 μF capacitor
between each 3.3 V supply pin (AVCC, DVCC, VTTI, and
VTTO) and ground to filter out supply noise. Generally, bypass
capacitors should be placed near the power pins and should
connect directly to the relevant supplies (without long inter-
vening traces). For example, to improve the parasitic inductance
of the power supply decoupling capacitors, minimize the trace
length between capacitor landing pads and the vias as shown in
Figure 33.
AVCC/AVEE
VTTI/AVEE
VTTO/AVEE
DVCC/DVEE
AMUXVCC/DVEE
Figure 33. Recommended Pad Outline for Bypass Capacitors
2
C, then AMUXVCC should be
RECOMMENDED
NOT RECOMMENDED
EXTRA ADDED INDUCTANCE