ASDL-3212-021 Avago Technologies US Inc., ASDL-3212-021 Datasheet - Page 12

• Manufacturer Part Number: ASDL-3212-021
• Description: Infrared Transceivers SFF MIR Front w/o Shield
• Manufacturer: Avago Technologies US Inc.

Specifications of ASDL-3212-021

• Wavelength: 870 nm, 875 nm
• Continual Data Transmission: 1.152 Mbit/s
• Transmission Distance: 50 cm
• Radiant Intensity: 80 mW/sr
• Half Intensity Angle Degrees: 15 deg
• Pulse Width: 1.5 us, 1.6 us
• Maximum Rise Time: 60 ns, 600 ns
• Maximum Fall Time: 60 ns, 600 ns
• Led Supply Voltage: 0 V to 6 V
• Maximum Forward Current: 60 mA
• Operating Voltage: 2.4 V to 3.6 V
• Maximum Operating Temperature: + 85 C
• Minimum Operating Temperature: - 25 C
• Dimensions: 7 mm x 2.73 mm x 1.64 mm
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Appendix B: PCB Layout Suggestion
The ASDL-3212 is a shieldless part and hence does not
contain a shield trace unlike the other transceivers. The
e ects of EMI and power supply noise can potentially
reduce the sensitivity of the receiver, resulting in reduced
link distance. The following PCB layout guidelines should
be followed to obtain a good PSRR and EM immunity
resulting in good electrical performance. Things to note:
1. The ground plane should be continuous under the
2. VLED and Vcc can be connected to either un ltered
3. CX2 is generally a ceramic capacitor of low inductance
4. Preferably a multi-layered board should be used
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part.
or unregulated power supply. If VLED and Vcc share
the same power supply, CX3 need not be used. The
connections for CX1 and CX2 should be connected
before the current limiting resistor R1.
providing a wide frequency response while CX1 and
CX3 are tantalum capacitor of big volume and fast
frequency response. The use of a tantalum capacitor
is more critical on the VLED line, which carries a high
current.
to provide su cient ground plane. Use the layer
underneath and near the transceiver module as Vcc,
and sandwich that layer between ground connected
board layers. The diagrams below demonstrate an
example of a 4-layer board :
Top layer
Connect the module ground pin to
bottom ground layer
Layer 2
Critical ground plane zone. Do not connect
directly to the module ground pin
Layer 3
Keep data bus away from critical ground
plane zone
Bottom layer (GND)
The area underneath the module at the second layer, and
3cm in all direction around the module is de ned as the
critical ground plane zone. The ground plane should be
maximized in this zone. The layout below is based on a
2-layer PCB.
Top Layer
Bottom Layer