Cirrus Logic CS8130 - Manual (Page 22)

Grounding & Layout
Grounding and layout for the CS8130 are criti-
cal, because of the sensitive nature of the PIN
diode amplifier. The CS8130 should be over its
own dedicated ground plane. The PIN diode
should be very close to the PINA and PINC
pins. The PIN diode traces should be very short
(< 5 mm), and should be surrounded by ground
plane. There should be holes in the ground plane
provided for mounting a metal shield over the
CS8130 and the PIN diode for EMI shielding.
The PIN diode and transmit LEDs should be po-
sitioned so as to line up the front optical surfaces
of the packages. The optical surface of the PIN
diode and transmit LED(s) should be positioned
1cm back from the daylight IR filter window in-
side the case of the equipment. This ensures that
direct sunlight does not fall upon the top surface
of the PIN diode.
An evaluation kit, CDB8130, is available from
Crystal. This may be used as an example of the
correct layout for the CS8130 and the optical
components.
Optical Components
TEMIC (Tel: 408 970 5684) provides Telefunken
infrared LEDs and PIN diodes which are com-
patible with the CS8130. Contact Crystal for
details of additional qualified LED and PIN di-
ode sources.
Example Application Schematics
Crystal has prepared some example schematics
which demonstrate possible uses for the CS8130.
Figure 8 shows a computer or PDA motherboard
example, where one UART is used to drive both
a wired RS232 COM port and an IR port.
Figure 9 shows a pod schematic. This is an ex-
ternal unit which can be plugged into any
existing COM port to create an IR port.
Schematic & Layout Review Service
Confirm Optimum
Schematic & Layout
Before Building Your Board.
For Our Free Review Service
Call Applications Engineering.
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CS8130
22 DS134PP2
CS8130
22 DS134F1