Micrel
TXRX_982_R1 Evaluation Board
Evaluation Board Setting
Driver Laser Coupling
Table 1 summarizes the setting of the board for the
two configurations, driver DC-coupled or AC-coupled
to the laser.
Configuration
Driver and Laser
DC-Coupled
Driver and Laser
AC-Coupled
Remove
L2, L3, L7, L8,
R14, R6, R13,
C24, C36
Install
Install a 0 at
C24 and C38.
L2, L3, L7, L8,
R14, R6, R13,
C24, C36
SY88843 Limiting Amplifier
The SY88843 limiting amplifier has a signal detect
(SD) indicator. To improve the hysteresis on the
receive signal LOS, remove R2 and install R3, Q6,
and R23. The combination of R3 and R1 will
determine the sensitivity of the transceiver and
hysteresis on the SD. Refer to the application note
entitled "Notes on Sensitivity and hysteresis in
Micrel's Post Amplifiers" available at
http://www.micrel.com/product-info/app_hints+notes.shtml.
TOSA and ROSA Installation
Check the pinout of the laser and receiver and install
them accordingly to the diagrams shown on Figure 1.
Board
Edge
Top Pad
LD Anode
Top Pad
LD Cathode
Top Pad
DATA-
Top Pad GND
Top Pad
DATA+
Bottom Pad
VCC
Bottom Pad
PD Cathode
Bottom Pad
NC
Bottom Pad
RSSI
Table 1. Configuration Settings
Receiver Sensitivity and Hysteresis Setting
SY88973 Limiting Amplifier
The SY88973 limiting amplifier is the default post
amplifier installed on the board. It has a receive signal
LOS indicator. To improve the hysteresis on the
receive signal LOS, install R2 and uninstall R3. The
combination of R2 and R1 will determine the
sensitivity of the transceiver and hysteresis on the
receive signal LOS. Refer to the application note
entitled "Notes on Sensitivity and hysteresis in
Micrel's Post Amplifiers" available at
http://www.micrel.com/product-info/app_hints+notes.shtml.
Figure 1. Mounting of Laser and Receive
September 2004
2
M9999-092304
hbwhelp@micrel.com
or (408) 955-1690
MICREL [ MICREL SEMICONDUCTOR ]
