REALTIME CONTROL

Laser Transceiver Parts List

C1 .47 uF decoupling and energy storage, part of C1/C2/R1 network which reduces laser output if the LASER_EN drive has a duty cycle of more than 20% and limits pulse width to approx 30 uSec
C2 .1 uF see C1
C3 .01 uF part of C3/R4 network to extend rise time of current through laser diode so that APC system prevents overshoot
C4 .1 uF decoupling, bypassing for wiring arrangements in which the shield of the TXD conductor is used as the +12V supply conductor
C5 10 uF 16 V tantalum decoupling
C6 .1 uF decoupling
C7 10 uF 16 V tantalum decoupling
C8 .1 uF decoupling
C9 10 uF 16 V tantalum timing capacitor for 555 which holds the CS8130 in CONTROL mode for a few seconds after power-up
C10 10 uF 16 V tantalum decoupling
C11 .1 uF decoupling
C12 10 uF 16 V tantalum CS8130 reset circuit timing capacitor
C13 18 pf crystal loading capacitor
C14 18 pf crystal loading capacitor
C15 10 uF 16 V tantalum see C4
C(DB9) .1 uF coupling capacitor, mounted inside DB9 connector if independently shielded twinlead
is used for the cable from the UPNLT  to the computer and power supply
D1 1N4004 reverse polarity protection
D2 1N4148 discharge path for CS8130 reset capacitor
D3 1N4148 reverse polarity snubber
LDPD1 HL6720G Hitachi 670 nm 5 mW laser diode with inbuilt photodiode
LED1 3 mm red voltage regulator
LED2 3 mm red CONTROL mode indicator
PD1 SFH213 receiver transducer
Q1 BC327 photodiode current amplifier
Q2 BC337 laser diode current regulator
Q3 BC327 RXD line driver
Q4 BC337 TXD line receiver
R1 180R current and duty cycle limiter, see also C1
R2 1K dropping resistor for LED1
R3 1K Q1 load resistor
R4 1R5 see C3
R5 4K7 laser diode forward biasing resistor
R6 470K timing resistor, see C9
R7 1K current limiting for LED2
R8 10R decoupling for analog +5V rail
R9 4K7 CS8130 reset circuit timing resistor
R10 4K7 Q4 load resistor
R11 4K7 CS8130 protection resistor
R12 4K7 Q3 base current limiter
R13 1K TXD line load resistor
R14 4K7 Q4 base current limiter
R15 47R Q3 protection
R16 180R Q3 load
Rtest1 47R Laser diode simulator resistor, used only during initial adjustment
Rtest2 47K Monitor diode simulator resistor, used only during initial adjustment
U1 MC78L05ACP +5V voltage regulator
U2 NE555 Timer which hold CS8130 in control mode for a few seconds after power-up.

Note that use of some other versions of the 555 can result in C9 retaining its charge for many seconds after power down, so a power-up within that period will give a shortened CONTROL mode time for the CS 8130

U3 CS8130-CP DIL version of Crystal's multistandard transceiver chip. This IC performs most of the complex, sensitive and critical functions required for the laser transceiver.
VR1 50K laser monitor diode feedback adjustment
VR2 100R laser current limit adjustment
X1 3.6864 MHz
HC18U
transceiver clock crystal
Z1 5V1 250 mW zener 5V rail clamp

lens assembly Collimating lens and laser diode housing to suit 9 mm laser diode
socket 20 pin .3" DIL socket for U3
socket 8 pin DIL socket for U2
terminal block 4 way, 5 mm spacing
saddle 3/8" copper saddle to secure laser diode assembly to PCB
shield 25 mm x 25 mm x .005" brass shim, shield for PD1
screws 2 off M3.5 x 10 mm, to secure saddle to PCB
nuts 2 off M3.5
PCB UPNLT, 55 mm x 87 mm single sided, printed component overlay

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