iC-HG
3 A LASER SWITCH
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Rev A1, Page 7/19
CONFIGURATION INPUT ELVDS
Pin ELVDS selects between 6 channel TTL mode or 3
channel LVDS mode and chooses slow or fast switch-
ing speed. The unconnected pin ELVDS is an error
condition signaled at pin NER with the laser current
disabled.
Pin ELVDS connected to GND selects the six channel
fast TTL mode. Pin ELVDS connected to 30% VDD
selects the six channel slow TTL mode. Pin ELVDS
connected to 70% VDD selects the three channel slow
LVDS mode. Pin ELVDS connected to VDD selects the
three channel fast LVDS mode.
An easy way to set the slow operation mode for TTL
and LVDS mode is to connect a voltage divider at pin
ELVDS. Figure 1 shows the recommended voltage di-
vider for slow TTL mode and Figure 2 shows the rec-
ommended voltage divider for slow LVDS mode.
Figure 1: TTL Slow
Figure 2: LVDS Slow
DIGITAL INPUTS EN1. . . 6
EN1. . . 6 are the digital switching inputs. With pin
ELVDS set to
6 channel TTL mode,
each pin ENx en-
ables the current sink at the respective LDKx. With pin
ELVDS set to
3 channel LVDS mode,
the odd ENx pins
are the positive and the even ENx pins are the neg-
ative LVDS inputs. EN1 and EN2 control LDK1 and
LDK2, EN3 and EN4 control LDK3 and LDK4 and EN5
and EN6 control LDK5 and LDK6. For correct LVDS
operation 100
Ω
terminating resistors between the re-
spective EPx and ENx pins, very close to the inputs,
are strongly recommended. Input pins from unused
channels have to be connected to GND (TTL opera-
tion) resp. EPx to GND and ENx to VDD (LVDS opera-
tion).
ANALOG CURRENT CONTROL VOLTAGE INPUTS CI1. . . 6
The Voltage at pins CI1. . . 6 set the current value at
pins LDK1. . . 6. The figures 3 and 4 shows the tem-
perature dependency of the current at LDK versus the
Voltage at CI. The figures 5 and 6 shows the min., typ.
and max. variations between devices.
ICHAUS [ IC-HAUS GMBH ]
