IC-NZP Datasheet, PDF (11/13 Pages) IC-Haus GmbH – P-TYPE LASER DIODE DRIVER

iC-NZP
P-TYPE LASER DIODE DRIVER
preliminary
Rev A1, Page 11/13
External capacitor mode
In applications where an external capacitor is required
(see best performance recommendations below), the
external capacitor mode must be enabled (NCID pin
set to low).
Best performance recommendations
The operating point for the laser diode is stored in an
on-chip capacitor. This permits a fast start-up but can
lead to an unstable control circuit under certain condi-
tions such as inadequate PCB layout or laser with very
low monitor current. In that cases, an external capaci-
tor is to be connected as close as possible to the chip,
across pin CI and CIS. This will prevent instability of
the control circuit. For averaging control a 10 nF ca-
pacitor at CI is recommended. Special care must be
taken in PCB layout when laying out the path from the
laser diode’s cathode to GND. This path must be kept
as short as possible to avoid parasitic inductances. A
snubber network across the laser diode also helps to
compensate for these parasitic inductances.
+3..+5.5V
CVDD
100 nF..
RSI
0.68.. 9kΩ
GND
VDD
RSI
NSLP
REGE
i(RSI)x540
LDA MONITOR
VD D
AVG
&
VSY
SYN
EP
EN
TTL
NCID
LVDS/TTL
+
-
VD D
VD D
NERR
T.PAD
GND
INPUT INTERFACE
OverTemp.
1
OverCurrent
Low V(LDA)
RVDD
VDDA
iC-NZP
VDDL
&
1
-
REF
+
ECI
CIS
ECI
x280
CI
LDA
IMON
MD
OUTPUT DRIVER
Bandgap, Reference, Overtemp
OUTPUT MONITOR
RGND
CVDDA
100 nF..
..10 nF..
CI
..300mA
RMD
PMD
Figure 7: Example set-up for current control
SLEEP MODE
The iC-NZP has a very low consuption mode that per-
mits hibernation in battery powered applications. Set-
ting the NSLP pin to low drives the chip into a state
where the VDDA pin is disconnected as supply and
pulled down. The wake up from sleep time is about
300 µs