iC-NZP
P-TYPE LASER DIODE DRIVER
Rev A1, Page 11/13
External capacitor mode
low monitor current. In that cases, an external capaci-
In applications where an external capacitor is required tor is to be connected as close as possible to the chip,
(see best performance recommendations below), the across pin CI and CIS. This will prevent instability of
external capacitor mode must be enabled (NCID pin the control circuit. For averaging control a 10 nF ca-
set to low).
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
Best performance recommendations
The operating point for the laser diode is stored in an as short as possible to avoid parasitic inductances. A
on-chip capacitor. This permits a fast start-up but can snubber network across the laser diode also helps to
lead to an unstable control circuit under certain condi- compensate for these parasitic inductances.
tions such as inadequate PCB layout or laser with very
RVDD
+3..+5.5V
VDDA
VDD
RSI
i(RSI)x540
CVDDA
100 nF..
CVDD
100 nF..
LDA MONITOR
iC-NZP
VDDL
CIS
RSI
NSLP
REGE
VDD
0.68..9kΩ
&
1
AVG
&
ECI
..10 nF..
CI
VSY
SYN
-
CI
x280
REF
LVDS/TTL
EP
+
+
-
LDA
IMON
MD
EN
VDD
VDD
..300mA
TTL
NCID
ECI
OUTPUT DRIVER
INPUT INTERFACE
OverTemp.
RMD
PMD
NERR
OverCurrent
Low V(LDA)
1
Bandgap, Reference, Overtemp
OUTPUT MONITOR
T.PAD
GND
RGND
GND
Figure 7: Example set-up for current control
SLEEP MODE
The iC-NZP has a very low consuption mode that per- where the VDDA pin is disconnected as supply and
mits hibernation in battery powered applications. Set- pulled down. The wake up from sleep time is about
ting the NSLP pin to low drives the chip into a state 300 µs
ICHAUS [ IC-HAUS GMBH ]
