M66515FP
Laser Diode Driver/Controller
REJ03F0084-0100Z
Rev.1.0
Sep.22.2003
Description
The M66515 is a laser diode driver/controller that performs drive and controls the laser power control of a type of
semiconductor laser diode the anode of which is connected, with the cathode of a photodiode for monitoring, to a stem
in which the semiconductor laser diode anode and monitoring photo diode cathode are connected to the stem.
This IC has a sink-type laser driving current output pin, and can drive a laser diode with a bias current of up to a
maximum 30 mA and with switched currents of up to 120 mA, switched at rates of up to 40 Mbps.
The IC incorporates a sample hold circuit, so that a self-APC (Automatic Power Control) system, which does not
require external laser power control, can be realized.
Features
•
•
•
•
•
Internal sample-and-hold circuit for self-APC configuration
High-speed switching (40 Mbps)
High driving currents (150 mA max)
Settable bias current (30 mA max)
Single 5 V power supply
Applications
•
Equipment employing semiconductor laser diodes
Function Overview
The M66515 is a laser diode driver/controller which drives and controls the laser power of a semiconductor laser diode
(LD) the anode of which is connected, with the cathode of a photodiode (PD) for monitoring, to a stem (among
Mitsubishi lasers, N type models).
LD driving and laser power control are executed by connecting an external capacitance to the C
H
pin and applying a
reference voltage to the V
r
pin.
The PD current occurring when a LD emits light flows through a resistance connected across 1RM and 2RM, resulting
in a potential difference (V
M
). This V
M
is compared with the voltage applied to the V
r
pin, and when V
M
<V
r
, a constant
current source from the C
H
pin flows to charge the external capacitor. When V
M
>V
r
, a constant current sink from the
C
H
pin causes the charge on the external capacitor to be discharged.
This operation is performed when the
S/H
input is "L" (sample); when the
S
/H input is in the "H" state, the C
H
pin is in
the high-impedance state (hold), regardless of V
M
, V
r
and the
DATA
input state.
The LD driving current consists of a switched current I
SW
, which is controlled by the
DATA
input, and I
B
, a LD bias
current which is independent of the
DATA
input state.
Rev.1.00, Sep.22.2003, page 1 of 11
RENESAS [ RENESAS TECHNOLOGY CORP ]
