M66515 Ver la hoja de datos (PDF) - Mitsumi
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M66515 Datasheet PDF : 7 Pages
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MITSUBISHI 〈DIGITAL ASSP〉
M66515FP
LASER-DIODE DRIVER/CONTROLLER
FUNCTION TABLE
Input
ENB
S/H
H
×
L
H
L
L
×: Don’t care
VM, Vr
×
×
VM < Vr
VM > Vr
Switch condition
SW1
SW2
OFF
OFF
OFF
OFF
ON
OFF
OFF
ON
Tr1
ON
OFF
OFF
OFF
Output
Fixed to “L”
High impedance state (hold)
Constant current sourcing (sample)
Constant current sinking (sample)
(2) APC Timing Chart
The following diagram is an APC timing chart, operation of
which is based on sample hold control signals.
Note that in the example it is assumed that the leak current
occurring at the CH pin under hold condition flows out from
the M66515 (in the negative direction).
Power supply
ENB input
S/H input
DATA input
Laser drive current
Hold
Hold
Hold
∆ILD
APC Timing Chart
7. Vcc and GND Pins
Pins related to the power supply function are Vcc 1, Vcc 2,
GND 1, and GND 2. The role of these pins in terms of the in-
ternal circuits are as follows.
Vcc 1, GND 1: connected to analog circuits
Vcc 2, GND 2: connected to digital circuits
In practical wiring, the following should be noted.
(1) Secure as much a width as possible for conductors and
avoid lengthy wiring.
(2) Allocate electrolytic capacitors for stable voltage near
vcc1 and GND 1.
(3) Allocate by-pass capacitors near Vcc2 and GND 2.
Notes on the Wiring for Peripheral Components
Lay out peripheral components necessary for the M66515 to
operate in closest possible proximity to the M66515.
Calculation Method for Power Dissipation
The approximate power dissipation, P, of the M66515FP is
determined by the following equation.
P = Icc × Vcc + I (RO) × V (RO) + I (LD) × V (LD) where V (RO):
voltage at RO pin
V (LD) : voltage at LD pin
I (RO) : load current at RO pin
I (LD) : load current at LD pin
If, for example, Vcc = 5.25V, V (RO) = V (LD) = 2.5V, and I (RO) =
I (LD) = 150mA, power dissipation at times of turning laser on
and off will be as follows.
(1) Laser ON (DATA = “L” and Icc = 75mA)
PON = 75 × 5.25 + 0 + 150 × 2.5 = 768.8 (mW)
(2) Laser OFF (DATA = “H” and Icc = 74mA)
POFF = 74 × 5.25 + 150 × 2.5 + 0 = 763.5 (mW)
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