vt5376 STMicroelectronics, vt5376 Datasheet - Page 15

• Manufacturer Part Number: vt5376
• Description: Ultra-low Power Laser Motion Sensor For Laser Mouse Applications
• Manufacturer: STMicroelectronics

VT5376
6
6.1
Figure 9.
A : LASER system driven by internal DAC
A : LASER system driven by internal DAC
BOBCAT_ASIC
A : LASER system driven by internal DAC
A : LASER system driven by internal DAC
BOBCAT_ASIC
BOBCAT_ASIC
LASER_OUT
LASER_NEN
LASER_OUT
LASER_OUT
LASER_NEN
LASER_NEN
LASER_OUT
LASER_NEN
VT5376
laser_selected = 1
laser_selected = 1
laser_selected = 1
laser_selected = 1
RBIN
RBIN
RBIN
RBIN
Laser
Direct laser drive and calibration
The sensor includes a 7-bit DAC and an output current source.
The DAC value must be set via two I2C commands after power-up (default is MIN = 3.4 mA,
with Rbin = 12 K).
To allow VCSEL output power measurements to be done, the user can set the laser out
(normally strobed during operation) to continuously on via an I2C command. This feature is
optional and is designed to offer maximum flexibility.
Alternatively, the user may be satisfied with adjusting the external Rbin resistor to control the
DAC current away from the nominal max value of 10mA (max 13mA). Rbin must be set to
12K nominally. Idac max is set by the formula:
Idac (max) = 120/Rbin (result in mA, Rbin in kohms)
No external driver is required, just a FET power switch controlled by LASER_NEN signal.
Application schematics using Laser or LED
(driven with internal DAC or external current source)
VTOP
VTOP
VTOP
VTOP
laser
laser
laser
laser
B : LED system driven by internal DAC
LASER_OUT
LASER_NEN
VT5376
laser_selected = 0
led_dac_drive = 1
RBIN
VTOP
LED
C : LED system driven with external drive
C : LED system driven with external drive
C : LED system driven with external drive
C : LED system driven with external drive
36X trk_led (active high)
as trk_led (active high)
as trk_led (active high)
as trk_led (active high)
BOBCAT_ASIC
BOBCAT_ASIC
BOBCAT_ASIC
laser_selected = 0
led_dac_drive = 0
laser_selected = 0
led_dac_drive = 0
laser_selected = 0
led_dac_drive = 0
laser_selected = 0
led_dac_drive = 0
LASER_OUT
LASER_NEN
LASER_OUT
LASER_NEN
LASER_OUT
LASER_OUT
LASER_NEN
LASER_NEN
VT5376
RBIN
RBIN
RBIN
RBIN
VLED
VLED
VLED
VLED
Laser
15/24
LED
LED
LED
LED