
Description (continued)
VT5365
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Description (continued)
The VT5365 has been optimized for low power operation enabling long battery life, achieved
by either a single 1.8V or 2.0 V to 3.2 V supply.
The on-chip regulators allow for a wide range of power supply taken from 2 batteries in
series, enabling a low cost BOM. However, for the most efficient power consumption, the
regulators can be bypassed so that the chip is driven at the minimal supply of 1.8V by an
external power source (typically a DC/DC convertor from a single cell voltage). In both
cases, an on-chip DCDC regulator controls the LED, so that only a single 1.8V supply is
required for the overall application. The supply scheme is selected by connecting an IO to
GND or VDD.
Care has been taken to implement ultra-low power idle/sleep modes with wake-ups at
programmable periods and/or external events enabling very long battery life. It is estimated
that with a typical user and 2 x AA Alkaline batteries configured in parallel a useful battery
lifetime of 9 months can be achieved.
STMicroelectronics default firmware supports 5 buttons, mechanical Z-Wheel, low battery
level detect/indicate output and internal DC/DC controller to supply the navigation LED.
The firmware generates baseband 4.8kbps, Manchester coded data with RF on signal for
standby.
The output can be selected as either baseband RF serial data, or 27.045MHz FSK digitally
modulated signal. In this case, very minimal external circuitry is required for filtering and
amplification, and the overall system can be achieved using a single 12MHz Xtal.
This firmware may be replaced allowing customers to build in their own features for their
particular mouse (including 2 extra GPIO).
The VT5365 sensor will operate over a wide range of illuminant wavelengths and is suitable
for use with visible, IR and laser light sources.
Figure 1.
VT5365 block diagram
TRK_LED
Pixel Array
365 Core
12 MHz
Buttons
Z-wheel
Vdd (1.8V)
LED control
VT5365
Power
SDA
SCL
Optional
Power Management
RFON
RFOUT
X1
X0
GPIO1-7
GPIO 0
LO BATT
SGPIO 0
SGPIO 1
PSU
Select
VGATE
VLED
VHIGH
27MHz
passive LC filter
1.8V Single Stage
amplifier
Single Cell Voltage