DC590A-1 Datasheet, PDF (5/9 Pages) Linear Integrated Systems – QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 590 USB SERIAL CONTROLLER FOR LINEAR TECHNOLOGY QUICKEVAL-TM DEMO BOARDS

QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 590
USB SERIAL CONTROLLER FOR LINEAR TECHNOLOGY QUICKEVAL™ DEMO BOARDS
LED INDICATORS
Two LED indicators are provided. The “ISOL PWR” LED
is lit when either the onboard switching power supply is
running or external power is applied to the isolated side
of the board.
The “COMMAND” LED indicates that a command has
been sent to the board by the host PC and is waiting to
be executed. The LED may not appear to be blinking in
some cases, as the duty cycle may be very short.
CIRCUIT DETAILS
Schematics for the isolated power supply and optical
signal isolation are attached to the end of this Quick
Start Guide. Example microcontroller code is device-
specific, and may be included in the Quick Start Guide
for the demonstration circuit under evaluation.
OPTICAL ISOLATION
The optical isolation scheme based on the Agilent HCPL
2300 high speed opto isolator and is designed to allow
bidirectional SPI and I²C communications. Isolation
schemes that are designed for only SPI or I²C will differ
slightly. Contact Linear Technology Applications Engi-
neering for more information.
SWITCHING POWER SUPPLY
The onboard switching supply is based on the LT1425
flyback regulator. Feedback is taken from the primary
side of T1, eliminating the need for optical feedback. T2
and C9 provide common mode filtering. Refer to the
LT1425 data sheet for details of operation.
TROUBLESHOOTING GUIDE
Problem: DC590 is plugged in, but QuickEval screen
still says “USB Serial Controller Not Connected”
Solution: The most likely cause is improper installa-
tion of the USB drivers, which causes Windows to rec-
ognize DC590 as an “Unknown Device.” Open the Win-
dows Control Panel, open “System” and click the “De-
vice manager” tab. Open the “Other Devices” item and
look for USB SERIAL CONTROLLER. Select this item and
click the remove button. Unplug DC590, Re-install the
QuickEval software, and follow the on-screen instruc-
tions.
Problem: Demo board software loads properly, but will
not run or gives “Device Not accessible” errors.
Solution: Verify that the demo board is properly
powered up. This Quick Start Guide lists the basic power
connections to DC590. Some demo boards may have
additional requirements; refer to the demo board’s Quick
Start guide for details.
Problem: After connecting the demo board to DC590
with the supplied 14 pin ribbon cable, QuickEval soft-
ware still displays “Evaluation Board is not Connected.”
Solution: Contact Linear Technology Applications
Engineering.
5