Linear Technology DC1427A User manual

QUICK START GUIDE FOR DEMONSTRATION CIRCUIT DC1427A
I2C/SMBUS/PMBUS CONTROLLER
1
DESCRIPTION
Demonstration circuit 1427A is a USB-based con-
troller with generic Inter Integrated Circuit (I
2
C )
ports. It is designed to mate with Linear Technol-
ogy’s family of LT Powerplay demonstration
boards. The demo board is fully isolated from the
host PC’s ground. The evaluation software auto-
matically detects which demo board is connected
and loads the appropriate control screen.
The LT Powerplay system provides a quick and
easy way to evaluate the performance of a wide
variety of Linear Technology’s products.
LT Powerplay is a trademark of Linear Technology Corporation; I
2
C is a
trademark of Philips Electronics N.V.; Ado e is a trademark of Ado e Sys-
tems, Inc.
Figure
FigureFigure
Figure 1.
1.1.
1. Basic Connection
Basic ConnectionBasic Connection
Basic Connections
ss
s
Demo Circuit
Under Evaluation
USB Ca le
To Host PC
ISOLATED
GROUND
Connect 2.7 to
5V Logic supply ONLY IF
VCCIO is set to EXT. See Text.
Connect external 10-12V sup
ply ONLY
IF JP5, ISO is set to OFF. See Text.
Do Not Connect
Isolated Power Supply
(Shown in OFF position)
Select Isolated Supply Volt-
age (2.7V, 3.3V, 5.0V, or
External. Normally, 3.3 V
Do Not Connect

QUICK START GUIDE FOR DEMONSTRATION CIRCUIT DC1427A
I2C/SMBUS/PMBUS CONTROLLER
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QUICK START PROCEDURE
For proper equipment setup, follow the procedure
below:
1.
1.1.
1. Do NOT plug in DC1427A before running the
installation program.
2.
2.2.
2. Download the LT Powerplay installation pro-
gram from
http://www.linear.com/software/.
3.
3.3.
3. Run the LT Powerplay installation program and
follow the on-screen instructions.
NOTE:
NOTE:NOTE:
NOTE: The LT Powerplay demo software requires
a PC that is running Windows XP (or later), and
has an available USB port.
4.
4.4.
4. Connect the demonstration circuit to be evalu-
ated to DCDC1427A using the supplied 14-
conductor ribbon cable. The demo software de-
tects the circuit and starts the appropriate con-
trol screen.
Each demonstration board also comes with a
Quick Start guide similar to this one. For usage
details relevant to a particular circuit refer to its
Quick Start Guide. Additional information and
documentation is available in the help menu.
SOFTWARE TOOLS
SOFTWARE TOOLS SOFTWARE TOOLS
SOFTWARE TOOLS
The LT Powerplay Demo software includes tools
for automatic software updates and for quickly re-
trieving relevant documentation from the World
Wide Web.
NOTE:
NOTE:NOTE:
NOTE: Adobe Acrobat reader is required to view
the documents and is available at
http://www.adobe.com.
To use the tools:
To use the tools:To use the tools:
To use the tools:
 • Quit the demonstration circuit software or dis-
connect the USB cable so that The main control
panel appears:
To
To To
To u
uu
update the software
pdate the softwarepdate the software
pdate the software (requ
(requ (requ
(requires internet
ires internet ires internet
ires internet
connection)
connection)connection)
connection):
::
:
 •
••
• Choose Update from the Tools menu.
This automatically updates the main program
and drivers for individual demo circuits.

QUICK START GUIDE FOR DEMONSTRATION CIRCUIT DC1427A
I2C/SMBUS/PMBUS CONTROLLER
3
CONNECTIONS TO THE DC1427A
Figure 1 shows the connections to the DC1427A.
Refer to the Controlled demo circuit's Quick Start
Guide for additional required connections.
Isolated Suppl O
Isolated Suppl OIsolated Suppl O
Isolated Suppl Options
ptionsptions
ptions
An LT3439 low-noise switching power supply pro-
vides isolated power to the demonstration circuit
under evaluation and to the isolation circuitry. This
is adequate in many cases, however an external
power supply can be used to reduce the load on
the host computer’s USB port or to reduce power
supply noise in the circuit under test.
The LT3439 switching power supply is enabled by
default but may be disabled by moving jumper
JP5 (ISO, to the left) to the OFF position. This al-
lows the isolated side of the board and the dem-
onstration circuit under evaluation to be powered
separately. This is recommended when testing
precision components such as high resolution
ADCs and DACs. After moving JP5 ISO to the
OFF position, apply a clean, regulated power sup-
ply from 7v to 10V to the V+ and AGND turret
posts.
Isolated Digital Suppl
Isolated Digital SupplIsolated Digital Suppl
Isolated Digital Suppl
The signal levels on the digital interface are de-
termined by the VCCA voltage. The onboard regu-
lator can be set to 5V, 3.3V, 2.7V by installing JP6
in the appropriate position (remove jumper for
2.7V.) Selecting EXT shuts the regulator down,
and an external supply between 2.7 and 5V must
be applied to the VCCA turret post.
The +5V turret is the digital supply for the isolated
portion of DC1427A. Do not draw current from this
point
LED Indicators
LED IndicatorsLED Indicators
LED Indicators
Two LED indicators are provided. The “ISO PWR”
LED is lit when either the onboard switching
power supply is running or external power is ap-
plied 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.
J
JJ
Jumper
umper umper
umper S
SS
Summar
ummarummar
ummar
Some jumpers on the DC1427 board are for future
use and MUST be left in the default positions.
JP1 – PROG – Microcontroller in-circuit program-
ming header, do NOT install jumper, make no
connections.
JP2 – MODE – do NOT install jumper, make no
connections.
JP3 – Watchdog enable - do NOT install jumper,
make no connections.
JP4 – EE – Jumper MUST be in the EN position.
JP5 – SW (right-hand side) MUST be in the ON
position. ISO (left-hand side) controls the isolated
supply. See Connections section.
JP6 – VCCA control. See Connections section.

QUICK START GUIDE FOR DEMONSTRATION CIRCUIT DC1427A
I2C/SMBUS/PMBUS CONTROLLER
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TROUBLESHOOTING GUIDE
DC1427A is plugged in, but LT Powerplay screen still says “USB Serial Controller Not Con-
nected”
The most likely cause is improper installation of the USB drivers, which causes Windows to
recognize DC1427A as an “Unknown Device.” Open the Windows Control Panel, open “System” and
click the “Device manager” tab. Open the “Other Devices” item and look for USB SERIAL
CONTROLLER. Select this item and click the remove button. Unplug DC1427, Re-install the LT Power-
play software, and follow the on-screen instructions.
Demo board software loads properly, but will not run or gives “Device Not accessible” errors.
Verify that the demo board is properly powered up. This Quick Start Guide lists the basic
power connections to DC1427. Some demo boards may have additional requirements; refer to the demo
board’s Quick Start guide for details.
Problem
ProblemProblem
Problem
:
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Solution
:
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Problem
ProblemProblem
Problem
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Solution
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QUICK START GUIDE FOR DEMONSTRATION CIRCUIT DC1427A
I2C/SMBUS/PMBUS CONTROLLER
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