3
dc590bf
DEMO MANUAL DC590B
connections to the Dc590B
Figure 1 shows the connections to the DC590B. In most
cases, DC590B and the demonstration circuit under evalu-
ation can operate from available USB power, and thus
require nothing more than a USB connection to the host
PC and a ribbon connecting DC590B to the demo circuit
under evaluation. The DC590B offers several other power
options, as described in the following text.
Isolated Supply Options
An LT3439 low noise switching power supply provides
isolated power to the demonstration circuit under evalua-
tion and to the isolation circuitry. This is adequate in many
cases, however an external power supply is recommended
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 allows the isolated side of the
board and the demonstration 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 supply from 7V to 10V to the V
+
and AGND turret posts.
Isolated Digital Supply
The signal levels on the digital interface are determined
by the VCCA voltage. The onboard regulator can be set
to 5V, 3.3V and 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 2.7V
and 5V must be applied to the VCCA turret post.
The +5V turret is the digital supply for the isolated portion
of DC590B. Do not draw current from this point.
LED Indicators
Tw o LED indicators are provided. The ISO 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 ex-
ecuted. The LED may not appear to be blinking in some
cases, as the duty cycle may be very short.
Jumper Summary
Some jumpers on the DC590B board are for future use
and MUST be left in the default positions.
JUMPER POSITION FUNCTION
JP1 PROG Microcontroller in-circuit programming
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.
See Connections section.
ISO
(Left-hand side)
Controls the isolated supply.
See Connections section.
JP6 VCCA Control See Connections section
