Analog Devices Linear Technology DC2692A Quick setup guide

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dc2692af
DEMO MANUAL DC2692A
DESCRIPTION
LTC2662
5-Channel, 16-/12-Bit, 300mA,
SoftSpan Current Source DACs
Demonstration circuit 2692A-A features the LT C
®
2662,
5-channel, 16-bit, 300mA, current source DACs with
10ppm/°C reference in a 5mm × 5mm QFN package.
Thisdevice features per-channel SoftSpan™configura-
tion of 3.125mA to 300mA, a separate supply for each
output, and an internal switch to allow any output pin to
be connected to V–.
L, LT, LTC, LTM, Linear Technology, the Linear logo and Linduino are registered trademarks
and QuikEval and SoftSpan are trademarks of Analog Devices, Inc. All other trademarks are the
property of their respective owners.
Pin-compatible 12-bit versions are available for lower
resolution requirements on the DC2692A-B.
Design files and Bill of Materials for this circuit board
are available at http://www.linear.com/demo/DC2692A
Figure 1. Connection Diagram

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DEMO MANUAL DC2692A
1. Download and install QuikEval™ from:
http://www.linear.com/quikeval
2. Connect a DC590 controller or DC2026 Linduino
®
with
the DC590 emulator firmware to the DC2692A with the
supplied ribbon cable.
3. Connect low noise analog power supplies as shown
in Figure 1. Refer to the data sheet for other supply
options.
4. Connect the controller to the host PC’s USB port and
run QuikEval. The DC2692A software will be down-
loaded and installed, after which the GUI will appear
ASSEMBLY TYPE PART NUMBER DAC CHANNELS BITS
MAX CURRENT PER
CHANNEL
DC2692A-A LTC2662-16 5 16 300mA
DC2692A-B LTC2662-12 5 12 300mA
as shown in Figure 2. The control panel gives access
to all of the LTC2662’s functionality including per-
channel SoftSpan ranges, toggling, power-down, etc.
Detailed instructions are provided in the Help menu.
Using External Reference for the DC2692
To use an external reference to drive the DC2692, move
the jumper named REF SEL (JP1) from the INT posi-
tion to the EXT position. Use the REF turret to drive the
reference voltage. If this is done after the DC2692 was
powered up, then the internal reference will need to be
disabled from the control register.
QUICK START PROCEDURE
ASSEMBLY OPTIONS
Figure 2. Main Control Panel

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DEMO MANUAL DC2692A
Using External Precision Resistor to Adjust
Full‑ScaleOutput Current
The DC2692 has an unstuffed resistor (R4) that can be
used to set and adjust the full-scale output current. Move
the jumper named FS ADJ (JP2) from INT to EXT. It is
recommended to use a resistor with better than 2ppm/°C
temperature coefficient to take advantage of the LTC2662
low temperature coefficient. Values between 19k and 50k
can be used for the precision resistor.
Using External Supplies for VDDx
The DC2692 can be configured to connect different sup-
plies than V+. Move the jumper labeled VDDx from V+to
EXT and connect the low noise supply to the correspond-
ing VDDx turret.
Connectors and Turrets
J1:Interface connector to DC590 controller or Lin-
duinoprovides IOVCC power, SPI interface, and board
identification.
V
–
, GND, V
+
:Analog supplies, connected to the LTC2662
V+and V–pins. Nominally positive supply should be 7V
to 33V and negative supply should be 0V to –15V. Refer
to the data sheet for other supply configurations.
GND: Additional ground posts and exposed ground plane
around the board edge allow solid connection to prototype
circuitry and measurement equipment.
VCC:Analog supply voltage. Normally supplied by an
onboard LT3042 regulator set to 5V that is powered from
the V+supply. For single supply applications, VCC may be
tied directly to V+and supplied with 2.85V to 5.5V.
VDD0 to VDD4:Output supply voltage. A jumper is used to
connect the output supply to V
+
. Placing the jumper in the
EXT position allows the output supply voltage channel to
be connected externally to this point.
REF:Connection to the REF pin. In internal reference
mode, the reference voltage may be monitored at this
point. Placing REF SEL jumper in EXT position allows an
external low noise reference to be connected to this point.
Refer to the data sheet for compatible voltages.
MUX:Monitor Mux output. Allows surveying the DACout-
puts under software control. Must be measured with a high
impedance meter (output impedance is nominally10kΩ).
OUT0 – OUT4: DAC outputs.
CLR:Asynchronous clear input (pulled high to IOVCC with
a 5k resistor). Pull to the ground to reset the DAC to the
power-on reset value.
TGP:Toggle input (pulled high to IOVCC with a 5k resis-
tor). A high level on this pin enables software toggling.
See data sheet for a complete description of toggle
operation.
LDAC:Asynchronous DAC update. If CS/LD is high at the
falling edge of LDAC, DAC outputs will be updated with
the contents of the input registers. If CS/LD is low when
LDAC goes low, the DAC registers are updated after CS/
LD returns high.
FAULT:Fault detection pin (pulled high to IOVCC with a
5k resistor). The LTC2662 pulls this pin low if a fault is
detected. It is released on the next rising edge of CS/LD.
Jumpers
REF SEL (JP1): Selects internal or external reference
mode.
FS ADJ (JP2): Sets the full-scale current for the DACs.
Ensure FS ADJ is set to EXT position when using an exter-
nal precision resistor.
V
DD0
, V
DD1
, V
DD2
, V
DD3
, V
DD4
(J3, J4, J5, J6, J7): Select
the output supply voltages for the DACs to be either V+or
external via the turret.
LEDs
FAULT:Lights when FAULT pin asserts, indicating a fault
has occurred. (Note that LED will light if positive analog
supply is present and IOVCC is not. IOVCC is normally
supplied by the controller.)
Test Points
The SPI bus is available on a row of through-hole test
points next to J1 that may be used to monitor the bus or
drive the bus with an external controller.
EEGND, WP: For factory use only.
QUICK START PROCEDURE

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DEMO MANUAL DC2692A
 LINEAR TECHNOLOGY CORPORATION 2017
LT 0817 • PRINTED IN USA
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This demonstration board (DEMO BOARD) kit being sold or provided by Linear Technology is intended for use for ENGINEERING DEVELOPMENT
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in terms of required design-, marketing-, and/or manufacturing-related protective considerations, including but not limited to product safety
measures typically found in finished commercial goods. As a prototype, this product does not fall within the scope of the European Union
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