DEMO MANUAL DC1678A
LTC2654:
Quad 16-Bit/12-Bit Rail-To-Rail SPI DACs
with 10ppm/°C Max Reference
DESCRIPTION
Demonstration circuit 1678A features the LTC2654 Quad
16-bit/12-bit DAC. The LTC2654 is a family of 16-bit/12-bit
rail-to-rail DACs with integrated 10ppm/°C maximum
reference. The LTC2654 advances performance standards
for output drive, crosstalk and load regulation in single
supply, voltage-output multiple DACs.
Design files for this circuit board are available at
http://www.linear.com/demo
L,
LT, LTC, LTM, μModule, Linear Technology and the Linear logo are registered trademarks of
Linear Technology Corporation. All other trademarks are the property of their respective owners.
TO DC590
ANALOG
OUTPUTS
Figure 1. Connection Diagram
Table 1. LTC2654 Demo board variations
DEMO BOARD TYPE
DC1678A-A
DC1678A-B
DC1678A-C
DC1678A-D
LTC2654 VARIATION
LTC2654CUF-L16
LTC2654CUF-H16
LTC2654CUF-L12
LTC2654CUF-H12
FULL-SCALE VOLTAGE
2.5V
4.096V
2.5V
4.096V
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DEMO MANUAL DC1678A
QUICK START PROCEDURE
Connect the DC1678A to a DC590 USB serial controller
using the supplied 14 conductor ribbon cable. Connect the
DC590 to a host PC with a standard USB A/B cable. Run
the QuikEval evaluation software supplied with the DC590
or download it from www.linear.com. The correct control
panel will be loaded automatically. To update DAC value,
fill in corresponding text box.
Figure 1. Demo Board Setup
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DEMO MANUAL DC1678A
QUICK START PROCEDURE
HARDWARE SET-UP
Jumpers
REF – V
REF
Select. This jumper selects which mode the
LTC2654 powers up in: External reference (EXT) or Internal
reference (INT).
PORSEL – Power Up Mode. The LTC2654 can be set to
either power up in Mid Scale or Zero Scale.
Analog Connections
DAC outputs – The 4 DAC outputs from the LTC2654 are
brought out to turrets labeled VOUTA through VOUTD.
These may be connected to external instruments or other
circuitry.
NOTE: DAC outputs are not in alphabetical order on the
circuit board.
V
REF
– The V
REF
turret is connected directly to the refer-
ence terminals of the LTC2654. The on-chip reference may
be turned off, allowing the DAC reference pin to be driven
from this turret. Alternatively, when the on-chip reference
is on and active, the voltage can be monitored at this turret.
V
+
– Unregulated 10V is present here when a DC590 is
connected. This turret is provided for monitoring purposes
only and should not be connected to any other turrets on
the board.
Grounding and Power Connections
Power (V
CC
) – Normally the DC1678A is powered by
the DC590 controller. V
CC
can be supplied to this turret,
however the power supply on DC590 must be disabled.
Refer to DC590 Quick Start Guide for more details on this
mode of operation.
Grounding – There are 3 ground turrets provided (labeled
GND), as well as ground strips on the top and the bottom
of the board.
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DEMO MANUAL DC1678A
PARTS LIST
ITEM
1
2
3
4
5
6
7
8
QTY
3
1
10
2
1
5
1
2
REFERENCE
C1,C2,C3
C4
E1-E10
JP1,JP2
J1
R1,R2,R3,R4,R5
U2
PART DESCRIPTION
Capacitor, X7R, 0.1μF 16V, 0402
Capacitor, X7R, 0.047μF 16V, 0402
TP Turret, 0.064"
,
Jumper, 3-Pin 1 Row 0.079CC
Header, 2X7 Pin, 0.079CC
Resistor, Chip 4.99k 1/16W 1%, 0402
IC, Serial EEPROM, TSSOP8
MANUFACTURER/PART NUMBER
TDK, C1005X7R1C104K
TDK, C1005X7R1C473K
Mill-Max, 2308-2-00-80-00-00-07-0
Samtec, TMM-103-02-L-S
Molex, 87831-1420
NIC, NRC04F4991TRF
Microchip, 24LC025-I /ST
Samtec, 2SN-BK-G
Linear Technology, LTC2654CUF-L16
Linear Technology, LTC2654CUF-H16
Linear Technology, LTC2654CUF-L12
Linear Technology, LTC2654CUF-H12
Required Circuit Components
Shunts as Shown Shunt, 0.079" Center
on Assy Dwg
U1-A
U1-B
U1-C
U1-D
IC, LTC2654CUF-L16, QFN20UF 4mm
×
4mm
IC, LTC2654CUF-H16, QFN20UF 4mm
×
4mm
IC, LTC2654CUF-L12, QFN20UF 4mm
×
4mm
IC, LTC2654CUF-H12, QFN20UF 4mm
×
4mm
dc1678af
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5
4
3
2
1
REVISION HISTORY
ECO
_
2
PRODUCTION
08-11-10
LEO C.
JP1
REF
VCC
D
E1
C4
0.047uF
1
2
3
JP2
C1
0.1uF
C2 VCC
0.1uF
LDAC CLR
R1
4.99K
R2
4.99K
VCC
VCC
PORSEL
1
MS
2
3
ZS
REV
DESCRIPTION
APPROVED
DATE
VREF
D
INT
EXT
V+ VCC
E2
VCC
SCHEMATIC DIAGRAM
E3
V+
E4
GND
2
4
5
18
12
11
C
LDAC
PORSEL
J1
HD2X7-079-MOLEX
VCC
CLR
REFIN/OUT
CS
SCK
SDI
SDO
GND
REFLO
GND
DNC
DNC
DNC
DNC
VOUTD
14
VOUTC
13
VOUTB
3
REFCOMP
6
VOUTA
7
9
10
1
CS/ CLK SDI SDO
U1
E5
E6
E7
E8
E9
E10
C
GND
VOUTA
VOUTB
VOUTC
VOUTD
GND
V+
5V
1
2
*
21
20
19
17
16
B
GND
GND
GND
C3
0.1uF
15
8
6
CS 4
SCK/SCL 7
MOSI/SDA 5
MISO
10
EEVCC 9
EESDA 11
EESCL 12
EEGND 14
AUX
R3
4.99K
B
13
8
3
1
2
3
4
Information furnished by Linear Technology Corporation is believed to be accurate and reliable.
However, no responsibility is assumed for its use. Linear Technology Corporation makes no representa-
tion that the interconnection of its circuits as described herein will not infringe on existing patent rights.
U2
24LC025-I /ST
8
A0 VCC
7
A1
WP
6
A2 SCL
5
VSS SDA
R4
R5
4.99K 4.99K
*
APPROVALS
KT
LEO C.
ASSY
-A
-B
-C
-D
U1
LTC2654CUF-L16
LTC2654CUF-H16
LTC2654CUF-L12
LTC2654CUF-H12
-BIT
16
16
12
12
CUSTOMER NOTICE
NOTES: UNLESS OTHERWISE SPECIFIED
TECHNOLOGY
TITLE: SCHEMATIC
1630 McCarthy Blvd.
Milpitas, CA 95035
Phone: (408)432-1900
www.linear.com
Fax: (408)434-0507
LTC Confidential-For Customer Use Only
A
A
1. ALL RESISTORS ARE IN OHMS, 0402.
ALL CAPACITORS ARE IN MICROFARADS, 0402.
2. INSTALL SHUNTS AS SHOWN.
LINEAR TECHNOLOGY HAS MADE A BEST EFFORT TO DESIGN A
CIRCUIT THAT MEETS CUSTOMER-SUPPLIED SPECIFICATIONS;
HOWEVER, IT REMAINS THE CUSTOMER'S RESPONSIBILITY TO PCB DES.
VERIFY PROPER AND RELIABLE OPERATION IN THE ACTUAL
APP ENG.
APPLICATION. COMPONENT SUBSTITUTION AND PRINTED
CIRCUIT BOARD LAYOUT MAY SIGNIFICANTLY AFFECT CIRCUIT
PERFORMANCE OR RELIABILITY. CONTACT LINEAR
TECHNOLOGY APPLICATIONS ENGINEERING FOR ASSISTANCE.
QUAD 12/16-BIT RAIL-TO-RAIL SPI DAC
WITH 10ppm/
O
C MAX REFERENCE
SIZE
IC NO.
REV.
N/A
SCALE = NONE
3
THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND
SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS.
4
LTC2654CUF FAMILY
DEMO CIRCUIT 1678A
DATE:
Wednesday, August 11, 2010
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DEMO MANUAL DC1678A
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