DC2319A - Demo Manual

DEMO MANUAL DC2319A
LTC6363
Fully Differential Amplifier
Description
The LTC®6363 is a low power, low noise differential op amp
with rail-to-rail output swing and good DC accuracy. The
amplifier may be configured to process a fully differential
input signal or to convert a single-ended input signal to
a differential output signal. The differential outputs of the
DC2319A can be configured with a first order RC network
for driving the differential inputs of an ADC. The DC2319A
can be DC-coupled or AC-coupled. Onboard jumpers configure the DC2319A for dual or single power supply. In
addition, there are multiple optional surface-mount pads
that can be used to change the LTC6363 configuration.
Design files for this circuit board are available at
http://www.linear.com/demo/DC2319A
L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear
Technology Corporation. All other trademarks are the property of their respective owners.
Table 1. LTC6363 Versions
PART NUMBER
DEMO CIRCUIT NUMBER
DESCRIPTION
LTC6363
DC2319A-A
Gain Set with External Resistors
LTC6363-1
DC2319A-B
Internal Gain Resistors G = 1
LTC6363-2
DC2319A-C
Internal Gain Resistors G = 2
LTC6363-05
DC2319A-D
Internal Gain Resistors G = 0.5
Quick Start Procedure
Refer to Figure 1a. Check to ensure that both jumpers, JP1
and JP2, are set as shown. (JP1 to PWR_ON and JP2 to
SINGLE SUPPLY). Power up the DC2319A from a single
power supply, V+ = 5V and GND = 0V. Connect VIN– to
ground using E8. Connect an input voltage to VIN+ using
E7. The differential output voltage can then be measured
on VOUT– and VOUT+ (E9 and E10). The outputs will be
level-shifted to be balanced symmetrical around approximately 2.5V. The difference between the outputs will be
the gain multiplied by the difference between the inputs.
For a similar setup using a split supply, change the setting
of JP2 to DUAL SUPPLY, and connect a negative supply
to V–. See Figure 1b.
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DEMO MANUAL DC2319A
Quick Start Procedure
Figure 1a. DC2319A Connection Diagram (Single Supply)
Figure 1b. DC2319A Connection Diagram (Dual Supply)
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DEMO MANUAL DC2319A
hardware Configuration
Internal or External Gain Settings
Table 1 summarizes the gain settings for the various versions of DC2319A.
The LTC6363 (without suffix) is a non-committed op amp,
which requires external feedback resistors to configure the
gain. On the DC2319A-A, these resistors (R1, R2, R3, R4)
are all set to 1k to configure a gain of G = 1, as shown in
Figure 2. To set other gains, simply replace these resistors
with other values.
The versions of LTC6363 with suffix (LTC6363-1,
LTC6363-2, LTC6363-05) include precision gain resistors
internal to the IC. The IC already sets its own gain, to
G = 1, G = 2 and G = 0.5 respectively, according to the suffix
(see Table 1). Therefore, on DC2319A-B, DC2319A-C and
DC2319A-D, the onboard feedback resistors (R3, R4) are
not populated, and the input resistors (R1, R2) are shorted
to 0Ω, resulting in the circuit of Figure 3.
VIN+
VIN+
R2, 1k
V+
R4, 1k
V+
EXT
VOCM
VIN–
R1, 1k
+ –
EXT
VOCM
VOUT–
LTC6363
– +
V–
R3, 1k
VOUT–
LTC6363-X
– +
VOUT+
V–
VOUT+
VIN–
DC2319A F02
+ –
DC2319A F03
Figure 3. DC2319A-B/-C/-D with Gain Setting Resistors
Internal to the IC (LTC6363-1/-2/-05)
Figure 2. DC2319A-A with External Gain Setting Resistors (LTC6363)
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DEMO MANUAL DC2319A
hardware Configuration
Single-Ended Input to Differential Output
Input or Output Filters
To configure the DC2319A for single-ended input to
differential output, simply connect a DC bias (such as
ground) to VIN– and connect the input signal to VIN+.
The differential output is measured on VOUT+ and VOUT–.
The unused input can also be grounded on the board by
populating R13 or R14.
There are many 0Ω resistors and non-installed resistors or
capacitors on the DC2319A board which can be populated
by appropriate R and C values to configure lowpass filters
at the inputs or outputs of the amplifier circuit.
Differential Input to Differential Output
To configure the DC2319A for differential input to differential output, simply connect the differential input signal
to VIN+ and VIN– respectively. The differential output is
measured on VOUT+ and VOUT–.
AC-Coupled Applications
In the default configuration, both the inputs and outputs of
the DC2319A are DC-coupled. To AC-couple the DC2319A,
at either the inputs or outputs or both, simply replace
the 0Ω resistors R5/R6/R11/R12 with appropriate value
0603 capacitors.
External Output Common Mode Adjust
The DC2319A is by default configured to bias the output
common mode at the voltage determined by the LTC6363
IC, which is at approximately the mid-point between the
amplifier’s V+ and V– pins. (For example, if single supply
is used, the output common mode will be at half the V+
voltage).
To set a different value for the output common mode
voltage, populate resistors R15 and R16. This will form a
resistor divider in parallel with the resistor divider internal
to the LTC6363 IC.
The most accurate way to set the output common mode
voltage is by applying the desired DC bias to the EXT
VOCM pin at E5. This will overdrive any of the on-chip or
onboard resistor dividers.
Active Feedback Filters
Various optional feedback components (such as R17,
R18, C15, C16, C17, C18) can be populated to configure
differential active feedback filters. This is most relevant
for the DC2319A-A (the version of LTC6363 without internal gain suffix). The other versions (with internal gain
resistors) do not provide access to the internal amplifier
feedback nodes, so that it is not possible to configure
external feedback filters. See Table 1.
Layout
The DC2319A PCB layout demonstrates the known bestpractices of PCB layout to get the best performance out of
the LTC6363. A ground plane is used, and supply bypass
capacitors are close to the supply pins. Use a symmetrical
layout around the analog inputs and outputs to minimize
the effects of parasitic elements. Shield analog input and
output traces with ground to minimize coupling from other
traces. Feedback traces are as short as possible.
Nevertheless, the DC2319A is a general purpose applications board with many placeholders for optional
components. After proto-typing a specific design on the
DC2319A, a final PCB layout can be further optimized by
removing the placeholders for the unused components. In
addition, the DC2319A is designed to accommodate both
single supply and dual supply circuits. A PCB design for
a single supply application would connect the amplifier’s
V– pin directly to the copper ground plane and use only one
supply bypass capacitor directly between V+ and ground.
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DEMO MANUAL DC2319A
Connectors and Jumpers
JP1: Jumper toggles the LTC6363 between SHDN and
PWR ON.
JP2: Jumper toggles the SUPPLY between DUAL and
SINGLE power supplies. If set to dual supply, connect a
negative supply voltage to V–.
V+: Connect to Positive Power Supply.
GND: Connect to Ground. Available at multiple turrets
on the board, all shorted together internally. Only need
to connect one, others can be used as ground point for
measurements.
V–: Negative Power Supply Voltage. No need to connect
if JP2 is set to single supply.
EXT SHDN: Externally Drives the SHDN Pin. No need to
connect. To turn the amplifier ON and OFF with a logic
signal, remove JP1 (or set to the PWR ON position) and
then connect an external logic signal here to EXT SHDN.
(See LTC6363 data sheet for logic levels)
EXT VOCM: Externally Drives the VOCM Pin. The voltage
on this pin sets the output common mode voltage level.
If left floating (default setting), then an internal resistor
divider develops a voltage that is approximately mid-way
between the LTC6363 V+ and V– supply rails.
VIN+: Connect noninverting input signal to the amplifier
circuit. Available as SMA connector J1 and as turret E7.
VIN–: Connect inverting input signal to the amplifier circuit.
Available as SMA connector J2 and as turret E8.
VOUT–: Measure inverting output signal from the amplifier
circuit. Available as SMA connector J3 and as turret E9.
VOUT+: Measure noninverting output signal from the
amplifier circuit. Available as SMA connector J4 and as
turret E10.
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DEMO MANUAL DC2319A
Parts List
ITEM
QTY
REFERENCE
PART DESCRIPTION
MANUFACTURER/PART NUMBER
Required Circuit Components
1
2
C1, C2
CAP, 0.1µF, X7R, 25V, ±10%, 0805
MURATA, GRM21BR71E104KA01L
2
2
C3, C4
CAP, 4.7µF, X5R, 16V, ±20%, 0805
TAIYO YUDEN, EMK212ABJ475MG-T
3
4
C5, C6, C7, C8
CAP, 0.1µF, X7R, 16V, ±10% 0603
AVX, 0603YC104KAT
4
0
C9 TO C18
CAP, 0603
OPT
5
10
E1 TO E10
TP, TURRET, 0.064" MTG HOLE
MILL-MAX, 2308-2-00-80-00-00-07-0
6
2
JP1, JP2
HEADER, 3PIN 1 ROW 0.079CC
SULLINS, NRPN031PAEN-RC
7
2
JP1, JP2
SHUNT, 0.079" CENTER
SAMTEC, 2SN-BK-G
8
4
J1, J2, J3, J4
CONN SMA 50Ω EDGE-LAUNCH
E.F. JOHNSON 142-0701-851
9
0
R13, TO, R18
RES, 0603
OPT
10
8
R5 TO R12
RES, 0Ω, 1/10W, 1%, 0603
NIC, NRC06ZOTRF
DC2319A-A Required Circuit Components
1
1
DC2319A-1 GENERAL BOM
2
4
R1, R2, R3, R4
RES, 1k, 1/10W 1%, 0603
NIC, NRC06F1001TRF
3
1
U1
I.C., FULLY DIFFERENTIAL AMPLIFIER
I.C., LINEAR TECHNOLOGY LTC6363CMS8 #PBF
DC2319A-B Required Circuit Components
1
1
DC2319A-1 GENERAL BOM
2
2
R1, R2,
RES, 0Ω, 1/10W, 1%, 0603
NIC, NRC06ZOTRF
3
0
R3, R4
RES, 0603
OPT
4
1
U1
I.C., FULLY DIFFERENTIAL AMPLIFIER
I.C., LINEAR TECHNOLOGY LTC6363CMS8-1 #PBF
DC2319A-C Required Circuit Components
1
1
DC2319A-1 GENERAL BOM
2
2
R1, R2,
RES, 0Ω, 1/10W, 1%, 0603
NIC, NRC06ZOTRF
3
0
R3, R4
RES, 0603
OPT
4
1
U1
I.C., FULLY DIFFERENTIAL AMPLIFIER
I.C., LINEAR TECHNOLOGY LTC6363CMS8-2 #PBF
DC2319A-D Required Circuit Components
1
1
DC2319A-1 GENERAL BOM
2
2
R1, R2,
RES, 0Ω, 1/10W, 1%, 0603
NIC, NRC06ZOTRF
3
0
R3, R4
RES, 0603
OPT
4
1
U1
I.C., FULLY DIFFERENTIAL AMPLIFIER
I.C., LINEAR TECHNOLOGY LTC6363CMS8-05 #PBF
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6
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 representation that the interconnection of its circuits as described herein will not infringe on existing patent rights.
D
C
B
A
V+
E1
E3
1
R6
0
R5
0
R14
OPT
R13
OPT
C3
4.7uF
R8
0
R7
0
V-
V-
U1
1
2
OPT
-D
OPT
LTC6363CMS8-2
-C
0 Ohms
LTC6363CMS8-1
LTC6363CMS8-05 0 Ohms
1K
R3, R4
OPT
1K
R1, R2
0 Ohms
LTC6363CMS8
-B
-A
ASSY
*
U1
R17
OPT
* 1KR1
OPT
C17
1K
*R3
OPT
C9
OPT
C18
* R4
1K
CUSTOMER NOTICE
OPT
C14
LTC6363CMS8
*
* 1KR2
OPT
R18
C16
OPT
C15
OPT
4
C10
OPT
3
4
THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND
SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS.
5
5
SCALE = NONE
KL
NC
JP1
C6
0.1uF
SHDN
R10
0
0
R9
1
R16
OPT
R15
OPT
DATE:
N/A
SIZE
6
9 - 08 - 14
IC NO.
E5
C13
OPT
SINGLE
EXT
VOCM
JP2
SUPPLY
DUAL
R12
0
R11
0
KL
VOUT-
J4
1
VOUT+
E10
J3
1
DATE
9 - 08 - 14
GND
E9
E6
APPROVED
8
7
LTC6363CMS8
DEMO CIRCUIT 2319A
SHEET
FULLY DIFFERENTIAL AMPLIFIER
8
1
OF
1
1
REV.
1630 McCarthy Blvd.
Milpitas, CA 95035
Phone: (408)432-1900 www.linear.com
Fax: (408)434-0507
LTC Confidential-For Customer Use Only
C12
OPT
C11
OPT
PROTOTYPE
DESCRIPTION
7
REVISION HISTORY
TECHNOLOGY
V-
REV
V+
PWR_ON
-
ECO
6
TITLE: SCHEMATIC
C7
0.1uF
C8
0.1uF
C5
0.1uF
E4
EXT
SHDN
APPROVALS
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.
1. ALL RESISTORS ARE IN OHMS, 0603
ALL CAPACITORS ARE IN MICROFARADS, 0603
NOTE : UNLESS OTHERWISE SPECIFIED
J2
VIN-
E8
J1
1
E7
C4
4.7uF
GND
0805
C1
0.1uF
0805
E2
0805
C2
0.1uF
GND
MAX ± 6V
0805
VIN+
V+
3
GND
2
1
5
4
3
2
5
4
3
2
8
IN+
IN-
7
SHDN
VOCM
2
6
VV+
3
5
OUTOUT+
4
2
3
4
5
2
3
4
5
1
D
C
B
A
DEMO MANUAL DC2319A
Schematic Diagram
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DEMO MANUAL DC2319A
DEMONSTRATION BOARD IMPORTANT NOTICE
Linear Technology Corporation (LTC) provides the enclosed product(s) under the following AS IS conditions:
This demonstration board (DEMO BOARD) kit being sold or provided by Linear Technology is intended for use for ENGINEERING DEVELOPMENT
OR EVALUATION PURPOSES ONLY and is not provided by LTC for commercial use. As such, the DEMO BOARD herein may not be complete
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
directive on electromagnetic compatibility and therefore may or may not meet the technical requirements of the directive, or other regulations.
If this evaluation kit does not meet the specifications recited in the DEMO BOARD manual the kit may be returned within 30 days from the date
of delivery for a full refund. THE FOREGOING WARRANTY IS THE EXCLUSIVE WARRANTY MADE BY THE SELLER TO BUYER AND IS IN LIEU
OF ALL OTHER WARRANTIES, EXPRESSED, IMPLIED, OR STATUTORY, INCLUDING ANY WARRANTY OF MERCHANTABILITY OR FITNESS
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ANY INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES.
The user assumes all responsibility and liability for proper and safe handling of the goods. Further, the user releases LTC from all claims
arising from the handling or use of the goods. Due to the open construction of the product, it is the user’s responsibility to take any and all
appropriate precautions with regard to electrostatic discharge. Also be aware that the products herein may not be regulatory compliant or
agency certified (FCC, UL, CE, etc.).
No License is granted under any patent right or other intellectual property whatsoever. LTC assumes no liability for applications assistance,
customer product design, software performance, or infringement of patents or any other intellectual property rights of any kind.
LTC currently services a variety of customers for products around the world, and therefore this transaction is not exclusive.
Please read the DEMO BOARD manual prior to handling the product. Persons handling this product must have electronics training and
observe good laboratory practice standards. Common sense is encouraged.
This notice contains important safety information about temperatures and voltages. For further safety concerns, please contact a LTC application engineer.
Mailing Address:
Linear Technology
1630 McCarthy Blvd.
Milpitas, CA 95035
Copyright © 2004, Linear Technology Corporation
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Linear Technology Corporation
LT 0915 • PRINTED IN USA
1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408) 432-1900
●
FAX: (408) 434-0507 ● www.linear.com
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