DC1833A - Demo Manual

DEMO MANUAL DC1833A
LTC6362
Fully Differential Amplifier
DESCRIPTION
The LTC®6362 is a low power, low noise differential op amp
with rail-to-rail input and output swing that has been
optimized to drive low power SAR ADCs. The amplifier may
be configured to buffer a fully differential input signal or
convert a single-ended input signal to a differential output
signal. Demo circuit 1833A contains the LTC6362 amplifier
configured as a unity gain amplifier with 1kΩ feedback
and input resistors, where both inputs are AC-coupled by
a 1μF capacitor. The differential outputs of the DC1833A
can be configured with a first order RC network for driving
PERFORMANCE SUMMARY
differential input, as given in Table 1. (TA = 25°C)
the differential inputs of an ADC. The LTC6362 differential
output can be DC-coupled or AC-coupled (AC-coupled is
the default configuration). Onboard jumpers configure
the DC1833A for dual or single power supply. In addition,
there are several optional surface mount pads that can be
used to change the LTC6362 configuration.
Design files for this circuit board are available at
http://www.linear.com/demo
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.
This demo board is factory tested by measuring distortion with an 8VP-P, 2kHz
Table 1. LTC6362 Noise and Distortion
Differential Input, Referred Noise Voltage Density
3.9nV/√Hz
Distortion, 8VP-P Differential Input, VS = 5V, FIN = 2kHz, RLOAD = 1000Ω
2nd Harmonic
3rd Harmonic
–128dBc
–114dBc
2kHz Sine Wave,
VIN Diff 8VP-P 16384 –Point FFT
R6, 1k
R3, 1k
V+ 0.1μF
– +
VOCM
0.1μF
VIN+
R5, 1k
R15
LTC6362
+ –
C18
CDIFF R14
C19
C15
VOUT+
VOUT–
R4, 1k
DC1833A F01a
MAGNITUDE (dB)
VIN–
0
–10
–20
–30
–40
–50
–60
–70
V+ = 5V
V– = 0V
HD2 = –128dBc
HD3 = –114dBc
–80
–90
–100
–110
–120
–130
–140
–150
0
2
4
6
8
10 12 14
FREQUENCY (kHz)
16
18
20
DC1833A FO1b
Figure 1. Typical Application for an LTC6362
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DEMO MANUAL DC1833A
QUICK START PROCEDURE
Check to ensure that both jumpers, JP1 and JP2, are set as
shown in Figure 2. Power the DC1833 from a single power
supply, V+ = 5V and V– = 0V. For distortion measurements,
a low noise, low distortion generator and an analyzer such
as Audio Precision SYS-2722 or Stanford Research SR1
should be used with the LTC6362 configured as shown in
Figure 1, the resulting distortion for an 8VP-P sine wave
input is shown in the FFT plot.
5V POWER SUPPLY
+
–
AUDIO PRECISION SYS - 2722
ANALOG GENERATOR
ANALOG OUTPUT A+
ASIN(WT)
VIN
2kHz
8VP-P
–ASIN(WT)
COMPUTER
–DISPLAY AP SYS-2722
RESULTS
ANALOG ANALYZER
+INPUT
–INPUT
ANALOG OUTPUT A–
DC1833A F02
USB CABLE
Figure 2. DC1833A Connection Diagram
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DEMO MANUAL DC1833A
QUICK START PROCEDURE
Single-Ended to Differential Output
Definitions
The DC1833A can be configured for single-ended input
to differential output by populating R1 with 0Ω, removing
C1, and replacing C8 with a 0Ω resistor. In this configuration, the input, J2, is now DC-coupled to the LTC6362
input. The differential output is AC-coupled in the default
setting. Driving the single-ended input of the LTC6362 at
full scale 10VP-P, each output will swing from 0.5V to 4.5V
when configured with gain of AV = –0.8 (AV = –0.8 is set
by changing the R5 and R6 values to 1.25k).
JP1: Toggles the LTC6362 ON and OFF. Part ON is the
default setting.
Differential Input to Differential Output
E3: Negative Power Supply Voltage, V–. In the default
configuration V– is tied to Ground.
Populate C1 and C8 pads with 0Ω resistors to set the
differential input mode.
DC-Coupled Output
The DC1833 is configured for an AC-coupled output via C16
and C17. For DC-coupled output, replace these capacitors
with 0Ω resistors.
Layout
A ground plane is necessary to obtain maximum performance. Keep bypass capacitors as close to supply pins
as possible. Use individual low impedance returns for all
bypass capacitors. Use a symmetrical layout around the
analog inputs to minimize the effects of parasitic elements.
Shield analog input traces with ground to minimize coupling from other traces. Keep traces as short as possible.
JP2: Toggles between single and dual power supplies for
the LTC6362. The single supply is the default configuration
for the DC1833A.
E1: Positive Power Supply Voltage. In the default configuration, V+ = 5V.
E2: Ground.
E4: Sets the input common mode voltage. In the default
the input common mode voltage is set by the output
common mode reference voltage. Please refer to the input
common mode voltage range section in the LTC6362 data
sheet for more details.
E5: The voltage on this pin sets the output common mode
voltage level. If left floating (default setting), an internal
resistor divider develops a default voltage of 2.5V with a
5V supply.
E6: Ground.
E7: Externally drives the SHDN pin. The default configuration the EXT SHDN pin is left floating (LTC6362 power on).
Use EXT SHDN only after JP1 is removed.
4.5V
4V
4.5V
5V
R6
1.25k
VOCM
SHDN
R5
1.25k
5V
R15
RFILT
C17
1μF
C18 R14
CDIFF RFILT
C16
1μF
– +
LTC6362
+ –
C19
CCM
R4, 1k
4.5V
0.5V
R3, 1k
–4V
0.5V
R3, 1k
–5V
VIN
DIFFERENTIAL
V
INPUT IN
VOUT+
VIN
VOUT+
5V
R6, 1k
VOUT+
VOUT–
VOCM
SHDN
R5, 1k
R15
RFILT
C17
VOUT+
C18 R14
CDIFF RFILT
C16
VOUT–
– +
LTC6362
+ –
C19
CCM
R4, 1k
4.5V
C15
CCM
C15
CCM
VOUT–
VOUT–
0.5V
0.5V
DC1833A F04
DC1833A F03
Figure 4. Differential Input to Differential Output
Figure 3. Single-Ended to Differential Output
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DEMO MANUAL DC1833A
PARTS LIST
ITEM
QTY
REFERENCE
PART DESCRIPTION
MANUFACTURER/PART NUMBER
Required Circuit Components
1
4
C1, C8, C16, C17
CAP, CER X5R 1μF 16V, 0603
AVX, 0603YD105KAT
2
2
C2, C3
CAP, CER 0.1μF 25V 10% X7R, 0805
MURATA, GRM21BR71E104KA01L
TAIYO YUDEN, EMK212ABJ475MG-T
3
2
C4, C5
CAP, CER X5R 4.7μF 16V, 0805
4
0
C6, C7, C9, C10, C15, C18,
C19 (OPT)
CAP, 0603
5
4
C11, C12, C13, C14
CAP, CER X7R 0.1μF 16V, 0603
AVX, 0603YC104KAT
6
2
JP1, JP2
HEADER, 3PIN 1 ROW 0.079CC
SAMTEC, TMM-103-02-L-S
7
2
JP1, JP2
SHUNT, 0.079” CENTER
SAMTEC, 2SN-BK-G
8
4
J1 TO J4
CONN SMA 50Ω EDGE LAUNCH
AMPHENOL/CONNEX 132357
9
7
E1 TO E7
TP, TURRET, 0.064”
MILL-MAX, 2308-2-00-80-00-00-07-0
10
0
R1, R8, R9, R10, R12, R13
(OPT)
RES, 0603
11
5
R2, R7, R11, R14, R15
RES, CHIP 0, 1%, 0603
NIC, NRC06ZOTRF
12
4
R3, R4, R5, R6
RES, CHIP 1k, 1%, 0603
NIC, NRC06F1001TRF
13
1
U1
IC, FULLY DIFFERENTIAL AMPLIFIER
IC, LINEAR TECH. LTC6362CMS8
14
2
STENCIL FOR BOTH SIDES
STENCIL, DC1833A-2
15
1
FAB, PRINTED CIRCUIT BOARD
DEMO CIRCUIT 1833A-2
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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
C8
1uF
C1
1uF
2
R1
OPT
R8
OPT
R7
0
R2
0
1
2
1. ALL RESISTORS ARE IN OHMS, 0603
ALL CAPACITORS ARE IN MICROFARADS, 0603.
NOTE: UNLESS OTHERWISE
SPECIFIED
J2
VIN-
J1
VIN+
1
E5
E4
R9
OPT
V+
E1
R10
OPT
0805
V+
C4
4.7uF
R13
OPT
R12
OPT
GND
C12
0.1uF
3
4
THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND
SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS.
4
3
2
1
ERJON Q .
5
SCALE = NONE
NC
PCB DES.
IN+
OUT-
V-
SHDN
5
6
7
8
2
-
DATE:
N/A
SIZE
6
10-13-11
IC NO.
7
R15
0
R14
0
J4
J3
VOUT+
VOUT-
E7
EXT
SHDN
GND
8
DATE
10-13-11
7
LTC6362CMS8
DEMO CIRCUIT 1833A
8
SHEET 1
OF
1
2
REV.
1630 McCarthy Blvd.
Milpitas, CA 95035
Phone: (408)432-1900 www.linear.com
Fax: (408)434-0507
LTC Confidential-For Customer Use Only
C17
1uF
C16
1uF
SINGLE
C19
OPT
C15
OPT
JP2
SUPPLY
DUAL
PWR_ON
SHDN
E6
ERJON Q .
APPROVED
FULLY DIFFERENTIAL AMPLIFIER
V-
JP1
PRODUCTION FAB
DESCRIPTION
REVISION HISTORY
TECHNOLOGY
C18
OPT
C13
0.1uF
0
R11
R5
1K
R4
1K
C7
OPT
REV
ECO
6
TITLE: SCHEMATIC
C14
0.1uF
OUT+
V+
VOCM
IN-
U1
LTC6362CMS8
V-
E3
APPROVALS
0805
0805
V-
5
APP ENG.
C11
0.1uF
R6
1K
R3
1K
C6
OPT
C5
4.7uF
C3
0.1uF
LINEAR TECHNOLOGY HAS MADE A BEST EFFORT TO DESIGN A
CIRCUIT THAT MEETS CUSTOMER-SUPPLIED SPECIFICATIONS;
HOWEVER, IT REMAINS THE CUSTOMER'S RESPONSIBILITY TO
VERIFY PROPER AND RELIABLE OPERATION IN THE ACTUAL
APPLICATION. COMPONENT SUBSTITUTION AND PRINTED
CIRCUIT BOARD LAYOUT MAY SIGNIFICANTLY AFFECT CIRCUIT
PERFORMANCE OR RELIABILITY. CONTACT LINEAR
TECHNOLOGY APPLICATIONS ENGINEERING FOR ASSISTANCE.
E2
V + / - = 2.8V - 5.25V
C2
0.1uF
0805
C10
OPT
V+
4
CUSTOMER NOTICE
EXT
VOCM
EXT
VCM
C9
OPT
3
D
C
B
A
DEMO MANUAL DC1833A
SCHEMATIC DIAGRAM
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DEMO MANUAL DC1833A
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
FOR ANY PARTICULAR PURPOSE. EXCEPT TO THE EXTENT OF THIS INDEMNITY, NEITHER PARTY SHALL BE LIABLE TO THE OTHER FOR
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
dc1833af
6
Linear Technology Corporation
LT 0312 • PRINTED IN USA
1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408) 432-1900
●
FAX: (408) 434-0507 ● www.linear.com
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