DC416A - Demo Manual

DEMO MANUAL DC416
LTC1864
16-Bit 250ksps ADC
Description
Demonstration circuit 416 features the LTC1864 16-bit
250ksps analog-to-digital converter.
is hence much greater than what would be required in
almost any practical application.
This board provides a means to evaluate the performance
of the LTC1864 with either the Linear Technology PScope™
data acquisition system, or with other parallel or serial
data acquisition systems.
The LTC1864 and its demo board are intended to be used
with the PScope data acquisition system for characterization of the ADC in AC applications extending from Hz to
MHz. The full power bandwidth of the LTC1864 is high
enough to produce good performance in under-sampling
applications, as well as applications where the signal
content is below Nyquist.
The board also demonstrates proper layout techniques in
the circuitry surrounding the ADC and in the segmentation of the planes required to achieve full performance
with the ADC.
These techniques include proper grounding of the device
and associated bypass capacitors, placement of the device
relative to interconnection of analog and digital subsystems
and signal routing in proximity to the ADC.
This board performs serial to parallel conversion in a manner that is unlikely to be used in an actual implementation,
but is representative of what could be implemented in an
FPGA. It is expected that with this ADC, the interface will
be performed serially with either programmable logic, a
general-purpose processor, a DSP, or across an isolated
link of one of many types. The complexity of the circuitry
The board contains a bandwidth-limiting filter at the input
of the ADC (C7, C8, C9, R1 and R2), as well as provision
for an amplifier (U2). This bandwidth-limiting filter (–3dB at
1.5MHz) is typical of what may be required for many applications, but it is not necessarily the best for all applications.
The board also incorporates an LTC1799 resistor programmable oscillator as an optional clock source.
Design files for this circuit board are available at
http://www.linear.com/demo/DC416
L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks and PScope
is a trademark of Linear Technology Corporation. All other trademarks are the property of their
respective owners.
quick start procedure
Demonstration circuit 416 is easy to set up to evaluate
the performance of the LTC1864. Refer to Figure 1 for
proper measurement equipment setup and follow the
procedure below:
NOTE: The demo board is shipped with jumpers in place
to allow the use of an external oscillator at 80× the sample
rate. Figure 1 shows the default jumper positions.
1.Connect the parallel output J4 to either the DC718 data
collection board, or to a suitable acquisition system.
Pin 3 of J4 is the data strobe.
2.Observe correct polarity; Connect +8V to +15V to
terminal E1. Note that –15V is only required if U2 is
installed. There are two on board regulators. Both are
5V, although U1 the reference can be substituted with
a lower voltage.
dc416f
1
DEMO MANUAL DC416
Quick Start Procedure
3.If the intent is to do an evaluation of AC performance,
connect a sinusoidal (or other) input signal to J1, or
J1 and J2, with a nominal DC bias of 2.5V. If only J1 is
used (single-ended operation), JP3 should be installed.
This converter converts unipolar differential inputs from
0 – VREF.
NOTE: The AIN inputs do not have 50Ω termination. Most
generators will produce the correct signal level only if the
cable is terminated at 50Ω. If you are driving this from
a generator, you should use 50Ω through terminators.
Take care not to overdrive the inputs if you do not use
terminators.
4.Connect a 20MHz digital clock to CLKIN. With default
jumpers in place, this will result in a 250ksps conversion rate.
5.Collect data via PScope for a Fourier transform into the
frequency domain, or to allow data to be collected and
saved to a file for subsequent import and analysis in
Excel, Matlab or other analysis packages.
Duplication of the FFT results shown in the data sheet
requires the use of a low jitter clock and waveform generators synchronized such that the input waveform must be
within a few ppm of an exact multiple of the conversion
clock divided by the FFT size (termed coherent). For 250kHz
sample rate and a 4096 point FFT, input frequencies should
be an exact multiple of 61.035156Hz, and preferably a prime
number multiple or at least an odd number multiple. The
use of an even number multiple will exercise a minimal
number of codes, producing poor results.
IF U2 POPULATED WITH BIPOLAR AMPLIFIER
–
+
+
–
SIGNAL
SOURCE
PARALLEL
DATA
COLLECTION
SYSTEM
IF DIFFERENTIAL
SIGNAL SOURCE
CLOCK
SOURCE
SERIAL DATA
COLLECTION SYSTEM
USE EITHER
PARALLEL OR SERIAL
DATA COLLECTION SYSTEM
DC416 F01
Figure 1. Proper Measurement Equipment Setup
2
dc416f
DEMO MANUAL DC416
OPERATION
The conversion clock (CONV) is derived from the CLKIN
connector (J3) via a programmable divider.
The board is shipped with this divider set to divide by 80
(JP8 and JP9). In order for this converter to achieve its
maximum throughput of 250ksps, the data transfer time
must be completed in 1/fSAMPLE – TCONV, which requires
that the SCLK be at 20MHz.
The programmable divider can be strapped for different divide ratios if the required sample rate is less than
250ksps, allowing a greater percentage of the time available doing data transfer (divide ratio of less than 80), or
if a comparable SCLK rate is used, with a lower sample
rate (divide ratio greater than 80).
JP8 and JP9 are set to code 16–(divide ratio/16) or 11 in
the case of a divide ratio of 80.
The counter circuitry gates a sequence of 16 clock pulses
during CONV = 0. These can be observed on CLKOUT, or
if CONV is introduced externally, (remove JP4) the clock
pulses can be introduced via CLKIN (JP6 to pin 1, JP7 to
pin 1 if no inversion is required).
JP6 (pin 2–3) allows the use of the onboard LTC1799
oscillator. Note that this oscillator will not produce data
sheet performance unless the input frequency is quite low,
as the phase jitter of this oscillator will be transformed in
the presence of high slew rate signals into random noise.
If the amplitude of the signal falls off with increasing
frequency as many natural phenomena do, this oscillator
may produce acceptable results.
If you are under-sampling, or operating the converter near
Nyquist, it is important to have a low jitter clock source.
The data output DOUT is shifted into a pair of 74HC595
serial to parallel shift registers that have output holding
registers, and tri-stateable outputs. If you intend to incorporate the demo board into a prototype of a system,
ENABLEDATA can be used to gate the outputs onto a
16-bit bus. Alternatively, all of the signals can be produced
externally, and data can be read into a DSP via DOUT.
If you elect to use the on-board timing to clock data into a
slaved serial input port, you can use DOUT, CKOUT, along
with CONV as a busy signal or as a means of producing
a frame sync.
In the event that you do not have “coherent” signal sources
as described above, you can use windowing functions
to reduce the “leakage” effect that occurs in the Fourier
transform and get a reasonably accurate figure for SNR,
THD, SINAD and the levels of the various harmonics.
dc416f
3
DEMO MANUAL DC416
Parts List
ITEM
QTY
REFERENCE
PART DESCRIPTION
MANUFACTURER/PART NUMBER
1
15
C1, C4-C6, C10, C11, C13-C20, C23
CAP., X7R, 0.1µF, 16V
AVX, 0603YC104MAT1A
2
1
C2
CAP., X7R, 1µF, 10V, 20%
AVX, 0805ZC105MAT1T
3
2
C3, C12
CAP., X5R, 10µF, 6.3V, 20%, 1206
TAIYO YUDEN JMK316BJ106MLT
4
2
C7,C9
CAP., NPO, 100PF, 50V, 1206
VITRAMON, VJ1206A101JXB
5
1
C8
CAP., NPO, 470PF, 100V,1206
AVX, 12061A471JAT
6
2
C21, C22
CAP., NPO, 47PF, 50V
AVX, 06035A470MAT1A
7
9
E1-E9
TP, TURRET, .094"
MILL-MAX, 2501-2
8
5
JP1, JP2, JP3, JP4, JP5
JMP, 1 × 2 .079CC
COMM-CON, 2802S-02-G1
9
2
JP6, JP7
JMP, 1 × 3 .079CC
COMM-CON, 2802S-03-G1
10
2
JP8, JP9
JMP, 2 × 3 .079CC
COMM-CON, 2202S-06-G2
11
9
SHUNTS FOR JP1-JP9
SHUNT, .079" CENTER
COMM-CON, CCIJ2MM-138G
12
3
J1-J3
CONN, BNC 50Ω, PCB-VERTICADTL
CONNEX, 112404
13
1
J4
CON, HDR, .1 × .1 CNTRS, 40PIN
COMMCON, 3201S-40G1
14
1
RN1
RES 2 × 4 ARRAY, CHIP, 330Ω, ISO
CTS, 742-C083-331JTR-ND
15
2
R1, R2
RES, CHIP 100, 1/16W, 5%, 1206
AAC, CR18-101JM
16
2
R3, R4
RES, CHIP 2, 1/16W, 5%, 0603
AAC, CR16-2R0JM
17
2
R5, R6
RES, CHIP 402, 1/16W, 1%,0603
AAC, CR16-4020FM
18
1
R7
RES, CHIP 20k, 1/16W, 5%,0603
AAC, CR16-203JM
19
1
R8
RES, CHIP 15k, 1/16W, 5%,0603
AAC, CR16-153JM
20
1
R9
RES, CHIP 51, 1/16W, 5%,0603
AAC, CR16-510JM
21
1
R10
RES POT3321H, POT-3321H-MURATA
MURATA, POT3321H-1-103
22
1
U1
IC, LT1021DCS8-5, SO8
LINEAR TECH., LT1021DCS8-5
23
0
U2
IC, OP AMP, SO8
TBD
24
1
U3
IC, LTC1864AIMS8, MSOP8
LINEAR TECH., LTC1864AIMS8
25
2
U4, U5
IC, MC74HC595ADT, TSSOP16
MOTOROLA, MC74HC595ADT
26
2
U6, U7
IC, MC74HC163AD, SO16
MOTOROLA, MC74HC163AD
27
1
U8
IC, MC74AC14DTR2, TSSOP14
ON SEMI., MC74AC14DTR2
28
1
U9
IC, MC74AC00DTR2, TSSOP14
ON SEMI., MC74AC00DTR2
29
1
U10
IC, LTC1799, SOT23-5
LINEAR TECH., LTC1799
30
1
U11
IC, LT1121CST-5, SOT223
LINEAR TECH., LT1121CST-5
31
1
U12
IC, MC74AC109DR2, SO16
ON SEMI., MC74AC109DR2
32
1
U13
IC, MC74AC32DTR2, TSSOP14
ON SEMI., MC74AC32DTR2
33
4
MTGS AT 4 CORNERS
SCREW, #4-40, 1/4"
ANY
34
4
MTGS AT 4 CORNERS
STANDOFF, NYLON HEX #4-40 1/2"
MICRO PLASTICS 14HTSP003
NOTES: UNLESS OTHERWISE SPECIFIED
1. ALL RESISTORS ARE IN OHMS.
2. INSTALL SHUNTS ON JP1, JP3-JP7 PIN 1 AND 2;
ON JP8 AND JP9 PIN 2 AND 4, PIN 3 AND 5.
4
dc416f
A
B
C
IN+
J1
IN-
AGND
-15V
J2
E9
E8
+5VDIG
1 IN-
1 IN+
JP8
JP9
5
2
3
-
+
-15V
6
JP2
JP3
1
1
JP1
VIN
2
2
1206
R2
100
1206
R1
100
VOUT
U1
LT1021-5
6
C8
470PF
1206
R3
2
C9
100PF
1206
C7
100PF
1206
C1
0.1UF
+5VDIG
8
7
6
5
4
3
2
1
RCO
Q0
Q1
Q2
Q3
ENT
LD
CLK
P0
P1
P2
P3
ENP
GND
74HC163AD
VCC
2
1
U9A
74AC00
6
RESET
U6
3
5
4
U9B
74AC00
9
10
11
12
13
14
15
16
PRE
CLR
CLK
K
J
8
7
6
5
4
3
2
1
6
4
4
3
2
1
CLK
1
2
U13A
74AC32
1
JP6
JP4
2
1
+15V
12
10
9
1
2
3
3
13
OUT
U13D
74AC32
U13C
74AC32
JP7
9
C22
47PF
C21
47PF
3
8
11
8
U8D
74AC14
3
1
+5VAN
+5VDIG C10
0.1UF
R6
402, 1%
R5
402, 1%
VIN
U11
LT1121CST-5
+5VDIG C19
0.1UF
4
3
5
4
5
6
3
OUT
7
8
2
1
RN1
330
SET
DIV
LTC1799
GND
V+
U10
C18
0.1UF
9
5
10
9
3
R10
10K
12
11
2
13
Q
1
R8
15K
R7
20K
+5VDIG
PRE
CLR
CLK
K
Q
10
U12B
74AC109
14
15
16
C17
0.1UF
11
15
12
13
J
C11
0.1UF
7
+5VDIG
5
6
7
8
4
LD
ENT
Q3
Q2
Q1
Q0
RCO
VCC
GND
14
+5VDIG
Q
Q
CONV
-IN
LTC1864CMS8
SCLK
DOUT
+IN
VCC
C4
0.1UF
VREF
U3
C3
10UF
6.3V
1206
+5VAN
6
U12A
74AC109
C23
0.1UF
C2
1UF 10V
0805
74HC163AD
GND
ENP
P3
P2
P1
P0
CLK
RESET
U7
C16
0.1UF
+5VDIG
5
1
4
3
2
U13B
74AC32
+5VDIG
+5VDIG
ANALOG GROUND PLANE
C6
0.1UF
U2
OPT
+15V C5
0.1UF
7
4
D
C20
0.1UF
2
1
GND
4
2
14
+15V
16
VCC
GND
16
VCC
GND
8
GND
2
14
7
14
7
14
7
E1
+15V
3
6
11
4
U8B
74AC14
2
U8A
74AC14
R4
2
2
KIM T.
2
DESIGNER:
ENGINEER: DEREK R.
APPROVED:
CHECKED:
DRAWN:
APPROVALS
CONTRACT NO.
DATE:
A
SIZE
12
CLKIN
CLKOUT
DOUT
R9
51
JP5
ENABLEDATA
1
8
U9C
74AC00
J3
E5
E4
E6
E7
E3
E2
13
12
CLKIN
CLKOUT
DOUT
DGND
DGND
ENABLEDATA
CONV
+5VDIG
Wednesday, February 06, 20 02
1
SHEET
DC416A-2 * LTC1864CMS8
16 BIT 250 KSPS ADC
DWG NO.
B
C
D
1
OF
1
A
REV
1630 McCarthy Blvd.
Milpitas, CA 95035
A
Phone: (408)432-1900
(408)434-0507
TECHNOLOGY Fax:
LTC Confidential-For Customer Use Only
11
C15
0.1UF
40
39
38
37
36
35
34
33
32
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
3201S-40G1
J4
U9D
74AC00
2. INSTALL SHUNTS ON JP1,JP3-JP7 PIN 1 AND 2;
ON JP8 AND JP9 PIN 2 AND 4, PIN 3 AND 5.
1. ALL RESISTORS ARE IN OHMS.
U8F
74AC14
9
10
CONV
8
7
6
5
4
3
2
1
8
7
6
5
4
3
2
1
1
NOTES: UNLESS OTHE RWISE SPECIFIED
13
74HC595ADT
GND
QH
SQH
QG
RESET
QF
QE
QD
QC
SCLK
LCLK
OENB
A
QA
VCC
U5
QB
GND
QH
SQH
QG
RESET
QF
QE
QD
QC
QB
SCLK
LCLK
OENB
A
QA
VCC
C14
0.1UF
+5VDIG
74HC595ADT
TITLE:
9
10
11
12
13
14
15
16
9
10
11
12
13
14
15
16
C13
0.1UF
+5VDIG
+5VDIG U4
U8C
74AC14
5
U8E
74AC14
10
C12
10UF
6.3V
1206
+5VDIG
14
7
14
7
5
4
3
2
5
4
3
2
4
3
2
1
6
5
6
5
2
1
4
3
14
7
7
14
7
2
1
4
2
14
7
14
7
8
14
7
1
14 3
7
14
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.
7
2
3
4
5
14
7
5
DEMO MANUAL DC416
Schematic Diagram
dc416f
5
DEMO MANUAL DC416
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
6
dc416f
Linear Technology Corporation
LT 0713 • PRINTED IN USA
1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408) 432-1900
●
FAX: (408) 434-0507 ● www.linear.com
 LINEAR TECHNOLOGY CORPORATION 2013
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