DEM-ADS7812 [ETC]
DEM-ADS7812 - EVALUATION FIXTURE ; DEM - ADS7812 - 评价灯具\n
| 型号： | DEM-ADS7812 |
| 厂家： | 
ETC |
| 描述： | DEM-ADS7812 - EVALUATION FIXTURE
|
| 文件： | 总8页 (文件大小：211K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
®
DEM-ADS7812/13P
EVALUATION FIXTURE
DESCRIPTION
FEATURES
● COMPUTER INTERFACE
● STAND-ALONE CAPABILITY
● BREADBOARD AREAS
The DEM-ADS7812/13P evaluation fixture is designed
for quick evaluation of Burr-Brown’s ADS7812 and
ADS7813. Breadboard areas are provided with
optional bipolar power supply connections to assist in
the evaluation of various driver amplifiers or multi-
plexed input circuits to the input of the analog-to-
digital converter. Additionally, the demonstration
fixture has flexibility in its clocking circuit to allow
for various fixed conversion rates. To further enhance
the clocking network, an external off board clock can
be connected through the BNC connector, P5. The
DEM-ADS7812/13P has been designed to accommo-
date stand-alone operation.
● INPUT RANGE EASILY CONFIGURED
FOR APPLICATION
APPLICATIONS
● TRANSDUCER INTERFACE
● MULTIPLEXED DAS
International Airport Industrial Park
•
Mailing Address: PO Box 11400, Tucson, AZ 85734
FAXLine: (800) 548-6133 (US/Canada Only)
• Street Address: 6730 S. Tucson Blvd., Tucson, AZ 85706 • Tel: (520) 746-1111 • Twx: 910-952-1111
Internet: http://www.burr-brown.com/
•
•
Cable: BBRCORP
•
Telex: 066-6491
•
FAX: (520) 889-1510
•
Immediate Product Info: (800) 548-6132
© 1997 Burr-Brown Corporation
Printed in U.S.A. April, 1998
LI-498A
GETTING STARTED
ANALOG
INPUT
RANGE
CONNECT
R1 IN
CONNECT
R2 IN
CONNECT
R3 IN
A/D INPUT
IMPEDANCE
(Ω)
The user must provide power to the analog input portion of
the board as well as power to the DUT and digital network.
P3 should be powered with ±15V which provides power to
U1. P4 should be powered with +5V, which provides power
to the DUT (X1), and digital network, U2, U3, U4, U5, and
U6. The ground connection of both power connectors are
tied together with the ground plane of the board. The factory
set position of the jumpers are shown below.
TO
TO
TO
±10V
J5-A (VIN
J5-A (VIN
)
)
J6-C (BUF) J7-B (GND)
45.7k
0.3125 to
2.8125V
J6-A (VIN
)
J7-A (VIN
)
> 10M
±5V
J5-B (GND)
J5-C (BUF)
J5-C (BUF)
J6-C (BUF)
J6-B (GND)
J7-A (VIN
J7-A (VIN
)
)
26.7k
26.7k
21.3k
21.3k
21.3k
0V to 10V
0V to 4V
±3.33V
J6-A (VIN
J6-C (BUF)
J6-A (VIN
)
J7-B (GND)
J7-A (VIN
J7-B (GND)
J5-A (VIN
)
)
J1 = not installed
J2 = A
J6 = C
J7 = B
0.5V to 4.5V J5-B (GND)
)
J3, J4, J8, J12, J14 = open
J5 = A
J10, J13 = installed
J9, J15 = short
TABLE II. These are the Jumper Settings (J5, J6 and J7) for
the Most Common Input Ranges to theADS7812
andADS7813. Note that all jumper configurations
on the DEM-ADS7812/13P board are acceptable.
Refer to Table IV of the ADS7812 or ADS7813
product data sheets for more details concerning
other input range options. Configured for CIB test-
ing.
DEM-ADS7812/13P BOARD DESCRIPTION
All of the jumper functions for the DEM-ADS7812/13P are
shown in Table I. These jumpers affect the circuit’s analog
front end, clocking circuit, and the shut down enhancement
circuit.
The combination of J1, J2, R3, R4, and C17 are used to
configure the front-end amplifier, U1. Figure 1 shows the
analog gain options available for this board. The various
configurations for this input stage are summarized in Table
III. R5 is used to isolate the output of the amplifier from the
input of the A/D converter. The factory setting for R5 is 0Ω,
however, an appropriate value for R5 could also be 50Ω.
JUMPER
NAME
JUMPER FUNCTION
J1, J2
Used to configure the input analog source to the
driver amplifier (U1). See Table III.
J3, J4
J5, J6, J7
J8, J9, J14, J15
J10, J13
Solderable power supply options for the driver
amplifier, U1.
Used to configure the analog input range of the A/D
converter (DUT). See Table II.
R4
Solderable connection options to enhance the shut
down capability of the A/D converter (DUT).
E3
E7
E4
E8
C17
Used to configure the clock generation circuit. See
Table IV.
B
AIN
P2
R3
J12
Determines serial clock source for serial I/O.
A
A
J1
J2
E1
E2
R5
E5 E6
U1
To DUT
TABLE I. Description of Jumpers on DEM-ADS7812/13P
Demonstration Fixture.
ANA
B
ANALOG INPUT CONFIGURATIONS
FIGURE 1. TheAnalog Input Section of the DEM-ADS7812/13P
Demonstration Fixture.
Input Range: J5, J6, J7—The input range of the A/D
converter is configured using J5, J6, and J7. In general, all
positions that are labeled “A” will connect the correspond-
ing input pin of the A/D converter to the analog input. All
positions that are labeled “B” of jumpers J5, J6, and J7 will
connect the corresponding input pin of the A/D converter to
“GND”. Finally, all positions that are labeled “C” will
connect the corresponding input pin of the A/D converter to
“BUF”. A quick look-up table for the more common analog
input ranges is shown in Table II. A complete list is given in
Table IV of either the ADS7812 or the ADS7813 data sheet.
J1
J2
ANALOG GAIN (V/V)
Inverting
A
B
ANA/AIN = –R3/R4
Configuration
Non-inverting
Configuration
B
A
ANA/AIN = 1 + R3/R4
TABLE III. The Gain of the Amplifier, U1, can be Config-
ured Negative or Positive with theAbove Jumper
Settings. R3, R4, R5 and C17 can be easily
changed by using the low-profile sockets, labeled
as E1 - E8.
Analog Input Driver Amplifier : J1, J2, J3, J4—J1 and J2
can be used to configure the on board amplifier in an
inverting or non-inverting gain. The values of R3, R4, R5,
and C17 are interchangeable by using the sockets provided,
E1 through E8. J3 and J4 are jumpers that can be shorted
with solder to allow for alternative power supply configura-
tions for the amplifier. All of these jumpers and components
allow for a variety of configurations for the front-end analog
driving amplifier.
An input signal can be connected to the circuit using the
coax connector, P2 (AIN). The breadboard is also connected
to AIN. Additionally, the breadboard ANA bus bypasses the
operational amplifier, U1, completely to allow for custom
driver circuits to be built on the breadboard.
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DEM-ADS7812/13P
The power supply to the amplifier, U1, is supplied from a
different connector (P3) than the power supply (P4) to the
A/D converter, X1 (DUT). This is done to allow for maxi-
mum flexibility. In addition, an alternative operational am-
plifier power supply connection is possible using J3 and J4.
These two jumpers, as with J14, J15, J8 and J9 (discussed
later) are solder options. In the case with J3 and J4 the
amplifier’s positive power supply can easily be attached to
pins 7 and 8 by connecting the solder switch, J3. The
negative supply can be connected to both pins 4 and 5 of the
amplifier is desired by connecting the solder switch, J4. This
option is useful if the operation amplifier in the U1 socket
has an alternative power supply connection with the positive
supply connected to pins 7 and 8 and the negative supply
connected to pins 4 and 5.
connected to CAP and REF, C3, C4, and C16, will begin to
discharge. When the power-down mode is exited, these
capacitors must be allowed to recharge and settle to a 16-bit
level. When the P-Channel, HEXFET Power MOSFET, U6,
(IRF7604) is included in the circuit (available on request),
the power up time can be significantly reduced. This func-
tion is enabled and disabled according to the settings speci-
fied in Table VII.
P1 PIN NUMBER
PIN DESCRIPTION
All Even Pins
Ground
39
31
29
25
Power-down mode pin, to X1 (DUT) pin 15
BUSY, connected to X1 (DUT) pin 14
CS (Chip Select), connected to X1 (DUT) pin 13
EXT/INT (External or internal DATACLK pin.
Selects the source of the synchronous clock for
serial data), connected to X1 (DUT) pin 11
DIGITAL OUTPUT CONFIGURATIONS
Clock Network : J13, J10, P5—The convert command to
the A/D converter is provided through one of two paths. The
first path is from the EXT CONV connector, (P5) and the
second path is from the clock generator network; U2, U3,
and U4. The jumper configuration is shown in Table IV. The
on board clock generator network divides a 16MHz oscilla-
tor signal (U2) to 40kHz at J10. 40kHz is the recommended
maximum throughput rate for the ADS7812 and ADS7813.
Slower clock signals can be generated by changing the
oscillator chip, U2 or by using an external clock source
through P5. The AND gate, implemented with U5, insures
that the timing between BUSY and CONV (t4, per product
data sheet) is not violated.
23
DATA (Serial data out), connected to X1 (DUT)
pin 10
21
7
DATACLK, connected to X1 (DUT) pin 9
CONV (or system clock)
TABLE V. External Digital Interface Connector, P1 Pin
Description.
J12
DESCRIPTION
Not installed
DUT EXT/INT is LOW. Synchronous clock for serial
data is derived from DUT internal conversion clock.
Installed
DUT EXT/INT is HIGH. Synchronous clock for
serial data is derived from P1-21 external connector.
TABLE VI. Serial Clock Source and the Setting for J12.
CLOCK OPTION
External Clock (P5)
On Board Clock
J10
J13
No Jumper
Connected
No Jumper
Connected
DESIRED
OPERATION
J8
J9
J14
J15
TABLE IV. Jumper Configuration of Clock Options on the
DEM-ADS7812/13P Demonstration Fixture.
Unenhanced No Connect
Power-Down
Connected
with Solder
Switch
No Connect
Connected
With Solder
Switch
Mode
Enhanced
Power-Down
Mode
Connected
with Solder
Switch
No Connect
Connected
with Solder
Switch
No Connect
External Digital Interface—All critical digital lines are
connected to the 25 x 2 pin connector, P1 (see Table V). This
connector is designed to interface to Burr-Brown’s Com-
puter Interface Board, DEM-CIB. The DEM-CIB and ac-
companying Windows compatible program allow the perfor-
mance of the ADS7812 and ADS7813 to be evaluated
directly from a PC. If an off board clock provides the
synchronous clock for serial I/O, then jumper J12 should be
installed (see Table VI).
TABLE VII. Jumper Solder Instructions for Standard Power-
Down Operation (unenhanced) and Accelerated
Power-Down Operation (enhanced) for the
ADS7812 and ADS7813. “No connect” implies
there is no solder switch connecting both pads
of the jumper. “Connected with solder switch”
requires that the user apply enough solder to short
both pads of the jumper.
Additionally, the user of the DEM-ADS7812/13P can use
the board in a stand-alone mode, using P1 as the interface
connection to a user designed interface.
POWER SAVING FEATURE
The ADS7812 and ADS7813 has a power-down mode that
is activated by taking CONV LOW and the PWRD HIGH.
This will power down all of the analog circuitry including
the reference. While in the power-down mode, the capacitors
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DEM-ADS7812/13P
PART IDENTIFIER
QUANTITY
PART NUMBER
DESCRIPTION
X1
U1
U6
1
1
1
ADS7813PB
OPA627BP
IRF7604
DUT, Low Power, Serial 16-Bit Sampling A/D Converter, Burr-Brown
Precision High-Speed DiFET® Op Amp, Burr-Brown
P-Channel, HEXFET Power MOSFET, International Rectifier
(Available on Request from Factory)
U5
1
1
1
1
1
1
74HC08N(1)
74AC11074N(1)
CTX116-ND(1)
74LS390N(1)
Quad 2-Input, AND Gate, TI
U3
Dual D-Type Flip Flop, TI
U2
16MHz Oscillator, Digi-Key (CTS)
U4
Dual Decade Counter, 4-Bit, TI
R3
RN55C75R0F(1)
0.0QBK-ND(1)
—
Resistor, 75Ω, 0.125Ω, 1%, Metal-film
Resistor, 0Ω, Yageo (Digi-Key part number)
None Installed
R5
R4
C17
—
None Installed
R1
1
1
2
3
6
5
1
2
1
1
3
2
3
7
1
1
1
8
5
8
1
2
1
RN55C1003F(1)
RN55C1002F(1)
T350A105K035AS(1)
CK05BX103K(1)
CK05BX104K(1)
T350B225K025AS(1)
IDH-50LP-SR3-TG(1)
KC-79-274-M06(1)
31165102(1)
Resistor, 100kΩ, 0.125Ω, 1%, Metal-film
Resistor, 10kΩ, 0.125Ω, 1%, Metal-film
Cap, 1µF, 35V, 10%, Tantalum, Diped/Radial
Cap, 0.01µF, X7R, 100V, 10%, Ceramic
Cap, 0.1µF, 50V, 10%, Ceramic X7R, Kemet
Cap, 2.2µF, 25V, 10%, Tantalum, Dipped/Radial Kemet
Robinson Nugent, Right Angle, 25 x 2
Connector BNC, PCB Mount, King
R2
C3, C7
C5, C8, C16
C1, C2, C9 - C12
C4, C5, C13 - C15
P1
P2, P5
P4
P3
2-Pin Term Block, 3.5mm Centers, RIACON Electronics
3-Pin Term Block, 3.5mm Centers, RIACON Electronics
Jumper, SAMTEC, 2 x 3 Terminal Strip
Jumper, SAMTEC, 2 x 2 Terminal Strip
Jumper, SAMTEC, 2 x 1 Terminal Strip
Test Point, 0.125 Pad, 0.093 Drill, USECO 1280B
DUT Socket, 16-Pin DIP, Augat
31165103(1)
J5 - J7
TSW-103-07-T-D(1)
TSW-102-07-T-D(1)
TSW-101-07-T-D(1)
HD411-2
J1 - J2
J10, J12, J13
TP1 - TP6, TP8
X1 Socket
AG-516-11-DES
AG-508-11-DES
1107741
U1 Socket
Op Amp Socket, 8-pin DIP, Augat
U2 Socket
Aries, 14-pin Oscillator Socket
E1 - E8
AMP50863-5
“E” Point 0.062 Drill, Resistor Sockets, Augat, Hotlite Socket .0
Rubber Feet, Newark
RB1, RB2, RB3, RB4, RB5
J1, J2, J5 - J7, J10, J12, J13 Tops
CR3
90F1533
SNT-100-BK-T-H
SA5.0AGICT-ND(1)
SA15AGICT-ND(1)
A2245
Jumper Tops, Samtec
5.0V Transient Voltage Suppressor, DO-204AC, Digi-Key
15V Transient Voltage Suppressor, DO-204AC, Digi-Key
DEM-ADS7812/13P, Burr-Brown
CR1, CR2
Bare PC Board
Sample
1
ADS7812P
DUT, Low Power Serial 14-Bit Sampling A/D Converter, Burr-Brown.
NOTE: (1) Substitutions Allowed.
TABLE VIII. Parts List for the DEM-ADS7812/13P.
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4
DEM-ADS7812/13P
FIGURE 2. Circuit Diagram of the DEM-ADS7812/13P Demonstration Fixture.
5
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DEM-ADS7812/13P
FIGURE 3. Silkscreen of the DEM-ADS7812/13P Demonstration Board.
FIGURE 4. Component Side of the DEM-ADS7812/13P Demonstration Board.
®
6
DEM-ADS7812/13P
FIGURE 5. Top Soldermask of the DEM-ADS7812/13P Demonstration Board.
FIGURE 6. Ground Plane of the DEM-ADS7812/13P Demonstration Board.
7
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DEM-ADS7812/13P
FIGURE 7. Bottom Soldermask of the DEM-ADS7812/13P Demonstration Board.
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DEM-ADS7812/13P
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