AD7899 [ADI]

Evaluation Board for 5V, 12-Bit, Serial 220kSPS ADC in 8-Pin Package; 评估板为5V ， 12位， 220kSPS串行ADC ，采用8引脚封装


型号：	AD7899
厂家：	ADI
描述：	Evaluation Board for 5V, 12-Bit, Serial 220kSPS ADC in 8-Pin Package 评估板为5V ， 12位， 220kSPS串行ADC ，采用8引脚封装
文件：	总12页 (文件大小：485K)
中文：	中文翻译
下载：	下载PDF数据表文档文件

EvaluationBoard400kSPS,14-BitADC

EVAL-AD7899CB

FEATURES

O P E RAT ING T H E AD 7899 E VALUAT IO N BO ARD

Full-Featured Evaluation Board for the AD7899

Eval-Board Controller Com patible

Stand Alone Capability

On-Board Analog Buffering and Reference

Various Linking Options

P ower Supplies

When using this evaluation board with the EVAL-BOARD

CONT ROLLER all supplies are provided from the EVAL-

BOARD CONT ROLLER through the 96 way connector.

When using the board as a stand alone unit external supplies

must be provided. T his evaluation board has seven power

supply inputs:

PC Softw are for Control and Data Analysis w hen used

w ith Eval-Board Controller

V_DD, A_GND, +12V, -12V, A_GND, V_DRIVEand

I N T R O D U C T I O N

D_GNDIf the evaluation board is used in stand-alone mode

T his T echnical Note describes the evaluation board for the

AD7899 high speed, low power, 14-bit A/D converter that

operates from a single 5 V supply. Full data on the AD7899

is available in the AD7899 data sheet available from Analog

Devices and should be consulted in conjunction with this

T echnical Note when using the Evaluation Board.

+5V must be connected to the V_{D D}input to supply the

AD7899 V_DDpin and the AD780 voltage reference. +12V and

-12V are used to supply the op-amps. T he V_DRIVEpin can be

driven by a voltage between +3V and +5V allowing the

evaluation board to be connected to both +3V and +5V

systems. T he supplies are decoupled to the relevant ground

plane with 10µF tantalum and 0.1µF multilayer ceramic

capacitors at the point where they enter the board. T he supply

pins of all the op-amps and reference are also decoupled to

A_GNDwith 10µF tantalum and a 0.1µF ceramic capacitor. T he

AD7899 AV_DDsupply pin is decoupled to A_GNDwith 47uF

tantalum and 0.1µF multilayer ceramic capacitors.

On-board components include an AD780 which is a +2.5V

ultra high precision bandgap reference and an op-amp for the

analog inputs. T here are various link options which are

explained in detail on page 2.

Interfacing to this board is through a 96-way connector. T his

96-way connector is compatible with the EVAL-BOARD

CON T ROLLER which is also available from Analog D e-

vices. External sockets are provided for the optional, exter-

nal, CONVST and C LKIN and V_{D RIVE}inputs and the

VIN 1-VIN 4 inputs.

Extensive ground planes are used on this board to minimize

the effect of high frequency noise interference. T here are two

ground planes, A_GNDand D_GND

location close to the AD7899.

. T hese are connected at one

Fig. 1: FUNCTIONAL BLOCK DIAGRAM

ANALOG

INPUT

ANALOG

SIGNAL

CONDITIONING

AD7899

EXTERNAL

REFERENCE

REV. 0

Inform ation furnished by Analog Devices is believed to be accurate and

reliable. However, no responsibility is assum ed by Analog Devices for

its use, nor for any infringem ents of patents or other rights of third

parties which m ay result from its use. No license is granted by

im plication or otherwise under any patent or patent rights of Analog

Devices.

OneTechnologyWay,P.O.Box9106,Norwood.MA02062-9106, U.S.A.

Tel:617/329-4700 Fax:617/326-8703

EVAL-AD7899CB

Link and Switch O ptions

T here are 9 link options which must be set for the required operating setup before using the evaluation board. T he

functions of these options are outlined below.

Lin k No.

F u n c t ion .

LK 1

T his link option selects the input range of the ADC. T he position of this link is determined by the input

range required by the user. Please refer to the AD7899 data sheet for more information.

When this link is in position "A" V_INBis connected to V_INA

When this link is in position "B" V_INBis connected toAGND.

LK 2

T his link selects the reference source for the AD7899.

When a link is in position "A" the AD780 is selected as the reference source.

When a link is in position "B" an external voltage applied to SK7 is selected as the reference source.

When the link is removed completly the internal reference of the AD7899 is used as the reference source.

LK 3

LK 4

LK 5

T his link selects the source of the +12V supply.

When this link is in position "A" an external +12V must be connected to J2-1.

When this link is in position "B" the EVAL-BOARD CONT ROLLER will provide the +12V supply

T his link selects the source of the VDD supply.

When this link is in position "A" an external +5V must be connected to J2-2.

When this link is in position "B" the EVAL-BOARD CONT ROLLER will provide the +5V supply

T his link selects the source of the -12V supply.

When this link is in position "A" an external -12V must be connected to J2-4.

When this link is in position "B" the EVAL-BOARD CONT ROLLER will provide the -12V supply

LK 6

T his link selects the source of the V_DRIVEsupply.

When this link is in position A the VDD supply is used as the V_DRIVEsupply.

When this link is in position B the DVDD supply of the EVAL-BOARD CONT ROLLER is used as the

V_DRIVEsupply.

When this link is in position C an external supply on SK6 is used as the V_DRIVEsupply.

LK 7

LK 8

T his link is used to select the source of the Conversion Start signal.

When this link is in position "A" the CONVST signal is generated by the EVAL-BOARD CONT ROL-

L E R.

When this link is in position "B" the CONVST signal is generated by an external signal connected to SK2.

T his link selects the source of the CLKIN signal for the AD7899.

When this link is in position "A" the CLKIN signal is provided by the EVAL-BOARD CONT ROLLER.

When this link is in position "B" the CLKIN signal can be provided by a signal applied to SK3. If no

signal is applied to SK3 the pin is pulled low and the internal oscillator is is used to control the conver-

sion.

LK 9

T his link sets the logic level of the ST BY pin.

When a link is in position "A" the ST BY pin is controlled by the FL1 flag pin of the EVAL-BOARD

C O N T RO L L E R.

When a link is in position "B" the ST BY pin is tied to VDD and the part is in normal operating mode.

When a link is in position "C" the ST BY pin is tied to DGND and the part is in standby mode.

–2 –

REV. 0

EVAL-AD7899CB

S E T - U P C O ND IT IO NS

Care should be taken before applying power and signals to the evaluation board to ensure that all link positions are as

per the required operating mode. T able I shows the position in which all the links are set when the evaluation board is

shipped. T he board is compatible with the EVAL-BOARD CONT ROLLER when shipped.

Table I. Initial Link and Switch P ositions

Link No.

LK 1

P osition

Function.

T he largest voltage range for the part is selected.

T he AD780 is selected as the reference source for the AD7899.

LK 2

LK3-5

T he EVAL-BOARD CONT ROLLER is used to provide the supply voltages for the

evaluation board.

LK 6

LK 7

T he V_DRIVEpin is connected to the VDD supply.

T he CON VST signal is provided by the EVAL-BOARD CON T ROLLER.

LK 8

LK 9

T he CLKIN can be supplied either by an external signal connected to SK3 or by the

AD 7899s internal oscillator.

T he ST BY pin is tied to VDD

–3 –

REV. 0

EVAL-AD7899CB

E VALU AT IO N B O AR D INT E R F AC ING

Table II. 96-Way Connector P in Functions.

Interfacing to the evaluation board is via a 96-way connector,

J1. J1 is used to connect the evaluation board to the EVAL-

BOARD CONT ROLLER or other system. T he pinout for

the J1 connector is shown in Figure 2 and its pin designations

are given in T able II.

RO W a

RowB

F L 1

D 0

RowC

SC LK 1

D G N D

D 1

SC LK 1

D G N D

D 2

Fig. 2. Pin Configuration for the 96-Way Connector, J1

D 3

D 4

96- Way C on n ector P in D escr iption

F L 1 Flag one. T his is a logic input and is connected

D 5

W R

C S

to the STBY pin of the AD7899. A logic high on

this pin allows normal operation of the AD7899.

A logic low on this pin puts the AD7899 into

standby mode.

D 6

D 7

D G N D

D 8

D G N D

D 0-D 13 Data Bit 0 to Data Bit 13. Bi-directional data

pins. T hese data bits provide the ADC conversion

results during a read operation.

D 9

D 10

D G N D

D 11

D 13

Read. T his is an active low logic input which is

used in conjunction with the CS pin to enable the

data outputs.

D G N D

F L 0

D G N D

IRQ2

W R

Write. A logic input. A rising edge on this input,

with CS low and RD high latches the logic state

on D0-D3 into the channel select register. Soft-

ware selection of channels is not supported by this

evaluation board.

D 12

D G N D

AG N D

D G N D

AG N D

D G N D

AG N D

C S

Chip Select. An active low logic input. A low

level on this input selects the AD7899.

F L 0

Flag zero. T his logic input is connected to the

CONVST input of the AD7899 via LK7. A low

to high transition on this input puts all the track/

holds into their hold mode and starts conversion

on the selected channels. In addition the state of

the channel sequence selection is also latched on

the rising edge of this input

IRQ2

Interrupt Request 2. T his is a logic output and is

connected to the BU SY logic output on the

AD7899. T his output will go high on the rising

edge of CONVST and will return low when

conversion is completed on all selected channels.

AG N D

-12V

AG N D

+ 12V

AVD D

D G N D

Digital Ground. T hese lines are connected to the

digital ground plane on the evaluation board. It

allows the user to provide the digital supply via

the connector along with the other digital signals.

Note : T he unused pins of the 96-way connector are not shown.

AG N D

AV_DD

Analog Ground. T hese lines are connected to the

analog ground plane on the evaluation board.

Analog +5V Supply. T hese lines are connected to

the V_DDsupply line on the board via LK4.

+ 12V

-12V

+12V Supply. T his line is connected to the +12V

supply line on the board via LK3.

-12V Supply. T his line is connected to the -12V

supply line on the board via LK5.

–4 –

REV. 0

EVAL-AD7899CB

S O C K E T S

O P E RAT ING WIT H T H E E VAL- B O ARD

T here are six input sockets relevant to the operation of the

AD 7899 on this evaluation board. T he function of these

sockets is outlined in T able III.

C O N T R O L L E R

T he evaluation board can be operated in a stand-alone mode

or operated in conjunction with the EVAL-BOARD CON-

T ROLLER. T he EVAL-BOARD CONT ROLLER is avail-

able from An alog D evices u n d er the ord er en try

"EVAL-BOARD C ON T ROLLER". When operated with

this control board, all supplies and control signals to operate

the AD 7899 are provided by the EVAL-BOARD C ON -

T ROLLER. Software to communicate with the C ontrol

Board and AD7899 is provided with the AD7899 evaluation

board package. T his EVAL-BOARD CON T ROLLER will

also operate with all Analog Devices evaluation boards which

end with the letters CB in their title.

Table III. Socket Functions

S o c ke t

F u n c t io n

SK 1

Sub-Miniature BNC Socket for the analog

input.

SK 2

SK 3

SK 4

SK 5

SK 6

Sub-Miniature BNC Socket for the exter-

nal reference

Sub-M iniature BN C Socket for external

V_DRIVEsupply.

Sub-M iniature BN C Socket for BU SY

output.

T he 96-way connector on the EVAL-AD 7899C B plugs

directly into the 96-way connector on the EVAL-BOARD

C O N T RO LLER. T he EVAL-BO ARD C O N T RO LLER

provides all the supplies for the evaluation board. Itis

powered from a 12VAV transformer. Suitable transformers

are available from Analog Devices as an accessory under the

following part numbers:

Sub-M iniature BN C Socket for external

CONVST input.

Sub-Miniature BNC Socket for the exter-

nal CLKIN input.

EVAL-110VAC -U S:

EVAL-220VAC -U K:

EVAL-220VAC -EU :

For use in the U.S. or Japan

For use in the U.K.

C O N N E C T O R S

T here are two connectors on the AD7899 evaluation board

as outlined in T able IV.

For use in Europe

T hese transformers are also available for other suppliers

including D igikey (U.S.) and Campbell Collins (U.K.).

Table IV. Connector Functions

C o n n e c t o r F u n c t io n

C onnection between the EVAL-BOARD C ON T ROLLER

and the serial port of a PC is via a standard Centronics printer

port cable which is provided as part the EVAL-BOARD

CONT ROLLER package. Please refer to the manual which

accompanies the EVAL-BOARD CONT ROLLER for more

details on the EVAL-BOARD C ON T ROLLER package.

96-Way Connector for Parallel Interface con-

nections.

External + 12V, -12V + 5V & A_{G N D}power

connector.

–5 –

REV. 0

EVAL-AD7899CB

Figure 2. AD7899 Main Screen

point in the graph will display the sample number and value

S O F T WAR E D E S C R IP T IO N

of the point directly beneath the cursor. Along the axis of the

graph are the "zoom handles". T hese allow the user to zoom

in and out to get a closer look at a particular sample if

required. When another set of samples is taken the graph will

attempt to display all values collected unless the H old Zoom

check box is ticked. In this case the graph will keep the same

axis settings as for the previous set of data samples. Addi-

tional check boxes are provided to give the user control over

the vertical an d horizon tal grid s and data poin ts.

T he lower third of the screen will show either a Fast

Fourier T ransform (FFT ) of the data or a Histogram which

shows the number of occurrances of each particular code read

back. T he FFT (the default option) is typically used when the

user is concerned with examining an ADC's performance in

the frequency domain while the H istogram will give an

indication of the AD C's performance to D C signals. T he

option displayed can be toggled by clicking on the FFT

Mode/Histogram Mode button in the top right of the screen.

Figure 3 shows how the main screen looks when the Histo-

gram Option is selected.

T he software which controls the Evaluation Board Control-

ler and hence the evaluation board has three main screens.

T he screen shown in Figure 1 shows the screen which appears

when the software is run. T he main function of this screen is

to allow the user to read a predetermined number of samples

from the evaluation board and display them in both the time

and frequency domain. T he screen can be divided into 3

sections. T he upper third of the screen contains the control

buttons, the menu bar and various status windows. T he

control buttons allow the user to enter the setup menu, take

samples and get information about the software. T he menu

bar allows the user to select which printer port is to be used

to control the Evaluation Board Controller, load and save

data etc. T he status windows indicate the setup of the

evaluation board/device, number of samples taken and any

inform ation /error

m essages

that

are

generated .

T he m iddle third of the screen is a D igital Storage

Oscilloscope (DSO). When samples are uploaded from the

Evaluation Board Controller they are displayed here. T he

samples can be displayed either as integer values or as

voltages (determined by the input range of the device in

question). Once samples have been displayed clicking at any

–6 –

REV. 0

EVAL-AD7899CB

Figure 3. AD7899 Main Screen - Histogram Mode

receive instructions. T he software which should have

been installed should be loaded before the printer port

cable is connected between the Evaluation Board Con-

troller and the PC. T his will ensure that the printer port

has been initialized properly. T he printer port cable can

then be connected between the PC and the Evaluation

Board C ontroller.

Setu p Scr een

T he Setup Screen is responsible for allowing the user to load

a configuration file for the evaluation board. T he configura-

tion file will give the software detailed information about the

evaluation board and part connected to the Evaluation Board

Controller such as number of bits, maximum sampling rate,

power supply requirements etc. T he configuration file also

tells the software the name of the DSP program file which it

should download to the Evaluation Board Controller. T hese

files are supplied by Analog D evices with the evaluation

board. Figure 4 shows the Setup Screen.

Ru n n in g th e Softwa r e

With the hardware setup the user is now in a position to

use the software to control the Evaluation Board Con-

troller and evaluation board. In the software the user

should select the File menu and click on Setup. T his will

display the setup form. A window on the left of the setup

form list all the available configuration files. T he con-

figuration files are text based files which contain infor-

mation about the particular evaluation board to be tested.

T he information will cover such things as the part name,

number of samples to be taken, default and maximum

sampling frequency power supply settings etc. T he

configuration file also contains the name of the D SP

program file which is to be downloaded to the Evaluation

Board Controller. T he user should select the relevant

SE T T ING UP T H E E VALUAT IO N BO ARD

C O N T R O L L E R

T he following text describes how the evaluation board

Evaluation Board Controller and software should be set up

for the user to begin using the com plete system . T he

Evaluation Board Controller and evaluation board should be

connected together (via the 96 way connector). T he power

should be applied to the Evaluation Board Controller. At this

stage the red LED should be flashing which indicates that the

Evaluation Board C ontroller is functional and ready to

–7 –

REV. 0

EVAL-AD7899CB

Figure 4. The Setup Screen

configuration file and click Loa d . T he Evaluation Board

C ontroller will be reset and the D SP program will be

downloaded. When the download has been completed the

power supply settings indicated in the configuration file are

set and the user may hear some of the relays clicking. T he

pull-down menus items such as number of samples and

sampling frequency will have been set to the default values

specified by the configuration file. T he user is free to change

these at will. Once all the settings had been decided the user

can click Close to return to the main form.

Load Raw D ata: Selecting this option allows the user to load

data which had been saved by the software during a previous

session.

Save Raw D ata: Selecting this option allows the user to save

the current set of sample data points. T he data can be

reloaded to the Evaluation Board Controller software at a

later date or can be used by other programs for further

analysis

Save Binar y D ata: Selecting this option allows the user to

save the current set of sample data points. T he data is saved

in binary format as a text file. T his method can be useful for

examining code flicker, looking for stuck bits etc.

Save FFT D ata: Selecting this option allows the user to save

the current set of FFT data points. FFT data cannot be

reloaded into the Evaluation Board Controller software but

can be loaded into other software packages for further

analysis.

T a kin g Sa m p les

When the user clicks Sam ple the software will instruct the

Evaluation Board Controller to take the required number of

samples at the required frequency from the evaluation board.

T hese samples are then uploaded and displayed. An FFT and

Histogram are also calculated and displayed. If the user clicks

Cont Sam p the software will repeat the process indefinitely

until the user clicks the button again. While the software is

continuously sampling data the other control buttons are

disabled.

E xit: Quits the program.

Printer Port:

T his menu item allows the user to select which printer port

should be used for communication with the Evaluation Board

C ontroller.

LP T1: T his option selects 0x378 as the printer port

address. T his is the default option.

O th er B u tton s

T he Reset button will cause the Evaluation Board Controller

to perform a reset function. When this happens the power

supplies are turned off and the program in DSP memory is

lost. T he user should repeat the setup instructions to down-

load another program if required.

LP T2: T his option selects 0x278 as the printer port

T he Q uit button will exit the software, the program running

address.

on the Evaluation Board Controller is not terminated.

P RN: T his option selects 0x3BC as the printer port

address.

ME NU BAR ITE MS

T he main screen of the Evaluation Board Controller contains

a number of options available as pull-down menu items. T he

functions of these are listed below.

File Menu:

Setup Menu: Selecting this option displays the Setup Screen

as shown in Figure 3.

Help:

T his menu item gives information about the current revision

of software for the particular evaluation board being used.

–8 –

REV. 0

EVAL-AD7899CB

SO F T WAR E C O NF IG U R AT IO N F ILE S

Software Configuration Files give the Evaluation Board Controller software information on how the software and hardware

should perform . T hey contain information such as the name of the DSP program to download, the default and maximum

sample frequencies, the number of samples to take and the power supply settings to use. A typical Software Configuration File

(*.cfg) is shown in T able V.

Table V.: Typical Softwar e Configur ation File.

[EVAL-C O N T RO L BO ARD ]

partname:AD 7899

programname:ad7899.PRG

samplefrequency:100000

maxsamplefrequency:380000

samples:2048

+ /-15V:on

dvdd:5:on

avdd:5:on

bus:on

;options 2scomp, binary

dataformat:2scomp

numberofbits:14

inputVmax:2.5

inputVmin:-2.5

Table VI.: Eval-AD 7899CB Bill O f Mater ials.

Item Q ty RefD es

D escription

M anufacturer/D isti

AVX /F E C

D isti N umber

FEC 498-737

FEC 499-687

C1 C4 C5 C7 C9 C12

10uF 16V T AJ_B T antalum cap

100nF 0805 Ceramic Capacitor

1 6

C2 C3 C6 C8 C10 C11 C13 C14

AVX /F E C

C15 C16 C18 C20 C22 C24 C26 C28

1 6

C17 C19 C21 C23 C25 C27

47uF 16V T AJ_C T antalum cap

22pF 0805 Ceramic Capacitor

0W 0.1W 0805 Resistor

180W 0.1W 0805 Resistor

10kW 0.1W 0805 Resistor

D IN 41612-96

AVX /F E C

FEC 197-32

C30 C31 C32

AVX /F E C

FEC 317-500

FEC 772-239

FEC 911-768

FEC 911-975

FEC 104-986

FEC 151-787

FEC 148-535

FEC 150-410

FEC 310-682

ADI Free Issue

FEC 380-362

ADI Free Issue

FEC 492-607

IC 179-28375-300

FEC 738-529

FEC 519-935

FEC 148-922

R1 R2

M u lticom p/F EC

H arting/F EC

Au gat/F EC

R3 R4 R5

R 6

1 0

1 1

1 2

1 3

1 4

1 5

1 6

1 7

1 8

1 9

2 0

2 1

2 2

2 3

4 pin terminal block

4 pin header (2x2)

LK1 LK2 LK3 LK4 LK5 LK7 LK8

H arwin/F EC

M AC O M /F E C

Analog D evices

Philips/F EC

LK6 LK9

6 pin header 3x2)

L K 1-9

"0.1"" pitch Jumper Socket"

50W SMB socket (vertical)

AD 7899AR-1

SK1 SK2 SK3 SK4 SK5 SK6

U 1

U 2

74H C 04N

U 3

AD 845K N

Analog D evices

Philips/F EC

U 4

AD 780AN

U5 U6

74H C 541D

U 1

28 pin SOIC Socket

14 pin DIP solder socket

Ultra low profile sockets

Yamaichi/Radiatron

H arwin/F EC

3M /F E C

U 2

U3 U4

Rubber stick-on feet

–9 –

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EVAL-AD7899CB

Figure 5. AD7899 Evaluation Board Circuit Diagram.

–1 0 –

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EVAL-AD7899CB

Figure 6. Component Side Artwork.

Figure 7. Solder Side Artwork.

–1 1 –

REV. 0

EVAL-AD7899CB

Figure 8. Component Side Silkscreen Artwork.

–1 2 –

REV. 0

AD7899 [ADI]

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