ADC100CA datasheet(4/7 Pages) ETC

Nome de Peças	ADC100CA

Descrição Electrónicos	Precision 22 Bit Integrating A/D Converter

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THEORY OF OPERATION

The timing control circuitry governs the counters that

measure the integration time in both directions.

The ADC100's on-board microprocessor is used to

calculate the results of the integration equation above.

It is also used to perform error corrections and to

control the built-in-auto-zero function. Note that the

mP automatically performs an auto-zero function at

start-up, but it is recommended, to achieve maximum

accuracy, that an auto-zero be performed again after

the ADC100 is fully warmed up.

When the µP detects a convert signal, it lowers the

status lines to indicate that the ADC is involved in a

conversion.

When it detects a change in slope

direction, the µP will collect the counts for the

integration time. When sufficient counts have been

collected, the µP performs the calculations described

above.

When the calculations are complete, the µmP places

the most significant byte in the output buffer and

raises the S

0 flag.

When another pulse is placed on

the convert line, the middle byte is placed on the

output, the S

0 flag is lowered and the S1 flag raised.

When the last pulse is placed in the convert line, the

least significant byte is placed in the output buffer and

both status flags are high indicating that the ADC100

is ready for another conversion.

Status line summary:

FIGURE 1. BLOCK DIAGRAM

Conversion in progress.

Conversion complete. MSB in output.

Middle byte in output register.

LSB in output. Ready for next conversion.

0

1

0

1

S

1

S

0

In the ADC100 block diagram (see Figure 1), V

hi

and V

low are the inputs. Both are buffered and fed

into a differential, voltage controlled, single output

current source.

This current is added to the

reference current at the input of the op amp

integrator. The output of the integrator is fed into

a Schmitt trigger, which in turn, is fed into the

ADC's

timing

control

circuitry.

When

the

integrator output actuates the Schmitt trigger, the

timing

circuit

changes

the

direction

of

the

reference current source and the integrator

begins integrating in the opposite direction. This

continues until the Schmitt trigger is actuated

again by the integrator and reverses the direction

of the reference current.

The equation for integration times are:

Tp=

V X C

I ref + I inp

Tm=

V X C

-I ref + I inp

Resolving these equations produces:

I inp = I ref

Tp - Tm

Tp + Tm

V = Voltage

C= Integration Capacitor Value

I ref = Reference Current

I inp = Input Current

Tp = Time Positive

Tm = Time Negative

ADC100DS REV. E MAR 00

Auto

Zero

Switch

Schmitt

Trigger

Bidirectional

Reference

Current Source

Current

Directional

Switch

Timing

Control

and

Counter

Microprocessor

Output

Buffer

Clock

Differential

Voltage Controlled

Current Source

V

hi

V

low

+15V

-15V

Auto

Zero

Convert

Status

Lines

Output Enable

Data

Output

ï

Nº de peça semelhante - ADC100CA

Fabricante Electrônico	Nome de Peças	Folha de dados	Descrição Electrónicos
List of Unclassifed Man...	ADC100	201Kb / 4P	Evaluation Kit For A/D Converters
MPS Industries, Inc.	ADC100	172Kb / 2P	1W, Miniature SIP, Single & Dual Output DC/DC Converters
Ohmite Mfg. Co.	ADC1000RE	43Kb / 1P	Epoxy Molded Precision Wirewound Axial Terminals
National Semiconductor ...	ADC1001	201Kb / 9P	10-Bit P Compatible A/D Converter
National Semiconductor ...	ADC1001	243Kb / 7P	10-BIT uP COMPATIBLKE A/D CONVERTERS

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Descrição semelhante - ADC100CA

Fabricante Electrônico	Nome de Peças	Folha de dados	Descrição Electrónicos
Mitsubishi Electric Sem...	M62301SP	102Kb / 9P	10~12-BIT 4CH INTEGRATING A-D CONVERTER
Microchip Technology	TC850	350Kb / 30P	15-Bit, Fast Integrating CMOS A/D Converter 11/29/12
Microchip Technology	TC850	539Kb / 26P	15-Bit, Fast Integrating CMOS A/D Converter 2006
RHOPOINT COMPONENTS	ADC180	259Kb / 7P	Programmable Integrating A/D Converter
List of Unclassifed Man...	ADC150	131Kb / 9P	Programmable Integrating A/D Converter
RHOPOINT COMPONENTS	ADC150	217Kb / 9P	Programmable Integrating A/D Converter
List of Unclassifed Man...	ADC180	137Kb / 7P	Programmable Integrating A/D Converter
Renesas Technology Corp	M62301SP	157Kb / 12P	10 to 12-bit 4-ch Integrating A/D Converter
ATMEL Corporation	AVR401	120Kb / 12P	8-bit Precision A/D Converter
Analog Devices	AD1175	3Mb / 8P	HIGH ACCURACY 22 BIT INTERGRATING A/D CONVERTER

More results

ADC100CA Folha de dados(PDF) 4 Page - List of Unclassifed Manufacturers

ADC100CA Folha de dados(HTML) 4 Page - List of Unclassifed Manufacturers

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