AD7653ACPZ datasheet(17/27 Pages) AD

17 / 27 page

AD7653

Data Sheet

Rev. C | Page 16 of 26

Transfer Functions

Using the OB/2C digital input, the AD7653 offers two output

codings: straight binary and twos complement. The LSB size is

VREF/65536, which is about 38.15 µV. The AD7653’s ideal

transfer characteristic is shown in Figure 21 and Table 7.

000...000

000...001

000...010

111...101

111...110

111...111

ANALOG INPUT

VREF – 1.5 LSB

VREF – 1 LSB

1 LSB

0.5 LSB

1 LSB = VREF/65536

02966-0-003

Figure 21. ADC Ideal Transfer Function

Table 7. Output Codes and Ideal Input Voltages

Digital Output Code (Hex)

Description

Analog

Input

Straight

Binary

Twos

Complement

FSR – 1 LSB

2.499962 V

FFFF1

7FFF1

FSR – 2 LSB

2.499923 V

FFFE

7FFE

Midscale + 1 LSB

1.250038 V

8001

0001

Midscale

1.25 V

8000

0000

Midscale – 1 LSB

1.249962 V

7FFF

FFFF

–FSR + 1 LSB

38 µV

0001

8001

–FSR

0 V

00002

80002

This is also the code for overrange analog input (VIN – VINGND above

VREF – VREFGND).

This is also the code for underrange analog input (VIN below VINGND).

NOTES

1THE CONFIGURATION SHOWN IS USING THE INTERNAL REFERENCE AND INTERNAL BUFFER.

2THE AD8021 IS RECOMMENDED. SEE DRIVER AMPLIFIER CHOICE SECTION.

3OPTIONAL LOW JITTER.

4A 10µF CERAMIC CAPACITOR (X5R, 1206 SIZE) IS RECOMMENDED (e.g., PANASONIC ECJ3YB0J106M).

SEE VOLTAGE REFERENCE INPUT SECTION.

AD7653

CLOCK

C/µP/DSP

SERIAL

PORT

DIGITAL SUPPLY

(3.3V OR 5V)

DVDD

100nF

10µF

100nF

10µF

20Ω

100nF

10µF

ANALOG

SUPPLY

(5V)

2.7nF

15Ω

ANALOG INPUT

(0VTO 2.5V)

RESET

IMPULSE

WARP

SER/PAR

OB/2C

BUSY

SDOUT

SCLK

INGND

REFGND

REF

GND

AVDD

DGND DVDD

OVDD

OGND

02966-A-004

U12

PDREF

PDBUF

BYTESWAP

CNVST

REFBUFIN1

100nF

CR4

Figure 22. Typical Connection Diagram

AD7653ACPZ датащи(PDF) 17 Page - Analog Devices

AD7653ACPZ датащи(HTML) 17 Page - Analog Devices

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27

датащи скачать

ссылки URL