Datasheet

ManualsBrandsTEXAS INSTRUMENTS ManualsData collecting ICsData acquisition IC - AD converter (ADC) External , Internal TQFP 32

DESCRIPTION

The ADS7852 is an 8-channel, 12-bit Analog-to-Digital

(A/D) converter complete with sample-and-hold, internal 2.5V

reference and a full 12-bit parallel output interface. Typical

power dissipation is 13mW at 500kHz throughput rate. The

ADS7852 features both a nap mode and a sleep mode, further

reducing the power consumption to 2mW. The input range is

from 0V to twice the reference voltage. The reference voltage

can be overdriven by an external voltage.

The ADS7852 is ideal for multi-channel applications where

low power and small size are critical. Medical instrumenta-

tion, high-speed data acquisition and laboratory equipment

are just a few of the applications that would take advantage of

the special features offered by the ADS7852. The ADS7852

is available in an TQFP-32 package and is fully specified and

ensured over the –40°C to +85°C temperature range.

12-Bit, 8-Channel, Parallel Output

ANALOG-TO-DIGITAL CONVERTER

FEATURES

● 2.5V INTERNAL REFERENCE

● 8 INPUT CHANNELS

● 500kHz SAMPLING RATE

● SINGLE 5V SUPPLY

●

±1LSB: INL, DNL

● NO MISSING CODES

● 70dB SINAD

● LOW POWER: 13mW

● TQFP-32 PACKAGE

APPLICATIONS

● DATA ACQUISITION

● TEST AND MEASUREMENT

● INDUSTRIAL PROCESS CONTROL

● MEDICAL INSTRUMENTS

SAR

CDAC

ADS7852

Output

Latches

and

3-State

Drivers

Comparator

CLK

BUSY

A0 A1 A2

8-Channel

MUX

Internal

+2.5V Ref

Buffer

REF

10kΩ

AIN0

AIN1

AIN2

AIN3

AIN4

AIN5

AIN6

AIN7

3-State

Parallel

Data Bus

ADS7852

SBAS111C – JANUARY 1998 – REVISED JULY 2004

www.ti.com

PRODUCTION DATA information is current as of publication date.

Products conform to specifications per the terms of Texas Instruments

standard warranty. Production processing does not necessarily include

testing of all parameters.

Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of

Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.

All trademarks are the property of their respective owners.

Summary of content (18 pages)

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ADS7852 ADS 785 2 ® SBAS111C – JANUARY 1998 – REVISED JULY 2004 12-Bit, 8-Channel, Parallel Output ANALOG-TO-DIGITAL CONVERTER FEATURES DESCRIPTION ● ● ● ● ● 2.5V INTERNAL REFERENCE 8 INPUT CHANNELS 500kHz SAMPLING RATE SINGLE 5V SUPPLY ● ● ● ● NO MISSING CODES 70dB SINAD LOW POWER: 13mW TQFP-32 PACKAGE The ADS7852 is an 8-channel, 12-bit Analog-to-Digital (A/D) converter complete with sample-and-hold, internal 2.5V reference and a full 12-bit parallel output interface.
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ABSOLUTE MAXIMUM RATINGS(1) Analog Inputs to AGND, Any Channel Input .............. –0.3V to (VD + 0.3V) REFIN ......................................................................... –0.3V to (VD + 0.3V) Digital Inputs to DGND .............................................. –0.3V to (VD + 0.3V) Ground Voltage Differences: AGND, DGND ..................................... ±0.3V +VSS to AGND .......................................................................... –0.3V to 6V Power Dissipation ..............
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ELECTRICAL CHARACTERISTICS At TA = –40°C to +85°C, fS = 500kHz, fCLK = 16 • fS, and VSS = +5V, using internal reference, unless otherwise specified.
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PIN DESCRIPTIONS PIN NAME 1 AIN0 Analog Input Channel 0 2 AIN1 Analog Input Channel 1 3 AIN2 Analog Input Channel 2 4 AIN3 Analog Input Channel 3 DB1 5 AIN4 Analog Input Channel 4 6 AIN5 Analog Input Channel 5 25 PIN CONFIGURATION 7 AIN6 Analog Input Channel 6 8 AIN7 Analog Input Channel 7 9 AGND 10 VREF 11 DGND 12 A2 Channel Address. See Channel Selection Table for details. 13 A1 Channel Address. See Channel Selection Table for details. 14 A0 Channel Address.
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TYPICAL CHARACTERISTICS At TA = +25°C, VSS = +5V, fSAMPLE = 500kHz, fCLK = 16 • fSAMPLE, and internal reference, unless otherwise specified. SPECTRAL PERFORMANCE (4096 Point FFT, fIN = 100.7081kHz, –0.5dB) 0 0 –20 –20 Amplitude (dB) Amplitude (dB) SPECTRAL PERFORMANCE (4096 Point FFT, fIN = 49.561kHz, –0.5dB) –40 –60 –80 –100 –80 –120 0 50 100 150 200 250 0 50 100 150 200 Frequency (kHz) Frequency (kHz) SPECTRAL PERFORMANCE (4096 Point FFT, fIN = 199.5851kHz, –0.
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TYPICAL CHARACTERISTICS (Cont.) At TA = +25°C, VSS = +5V, fSAMPLE = 500kHz, fCLK = 16 • fSAMPLE, and internal reference, unless otherwise specified.
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TYPICAL CHARACTERISTICS (Cont.) At TA = +25°C, VSS = +5V, fSAMPLE = 500kHz, fCLK = 16 • fSAMPLE, and internal reference, unless otherwise specified. CHANGE IN GAIN ERROR vs TEMPERATURE (With External 2.5V Reference) CHANGE IN OFFSET vs TEMPERATURE 0.5 1.0 0.8 0.3 Delta from +25°C (LSB) Delta from +25°C (LSB) 0.4 0.2 0.1 0 –0.1 –0.2 –0.3 0.6 0.4 0.2 0.0 –0.2 –0.4 –0.5 –0.
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TYPICAL CHARACTERISTICS (Cont.) At TA = +25°C, VSS = +5V, fSAMPLE = 500kHz, fCLK = 16 • fSAMPLE, and internal reference, unless otherwise specified. SUPPLY CURRENT vs SAMPLE RATE SUPPLY CURRENT vs TEMPERATURE 2.9 2.680 fSAMPLE = 500kHz 2.8 Supply Current (mA) Supply Current (mA) 2.675 2.670 2.665 2.660 2.7 2.6 2.5 2.4 2.3 2.655 –50 –25 0 25 50 75 100 100 200 CHANGE IN NAP CURRENT AND SLEEP CURRENT vs TEMPERATURE 400 500 600 CHANGE IN GAIN AND OFFSET vs SUPPLY VOLTAGE 25 0.
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THEORY OF OPERATION Read Input Clock Input Busy Output CLK 29 BUSY 28 0V to 5V DB1 25 DB0 (LSB) 26 0.1µF WR 27 1 AIN0 2 AIN1 DB3 23 3 AIN2 DB4 22 4 AIN3 5 AIN4 DB6 20 6 AIN5 DB7 19 7 AIN6 DB8 18 8 AIN7 DB5 21 14 A0 A0 Select DB9 17 16 DB10 13 A1 11 DGND A1 Select + 12 A2 2.2µF A2 Select + 10 VREF AGND 9 0.
PAGE 10
ANALOG INPUTS The ADS7852 features eight single-ended inputs. While the static current into each analog input is basically zero, the dynamic current depends on the input voltage and sample rate. The current into the device must charge the internal hold capacitor during the sample period. After this capacitor has been fully charged, no further input current is required.
PAGE 11
HOLD tCKH CLK 1 2 3 4 5 6 tCKP 7 8 9 10 11 tCKL t1 12 13 14 15 16 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 1 2 3 4 5 6 7 8 t4 t2 WR t4 t3 CS t5 BUSY Conversion n tCONV Conversion n + 1 tACQ t6 RD t7 t8 Address Bus Address n + 1 Address n + 2 t9 t10 Data Bus Hi-Z SYMBOL tCONV tACQ tCKP tCKL tCKH t1 t2 t3 t4 t5 t6 t7 t8 t9 t10 t11 t12 t13 t14 t15 Data Valid Data Valid Hi-Z DESCRIPTION MIN Conversion Time Acquisition Time Clock Period Clock LOW Clock HIG
PAGE 12
POWER-DOWN MODE The ADS7852 has two different power-down modes: the Nap mode and the Sleep mode. In Nap mode, all analog and digital circuitry is powered off, with the exception of the voltage reference. In Sleep mode, the device is completely powered off. While the Sleep mode affords the lowest power consumption, the time to come out of Sleep mode can be considerable since it takes the internal reference voltage a finite amount of time to power up and reach a stable value.
PAGE 13
LAYOUT Test Point VCC DOUT tdis Waveform 2, ten 3kΩ tdis Waveform 1 100pF CLOAD Load Circuit for tdis and ten VIH CS/SHDN DOUT Waveform 1(1) 90% tdis DOUT Waveform 2(2) 10% Voltage Waveforms for tdis NOTES: (1) Waveform 1 is for an output with internal conditions such that the output is HIGH unless disabled by the output control. (2) Waveform 2 is for an output with internal conditions such that the output is LOW unless disabled by the output control. FIGURE 5.
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PACKAGE OPTION ADDENDUM www.ti.
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PACKAGE OPTION ADDENDUM www.ti.com 6-Dec-2010 Important Information and Disclaimer:The information provided on this page represents TI's knowledge and belief as of the date that it is provided. TI bases its knowledge and belief on information provided by third parties, and makes no representation or warranty as to the accuracy of such information. Efforts are underway to better integrate information from third parties.
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