Datasheet

ManualsBrandsTEXAS INSTRUMENTS ManualsData collecting ICsData acquisition IC - AD converter (ADC) External , Internal SOIC 20

12-Bit 10µs Serial CMOS Sampling

ANALOG-to-DIGITAL CONVERTER

FEATURES

● 100kHz SAMPLING RATE

● 72dB SINAD WITH 45kHz INPUT

● ±1/2 LSB INL AND DNL

● SIX SPECIFIED INPUT RANGES

● SERIAL OUTPUT

● SINGLE +5V SUPPLY OPERATION

● PIN-COMPATIBLE WITH 16-BIT ADS7809

● USES INTERNAL OR EXTERNAL

REFERENCE

● 100mW MAX POWER DISSIPATION

● 0.3" SO-20

● SIMPLE DSP INTERFACE

DESCRIPTION

The ADS7808 is a complete 12-bit sampling analog-to-digital

using state-of-the-art CMOS structures. It contains a 12-bit

capacitor-based SAR A/D with S/H, reference, clock, and a

serial data interface. Data can be output using the internal

clock, or can be synchronized to an external data clock. The

ADS7808 also provides an output synchronization pulse for

ease of use with standard DSP processors.

The ADS7808 is specified at a 100kHz sampling rate, and

specified over the full temperature range. Laser-trimmed

scaling resistors provide various input ranges including ±10V

and 0V to 5V, while an innovative design operates from a

single +5V supply, with power dissipation under 100mW.

The ADS7808 is available in a 0.3" SO-20, fully specified for

operation over the industrial –40°C to +85°C range.

10kΩ

CDAC

4kΩ

20kΩ

5kΩ

Internal

+2.5V Ref

Clock

BUSY

Data Clock

Serial Data

Successive Approximation Register and Control Logic

Serial

Data

Out

Comparator

Buffer

20kΩ

R/C

REF

Power Down

CAP

ADS7808

SBAS018A – JANUARY 1992 – REVISED SEPTEMBER 2003

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.

7808

Summary of content (17 pages)

PAGE 1
ADS7808 ADS 7808 SBAS018A – JANUARY 1992 – REVISED SEPTEMBER 2003 12-Bit 10µs Serial CMOS Sampling ANALOG-to-DIGITAL CONVERTER FEATURES DESCRIPTION ● ● ● ● ● ● ● ● The ADS7808 is a complete 12-bit sampling analog-to-digital using state-of-the-art CMOS structures. It contains a 12-bit capacitor-based SAR A/D with S/H, reference, clock, and a serial data interface. Data can be output using the internal clock, or can be synchronized to an external data clock.
PAGE 2
ABSOLUTE MAXIMUM RATINGS(1) ELECTROSTATIC DISCHARGE SENSITIVITY Analog Inputs: R1IN .......................................................................... ±25V R2IN .......................................................................... ±25V R3IN .......................................................................... ±25V CAP ..................................... VANA+0.3V to AGND2 –0.3V REF .......................................
PAGE 3
ELECTRICAL CHARACTERISTICS (Cont.) At TA = –40°C to +85°C, fS = 100kHz, VDIG = VANA = +5V, using internal reference and fixed resistors shown in Figure 4, unless otherwise specified.
PAGE 4
PIN ASSIGNMENTS PIN # NAME 1 R1IN 2 AGND1 3 R2IN DESCRIPTION Analog Input. See Table I and Figure 4 for input range connections. Analog Ground. Used internally as ground reference point. Minimal current flow. Analog Input. See Table I and Figure 4 for input range connections. 4 R3IN Analog Input. See Table I and Figure 4 for input range connections. 5 CAP Reference Buffer Capacitor. 2.2µF Tantalum to ground. 6 REF Reference Input/Output. Outputs internal 2.5V reference.
PAGE 5
SYMBOL DESCRIPTION MIN TYP MAX UNITS t1 Convert Pulse Width t2 BUSY Delay 65 ns t3 BUSY LOW 8 µs t4 BUSY Delay after End of Conversion 220 ns t5 Aperture Delay 40 ns t6 Conversion Time 5.
PAGE 6
SPECIFIC FUNCTION CS R/C Initiate Conversion and Output Data Using Internal Clock 1>0 0 1 0 Output 0 x Initiates conversion “n”. Data from conversion “n–1” clocked out on DATA synchronized to 12 clock pulses output on DATACLK. 0 1>0 1 0 Output 0 x Initiates conversion “n”. Data from conversion “n–1” clocked out on DATA synchronized to 12 clock pulses output on DATACLK. 1>0 0 1 1 Input 0 x Initiates conversion “n”. 0 1>0 1 1 Input 0 x Initiates conversion “n”.
PAGE 7
FIGURE 3a. Conversion and Read Timing with External Clock. (EXT/INT Tied HIGH). Read After Conversion. ADS7808 SBAS018A www.ti.
PAGE 8
Tag 15 Tag 14 Tag 13 Tag 1 Tag 1 t15 t17 Tag 0 t12 t18 t20 Bit 11 (MSB) Tag 12 Bit 0 (LSB) Tag 0 t19 t1 t14 t12 TAG DATA SYNC BUSY R/C CS EXTERNAL DATACLK t16 t2 t13 FIGURE 3b. Conversion and Read Timing with External Clock. (EXT/INT Tied HIGH.) Read During Conversion (Previous Conversion Results). 8 ADS7808 www.ti.
PAGE 9
Input Range With Trim (Adjust offset first at 0V, then adjust gain) Without Trim 200Ω 200Ω R1IN R1IN AGND1 AGND1 100Ω 100Ω VIN R2IN 33.2kΩ R3IN 0V – 10V R2IN VIN 33.2kΩ R3IN +5V 2.2µF CAP + CAP 50kΩ 2.2µF 576kΩ REF 2.2µF + +5V REF 50kΩ + + 2.2µF AGND2 AGND2 200Ω 200Ω R1IN R1IN AGND1 AGND1 100Ω 100Ω R2IN 33.2kΩ 0V – 5V R3IN VIN R2IN 33.2kΩ R3IN VIN +5V CAP CAP + +5V 2.2µF REF 2.2µF 576kΩ + 50kΩ 2.2µF REF 50kΩ + 2.
PAGE 10
Input Range With Trim (Adjust offset first at 0V, then adjust gain) Without Trim 200Ω 200Ω VIN VIN R1IN R1IN AGND1 AGND1 100Ω 100Ω R2IN ±10V R2IN +5V 33.2kΩ R3IN 33.2kΩ R3IN 50kΩ +5V CAP + 2.2µF 576kΩ 2.2µF REF 2.2µF CAP + REF 50kΩ + 2.2µF + AGND2 AGND2 200Ω 200Ω R1IN R1IN AGND1 AGND1 100Ω 100Ω R2IN VIN 33.2kΩ R2IN VIN 33.2kΩ ±5V R3IN 2.2µF +5V CAP + REF 2.2µF CAP +5V 50kΩ 2.2µF R3IN + 576kΩ REF 50kΩ + + 2.
PAGE 11
PACKAGE OPTION ADDENDUM www.ti.
PAGE 12
PACKAGE OPTION ADDENDUM www.ti.com 11-Apr-2013 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.
PAGE 13
PACKAGE MATERIALS INFORMATION www.ti.com 9-Sep-2013 TAPE AND REEL INFORMATION *All dimensions are nominal Device ADS7808U/1K Package Package Pins Type Drawing SOIC DW 20 SPQ Reel Reel A0 Diameter Width (mm) (mm) W1 (mm) 1000 330.0 24.4 Pack Materials-Page 1 10.8 B0 (mm) K0 (mm) P1 (mm) W Pin1 (mm) Quadrant 13.3 2.7 12.0 24.
PAGE 14
PACKAGE MATERIALS INFORMATION www.ti.com 9-Sep-2013 *All dimensions are nominal Device Package Type Package Drawing Pins SPQ Length (mm) Width (mm) Height (mm) ADS7808U/1K SOIC DW 20 1000 367.0 367.0 45.
PAGE 15
PAGE 16
PAGE 17
IMPORTANT NOTICE Texas Instruments Incorporated and its subsidiaries (TI) reserve the right to make corrections, enhancements, improvements and other changes to its semiconductor products and services per JESD46, latest issue, and to discontinue any product or service per JESD48, latest issue. Buyers should obtain the latest relevant information before placing orders and should verify that such information is current and complete.