Datasheet

ManualsBrandsTEXAS INSTRUMENTS ManualsData collecting ICsData acquisition IC - AD converter (ADC) Internal VSON 10

FEATURES

D COMPLETE DATA ACQUISITION SYSTEM IN

THE MSOP-10 AND LEADLESS QFN-STYLE

PACKAGES

D MEASUREMENTS FROM TWO DIFFERENTIAL

CHANNELS OR THREE SINGLE-ENDED

CHANNELS

D I

CINTERFACE—EIGHT ADDRESSES PIN-

SELECTABLE

D ONBOARD REFERENCE:

Accuracy: 2.048V ±0.05%

Drift: 5ppm/°C

D ONBOARD PGA

D ONBOARD OSCILLATOR

D 16 BITS, NO MISSING CODES

D INL: 0.01% of FSR max

D CONTINUOUS SELF-CALIBRATION

D SINGLE-CYCLE CONVERSION

D PROGRAMMABLE DATA RATE: 15SPS to

240SPS

D POWER SUPPLY: 2.7V to 5.5V

D LOW CURRENT CONSUMPTION: 240µA

APPLICATIONS

D PORTABLE INSTRUMENTATION

D INDUSTRIAL PROCESS CONTROL

D SMART TRANSMITTERS

D CONSUMER GOODS

D FACTORY AUTOMATION

D TEMPERATURE MEASUREMENT

DESCRIPTION

The ADS1112 is a precision, continuously self-calibrating

Analog-to-Digital (A/D) converter with two differential or three

single-ended channels and up to 16 bits of resolution in the

small MSOP-10 and leadless QFN-style (small-outline,

no-lead) packages. The onboard 2.048V reference provides

an input range of ±2.048V differentially. The ADS1112 uses

an I

C-compatible serial interface and has two address pins

that allow a user to select one of the eight I

C Slave

addresses. The ADS1112 operates from a single power

supply ranging from 2.7V to 5.5V.

The ADS1112 can perform conversions at rates of 15, 30, 60,

or 240 samples per second (SPS). The onboard

programmable gain amplifier (PGA), which offers gains of up

to eight, allows smaller signals to be measured with high

resolution. In single-conversion mode, the ADS1112

automatically powers down after a conversion, greatly

reducing current consumption during idle periods.

The ADS1112 is designed for applications requiring

high-resolution measurement, where space and power

consumption are major considerations. Typical applications

include portable instrumentation, industrial process control,

and smart transmitters.

All trademarks are the property of their respective owners.

ADS1112

SBAS282D − JUNE 2003 − REVISED MARCH 2004

16-Bit Analog-to-Digital Converter with

Input Multiplexer and Onboard Reference

www.ti.com

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.

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Summary of content (25 pages)

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ADS1112 SBAS282D − JUNE 2003 − REVISED MARCH 2004 16-Bit Analog-to-Digital Converter with Input Multiplexer and Onboard Reference FEATURES DESCRIPTION D COMPLETE DATA ACQUISITION SYSTEM IN THE MSOP-10 AND LEADLESS QFN-STYLE PACKAGES D MEASUREMENTS FROM TWO DIFFERENTIAL CHANNELS OR THREE SINGLE-ENDED CHANNELS D I2CINTERFACE—EIGHT ADDRESSES PINSELECTABLE D ONBOARD REFERENCE: Accuracy: 2.048V ±0.05% Drift: 5ppm/°C D D D D D D D ONBOARD PGA ONBOARD OSCILLATOR 16 BITS, NO MISSING CODES INL: 0.
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"###$ www.ti.com SBAS282D − JUNE 2003 − REVISED MARCH 2004 ABSOLUTE MAXIMUM RATINGS(1) VDD to GND −0.3V to +6V Input Current 100mA, Momentary Input Current 10mA, Continuous Analog Inputs, A0, A1, Voltage to GND −0.3V to VDD + 0.3V SDA, SCL Voltage to GND −0.5V to 6V Maximum Junction Temperature +150°C Operating Temperature Range −40°C to +125°C Storage Temperature Range −60°C to +150°C This integrated circuit can be damaged by ESD.
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"###$ www.ti.com SBAS282D − JUNE 2003 − REVISED MARCH 2004 ELECTRICAL CHARACTERISTICS All specifications at −40°C to +85°C, VDD = 5V, and all PGAs, unless otherwise noted. ADS1112 PARAMETER CONDITIONS MIN TYP MAX UNIT ANALOG INPUT Full-Scale Input Voltage Analog Input Voltage (VIN+) − (VIN−) VIN+ to GND or VIN− to GND ±2.048/PGA GND − 0.2 Differential Input Impedance Common-Mode Input Impedance PGA = 1 PGA = 2 PGA = 4 PGA = 8 V VDD + 0.2 V 2.8/PGA MΩ 3.5 3.5 1.8 0.
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"###$ www.ti.com SBAS282D − JUNE 2003 − REVISED MARCH 2004 TYPICAL CHARACTERISTICS At TA = 25°C and VDD = 5V, unless otherwise noted.
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"###$ www.ti.com SBAS282D − JUNE 2003 − REVISED MARCH 2004 TYPICAL CHARACTERISTICS (continued) At TA = 25°C and VDD = 5V, unless otherwise noted.
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"###$ www.ti.com SBAS282D − JUNE 2003 − REVISED MARCH 2004 TYPICAL CHARACTERISTICS (continued) At TA = 25°C and VDD = 5V, unless otherwise noted. THEORY OF OPERATION The ADS1112 is a 16-bit, self-calibrating, delta-sigma A/D converter with an input multiplexer. Extremely easy to design with and configure, the ADS1112 allows precise measurements to be obtained with a minimum of effort. The ADS1112 consists of a delta-sigma A/D converter core with adjustable gain, a 2.
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"###$ www.ti.com SBAS282D − JUNE 2003 − REVISED MARCH 2004 absolute values of the minima and maxima are not the same; the maximum n-bit code is 2n−1 − 1, while the minimum n-bit code is −1 × 2n−1. values depend on the PGA setting. The switching clock is generated by the onboard clock oscillator, so its frequency (nominally 275kHz) is dependent on supply voltage and temperature.
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"###$ www.ti.com SBAS282D − JUNE 2003 − REVISED MARCH 2004 USING THE ADS1112 OPERATING MODES The ADS1112 operates in one of two modes: continuousconversion or single-conversion. In continuous-conversion mode, the ADS1112 continuously performs conversions. Once a conversion has been completed, the ADS1112 places the result in the output register and immediately begins another conversion. In single-conversion mode, the ADS1112 waits until the ST/DRDY bit in the conversion register is set to 1.
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"###$ www.ti.com SBAS282D − JUNE 2003 − REVISED MARCH 2004 When a master has finished communicating with a slave, it may issue a STOP condition. When a STOP condition is issued, the bus becomes idle again. A master may also issue another START condition. When a START condition is issued while the bus is active, it is called a repeated START condition. addresses to be selected with only two pins as shown in Table 4.
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"###$ www.ti.com SBAS282D − JUNE 2003 − REVISED MARCH 2004 A0 A1 SLAVE ADDRESS 0 0 1001000 0 Float 1001001 0 1 1001010 1 0 1001100 1 Float 1001101 1 1 1001110 Float 0 1001011 Float 1 1001111 Float Float Invalid from normal address bytes; the low bit does not indicate read/write status.) The ADS1112 will not acknowledge this byte; the I2C specification prohibits acknowledgment of the Hs master code.
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"###$ www.ti.com SBAS282D − JUNE 2003 − REVISED MARCH 2004 CONFIGURATION REGISTER Bits 6-5: INP The 8-bit configuration register can be used to control the ADS1112 operating mode, input selection, data rate, and PGA settings. The configuration register format is shown in Table 6. The default setting is 8CH. INP controls which two of the four analog inputs are used to measure data in the ADC. This is shown in Table 7.
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"###$ www.ti.com SBAS282D − JUNE 2003 − REVISED MARCH 2004 READING FROM THE ADS1112 To read the output register and the configuration register from the ADS1112, first address the ADS1112 for reading, then read three bytes. The first two bytes will be the output register’s contents, and the third will be the configuration register’s contents. It is not required to read the configuration register byte. It is permissible to read fewer than three bytes during a read operation.
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"###$ www.ti.com SBAS282D − JUNE 2003 − REVISED MARCH 2004 APPLICATIONS INFORMATION The sections that follow give example circuits and tips for using the ADS1112 in various situations. BASIC CONNECTIONS For many applications, connecting the ADS1112 is extremely simple. A basic connection diagram for the ADS1112 is shown in Figure 4. Pull-up resistors are required on both the SDA and SCL lines because I2C bus drivers are open-drain.
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"###$ www.ti.com SBAS282D − JUNE 2003 − REVISED MARCH 2004 Note that only one set of pull-up resistors is needed per bus. The pull-up resistor values may need to be lowered slightly to compensate for the additional bus capacitance presented by multiple devices and increased line length. Figure 7. Using GPIO with a Single ADS1112 Bit-banging I2C with GPIO pins can be done by setting the GPIO line to zero and toggling it between input and output modes to apply the proper bus states.
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"###$ www.ti.com SBAS282D − JUNE 2003 − REVISED MARCH 2004 SINGLE-ENDED INPUTS Although the ADS1112 has two differential inputs, it can easily measure three single-ended signals. A singleended connection scheme is shown in Figure 8. The ADS1112 is configured for single-ended measurement by grounding the AIN3 pin and applying the input signals to any of AIN0, AIN1, or AIN2. Then the data is read out of one of the inputs based on the selection on the configuration register.
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PACKAGE OPTION ADDENDUM www.ti.
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PACKAGE OPTION ADDENDUM www.ti.com 11-Apr-2013 (4) Multiple Top-Side Markings will be inside parentheses. Only one Top-Side Marking contained in parentheses and separated by a "~" will appear on a device. If a line is indented then it is a continuation of the previous line and the two combined represent the entire Top-Side Marking for that device. Important Information and Disclaimer:The information provided on this page represents TI's knowledge and belief as of the date that it is provided.
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PACKAGE MATERIALS INFORMATION www.ti.com 26-Jan-2013 TAPE AND REEL INFORMATION *All dimensions are nominal Device Package Package Pins Type Drawing ADS1112IDGSR VSSOP DGS 10 SPQ Reel Reel A0 Diameter Width (mm) (mm) W1 (mm) B0 (mm) K0 (mm) P1 (mm) W Pin1 (mm) Quadrant 2500 330.0 12.4 5.3 3.4 1.4 8.0 12.0 Q1 ADS1112IDGST VSSOP DGS 10 250 180.0 12.4 5.3 3.4 1.4 8.0 12.0 Q1 ADS1112IDRCR SON DRC 10 2500 330.0 12.4 3.3 3.3 1.1 8.0 12.
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PACKAGE MATERIALS INFORMATION www.ti.com 26-Jan-2013 *All dimensions are nominal Device Package Type Package Drawing Pins SPQ Length (mm) Width (mm) Height (mm) ADS1112IDGSR VSSOP DGS 10 2500 367.0 367.0 35.0 ADS1112IDGST VSSOP DGS 10 250 210.0 185.0 35.0 ADS1112IDRCR SON DRC 10 2500 367.0 367.0 35.0 ADS1112IDRCT SON DRC 10 250 210.0 185.0 35.
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