Datasheet

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

SPI

Interface

Oscillator

Voltage

Reference

High Accuracy

Temp Sensor

MUX

PGA

12-Bit DS

ADC

GND

VDD

500 W

0.1 Fm

1 Fm

0.1 Fm

GND

1 MW

GND

VDD

500 W

1 Fm

0.1 Fm

GND

1 MW

GND

VDD

0.1 Fm

GND

AIN0

AIN1

AIN2

AIN3

SCLK

VDD

GND

DOUT/DRDY

DIN

Device

1 MW

GND

ADS1018

www.ti.com

SBAS526B –NOVEMBER 2012–REVISED OCTOBER 2013

Ultra-Small, Low-Power, SPI™-Compatible, 12-Bit,

Analog-to-Digital Converter and Temperature Sensor with Internal Reference

Check for Samples: ADS1018

FEATURES

DESCRIPTION

The ADS1018 is a precision analog-to-digital

• Ultra-Small QFN Package:

converter (ADC) with 12 bits of resolution offered in

2 mm × 1,5 mm × 0,4 mm

an ultra-small, leadless QFN-10 package or an

• Wide Supply Range: 2.0 V to 5.5 V

MSOP-10 package. The ADS1018 is designed with

• Low Current Consumption:

precision, power, and ease of implementation in

mind. The ADS1018 features an integrated voltage

– Continuous Mode: Only 150 μA

reference and oscillator. Data are transferred via a

– Single-Shot Mode: Auto Power-Down

SPI-compatible serial interface. The ADS1018

• Programmable Data Rate:

operates from a single power supply ranging from

128 SPS to 3300 SPS

2.0 V to 5.5 V.

• Single-Cycle Settling

The ADS1018 can perform conversions at rates up to

3300 samples per second (SPS). A programmable

• Internal Temperature Sensor:

gain amplifier (PGA) is integrated in the ADS1018

1°C (max) Error

that offers input ranges from as low as ±256 mV up to

• Internal Low-Drift Voltage Reference

the supply rails, allowing both large and small signals

• Internal Oscillator

to be measured with high resolution. The ADS1018

also features an input multiplexer (MUX) that provides

• Internal PGA

two differential or four single-ended inputs. The

• Four Single-Ended or Two Differential Inputs

ADS1018 can also function as a high-accuracy

temperature sensor. This temperature sensor can be

APPLICATIONS

used for system-level temperature monitoring or cold-

junction compensation for thermocouples.

• Temperature Measurement

• Portable Instrumentation

The ADS1018 operates either in continuous

conversion mode or single-shot mode that

• Consumer Goods

automatically powers down after a conversion and

• Battery Monitoring

greatly reduces current consumption during idle

• Factory Automation and Process Controls

periods. The ADS1018 is specified from –40°C to

+125°C.

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.

2SPI is a trademark of Motorola.

3All other trademarks are the property of their respective owners.

PRODUCTION DATA information is current as of publication date.

Products conform to specifications per the terms of the Texas

Instruments standard warranty. Production processing does not

necessarily include testing of all parameters.

Summary of content (36 pages)

PAGE 1
ADS1018 www.ti.com SBAS526B – NOVEMBER 2012 – REVISED OCTOBER 2013 Ultra-Small, Low-Power, SPI™-Compatible, 12-Bit, Analog-to-Digital Converter and Temperature Sensor with Internal Reference Check for Samples: ADS1018 FEATURES DESCRIPTION • The ADS1018 is a precision analog-to-digital converter (ADC) with 12 bits of resolution offered in an ultra-small, leadless QFN-10 package or an MSOP-10 package. The ADS1018 is designed with precision, power, and ease of implementation in mind.
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ADS1018 SBAS526B – NOVEMBER 2012 – REVISED OCTOBER 2013 www.ti.com This integrated circuit can be damaged by ESD. Texas Instruments recommends that all integrated circuits be handled with appropriate precautions. Failure to observe proper handling and installation procedures can cause damage. ESD damage can range from subtle performance degradation to complete device failure.
PAGE 3
ADS1018 www.ti.com SBAS526B – NOVEMBER 2012 – REVISED OCTOBER 2013 ELECTRICAL CHARACTERISTICS Maximum and minimum specifications apply from TA = –40°C to +125°C, unless otherwise noted. Typical values are at TA = +25°C. All specifications are at VDD = 3.3 V and full-scale (FS) = ±2.048 V, unless otherwise noted.
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ADS1018 SBAS526B – NOVEMBER 2012 – REVISED OCTOBER 2013 www.ti.com ELECTRICAL CHARACTERISTICS (continued) Maximum and minimum specifications apply from TA = –40°C to +125°C, unless otherwise noted. Typical values are at TA = +25°C. All specifications are at VDD = 3.3 V and full-scale (FS) = ±2.048 V, unless otherwise noted. PARAMETER TEST CONDITIONS MIN TYP MAX UNIT POWER-SUPPLY REQUIREMENTS Power-supply voltage 2 Power-down current at TA = +25°C ICC 5.5 V 0.
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ADS1018 www.ti.com SBAS526B – NOVEMBER 2012 – REVISED OCTOBER 2013 PARAMETER MEASUREMENT INFORMATION SPI TIMING CHARACTERISTICS tCSH CS tSCLK tCSSC tSPWH tSCCS SCLK tDIHD tDIST tSPWL tSCSC DIN tCSDOD tDOPD tDOHD Hi-Z tCSDOZ Hi-Z DOUT Figure 1.
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ADS1018 SBAS526B – NOVEMBER 2012 – REVISED OCTOBER 2013 www.ti.com PIN CONFIGURATIONS RUG PACKAGE QFN-10 (Top View) DGS PACKAGE MSOP-10 (Top View) DIN 10 SCLK 1 9 DOUT/DRDY CS 2 8 VDD GND 3 7 AIN3 AIN0 4 6 AIN2 SCLK 1 10 DIN CS 2 9 DOUT/DRDY GND 3 8 VDD AIN0 4 7 AIN3 AIN1 5 6 AIN2 5 AIN1 PIN DESCRIPTIONS 6 PIN NAME PIN NO.
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ADS1018 www.ti.com SBAS526B – NOVEMBER 2012 – REVISED OCTOBER 2013 TYPICAL CHARACTERISTICS At TA = +25°C and VDD = 3.3 V, unless otherwise noted. 5 300 4.5 Power-Down Current (mA) Operating Current (mA) 250 VDD = 5 V 200 150 VDD = 3.3 V VDD = 2 V 100 50 4 3.5 VDD = 2 V 3 2.5 2 VDD = 3.3 V 1.5 1 0.5 0 -40 -20 0 20 40 60 80 100 120 VDD = 5 V 0 -40 140 0 -20 20 Temperature (°C) Figure 2. OPERATING CURRENT vs TEMPERATURE (1) FS = ±1.024 V FS = ±0.
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ADS1018 SBAS526B – NOVEMBER 2012 – REVISED OCTOBER 2013 www.ti.com TYPICAL CHARACTERISTICS (continued) At TA = +25°C and VDD = 3.3 V, unless otherwise noted. 1 Average Temperature Error Average 3 sigma Average 6 sigma Temperature Error (C) 0.8 0.6 0.4 0.2 0 -0.2 -0.4 -0.6 -0.8 -1 -40 -20 0 20 40 60 80 100 Temperature (C) 120 C001 Figure 8.
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ADS1018 www.ti.com SBAS526B – NOVEMBER 2012 – REVISED OCTOBER 2013 OVERVIEW The ADS1018 is a very small, low-power, 12-bit, delta-sigma (ΔΣ) analog-to-digital converter (ADC). The ADS1018 is extremely easy to configure and design into a wide variety of applications, and allows precise measurements to be obtained with very little effort. Both experienced and novice users of data converters find designing with the ADS1018 to be intuitive and problem-free.
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ADS1018 SBAS526B – NOVEMBER 2012 – REVISED OCTOBER 2013 www.ti.com MULTIPLEXER The ADS1018 contains an input multiplexer, as shown in Figure 10. Either four single-ended or two differential signals can be measured. Additionally, AIN0, AIN1, and AIN2 may be measured differentially to AIN3. The multiplexer is configured by three bits (MUX[2:0], bits 14-12) in the Config register.
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ADS1018 www.ti.com SBAS526B – NOVEMBER 2012 – REVISED OCTOBER 2013 ANALOG INPUTS The ADS1018 uses a switched-capacitor input stage in which capacitors are continuously charged and then discharged to measure the voltage between AINP and AINN. The capacitors used are small, and to external circuitry, the average loading appears resistive. This structure is shown in Figure 11. The resistance is set by the capacitor values and the rate at which they are switched.
PAGE 12
ADS1018 SBAS526B – NOVEMBER 2012 – REVISED OCTOBER 2013 www.ti.com The typical value of the input impedance cannot be neglected. Unless the input source has a low impedance, the ADS1018 input impedance may affect the measurement accuracy. For sources with high output impedance, buffering may be necessary. Note that active buffers introduce noise and also introduce offset and gain errors. All of these factors should be considered in high-accuracy applications.
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ADS1018 www.ti.com SBAS526B – NOVEMBER 2012 – REVISED OCTOBER 2013 DATA FORMAT The ADS1018 provides 12 bits of data in binary twos complement format. The positive full-scale input produces an output code of 7FF0h and the negative full-scale input produces an output code of 8000h. The output clips at these codes for signals that exceed full-scale. Table 3 summarizes the ideal output codes for different input signals. Figure 13 shows code transitions versus input voltage. Table 3.
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ADS1018 SBAS526B – NOVEMBER 2012 – REVISED OCTOBER 2013 www.ti.com TEMPERATURE SENSOR The ADS1018 temperature measurement mode is configured as a 12-bit result when enabled. Two bytes must be read to obtain data. The first byte is the most significant byte (MSB) and is followed by a second byte, the least significant byte (LSB). The first 12 bits are used to indicate temperature.
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ADS1018 www.ti.com SBAS526B – NOVEMBER 2012 – REVISED OCTOBER 2013 ALIASING As with any data converter, if the input signal contains frequencies greater than half the data rate, aliasing occurs. To prevent aliasing, the input signal must be bandlimited. However, some signals are inherently bandlimited. For example, the output of a thermocouple (which has a limited rate of change) is inherently bandlimited. Nevertheless, these signals can still contain noise and interference components.
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ADS1018 SBAS526B – NOVEMBER 2012 – REVISED OCTOBER 2013 www.ti.com SERIAL INTERFACE The SPI-compatible serial interface consists of either four signals (CS, SCLK, DIN, and DOUT/DRDY), or three signals (in which case CS may be tied low). The interface is used to read conversion data, read and write registers, and control device operation. CHIP SELECT (CS) The chip select (CS) selects the ADS1018 for SPI communication. This feature is useful when multiple devices share the same serial bus.
PAGE 17
ADS1018 www.ti.com SBAS526B – NOVEMBER 2012 – REVISED OCTOBER 2013 REGISTERS The ADS1018 has two registers that are accessible via the SPI port. The Conversion register contains the result of the last conversion. The Config register allows the user to change the ADS1018 operating modes and query the status of the devices. Conversion Register The 16-bit Conversion register contains the result of the last conversion in binary twos complement format.
PAGE 18
ADS1018 SBAS526B – NOVEMBER 2012 – REVISED OCTOBER 2013 Bit 8 www.ti.com MODE: Device operating mode This bit controls the ADS1018 operating mode. 0 = Continuous conversion mode 1 = Power-down and single-shot mode (default) Bits[7:5] DR[2:0]: Data rate These bits control the data rate setting.
PAGE 19
ADS1018 www.ti.com SBAS526B – NOVEMBER 2012 – REVISED OCTOBER 2013 DATA RETRIEVAL Data can be written to and read from the ADS1018 in the same manner in single-shot mode as in continuous conversion mode, without having to issue any commands. The mode in which ADS1018 operates in can be selected by the MODE bit in the Config register. Setting the MODE bit to '0' puts the device in continuous conversion mode. In this mode, the device is constantly starting new conversions even when CS is high.
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ADS1018 SBAS526B – NOVEMBER 2012 – REVISED OCTOBER 2013 www.ti.com 16-Bit Data Transmission Cycle If Config register data are not required to be readback, the ADS1018 conversion data can also be clocked out in a short 16-bit data transmission cycle, as shown in Figure 17. Therefore, CS must be taken high after the 16th SCLK cycle. Taking CS high resets the SPI interface. The next time CS is taken low, data transmission starts with the currently buffered conversion result on the first SCLK rising edge.
PAGE 21
ADS1018 www.ti.com SBAS526B – NOVEMBER 2012 – REVISED OCTOBER 2013 APPLICATION INFORMATION The following sections give example circuits and suggestions for using the ADS1018 in various situations. BASIC CONNECTIONS AND LAYOUT CONSIDERATIONS For many applications, connecting the ADS1018 is simple. A basic connection diagram for the ADS1018 is shown in Figure 18. Most microcontroller SPI peripherals can operate with the ADS1018. The interface operates in SPI mode 1 where CPOL = 0 and CPHA = 1.
PAGE 22
ADS1018 SBAS526B – NOVEMBER 2012 – REVISED OCTOBER 2013 www.ti.com TI recommends employing best design practices when laying out a printed circuit board (PCB) for both analog and digital components.
PAGE 23
ADS1018 www.ti.com SBAS526B – NOVEMBER 2012 – REVISED OCTOBER 2013 CONNECTING MULTIPLE DEVICES Connecting multiple ADS1018s to a single bus is simple. SCLK, DIN, and DOUT/DRDY can be safely shared by using a dedicated chip-select (CS) for each SPI-enabled device. By default, when CS goes high for the ADS1018, DOUT/DRDY is pulled up to the supply of the ADS1018 by a weak 400 kΩ resistor.
PAGE 24
ADS1018 SBAS526B – NOVEMBER 2012 – REVISED OCTOBER 2013 www.ti.com USING GPIO PORTS FOR COMMUNICATION Most microcontrollers have programmable input/output (I/O) pins that can be set in software to act as inputs or outputs. If an SPI controller is not available, the ADS1018 can be connected to GPIO pins and the SPI bus protocol can be simulated. Using GPIO pins to generate the SPI interface only requires that the pins be configured as push or pull inputs or outputs.
PAGE 25
ADS1018 www.ti.com SBAS526B – NOVEMBER 2012 – REVISED OCTOBER 2013 THERMOCOUPLE MEASUREMENT WITH COLD-JUNCTION COMPENSATION For an independent, two-channel thermocouple system, Figure 22 shows the basic connections. This circuit contains a simple low-pass, anti-aliasing filter, mid-point bias, and open detection.
PAGE 26
ADS1018 SBAS526B – NOVEMBER 2012 – REVISED OCTOBER 2013 www.ti.com The two 1-MΩ resistors (RPU and RPD) serve two purposes. The first purpose is to offer a common-mode bias near midsupply. Although the ADS1018 does offer the ability to float the common-mode of a signal or connect any of the inputs to a common point such as ground or supply, TI generally recommends avoiding such situations.
PAGE 27
ADS1018 www.ti.com SBAS526B – NOVEMBER 2012 – REVISED OCTOBER 2013 REVISION HISTORY NOTE: Page numbers for previous revisions may differ from page numbers in the current version. Changes from Revision A (December 2012) to Revision B Page • Deleted device graphic ......................................................................................................................................................... 1 • Changed bit 1 to NOP0 in Table 6 ...................................................
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PACKAGE OPTION ADDENDUM www.ti.
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PACKAGE OPTION ADDENDUM www.ti.com 18-Oct-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.
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PACKAGE MATERIALS INFORMATION www.ti.com 18-Oct-2013 TAPE AND REEL INFORMATION *All dimensions are nominal Device Package Package Pins Type Drawing ADS1018IDGSR VSSOP DGS 10 SPQ Reel Reel A0 Diameter Width (mm) (mm) W1 (mm) 2500 330.0 12.4 5.3 B0 (mm) K0 (mm) P1 (mm) W Pin1 (mm) Quadrant 3.3 1.3 8.0 12.0 Q1 ADS1018IDGST VSSOP DGS 10 250 180.0 12.4 5.3 3.3 1.3 8.0 12.0 Q1 ADS1018IRUGR X2QFN RUG 10 3000 179.0 8.4 1.75 2.25 0.65 4.0 8.
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PACKAGE MATERIALS INFORMATION www.ti.com 18-Oct-2013 *All dimensions are nominal Device Package Type Package Drawing Pins SPQ Length (mm) Width (mm) Height (mm) ADS1018IDGSR VSSOP DGS 10 2500 370.0 355.0 55.0 ADS1018IDGST VSSOP DGS 10 250 195.0 200.0 45.0 ADS1018IRUGR X2QFN RUG 10 3000 203.0 203.0 35.0 ADS1018IRUGT X2QFN RUG 10 250 203.0 203.0 35.
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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.