Datasheet

ManualsBrandsTEXAS INSTRUMENTS ManualsData collecting ICsData acquisition IC - AD converter (ADC) External TSSOP 16

DS ADC

REFP REFNCAP DVDD

DGND

GAIN

AINP

AINN

SCLK

SPEED

DRDY/DOUT

PDWN

AVDD

CAP

Internal

Oscillator

CLKIN

Gain=64or128

PGA

AGND

ADS1230

www.ti.com

SBAS366B –OCTOBER 2006–REVISED SEPTEMBER 2012

20-Bit Analog-to-Digital Converter

For Bridge Sensors

Check for Samples: ADS1230

FEATURES

DESCRIPTION

The ADS1230 is a precision 20-bit analog-to-digital

• Complete Front-End for Bridge Sensor

converter (ADC). With an onboard low-noise

• Onboard PGA with Gain of 64 or 128

programmable gain amplifier (PGA), onboard

• Onboard Oscillator

oscillator, and precision 20-bit delta-sigma ADC, the

ADS1230 provides a complete front-end solution for

• RMS Noise:

bridge sensor applications including weigh scales,

40nV at 10SPS (G = 128)

strain gauges, and pressure sensors.

88nV at 80SPS (G = 128)

The low-noise PGA has a gain of 64 or 128,

• 18-Bit Noise-Free Resolution

supporting a full-scale differential input of ±39mV or

• Selectable 10SPS or 80SPS Data Rates

±19.5mV, respectively. The delta-sigma ADC has 20-

• Simultaneous 50Hz and 60Hz Rejection at

bit effective resolution and is comprised of a 3rd-

10SPS

order modulator and 4th-order digital filter. Two data

rates are supported: 10SPS (with both 50Hz and

• External Voltage Reference up to 5V for

60Hz rejection) and 80SPS. The ADS1230 can be

Ratiometric Measurements

clocked by the internal oscillator or an external clock

• Simple, Pin-Driven Control

source. Offset calibration is performed on-demand,

• Two-Wire Serial Digital Interface

and the ADS1230 can be put in a low-power standby

mode or shut off completely in power-down mode.

• Tiny 16-pin TSSOP Package

• Supply Range: 2.7V to 5.3V

All of the features of the ADS1230 are controlled by

dedicated pins; there are no digital registers to

• –40°C to +85°C Temperature Range

program. Data are output over an easily-isolated

serial interface that connects directly to the MSP430

APPLICATIONS

and other microcontrollers.

• Weigh Scales

The ADS1230 is available in a TSSOP-16 package

• Strain Gauges

and is specified from –40°C to +85°C.

• Pressure Sensors

• Industrial Process Control

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.

2All 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 (29 pages)

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ADS1230 www.ti.com SBAS366B – OCTOBER 2006 – REVISED SEPTEMBER 2012 20-Bit Analog-to-Digital Converter For Bridge Sensors Check for Samples: ADS1230 FEATURES DESCRIPTION • • • • The ADS1230 is a precision 20-bit analog-to-digital converter (ADC).
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ADS1230 SBAS366B – OCTOBER 2006 – REVISED SEPTEMBER 2012 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.
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ADS1230 www.ti.com SBAS366B – OCTOBER 2006 – REVISED SEPTEMBER 2012 ELECTRICAL CHARACTERISTICS All specifications at TA = –40°C to +85°C, AVDD = DVDD = REFP = +5V, REFN = AGND, and Gain = 64, unless otherwise noted. ADS1230 PARAMETER CONDITIONS MIN TYP MAX UNIT Analog Inputs Full-Scale Input Voltage (AINP – AINN) ±0.5VREF/PGA Common-Mode Input Range AGND + 1.5V Differential Input Current V AVDD – 1.
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ADS1230 SBAS366B – OCTOBER 2006 – REVISED SEPTEMBER 2012 www.ti.com ELECTRICAL CHARACTERISTICS (continued) All specifications at TA = –40°C to +85°C, AVDD = DVDD = REFP = +5V, REFN = AGND, and Gain = 64, unless otherwise noted. ADS1230 PARAMETER CONDITIONS MIN TYP MAX UNIT 5.3 V Normal Mode, AVDD = 3V 900 1400 μA Normal Mode, AVDD = 5V 900 1400 μA Standby Mode 0.1 1 μA Power-Down 0.
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ADS1230 www.ti.com SBAS366B – OCTOBER 2006 – REVISED SEPTEMBER 2012 PIN CONFIGURATION PW PACKAGE TSSOP-16 (Top View) DVDD 1 16 DRDY/DOUT DGND 2 15 SCLK CLKIN 3 14 PDWN GAIN 4 13 SPEED ADS1230 CAP 5 12 AVDD CAP 6 11 AGND AINP 7 10 REFP AINN 8 9 REFN PIN DESCRIPTIONS NAME TERMINAL ANALOG/DIGITAL INPUT/OUTPUT DVDD 1 Digital Digital Power Supply: 2.7V to 5.
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ADS1230 SBAS366B – OCTOBER 2006 – REVISED SEPTEMBER 2012 www.ti.com NOISE PERFORMANCE The ADS1230 offers outstanding noise performance. Table 1 summarizes the typical noise performance with inputs shorted externally for different data rates and voltage reference values. The RMS and Peak-to-Peak noise are referred to the input.
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ADS1230 www.ti.com SBAS366B – OCTOBER 2006 – REVISED SEPTEMBER 2012 TYPICAL CHARACTERISTICS At TA = +25°C, AVDD = DVDD = REFP = 5V, and REFN = AGND, unless otherwise noted. NOISE PLOT NOISE PLOT 3 PGA = 64 Data Rate = 10SPS PGA = 64 Data Rate = 80SPS 2 1 3 Output Code (LSB) Output Code (LSB) 4 2 1 0 -1 -2 -3 -4 -5 0 -6 0 200 400 600 800 1000 0 200 Figure 2.
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ADS1230 SBAS366B – OCTOBER 2006 – REVISED SEPTEMBER 2012 www.ti.com TYPICAL CHARACTERISTICS (continued) At TA = +25°C, AVDD = DVDD = REFP = 5V, and REFN = AGND, unless otherwise noted. NOISE HISTOGRAM NOISE HISTOGRAM 500 250 PGA = 128 Data Rate = 10SPS 450 PGA = 128 Data Rate = 80SPS 400 200 Occurrence Occurrence 350 300 250 200 150 100 150 100 50 50 0 0 -5 -4 -3 -2 0 -1 -7 -6 -5 -4 -3 -2 -1 0 Output Code (LSB) Figure 8. OFFSET vs TEMPERATURE GAIN ERROR vs TEMPERATURE -0.
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ADS1230 www.ti.com SBAS366B – OCTOBER 2006 – REVISED SEPTEMBER 2012 TYPICAL CHARACTERISTICS (continued) At TA = +25°C, AVDD = DVDD = REFP = 5V, and REFN = AGND, unless otherwise noted. INTEGRAL NONLINEARITY vs INPUT SIGNAL INTEGRAL NONLINEARITY vs INPUT SIGNAL 10 1.0 -20°C +25°C 5 0 -20°C INL (ppm) INL (ppm) 0.5 +70°C 0 +85°C -0.5 -40°C -1.0 +25°C -5 -1.5 PGA = 64 Data Rate = 10SPS PGA = 128 Data Rate = 10SPS -40°C -10 +70°C +85°C -2.
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ADS1230 SBAS366B – OCTOBER 2006 – REVISED SEPTEMBER 2012 www.ti.com OVERVIEW The ADS1230 is a precision, 20-bit ADC that includes a low-noise PGA, internal oscillator, third-order deltasigma (ΔΣ) modulator, and fourth-order digital filter. The ADS1230 provides a complete front-end solution for bridge sensor applications such as weigh scales, strain guages, and pressure sensors. Clocking can be supplied by an external clock or by a precision internal oscillator.
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ADS1230 www.ti.com SBAS366B – OCTOBER 2006 – REVISED SEPTEMBER 2012 VOLTAGE REFERENCE INPUTS (REFP, REFN) The voltage reference used by the modulator is generated from the voltage difference between REFP and REFN: VREF = REFP – REFN. The reference inputs use a structure similar to that of the analog inputs. In order to increase the reference input impedance, a switching buffer circuitry is used to reduce the input equivalent capacitance. The reference drift and noise impact ADC performance.
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ADS1230 SBAS366B – OCTOBER 2006 – REVISED SEPTEMBER 2012 www.ti.com FREQUENCY RESPONSE 0 Data Rate = 10SPS 4 -50 Gain (dB) The ADS1230 uses a sinc digital filter with the frequency response (fCLK = 4.9152MHz) shown in Figure 21. The frequency response repeats at multiples of the modulator sampling frequency of 76.8kHz. The overall response is that of a low-pass filter with a –3dB cutoff frequency of 3.32Hz with the SPEED pin tied low (10SPS data rate) and 11.
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ADS1230 www.ti.com SBAS366B – OCTOBER 2006 – REVISED SEPTEMBER 2012 SETTLING TIME DATA FORMAT In certain instances, large changes in input will require settling time. For example, an external multiplexer in front of the ADS1230 can put large changes in input voltage by simply switching the multiplexer input channels. Abrupt changes in the input will require four data conversion cycles to settle. When continuously converting, five readings may be necessary in order to settle the data.
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ADS1230 SBAS366B – OCTOBER 2006 – REVISED SEPTEMBER 2012 www.ti.com DATA READY/DATA OUTPUT (DRDY/DOUT) DATA RETRIEVAL This digital output pin serves two purposes. First, it indicates when new data are ready by going low. Afterwards, on the first rising edge of SCLK, the DRDY/DOUT pin changes function and begins outputting the conversion data, most significant bit (MSB) first. Data are shifted out on each subsequent SCLK rising edge.
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ADS1230 www.ti.com SBAS366B – OCTOBER 2006 – REVISED SEPTEMBER 2012 Data a) 20 Bits of Data Retrieval New Data Ready Data Ready MSB DRDY/DOUT LSB 19 17 18 0 tPD tHT tDS tSCLK tUPDATE 1 SCLK 20 tSCLK tCONV Data b) 24 Bits of Data Retrieval Data Ready New Data Ready MSB DRDY/DOUT LSB 19 18 17 0 4 tHT tPD tDS tUPDATE tSCLK 1 SCLK 3 2 1 20 21 22 23 24 tSCLK tCONV Figure 25.
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ADS1230 SBAS366B – OCTOBER 2006 – REVISED SEPTEMBER 2012 www.ti.com OFFSET CALIBRATION During this time, the analog input pins are disconnected within the ADC and the appropriate signal is applied internally to perform the calibration. When the calibration is completed, DRDY/DOUT goes low, indicating that new data are ready. The first conversion after a calibration is fully settled and valid for use.
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ADS1230 www.ti.com SBAS366B – OCTOBER 2006 – REVISED SEPTEMBER 2012 STANDBY MODE When tSTANDBY has passed with SCLK held high, Standby mode activates. DRDY/DOUT stays high when Standby mode begins. SCLK must remain high to stay in Standby mode. To exit Standby mode (wakeup), set SCLK low. The first data after exiting Standby mode is valid. Standby mode dramatically reduces power consumption by shutting down most of the circuitry.
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ADS1230 SBAS366B – OCTOBER 2006 – REVISED SEPTEMBER 2012 www.ti.com STANDBY MODE WITH OFFSETCALIBRATION To force an offset-calibration with Standby mode, shift 25 SCLKs and bring the SCLK pin high to enter Standby mode. Offset-calibration then begins after wake-up; Figure 29 shows the appropriate timing. Note the extra time needed after wake-up for calibration before data are ready. The first data after Standby mode with offset-calibration is fully settled and can be used right away.
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ADS1230 www.ti.com SBAS366B – OCTOBER 2006 – REVISED SEPTEMBER 2012 POWER-UP SEQUENCE blank When powering up the ADS1230, AVDD and DVDD must be powered up before the PDWN pin goes high, as shown in Figure 30. If PDWN is not controlled by a microprocessor, a simple RC delay circuit must be implemented, as shown in Figure 31. AVDD DVDD PDWN ³ 10ms POWER-DOWN MODE Power-Down mode shuts down the entire ADC circuitry and reduces the total power consumption close to zero.
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ADS1230 SBAS366B – OCTOBER 2006 – REVISED SEPTEMBER 2012 www.ti.com FS ǒFS Ǔ APPLICATION EXAMPLES LC Noise−Free Counts + ǒ2 BITEffǓ Weigh Scale System Figure 33 shows a typical ADS1230 hook-up as part of a weigh scale system. In this setup, the ADS1230 is configured at a 10SPS data rate. Note that the internal oscillator is used by grounding the CLKIN pin. The user can also apply a 4.9152MHz clock to the CLKIN pin.
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ADS1230 www.ti.
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ADS1230 SBAS366B – OCTOBER 2006 – REVISED SEPTEMBER 2012 www.ti.
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ADS1230 www.ti.com SBAS366B – OCTOBER 2006 – REVISED SEPTEMBER 2012 REVISION HISTORY NOTE: Page numbers for previous revisions may differ from page numbers in the current version. Changes from Revision A (July 2007) to Revision B • Page Deleted "Not recommended for new design" watermark from entire document ................................................................... 1 Changes from Original (October 2006) to Revision A Page • Deleted min and max values for Data Rate Internal Oscillator ......
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PACKAGE OPTION ADDENDUM www.ti.
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PACKAGE MATERIALS INFORMATION www.ti.com 31-Aug-2012 TAPE AND REEL INFORMATION *All dimensions are nominal Device ADS1230IPWR Package Package Pins Type Drawing TSSOP PW 16 SPQ Reel Reel A0 Diameter Width (mm) (mm) W1 (mm) 2000 330.0 12.4 Pack Materials-Page 1 6.9 B0 (mm) K0 (mm) P1 (mm) 5.6 1.6 8.0 W Pin1 (mm) Quadrant 12.
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PACKAGE MATERIALS INFORMATION www.ti.com 31-Aug-2012 *All dimensions are nominal Device Package Type Package Drawing Pins SPQ Length (mm) Width (mm) Height (mm) ADS1230IPWR TSSOP PW 16 2000 367.0 367.0 35.
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