The ADS1232 and ADS1234 are precision 24-bit analog-to-digital converters (ADCs)

ADS1232

Manufacturer Part NumberADS1232
DescriptionThe ADS1232 and ADS1234 are precision 24-bit analog-to-digital converters (ADCs)
ManufacturerTexas Instruments
ADS1232 datasheet
 

Specifications of ADS1232

Resolution(bits)24Sample Rate (max)(sps)80SPS
# Input Channels2InterfaceSerial SPI
Dnl(max)(+/-lsb)1Input Range0.5Vref/PGA (1,2,64,128)
Power Consumption(typ)(mw)4.3Reference ModeExt
ArchitectureDelta-SigmaAnalog Voltage Av/dd(min)(v)2.7
Analog Voltage Av/dd(max)(v)5.3Digital Supply(min)(v)2.7
Digital Supply(max)(v)5.3Operating Temperature Range(c)-40 to 105
Pin/package24TSSOPIntegrated FeaturesPGA,Oscillator,50/60 Hz rejection
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FEATURES
1
Complete Front-End for Bridge Sensors
2
Up to 23.5 Effective Bits
Onboard, Low-Noise PGA
RMS Noise:
17nV at 10SPS (PGA = 128)
44nV at 80SPS (PGA = 128)
19.2-Bit Noise-Free Resolution at Gain = 64
Over 100dB Simultaneous 50Hz and 60Hz
Rejection
Flexible Clocking:
Low-Drift Onboard Oscillator (±3%)
Optional External Crystal
Selectable Gains of 1, 2, 64, and 128
Easy Ratiometric Measurements–
External Voltage Reference up to 5V
Selectable 10SPS or 80SPS Data Rates
Two-Channel Differential Input with Built-In
Temperature Sensor (ADS1232)
Four-Channel Differential Input (ADS1234)
Simple Serial Digital Interface
Supply Range: 2.7V to 5.3V
–40 C to +105 C Temperature Range
APPLICATIONS
Weigh Scales
Strain Gauges
Pressure Sensors
Industrial Process Control
AINP1
AINN1
AINP2
AINN2
AINP3
AINN3
ADS1234
AINP4
Only
AINN4
NOTE: (1) A1 for ADS1234, TEMP for ADS1232.
1
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.
2
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.
24-Bit Analog-to-Digital Converter
For Bridge Sensors
DESCRIPTION
The ADS1232 and ADS1234 are precision 24-bit
analog-to-digital converters (ADCs). With an onboard,
low-noise
precision delta-sigma ADC and internal oscillator, the
ADS1232/4 provide a complete front-end solution for
bridge sensor applications including weigh scales,
strain gauges and pressure sensors.
The input multiplexer accepts either two (ADS1232)
or four (ADS1234) differential inputs. The ADS1232
also includes an onboard temperature sensor to
monitor ambient temperature. The onboard, low-noise
PGA has a selectable gain of 1, 2, 64, or 128
supporting a full-scale differential input of ±2.5V,
±1.25V, ±39mV, or ±19.5mV. The delta-sigma ADC
has 23.5-bit effective resolution and is comprised of a
3rd-order modulator and 4th-order digital filter. Two
data rates are supported: 10SPS (with both 50Hz and
60Hz rejection) and 80SPS. The ADS1232/4 can be
clocked externally using an oscillator or a crystal.
There is also an internal oscillator available that
requires no external components. Offset calibration is
performed on-demand and the ADS1232/4 can be
put in a low-power standby mode or shut off
completely in power-down mode. All of the features of
the
ADS1232/4
pin-driven control. There are no digital registers to
program in order to simplify software development.
Data are output over an easily-isolated serial
interface that connects directly to the MSP430 and
other microcontrollers.
The ADS1232 is available in a TSSOP-24 package
and the ADS1234 is in a TSSOP-28. Both are fully
specified from -40 C to +105 C.
CAP
REFP REFN
AVDD
Gain =
1, 2, 64, or 128
Input
PGA
Mux
Internal Oscillator
External Oscillator
(1)
A1/TEMP
A0
AGND
CAP
CLKIN/XTAL1 XTAL2
SBAS350F – JUNE 2005 – REVISED FEBRUARY 2008
programmable
gain
amplifier
are
operated
through
DVDD
GAIN [1:0]
PDWN
DRDY/DOUT
DS ADC
SCLK
SPEED
DGND
Copyright © 2005–2008, Texas Instruments Incorporated
ADS1232
ADS1234
(PGA),
simple

ADS1232 Summary of contents

  • Page 1

    ... Data are output over an easily-isolated serial interface that connects directly to the MSP430 and other microcontrollers. The ADS1232 is available in a TSSOP-24 package and the ADS1234 TSSOP-28. Both are fully specified from - +105 C. CAP REFP REFN ...

  • Page 2

    ... Conditions is not implied. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability. 2 ORDERING INFORMATION (1) ADS1232, ADS1234 100, Momentary –0.3 to AVDD + 0.3 –0.3 to DVDD + 0.3 Copyright © 2005–2008, Texas Instruments Incorporated Product Folder Link(s): ADS1232 ADS1234 www.ti.com UNIT –0 –0 –0 ...

  • Page 3

    ... Offset calibration can minimize these errors to the level of noise at any temperature. (3) Gain errors are calibrated at the factory (AVDD = +5V, all gains, T (4) Specification is assured by the combination of design and final production test. Copyright © 2005–2008, Texas Instruments Incorporated ADS1232, ADS1234 CONDITIONS MIN AGND – 0.1 AGND + 1 ...

  • Page 4

    ... Normal Mode, AVDD = DVDD = 5V, Gain = 64, 128 Standby Mode, AVDD = DVDD = 5V 4 ADS1232, ADS1234 CONDITIONS MIN 0.7 DVDD DGND DVDD – 0.4 0.2 2.7 Copyright © 2005–2008, Texas Instruments Incorporated Product Folder Link(s): ADS1232 ADS1234 www.ti.com TYP MAX UNIT DVDD + 0.1 V 0.2 DVDD V V 0.2 DVDD V ± ...

  • Page 5

    ... The ADS1232/4 offer outstanding noise performance that can be optimized for a given full-scale range using the on-chip programmable gain amplifier. inputs shorted externally for different gains, data rates, and voltage reference values. The RMS and Peak-to-Peak noise are referred to the input. The Effective Number of Bits (ENOB) is defined as: ...

  • Page 6

    ... A0 17 AGND CAP 9 CAP 10 16 REFP 11 15 REFN AINP1 14 AINP2 AINN1 AINN2 AINP3 AINN3 14 Copyright © 2005–2008, Texas Instruments Incorporated Product Folder Link(s): ADS1232 ADS1234 www.ti.com 28 DRDY/DOUT 27 SCLK 26 PDWN 25 SPEED 24 GAIN1 23 GAIN0 22 AVDD ADS1234 21 AGND 20 REFP 19 REFN 18 AINP2 ...

  • Page 7

    ... See text for more details. Dual-Purpose Output: Data Ready: Indicates valid data by going low. Data Output: Outputs data, MSB first, on the first rising edge of SCLK. Product Folder Link(s): ADS1232 ADS1234 ADS1232 ADS1234 SBAS350F – JUNE 2005 – REVISED FEBRUARY 2008 7 ...

  • Page 8

    ... Data Rate = 80SPS 800 1000 0 200 Copyright © 2005–2008, Texas Instruments Incorporated Product Folder Link(s): ADS1232 ADS1234 www.ti.com NOISE PLOT PGA = 128 Data Rate = 10SPS 400 600 800 1000 Time (Reading Number) Figure 2. NOISE HISTOGRAM ...

  • Page 9

    ... PGA = 1 18 Data Rate = 10SPS 90 Samples from 3 Lots Product Folder Link(s): ADS1232 ADS1234 ADS1232 ADS1234 SBAS350F – JUNE 2005 – REVISED FEBRUARY 2008 NOISE HISTOGRAM Output Code (LSB) Figure 8. Offset Drift (nV/ C) ° Figure 10. ...

  • Page 10

    ... Data Rate = 10SPS 0.03 0.02 0.01 0 0.01 0. 110 50 30 Product Folder Link(s): ADS1232 ADS1234 www.ti.com OFFSET DRIFT (+ +105 C) PGA = 128 Data Rate = 10SPS 90 Samples from 3 Lots Offset Drift (nV/ C) ° Figure 14. GAIN DRIFT (+ +105 C) PGA = 128 Data Rate = 10SPS 90 Samples from 3 Lots Gain Drift (ppm/ C) ° ...

  • Page 11

    ... Product Folder Link(s): ADS1232 ADS1234 ADS1232 ADS1234 SBAS350F – JUNE 2005 – REVISED FEBRUARY 2008 NOISE vs INPUT SIGNAL 9.5 4.75 0 4.75 9.5 14.25 V (mV) IN Figure 20. INTEGRAL NONLINEARITY vs INPUT SIGNAL 390.625 312.5 234.375 156.25 78.125 0 78.125 156 ...

  • Page 12

    ... +25 C, AVDD = DVDD = VREFP = 5V, and VREFN = AGND, unless otherwise noted. A 10.06 10.01 9.96 9.91 9.86 12 DATA RATE vs TEMPERATURE SPEED = LOW CLKIN/XTAL1 = LOW (Internal Oscillator Temperature (_C) Figure 25. Copyright © 2005–2008, Texas Instruments Incorporated Product Folder Link(s): ADS1232 ADS1234 www.ti.com 90 110 ...

  • Page 13

    ... A0 and A1 (ADS1234 only), as shown in Table 5. For the ADS1232, the A1 pin is replaced by the TEMP pin to activate the onboard diodes (see the Temperature Sensor section for more details). The ADS1232/4 accept differential input signals, but can also measure unipolar signals ...

  • Page 14

    ... With the combination of both gain stages, the PGA can be set 128. The PGA of the ADS1232/4 can be set 64, or 128 with pins GAIN1 (MSB) and GAIN0 (LSB). By using AVDD as the reference input, the bipolar input ranges from ± ...

  • Page 15

    ... GND by more than 100mV, and likewise, do not exceed AVDD by 100mV: GND – 100mV < (REFP or REFN) < AVDD + 100mV CLOCK SOURCES The ADS1232/4 can use an external clock source, external crystal, or internal oscillator to accommodate a wide variety of applications. Figure 29 equivalent ...

  • Page 16

    ... Figure 31. Frequency Response Out To 100Hz normal-mode The ADS1232/4 data rate and frequency response scale directly with clock frequency. For example increases from 4.9152MHz to 6.144MHz when CLK the SPEED pin is tied high, the data rate increases from 80SPS to 100SPS, while notches also increase from 80Hz to 100Hz ...

  • Page 17

    ... SETTLING TIME After changing the input multiplexer, the first data are fully settled. In both the ADS1232/4, the digital filter is allowed to settle after toggling either the pin. Toggling any of these digital pins will hold the DRDY/DOUT line high until the digital filter is fully settled ...

  • Page 18

    ... Internal Oscillator PIN or 4.9152MHz Crystal 0 10SPS 1 80SPS DATA FORMAT The ADS1232/4 output 24 bits of data in binary two’s complement format. The least significant bit (LSB) 23 has a weight of 0.5V /(2 – 1). The positive REF full-scale input produces an output code of 7FFFFFh and the negative full-scale input produces an output code of 800000h ...

  • Page 19

    ... DATA RETRIEVAL The ADS1232/4 continuously convert the analog input signal. To retrieve data, wait until DRDY/DOUT goes low, as shown in Figure 34. After this occurs, begin shifting out the data by applying SCLKs. Data are shifted out MSB first not required to shift out ...

  • Page 20

    ... SBAS350F – JUNE 2005 – REVISED FEBRUARY 2008 OFFSET CALIBRATION Offset calibration can be initiated at any time to remove the ADS1232/4 inherited offset error. To initiate offset calibration, apply at least two additional SCLKs after retrieving 24 bits of data. shows the timing pattern. The 25th SCLK will send DRDY/DOUT high ...

  • Page 21

    ... SPEED = 1 SPEED = 0 SPEED = 1 12.46 SPEED = 0 99.96 SPEED = 1 52.51 SPEED = 0 401.8 frequencies, scale proportional to CLK period. Expect a ±3% variation when an CLK Product Folder Link(s): ADS1232 ADS1234 ADS1232 ADS1234 SBAS350F – JUNE 2005 – REVISED FEBRUARY 2008 Data Ready 23 Start Conversion t 11 MIN MAX UNITS 0 12. ...

  • Page 22

    ... SBAS350F – JUNE 2005 – REVISED FEBRUARY 2008 STANDBY MODE WITH OFFSET-CALIBRATION Offset-calibration can be set to run immediately after exiting Standby mode. This is useful when the ADS1232/4 is put in Standby mode for long periods of time, and offset-calibration is desired afterwards to compensate for temperature or supply voltage changes. DRDY/DOUT ...

  • Page 23

    ... POWER-UP SEQUENCE When powering up the ADS1232/34, AVDD and DVDD must be powered up before the PDWN pin goes high, as shown in Figure 39. If PDWN is not controlled by a microprocessor, a simple RC delay circuit must be implemented, as shown in POWER-DOWN MODE Power-Down mode shuts down the entire ADC circuitry and reduces the total power consumption close to zero ...

  • Page 24

    ... If either a wider temperature range application is required (up to +1350 C, for example grounded junction thermocouple is used, pin 1 of the thermocouple can be grounded (see When the gain is set to 2, the ADS1232 input has a typical 500nV offset error and a noise level of 270nV , which is good for all kinds of low-voltage RMS output sensors ...

  • Page 25

    ... CAP PDWN 11 AINP1 12 AINN1 14 AINP2 CLKIN/XTAL1 13 AINN2 SPEED 15 REFN AGND DGND 17 Product Folder Link(s): ADS1232 ADS1234 ADS1232 ADS1234 SBAS350F – JUNE 2005 – REVISED FEBRUARY 2008 3V VDD MSP430x4xx or Other Microprocessor GND 3V 1 VDD 20 19 Gain = 128 24 23 SCLK 22 MSP430x4xx or Other ...

  • Page 26

    ... CAP SCLK PDWN 11 AINP1 XTAL2 12 AINN1 14 AINP2 CLKIN/XTAL1 13 AINN2 SPEED A0 15 REFN TEMP AGND DGND Copyright © 2005–2008, Texas Instruments Incorporated Product Folder Link(s): ADS1232 ADS1234 www.ti.com 3V VDD 19 Gain = MSP430x4xx or Other 4 Microprocessor GND ...

  • Page 27

    ... NOTE lead resistance. L Figure 45. Style 2 (Three-Wire) RTD Schematic Copyright © 2005–2008, Texas Instruments Incorporated By using both differential channels of the ADS1232, the temperature change in lead resistance eliminated. This condition is accomplished by are used to 2 using the following formula: establish the (AINP1 – ...

  • Page 28

    ... Standby Mode (d) Standby Mode/Single Conversions Standby Mode Product Folder Link(s): ADS1232 ADS1234 www.ti.com 25 Data Ready After Calibration Calibration Begins 26 Data Ready Start Conversion Data Ready After Calibration Calibration Begins Copyright © 2005–2008, Texas Instruments Incorporated ...

  • Page 29

    ... Overview. Low-Noise PGA section of Overview.......................................................................... 14 Standby Mode section of Overview. row in table below Figure 37. ................................................................................. 21 10 Figure 41............................................................................................ 23 Product Folder Link(s): ADS1232 ADS1234 ADS1232 ADS1234 SBAS350F – JUNE 2005 – REVISED FEBRUARY 2008 table ......................................... 3 to Figure 16)...................................... 9 Temperature Sensor section .................... 13 ......................................................... 14 and Figure 40) ...

  • Page 30

    ... PACKAGING INFORMATION Orderable Device (1) Package Type Package Status ADS1232IPW ACTIVE TSSOP ADS1232IPWG4 ACTIVE TSSOP ADS1232IPWR ACTIVE TSSOP ADS1232IPWRG4 ACTIVE TSSOP ADS1234IPW ACTIVE TSSOP ADS1234IPWG4 ACTIVE TSSOP ADS1234IPWR ACTIVE TSSOP ADS1234IPWRG4 ACTIVE TSSOP (1) The marketing status values are defined as follows: ACTIVE: Product device recommended for new designs ...

  • Page 31

    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 ...

  • Page 32

    ... TAPE AND REEL INFORMATION *All dimensions are nominal Device Package Package Type Drawing ADS1232IPWR TSSOP PW ADS1234IPWR TSSOP PW PACKAGE MATERIALS INFORMATION Pins SPQ Reel Reel A0 Diameter Width (mm) (mm) W1 (mm) 24 2000 330.0 16.4 6.95 28 2000 330.0 16.4 6.9 Pack Materials-Page 1 19-Mar-2012 Pin1 (mm) ...

  • Page 33

    ... Device Package Type ADS1232IPWR TSSOP ADS1234IPWR TSSOP PACKAGE MATERIALS INFORMATION Package Drawing Pins SPQ Length (mm 2000 PW 28 2000 Pack Materials-Page 2 19-Mar-2012 Width (mm) Height (mm) 346.0 346.0 33.0 346.0 346.0 33.0 ...

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