TEXAS INSTRUMENTS ADS1232, ADS1234 Technical data

    

Input

Mux

∆Σ

ADC

REFP REFN

PGA

A = 1, 2, 64, 128

CAP DVDD

DGND

AGNDA1/TEMP

(1)

NOTE: (1) A1 for ADS1234, TEMP for ADS1232.

AINP1 AINN1

AINP2 AINN2

AINP3 AINN3

AINP4 AINN4

ADS1234 Only

SCLK

SPEED

DRDY/DOUT

PDWN

GAIN [1:0]

AVDD

CAP

External Oscillator

Internal Oscillator

XTAL1/CLKIN XTAL2

查询ADS1232供应商查询ADS1232供应商

Ultra Low-Noise, 24-Bit Analog-to-Digital Converter

FEATURES DESCRIPTION

• Up to 23.5 Effective Bits

• RMS Noise:

– 17nV at 10Hz – 44nV at 80Hz

• On-Board Low Noise Gain-Amp ± 19.5mV with a +5V reference. While the ADS1232

• 19.2-Bit Noise-Free Resolution at Gain = 64

• Simultaneous 50Hz and 60Hz Rejection:

– Internal Clock: 110 dB – External Clock: 130 dB

• ± 1% Low-Drift On-Board Oscillator

• Selectable Gains of 1, 2, 64, and 128

• Selectable 10/80SPS Conversion Rates

• 2-Channel Differential Input with Built-In Temp

sensor (ADS1232)

• 4-Channel Differential Input (ADS1234)

• External Reference up to AVDD

• Simple Serial Digital Interface

• Supply Range: 2.7V to 5.3V

• –40 ° C to +105 ° C Temperature Range

The ADS1232 and ADS1234 are precision analog-to-digital (A/D) converters featuring true 23.5 effective-bit performance and exceptional ease of use. Selectable gains of 1, 2, 64, or 128 allow full-scale differential input ranges of ± 2.5V to

offers a two-channel differential input and a built-in temperature sensor, the ADS1234 features a four-channel differential input multiplexer. A very low-noise Gain-Amp features low differential input current to minimize errors when using high-impedance transducers. An on-board oscillator is provided for excellent 50Hz and 60Hz rejection without an external clock source. The devices also feature a low current driver to accommodate an external crystal; they also accept external clock sources for all applications.

All of the features of the ADS1232/ADS1234 are hard-wire selected, without software programming. Data is accessed over a simple serial interface compatible with popular microcontrollers such as the MSP430. The ADS1232 is available in the 24-pin TSSOP package, and the ADS1234 is available in the 28-pin TSSOP.

ADS1232 ADS1234

SBAS350 – JUNE 2005

APPLICATIONS

• Weigh Scales

• Strain Gauges

• Bridge Sensors

• Industrial Process Control

PRODUCT PREVIEW information concerns products in the formative or design phase of development. Characteristic data and other specifications are design goals. Texas Instruments reserves the right to change or discontinue these products without notice.

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.

www.ti.com

PRODUCT PREVIEW

ADS1232 ADS1234

SBAS350 – JUNE 2005

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. Precision integrated circuits may be more susceptible to damage because very small parametric changes could cause the device not to meet its published specifications.

ORDERING INFORMATION

PRODUCT PACKAGE-LEAD TEMPERATURE

ADS1232 TSSOP-24 PW –40°C to 105°C ADS1232

ADS1234 TSSOP-28 PW –40°C to 105°C ADS1234

(1) For the most current package and ordering information, see the Package Option Addendum at the end of this document, or see the TI

website at www.ti.com.

PACKAGE PACKAGE ORDERING TRANSPORT MEDIA,

DESIGNATOR MARKING NUMBER QUANTITY

SPECIFIED

RANGE

(1)

ADS1232IPWT Tape and Reel, 250 ADS1232IPWR Tape and Reel, 2500 ADS1234IPWT Tape and Reel, 250 ADS1234IPWR Tape and Reel, 2500

ABSOLUTE MAXIMUM RATINGS

over operating free-air temperature range (unless otherwise noted)

AVDD to AGND –0.3 to +6 V DVDD to DGND –0.3 to +6 V AGND to DGND –0.3 to +0.3 V Input Current 100, Momentary mA Input Current 10, Continuous mA Analog Input Voltage to AGND –0.3 to AVDD + 0.3 V Digital Input Voltage to DGND –0.3 to DVDD + 0.3 V Maximum Junction Temperature +150 °C Operating Temperature Range –40 to +105 °C Storage Temperature Range –60 to +150 °C Lead Temperature (soldering, 10s) +300 °C

(1) Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. These are stress ratings

only, and functional operation of the device at these or any other conditions beyond those indicated under Recommended Operating Conditions is not implied. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.

(1)

ADS1232, ADS1234 UNIT

www.ti.com

ADS1232 ADS1234

SBAS350 – JUNE 2005

ELECTRICAL CHARACTERISTICS: V

= +5V

REF

All specifications TA= –40°C to +105°C, AVDD = DVDD = VREFP = +5V, VREFN = AGND, Internal Oscillator, SPEED = Low, Gain = 64 (unless otherwise specified).

ADS1232, ADS1234

PARAMETER CONDITIONS MIN TYP MAX UNIT

Analog Inputs

Full-Scale Input Voltage (AIN

- AIN

)

Common-mode Input Range

AINxP or AINxN with respect to GND, Gain = 1

AGND – 0.1 AVDD + 0.1 V

Gain = 64, 128 (0.5)AVDD – 1 (0.5)AVDD + 1 V

Differential Input Current

Gain = 1, 2 500 nA Gain = 64, 128 50 nA

System Performance

Resolution No missing codes 24 Bits

Internal Oscillator, SPEED = High TBD 80 TBD SPS

Conversion Rate

Internal Oscillator, SPEED = Low TBD 10 TBD SPS External Oscillator, SPEED = High f External Oscillator, SPEED = Low f

Digital Filter Settling Time Full Settling 4 Conversions

Differential input, End point fit

Integral Non-Linearity (INL)

Gain = 1, 2 Differential input, End point fit

Gain = 64, 128

Input Offset Error

Input Offset Error Drift

Gain Error

(3)

Gain Error Drift

(2)

Gain = 1 ± 0.2 TBD ppm of FS Gain = 64 ± 2 TBD ppm of FS Gain = 1 1 µV/°C Gain = 64 15 nV/°C Gain = 1 0.001 TBD % Gain = 64 0.001 TBD % Gain = 1 0.5 ppm/ ° C Gain = 64 ± 4 ppm/ ° C Internal oscillator, 50Hz and 60Hz 100 110 dB

Normal-mode Rejection

(4)

External oscillator, 50Hz and 60Hz, ± 1Hz

Common-mode Rejection

at DC, Gain = 1, ∆ VDD = 1V TBD 100 dB at DC, Gain = 64, ∆ VDD = 0.1V TBD 75 dB

Input-Referred Noise See Noise Performance Tables

Power-Supply Rejection

at DC, Gain = 1, ∆ VDD = 1V TBD 100 dB at DC, Gain = 64, ∆ VDD = 0.1V TBD 85 dB

Voltage Reference Input

Voltage Reference Input (V

)

REF

Negative Reference Input (VREFN)

Positive Reference Input (VREFP)

= VREFP - VREFN 1 AVDD AVDD + 0.1V V

REF

AGND – 0.1 VREFP – 1.0 V

VREFN + 1.0 AVDD + 0.1 V

Voltage Reference Input Current

(1) FSR = full scale range = V (2) Offset calibration can minimize these errors to the level of noise at any temperature.

/Gain

REF

(3) Gain errors are calibrated at the factory (AVDD = +5V, all gains, TA= +25 ° C). (4) Specification is assured by the combination of design and final production test.

±0.5V

/Gain V

REF

/ 61440 SPS

CLK

/ 491520 SPS

CLK

± 0.0002 ± 0.0015 % of FSR

± 0.0010 TBD % of FSR

120 130 dB

50 nA

(1)

+ 7 hidden pages