Datasheet

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

16-Bit, 4-Channel Serial Output Sampling

ANALOG-TO-DIGITAL CONVERTER

FEATURES

● PIN FOR PIN WITH ADS7841

● SINGLE SUPPLY: 2.7V to 5V

● 4-CHANNEL SINGLE-ENDED OR

2-CHANNEL DIFFERENTIAL INPUT

● UP TO 100kHz CONVERSION RATE

● 86dB SINAD

● SERIAL INTERFACE

● SSOP-16 PACKAGE

DESCRIPTION

The ADS8341 is a 4-channel, 16-bit sampling Analog-to-

Digital (A/D) converter with a synchronous serial interface.

Typical power dissipation is 8mW at a 100kHz throughput

rate and a +5V supply. The reference voltage (V

REF

) can be

varied between 500mV and V

, providing a corresponding

input voltage range of 0V to V

REF

. The device includes a

shutdown mode that reduces power dissipation to under

15µW. The ADS8341 is tested down to 2.7V operation.

Low power, high speed, and an onboard multiplexer make

the ADS8341 ideal for battery-operated systems such as

personal digital assistants, portable multi-channel data log-

gers, and measurement equipment. The serial interface also

provides low-cost isolation for remote data acquisition. The

ADS8341 is available in an SSOP-16 package and is en-

sured over the –40°C to +85°C temperature range.

APPLICATIONS

● DATA ACQUISITION

● TEST AND MEASUREMENT

● INDUSTRIAL PROCESS CONTROL

● PERSONAL DIGITAL ASSISTANTS

● BATTERY-POWERED SYSTEMS

CDAC

SAR

Comparator

Four

Channel

Multiplexer

Serial

Interface

and

Control

CH0

CH1

CH2

CH3

COM

REF

SHDN

DIN

DOUT

BUSY

DCLK

ADS8341

SBAS136D – SEPTEMBER 2000 – APRIL 2003

www.ti.com

PRODUCTION DATA information is current as of publication date.

Products conform to specifications per the terms of Texas Instruments

standard warranty. Production processing does not necessarily include

testing of all parameters.

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.

Summary of content (24 pages)

PAGE 1
ADS8341 ADS8 341 SBAS136D – SEPTEMBER 2000 – APRIL 2003 16-Bit, 4-Channel Serial Output Sampling ANALOG-TO-DIGITAL CONVERTER FEATURES DESCRIPTION ● PIN FOR PIN WITH ADS7841 The ADS8341 is a 4-channel, 16-bit sampling Analog-toDigital (A/D) converter with a synchronous serial interface. Typical power dissipation is 8mW at a 100kHz throughput rate and a +5V supply. The reference voltage (VREF) can be varied between 500mV and VCC, providing a corresponding input voltage range of 0V to VREF.
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ABSOLUTE MAXIMUM RATINGS(1) PIN CONFIGURATIONS +VCC to GND ........................................................................ –0.3V to +6V Analog Inputs to GND ............................................ –0.3V to +VCC + 0.3V Digital Inputs to GND ........................................................... –0.3V to +6V Power Dissipation .......................................................................... 250mW Maximum Junction Temperature ...................................................
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ELECTRICAL CHARACTERISTICS: +5V At TA = –40°C to +85°C, +VCC = +5V, VREF = +5V, fSAMPLE = 100kHz, and fCLK = 24 • fSAMPLE = 2.4MHz, unless otherwise noted. ADS8341E, P PARAMETER CONDITIONS MIN TYP MAX RESOLUTION ANALOG INPUT Full-Scale Input Span Absolute Input Range Positive Input - Negative Input Positive Input Negative Input 0 –0.2 –0.2 POWER SUPPLY REQUIREMENTS +VCC Quiescent Current 1.0 20 3 +4.75V < VCC < 5.25V ±8 ±2 4.0 ±0.05 4.0 ✻ ✻ ✻ ✻ = = = = 5Vp-p 5Vp-p 5Vp-p 5Vp-p at at at at 0.
PAGE 4
ELECTRICAL CHARACTERISTICS: +2.7V At TA = –40°C to +85°C, +VCC = +2.7V, VREF = +2.5V, fSAMPLE = 100kHz, and fCLK = 24 • fSAMPLE = 2.4MHz, unless otherwise noted. ADS8341E, P PARAMETER CONDITIONS MIN TYP MAX RESOLUTION ANALOG INPUT Full-Scale Input Span Absolute Input Range MIN TYP 16 Positive Input - Negative Input Positive Input Negative Input 0 –0.2 –0.2 VREF +VCC +0.2 +0.
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TYPICAL CHARACTERISTICS: +5V At TA = +25°C, +VCC = +5V, VREF = +5V, fSAMPLE = 100kHz, and fCLK = 24 • fSAMPLE = 2.4MHz, unless otherwise noted. FREQUENCY SPECTRUM (4096 Point FFT; fIN = 9.985kHz, –0.2dB) 0 0 –20 –20 –40 –40 Amplitude (dB) Amplitude (dB) FREQUENCY SPECTRUM (4096 Point FFT; fIN = 1.001kHz, –0.
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TYPICAL CHARACTERISTICS: +5V (Cont.) At TA = +25°C, +VCC = +5V, VREF = +5V, fSAMPLE = 100kHz, and fCLK = 24 • fSAMPLE = 2.4MHz, unless otherwise noted. DIFFERENTIAL LINEARITY ERROR vs CODE 4 2 3 DLE (LSBS) ILE (LSBS) INTEGRAL LINEARITY ERROR vs CODE 3 1 0 2 1 –1 0 –2 –1 –3 0000h 4000h 8000h C000h –2 0000h FFFFh 4000h 8000h C000h FFFFh Output Code Output Code CHANGE IN OFFSET vs TEMPERATURE CHANGE IN GAIN vs TEMPERATURE 1.0 0.40 Change in Gain (LSB) Change in Offset (LSB) 0.
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TYPICAL CHARACTERISTICS: +5V (Cont.) At TA = +25°C, +VCC = +5V, VREF = +5V, fSAMPLE = 100kHz, and fCLK = 24 • fSAMPLE = 2.4MHz, unless otherwise noted. IQ vs TEMPERATURE 1.45 IQ (mA) 1.40 1.35 1.20 1.
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TYPICAL CHARACTERISTICS: +2.7V At TA = +25°C, +VCC = +2.7V, VREF = +2.5V, fSAMPLE = 100kHz, and fCLK = 24 • fSAMPLE = 2.4MHz, unless otherwise noted. FREQUENCY SPECTRUM (4096 Point FFT; fIN = 9.985kHz, –0.2dB) 0 0 –20 –20 –40 –40 Amplitude (dB) Amplitude (dB) FREQUENCY SPECTRUM (4096 Point FFT; fIN = 1.001kHz, –0.
PAGE 9
TYPICAL CHARACTERISTICS: +2.7V (Cont.) At TA = +25°C, +VCC = +2.7V, VREF = +2.5V, fSAMPLE = 100kHz, and fCLK = 24 • fSAMPLE = 2.4MHz, unless otherwise noted. DIFFERENTIAL LINEARITY ERROR vs CODE 4 2 3 DLE (LSBS) ILE (LSBS) INTEGRAL LINEARITY ERROR vs CODE 3 1 0 2 1 –1 0 –2 –1 –3 0000h 4000h 8000h C000h –2 0000h FFFFh 4000h Output Code CHANGE IN OFFSET vs TEMPERATURE FFFFh CHANGE IN GAIN vs TEMPERATURE 0.200 0.20 0.
PAGE 10
TYPICAL CHARACTERISTICS: +2.7V (Cont.) At TA = +25°C, +VCC = +2.7V, VREF = +2.5V, fSAMPLE = 100kHz, and fCLK = 24 • fSAMPLE = 2.4MHz, unless otherwise noted. IQ vs TEMPERATURE SUPPLY CURRENT vs +VSS 1.15 1.6 fSAMPLE = 100kHz VREF vs +VSS 1.10 1.4 IQ (mA) Supply Current (mA) 1.5 1.3 1.05 1.2 1.00 1.1 0.95 1.0 2.5 3.0 3.5 4.0 +VSS (V) 10 4.5 5.
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THEORY OF OPERATION The input current on the analog inputs depends on the conversion rate of the device. During the sample period, the source must charge the internal sampling capacitor (typically 25pF). After the capacitor has been fully charged, there is no further input current. The rate of charge transfer from the analog source to the converter is a function of conversion rate. The ADS8341 is a classic Successive Approximation Register (SAR) A/D converter.
PAGE 12
rate and reference voltage. As the current from the reference is drawn on each bit decision, clocking the converter more quickly during a given conversion period will not reduce overall current drain from the reference. REFERENCE INPUT The external reference sets the analog input range. The ADS8341 will operate with a reference in the range of 500mV to +VCC. Keep in mind that the analog input is the difference between the +IN input and the –IN input, see Figure 2.
PAGE 13
BIT NAME 7 DESCRIPTION PD1 PD0 0 0 Power-down between conversions. When each conversion is finished, the converter enters a low power mode. At the start of the next conversion, the device instantly powers up to full power. There is no need for additional delays to assure full operation and the very first conversion is valid. Single-Ended/Differential Select Bit. Along with bits A2 - A0, this bit controls the setting of the multiplexer input, see Tables I and II.
PAGE 14
The other method is shown in Figure 5, which uses 32 clock cycles per conversion; the last seven clock cycles simply shift out zeros on the DOUT line. BUSY and DOUT go into a high-impedance state when CS goes high; after the next CS falling edge, BUSY will go LOW. SYMBOL DESCRIPTION MIN tACQ Acquisition Time 1.
PAGE 15
Data Format The ADS8341 output data is in straight binary format, as shown in Figure 7. This figure shows the ideal output code for the given input voltage and does not include the effects of offset, gain, or noise. If DCLK is active and CS is LOW while the ADS8341 is in auto power-down mode, the device will continue to dissipate some power in the digital logic. The power can be reduced to a minimum by keeping CS HIGH. The differences in supply current for these two cases are shown in Figure 9.
PAGE 16
NOISE The noise floor of the ADS8341 itself is extremely low, as can be seen from Figures 10 thru 13, and is much lower than competing A/D converters. The ADS8341 was tested at both 5V and 2.7V and in both the internal and external clock modes. A low-level DC input was applied to the analog input pins and the converter was put through 5,000 conversions. The digital output of the A/D converter will vary in output code due to the internal noise of the ADS8341.
PAGE 17
LAYOUT For optimum performance, care should be taken with the physical layout of the ADS8341 circuitry. This is particularly true if the reference voltage is low and/or the conversion rate is high. The basic SAR architecture is sensitive to glitches or sudden changes on the power supply, reference, ground connections, and digital inputs that occur just prior to latching the output of the analog comparator.
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PACKAGE OPTION ADDENDUM www.ti.
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PACKAGE OPTION ADDENDUM www.ti.com (3) 11-Apr-2013 MSL, Peak Temp. -- The Moisture Sensitivity Level rating according to the JEDEC industry standard classifications, and peak solder temperature. (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.
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PACKAGE MATERIALS INFORMATION www.ti.com 24-Jul-2013 TAPE AND REEL INFORMATION *All dimensions are nominal Device Package Package Pins Type Drawing SPQ Reel Reel A0 Diameter Width (mm) (mm) W1 (mm) B0 (mm) K0 (mm) P1 (mm) W Pin1 (mm) Quadrant ADS8341E/2K5 SSOP DBQ 16 2500 330.0 12.4 6.4 5.2 2.1 8.0 12.0 Q1 ADS8341EB/2K5 SSOP DBQ 16 2500 330.0 12.4 6.4 5.2 2.1 8.0 12.
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PACKAGE MATERIALS INFORMATION www.ti.com 24-Jul-2013 *All dimensions are nominal Device Package Type Package Drawing Pins SPQ Length (mm) Width (mm) Height (mm) ADS8341E/2K5 SSOP DBQ 16 2500 367.0 367.0 35.0 ADS8341EB/2K5 SSOP DBQ 16 2500 367.0 367.0 35.
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