Datasheet

ManualsBrandsTEXAS INSTRUMENTS ManualsData collecting ICsData acquisition IC - AD converter (ADC) External SSOP 20

16-Bit, 8-Channel Serial Output Sampling

ANALOG-TO-DIGITAL CONVERTER

FEATURES

● PIN FOR PIN WITH ADS7844

● SINGLE SUPPLY: 2.7V to 5V

● 8-CHANNEL SINGLE-ENDED OR

4-CHANNEL DIFFERENTIAL INPUT

● UP TO 100kHz CONVERSION RATE

● 84dB SINAD

● SERIAL INTERFACE

● QSOP-20 AND SSOP-20 PACKAGES

APPLICATIONS

● DATA ACQUISITION

● TEST AND MEASUREMENT EQUIPMENT

● INDUSTRIAL PROCESS CONTROL

● PERSONAL DIGITAL ASSISTANTS

● BATTERY-POWERED SYSTEMS

DESCRIPTION

The ADS8344 is an 8-channel, 16-bit, sampling

Analog-to-Digital (A/D) converter with a synchronous serial

interface. Typical power dissipation is 10mW at a 100kHz

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

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 dissi-

pation to under 15µW. The ADS8344 is tested down to 2.7V

operation.

Low power, high speed, and an on-board multiplexer make

the ADS8344 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

ADS8344 is available in a QSOP-20 or SSOP-20 package

and is ensured over the –40°C to +85°C temperature range.

CDAC

SAR

Comparator

8-Channel

Multiplexer

Serial

Interface

and

Control

CH4

CH5

CH6

CH7

COM

REF

SHDN

OUT

BUSY

DCLK

CH0

CH1

CH2

CH3

4-Channel

Multiplexer

CH0

CH1

CH2

CH3

COM

ADS8343

ADS8341

ADS8345

ADS8344

SBAS139E – SEPTEMBER 2000 – REVISED SEPTEMBER 2006

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.

All trademarks are the property of their respective owners.

Summary of content (25 pages)

PAGE 1
ADS ADS 834 ADS8344 ¤ 834 4 ¤ 4 SBAS139E – SEPTEMBER 2000 – REVISED SEPTEMBER 2006 16-Bit, 8-Channel Serial Output Sampling ANALOG-TO-DIGITAL CONVERTER FEATURES DESCRIPTION ● PIN FOR PIN WITH ADS7844 The ADS8344 is an 8-channel, 16-bit, sampling Analog-to-Digital (A/D) converter with a synchronous serial interface. Typical power dissipation is 10mW at a 100kHz throughput rate and a +5V supply.
PAGE 2
ELECTROSTATIC DISCHARGE SENSITIVITY ABSOLUTE MAXIMUM RATINGS(1) +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 .......................................
PAGE 3
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. ADS8344E, N PARAMETER CONDITIONS MIN 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 ±0.05 4 ✻ ✻ ✻ ✻ = = = = 5Vp-p 5Vp-p 5Vp-p 5Vp-p at at at at 0.024 0 2.
PAGE 4
ELECTRICAL CHARACTERISTICS: +2.7V At TA = –40°C to +85°C, +VCC = +2.7V, VREF = +2.7V, fSAMPLE = 100kHz, and fCLK = 24 • fSAMPLE = 2.4MHz, unless otherwise noted.
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TYPICAL CHARACTERISTICS: +5V At TA = +25°C, +VCC = +5V, VREF = +5V, fSAMPLE = 100kHz, and fDCLK = 24 • fSAMPLE = 2.4MHz, unless otherwise noted. FREQUENCY SPECTRUM (4096 Point FFT; fIN = 9.985kHz, –0.
PAGE 6
TYPICAL CHARACTERISTICS: +5V (Cont.) At TA = +25°C, +VCC = +5V, VREF = +5V, fSAMPLE = 100kHz, and fDCLK = 24 • fSAMPLE = 2.4MHz, unless otherwise noted. 1 2 0 1 –1 0 –2 –1 –3 –2 –4 0000H 4000H C000H 8000H –3 0000H FFFFH C000H 8000H Output Code WORST CASE CHANNEL-TO-CHANNEL OFFSET MATCH vs TEMPERATURE WORST CASE CHANNEL-TO-CHANNEL GAIN MATCH vs TEMPERATURE 3.0 2.0 2.5 1.5 2.0 1.5 1.
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TYPICAL CHARACTERISTICS: +5V (Cont.) At TA = +25°C, +VCC = +5V, VREF = +5V, fSAMPLE = 100kHz, and fDCLK = 24 • fSAMPLE = 2.4MHz, unless otherwise noted. POWER DOWN SUPPLY CURRENT vs TEMPERATURE SUPPLY CURRENT vs TEMPERATURE 3.0 1.8 Supply Current (µA) Supply Current (mA) 1.7 1.6 1.5 2.5 2.0 1.5 1.4 1.3 –50 –25 0 25 Temperature (°C) ADS8344 SBAS139E 50 75 100 1.
PAGE 8
TYPICAL CHARACTERISTICS: +2.7V At TA = +25°C, +VCC = +2.7V, VREF = +2.7V, fSAMPLE = 100kHz, and fDCLK = 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 = +2.7V, fSAMPLE = 100kHz, and fDCLK = 24 • fSAMPLE = 2.4MHz, unless otherwise noted.
PAGE 10
TYPICAL CHARACTERISTICS: +2.7V (Cont.) At TA = +25°C, +VCC = +2.7V, VREF = +2.7V, fSAMPLE = 100kHz, and fDCLK = 24 • fSAMPLE = 2.4MHz, unless otherwise noted. SUPPLY CURRENT vs TEMPERATURE SUPPLY CURRENT vs +VSS 1.25 1.6 1.20 1.5 Supply Current (mA) Supply Current (mA) fSAMPLE = 100kHz, VREF = +VSS 1.15 1.10 1.05 1.00 –50 1.4 1.3 1.2 1.1 1.0 –25 0 25 50 75 100 2.5 3.0 Temperature (°C) 3.5 4.0 4.5 5.0 +VSS (V) POWER DOWN SUPPLY CURRENT vs TEMPERATURE Supply Current (µA) 3.0 2.
PAGE 11
THEORY OF OPERATION ANALOG INPUT See Figure 2 for a block diagram of the input multiplexer on the ADS8344. The differential input of the converter is derived from one of the eight inputs in reference to the COM pin, or four of the eight inputs. Table I and Table II show the relationship between the A2, A1, A0, and SGL/DIF control bits and the configuration of the analog multiplexer.
PAGE 12
(Least Significant Bit) size and is equal to the reference voltage divided by 65536. Any offset or gain error inherent in the A/D converter will appear to increase, in terms of LSB size, as the reference voltage is reduced. For example, if the offset of a given converter is 2LSBs with a 2.5V reference, then it will typically be 10LSBs with a 0.5V reference. In each case, the actual offset of the device is the same, 76.3µV.
PAGE 13
The first eight clock cycles are used to provide the control byte via the DIN pin. When the converter has enough information about the following conversion to set the input multiplexer appropriately, it enters the acquisition (sample) mode. After four more clock cycles, the control byte is complete and the converter enters the conversion mode. At this point, the input sample-and-hold goes into the Hold mode. The next sixteen clock cycles accomplish the actual A/D conversion.
PAGE 14
Since one clock cycle of the serial clock is consumed with BUSY going HIGH (while the MSB decision is being made), 16 additional clocks must be given to clock out all 16 bits of data; thus, one conversion takes a minimum of 25 clock cycles to fully read the data. Since most microprocessors communicate in 8-bit transfers, this means that an additional transfer must be made to capture the LSB.
PAGE 15
SYMBOL DESCRIPTION MIN tACQ tDS tDH tDO tDV tTR tCSS tCSH tCH tCL tBD tBDV tBTR Acquisition Time DIN Valid Prior to DCLK Rising DIN Hold After DCLK HIGH DCLK Falling to DOUT Valid CS Falling to DOUT Enabled CS Rising to DOUT Disabled CS Falling to First DCLK Rising CS Rising to DCLK Ignored DCLK HIGH DCLK LOW DCLK Falling to BUSY Rising CS Falling to BUSY Enabled CS Rising to BUSY Disabled 1.7 50 10 TYP MAX UNITS 100 70 70 50 0 150 150 100 70 70 µs ns ns ns ns ns ns ns ns ns ns ns ns TABLE VII.
PAGE 16
sion results will reduce the transition noise by 1/2 to ±0.25LSBs. Averaging should only be used for input signals with frequencies near DC. For AC signals, a digital filter can be used to low-pass filter and decimate the output codes. This works in a similar manner to averaging: for every decimation by 2, the signal-to-noise ratio will improve 3dB. 4507 LAYOUT 0 251 7FFD 7FFE 7FFF 242 0 8000 8001 Code FIGURE 9.
PAGE 17
Revision History DATE REVISION 9/06 E PAGE SECTION 2 Package/Ordering Info 4 Electrical Characteristics DESCRIPTION Added quantity to last column. Fixed typo. Changed +2.7V Gain Error minimum value (for EB, NB grade) from ±0.0024 to ±0.024. NOTE: Page numbers for previous revisions may differ from page numbers in the current version.
PAGE 18
PACKAGE OPTION ADDENDUM www.ti.
PAGE 19
PACKAGE OPTION ADDENDUM www.ti.com 11-Apr-2013 LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect. NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in a new design. PREVIEW: Device has been announced but is not in production. Samples may or may not be available. OBSOLETE: TI has discontinued the production of the device.
PAGE 20
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 8.0 16.0 Q1 ADS8344E/2K5 SSOP DBQ 20 2500 330.0 16.4 6.5 9.0 2.1 ADS8344EB/2K5 SSOP DBQ 20 2500 330.0 16.4 6.5 9.0 2.1 8.0 16.0 Q1 ADS8344N/1K SSOP DB 20 1000 330.0 16.4 8.2 7.5 2.5 12.0 16.
PAGE 21
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) ADS8344E/2K5 SSOP DBQ 20 2500 367.0 367.0 38.0 ADS8344EB/2K5 SSOP DBQ 20 2500 367.0 367.0 38.0 ADS8344N/1K SSOP DB 20 1000 367.0 367.0 38.0 ADS8344NB/1K SSOP DB 20 1000 367.0 367.0 38.
PAGE 22
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MECHANICAL DATA MSSO002E – JANUARY 1995 – REVISED DECEMBER 2001 DB (R-PDSO-G**) PLASTIC SMALL-OUTLINE 28 PINS SHOWN 0,38 0,22 0,65 28 0,15 M 15 0,25 0,09 8,20 7,40 5,60 5,00 Gage Plane 1 14 0,25 A 0°–ā8° 0,95 0,55 Seating Plane 2,00 MAX 0,10 0,05 MIN PINS ** 14 16 20 24 28 30 38 A MAX 6,50 6,50 7,50 8,50 10,50 10,50 12,90 A MIN 5,90 5,90 6,90 7,90 9,90 9,90 12,30 DIM 4040065 /E 12/01 NOTES: A. B. C. D. All linear dimensions are in millimeters.
PAGE 25
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.