Datasheet

ManualsBrandsTEXAS INSTRUMENTS ManualsData collecting ICsData acquisition IC - AD converter (ADC) External , Internal SSOP 28

12-Bit, 10MHz Sampling

ANALOG-TO-DIGITAL CONVERTER

FEATURES

● HIGH SFDR: 80dB at NYQUIST

● HIGH SNR: 69dB

● LOW POWER: 180mW

● LOW DLE: ±0.3LSB

● FLEXIBLE INPUT RANGE

● OVERRANGE INDICATOR

APPLICATIONS

● IF AND BASEBAND DIGITIZATION

● CCD IMAGING

● SCANNERS

● TEST INSTRUMENTATION

DESCRIPTION

The ADS804 is a high-speed, high dynamic range, 12-bit,

pipelined Analog-to-Digital (A/D) converter. This converter

includes a high-bandwidth track-and-hold that gives excel-

lent spurious performance up to and beyond the Nyquist

rate. This high-bandwidth, linear track-and-hold minimizes

harmonics and has low jitter, leading to excellent SNR

performance. The ADS804 is also pin-compatible with the

5MHz ADS803 and the 20MHz ADS805.

The ADS804 provides an internal reference and can be

programmed for a 2Vp-p input range for the best spurious

performance and ease of driving. Alternatively, the 5Vp-p

input range can be used for the lowest input referred noise

of 0.09LSBs rms giving superior imaging performance. There

is also a capability to set the input range in between the 2Vp-

p and 5Vp-p input ranges or to use external reference. The

ADS804 also provides an over-range indicator flag to indi-

cate an input range that exceeds the full-scale input range of

the converter. This flag can be used to reduce the gain of the

front end gain-ranging circuitry.

The ADS804 employs digital error correction techniques to

provide excellent differential linearity for demanding imaging

applications. Its low distortion and high SNR give the extra

margin needed for communications, medical imaging, video,

and test instrumentation applications. The ADS804 is avail-

able in a SSOP-28 package.

12-Bit

Pipelined

A/D Converter Core

Reference and

Mode Select

Reference Ladder

and Driver

Timing Circuitry

Error

Correction

Logic

3-State

Outputs

T&H

D11

•

CLK

ADS804

VDRV

SEL REFBV

REF

REFT

INV

(Opt.)

OVR

ADS804

SBAS068B – JANUARY 1997 – REVISED AUGUST 2002

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.

ADS804E

Summary of content (17 pages)

PAGE 1
ADS804 ADS 804 E SBAS068B – JANUARY 1997 – REVISED AUGUST 2002 12-Bit, 10MHz Sampling ANALOG-TO-DIGITAL CONVERTER FEATURES APPLICATIONS ● ● ● ● ● ● ● ● ● ● HIGH SFDR: 80dB at NYQUIST HIGH SNR: 69dB LOW POWER: 180mW LOW DLE: ±0.3LSB FLEXIBLE INPUT RANGE OVERRANGE INDICATOR DESCRIPTION The ADS804 is a high-speed, high dynamic range, 12-bit, pipelined Analog-to-Digital (A/D) converter.
PAGE 2
ABSOLUTE MAXIMUM RATINGS(1) ELECTROSTATIC DISCHARGE SENSITIVITY +VS, VDRV ........................................................................................... +6V Analog Input .......................................................... (–0.3V) to (+VS + 0.3V) Logic Input ............................................................ (–0.3V) to (+VS + 0.3V) Case Temperature ......................................................................... +100°C Junction Temperature ............................
PAGE 3
ELECTRICAL CHARACTERISTICS (Cont.) At TA = full specified temperature range, VS = +5V, specified single-ended input range = 1.5V to 3.5V, and sampling rate = 10MHz, unless otherwise specified.
PAGE 4
PIN DESCRIPTIONS PIN CONFIGURATION Top View SSOP OVR 1 28 VDRV B1 2 27 +VS B2 3 26 GND B3 4 25 IN B4 5 24 GND B5 6 23 IN B6 7 22 REFT B7 8 21 CM B8 9 20 REFB B9 10 19 VREF B10 11 18 SEL B11 12 17 GND B12 13 16 +VS CLK 14 15 OE ADS804 PIN DESIGNATOR 1 OVR 2 3 4 5 6 7 8 9 10 11 12 13 14 15 B1 B2 B3 B4 B5 B6 B7 B8 B9 B10 B11 B12 CLK OE 16 17 18 +VS GND SEL 19 20 21 22 23 24 25 26 27 28 VREF REFB CM REFT IN GND IN GND +VS VDRV DESCRIPTION Over-Ran
PAGE 5
TYPICAL CHARACTERISTICS At TA = full specified temperature range, VS = +5V, specified single-ended input range = 1.5V to 3.5V, and sampling rate = 10MHz, unless otherwise specified. SPECTRAL PERFORMANCE SPECTRAL PERFORMANCE 0 0 fIN = 4.8MHz –20 –40 –40 Amplitude (dB) Amplitude (dB) fIN = 500kHz –20 –60 –80 –100 –60 –80 –100 –120 –120 0 1.0 2.0 3.0 4.0 5.0 0 1.0 2.0 Frequency (MHz) 2-TONE INTERMODULATION 4.0 5.0 DIFFERENTIAL LINEARITY ERROR 0 1.0 fIN = 4.8MHz f1 = 3.
PAGE 6
TYPICAL CHARACTERISTICS (Cont.) At TA = full specified temperature range, VS = +5V, specified single-ended input range = 1.5V to 3.5V, and sampling rate = 10MHz, unless otherwise specified. DYNAMIC PERFORMANCE vs INPUT FREQUENCY (Differential Input, VIN = 5Vp-p) 85 85 80 80 SFDR, SNR (dBFS) SFDR, SNR (dBFS) DYNAMIC PERFORMANCE vs INPUT FREQUENCY SFDR 75 70 SNR 65 SFDR 75 70 SNR 65 60 60 0.1 1 0.
PAGE 7
TYPICAL CHARACTERISTICS (Cont.) At TA = full specified temperature range, VS = +5V, specified single-ended input range = 1.5V to 3.5V, and sampling rate = 10MHz, unless otherwise specified.
PAGE 8
APPLICATION INFORMATION configurations. This will decouple the op amp’s output from the capacitive load and avoid gain peaking, which can result in increased noise. For best spurious and distortion performance, the resistor value should be kept below 100Ω. Furthermore, the series resistor together with the 100pF capacitor establish a passive low-pass filter, limiting the bandwidth for the wideband noise thus, help improving the SNR performance.
PAGE 9
RF RIN +1V 0 +VS VIN REFT 2kΩ RS 24.9Ω IN OPA691 –1V 2Vp-p 100pF R1 ADS804 R2 +VS +2.5V + 0.1µF IN 0.1µF 10µF REFB (+1V) VREF SEL 2kΩ NOTE: RF = RIN, G = –1 FIGURE 2. DC-Coupled, Single-Ended Input Configuration with DC-Level Shift. DC voltage differences between the IN and IN inputs of the ADS804 effectively will produce an offset, which can be corrected for by adjusting the values of resistors R1 and R2. The bias current of the op amp may also result in an undesired offset.
PAGE 10
A simple model of the internal reference circuit is shown in Figure 4. The internal blocks are a 1V-bandgap voltage reference, buffer, the resistive reference ladder, and the drivers for the top and bottom reference which supply the necessary current to the internal nodes. As shown, the output of the buffer appears at the VREF pin. The full-scale input span of the ADS804 is determined by the voltage at VREF, according to equation (1): Full-Scale Input Span = 2 • VREF ADS804 REFT 0.1µF + 0.1µF 0.
PAGE 11
EXTERNAL REFERENCE OPERATION SELECTING THE INPUT RANGE AND REFERENCE Figures 7 through 9 show a selection of circuits for the most common input ranges when using the internal reference of the ADS804. All examples are for single-ended input and operate with a nominal common-mode voltage of +2.5V. 5V VIN IN 0V as described for the internal reference operation. ADS804 IN VREF Depending on the application requirements, it might be advantageous to operate the ADS804 with an external reference.
PAGE 12
MSB Over = HI OVR Under = HI provide the added benefit of isolating the ADS804 from any digital noise activities on the bus coupling back high frequency noise. In addition, resistors in series with each data line may help maintain the ac performance of the ADS804. Their use depends on the capacitive loading seen by the converter.
PAGE 13
PACKAGE OPTION ADDENDUM www.ti.
PAGE 14
PACKAGE OPTION ADDENDUM www.ti.com 23-May-2013 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 warranty as to the accuracy of such information. Efforts are underway to better integrate information from third parties.
PAGE 15
PACKAGE MATERIALS INFORMATION www.ti.com 31-May-2013 TAPE AND REEL INFORMATION *All dimensions are nominal Device ADS804E/1K Package Package Pins Type Drawing SSOP DB 28 SPQ Reel Reel A0 Diameter Width (mm) (mm) W1 (mm) 1000 330.0 16.4 Pack Materials-Page 1 8.1 B0 (mm) K0 (mm) P1 (mm) W Pin1 (mm) Quadrant 10.4 2.5 12.0 16.
PAGE 16
PACKAGE MATERIALS INFORMATION www.ti.com 31-May-2013 *All dimensions are nominal Device Package Type Package Drawing Pins SPQ Length (mm) Width (mm) Height (mm) ADS804E/1K SSOP DB 28 1000 367.0 367.0 38.
PAGE 17
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.