Datasheet

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

Pipeline

A/D

Reference

Ladder

Timing

Circuitry

Error

Correction

Logic

3-State

Outputs

T/H

10-Bit

Digital

Data

CLK

ADS901

OEPwrdn

REFBCMREFT

DESCRIPTION

The ADS901 is a high-speed pipelined analog-to-digital

converter that operates from a +3V power supply. This

complete converter includes a wide bandwidth track/hold

and a 10-bit quantizer. The full scale input range is set by

external references.

The ADS901 employs digital error correction techniques to

provide excellent differential linearity for demanding imag-

ing applications. Its low distortion and high SNR give the

extra margin needed for telecommunications, video and test

instrumentation applications. The ADS901 is available in an

SSOP-28 package.

10-Bit, 20MHz, +3V Supply

ANALOG-TO-DIGITAL CONVERTER

APPLICATIONS

● BATTERY POWERED EQUIPMENT

● CAMCORDERS

● DIGITAL CAMERAS

● COMPUTER SCANNERS

● COMMUNICATIONS

FEATURES

● LOW POWER: 48mW at +3V

● SUPPLY RANGE: +2.7V to +3.7V

● ADJUSTABLE FULL SCALE RANGE WITH

EXTERNAL REFERENCES

● NO MISSING CODES

● WIDEBAND TRACK/HOLD: 350MHz

● POWER DOWN: 15mW

● SSOP-28 PACKAGE

ADS901

SBAS054A – MAY 2001

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 (13 pages)

PAGE 1
ADS901 AD S 901 E SBAS054A – MAY 2001 10-Bit, 20MHz, +3V Supply ANALOG-TO-DIGITAL CONVERTER TM FEATURES DESCRIPTION ● LOW POWER: 48mW at +3V ● SUPPLY RANGE: +2.7V to +3.7V ● ADJUSTABLE FULL SCALE RANGE WITH EXTERNAL REFERENCES ● NO MISSING CODES ● WIDEBAND TRACK/HOLD: 350MHz ● POWER DOWN: 15mW ● SSOP-28 PACKAGE The ADS901 is a high-speed pipelined analog-to-digital converter that operates from a +3V power supply. This complete converter includes a wide bandwidth track/hold and a 10-bit quantizer.
PAGE 2
ABSOLUTE MAXIMUM RATINGS ELECTROSTATIC DISCHARGE SENSITIVITY +VS ....................................................................................................... +6V Logic VDD ............................................................................................. +6V Analog Input ............................................................................... +VS +0.3V Logic Input ................................................................................. +VS +0.3V Case Temperature .....
PAGE 3
ELECTRICAL CHARACTERISTICS (Cont.) At TA = +25°C, VS = LVDD = +3V, REFB = 1V, REFT = 2V, Specified Input Range = 1V to 2V, Sampling Rate = 20MHz, unless otherwise specified.
PAGE 4
PIN CONFIGURATION PIN DESCRIPTIONS TOP VIEW SSOP +VS 1 28 +VS LVDD 2 27 IN (LSB) Bit 10 3 26 CM Bit 9 4 25 LnBy Bit 8 5 24 REFB Bit 7 6 23 NC Bit 6 7 22 REFT PIN DESIGNATOR 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 +VS LVDD Bit 10 Bit 9 Bit 8 Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 GND GND CLK OE Pwrdn +VS GND GND LpBy REFT NC REFB LnBy CM IN +VS ADS901 Bit 5 8 21 LpBy Bit 4 9 20 GND Bit 3 10 19 GND Bit 2 11 18 +VS (MSB)
PAGE 5
TYPICAL CHARACTERISTICS At TA = +25°C, VS = Logic VDD = +3V, REFB = 1V, REFT = 2V, Specified Input Range = 1V to 2V, Sampling Rate = 20MHz, unless otherwise specified. SPECTRAL PERFORMANCE SPECTRAL PERFORMANCE 0 0 fIN = 500kHz fIN = 3.58MHz –20 Amplitude (dB) Amplitude (dB) –20 –40 –60 –40 –60 –80 –80 –100 –100 0 2 4 6 8 0 10 2 4 6 SPECTRAL PERFORMANCE 0 fIN = 9MHz –20 f1 = 4.5MHz f2 = 5.0MHz Amplitude (dB) –20 –40 –60 –40 –60 –80 –80 –100 –100 0 2 4 6 8 10 0 2.
PAGE 6
TYPICAL CHARACTERISTICS (Cont.) At TA = +25°C, VS = Logic VDD = +3V, REFB = 1V, REFT = 2V, Specified Input Range = 1V to 2V, Sampling Rate = 20MHz, unless otherwise specified.
PAGE 7
TYPICAL CHARACTERISTICS (Cont.) At TA = +25°C, VS, Logic VDD = +3V, REFB = 1V, REFT = 2V, Specified Input Range = 1V to 2V, Sampling Rate = 20MHz, unless otherwise specified. POWER DISSIPATION vs TEMPERATURE SIGNAL-TO-NOISE RATIO vs TEMPERATURE 50 Power Dissipation (mW) 55 fIN = 500kHz SNR (dB) 54 fIN = 9MHz 53 52 49 48 47 46 45 –50 –25 0 25 50 75 –50 100 –25 0 GAIN ERROR vs TEMPERATURE 75 100 0.6 Offset Error (% FS) 2.7 Gain Error (%FS) 50 OFFSET ERROR vs TEMPERATURE 2.8 2.
PAGE 8
THEORY OF OPERATION The ADS901 is a high speed sampling analog-to-digital converter that utilizes a pipeline architecture. The fully differential topology and digital error correction guarantee 10-bit resolution. The differential track/hold circuit is shown in Figure 1. The switches are controlled by an internal clock which has a non-overlapping two phase signal, φ1 and φ2. At the sampling time the input signal is sampled on the bottom plates of the input capacitors.
PAGE 9
dual supplies (OPA650, OPA658). The mid-point reference voltage, VCM, biases the bipolar, ground-referenced input signal. The capacitor C1 and resistor R1 form a high-pass filter with the –3dB frequency set at f–3dB = 1/(2 π R1 C1) on a +3V supply voltage. The OPA632 provides excellent performance in this demanding application. Its wide input and output voltage ranges, an low distortion, supports the ADS901 well. The OPA632 is configured for a gain of +2. The 374Ω and 2.
PAGE 10
LOW-COST REFERENCE SOLUTION The easiest way to achieve the required reference voltages is to place the reference ladder of the ADS901 between the supply rails, as shown in Figure 5. Two additional resistors (RT, RB) are necessary to set the correct current through the ladder. However depending on the desired full-scale swing and supply voltage different resistor values might be selected.
PAGE 11
+VS 10Ω 1/2 A1 +VS +VS +LVDD Top Reference (REFT) Digital Output Stage ADS901 RF1 10kΩ RG1 REF1004 +1.2V 5kΩ FIGURE 7. Independent Supply Connection for Output Stage. 3kΩ 10Ω 1/2 A1 Bottom Reference (REFB) RF2 During power-down the digital outputs are set in 3-state. With the clock applied, the converter does not accurately process the sampled signal. After removing the power-down condition the output data from the following 5 clock cycles is invalid (data latency).
PAGE 12
PACKAGE OPTION ADDENDUM www.ti.com 26-Aug-2009 PACKAGING INFORMATION Orderable Device Status (1) Package Type Package Drawing Pins Package Eco Plan (2) Qty ADS901E ACTIVE SSOP DB 28 50 Green (RoHS & no Sb/Br) CU NIPDAU Level-1-260C-UNLIM ADS901EG4 ACTIVE SSOP DB 28 50 Green (RoHS & no Sb/Br) CU NIPDAU Level-1-260C-UNLIM Lead/Ball Finish MSL Peak Temp (3) (1) The marketing status values are defined as follows: ACTIVE: Product device recommended for new designs.
PAGE 13
IMPORTANT NOTICE Texas Instruments Incorporated and its subsidiaries (TI) reserve the right to make corrections, modifications, enhancements, improvements, and other changes to its products and services at any time and to discontinue any product or service without notice. Customers should obtain the latest relevant information before placing orders and should verify that such information is current and complete.