Analog-devices AD604 Bedienungsanleitung PDF herunterladen

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ANALOG

DEVICES

Dual, Ultralow Noise

Variable Gain Amplifier

AD604

FEATURES

Ultralow input noise at maximum gain

0.80 nV/VHz, 3.0 pA/VHz

2 independent linear-in-dB channels

Absolute gain range per channel programmable

0 dB to 48 dB (preamplifier gain = 14 dB) through 6 dB to

54 dB (preamplifier gain = 20 dB)

±1.0 dB gain accuracy

Bandwidth: 40 MHz (-3 dB)

Input resistance: 300 kO

Variable gain scaling: 20 dB/V through 40 dB/V

Stable gain with temperature and supply variations

Single-ended unipolar gain control

Power shutdown at lower end of gain control

Drive ADCs directly

APPLICATIONS

Ultrasound and sonar time-gain controls

High performance AGC systems

Signal measurement

GE«E.AiLwciR(

Tii

.BDTIC., c::pi:iii

The AD604 is an ultralow noise, very accurate, dual-channel, Preamplifier gains oetv

FUNCTIONAL BLOCK DIAGRAM

Figure 1.

linear-in-dB variable gain amplifier (VGA) optimized for time-

based variable gain control in ultrasound applications; however,

it supports any application requiring low noise, wide bandwidth,

variable gain control. Each channel of the AD604 provides a

300 kP input resistance and unipolar gain control for ease of

use. User-determined gain ranges, gain scaling (dB/V), and dc

level shifting of output further optimize performance.

Each channel of the AD604 uses a high performance

preamplifier that provides an input-referred noise voltage of

0.8 nV/VUz. The very accurate linear-in-dB response of the

AD604 is achieved with the differential input exponential

amplifier (DSX-AMP) architecture. Each DSX-AMP comprises

a variable attenuator of 0 dB to 48.36 dB followed by a high

speed fixed-gain amplifier. The attenuator is a 7-stage

R-1.5R ladder network. The attenuation between tap points is

6.908 dB and 48.36 dB for the ladder network.

The equation for the linear-in-dB gain response is

G (dB) =

(Gain Scaling (dB/V) x VGN (V)) + (Preamp Gain (dB) - 19 dB)

Preamplifier gains between 5 and 10 (14 dB and 20 dB) provide

overall gain ranges per channel of 0 dB through 48 dB and 6 dB

through 54 dB. The two channels of the AD604 can be cascaded

to provide greater levels of gain range by bypassing the preamplifier

of the second channel. However, in multiple channel systems,

cascading the AD604 with other devices in the AD60x VGA

family that do not include a preamplifier may provide a more

efficient solution. The AD604 provides access to the output of

the preamplifier, allowing for external filtering between the

preamplifier and the differential attenuator stage.

Note that scale factors up to 40 dB/V are achievable with reduced

accuracy for scales above 30 dB/V. The gain scales linearly in

decibels with control voltages of 0.4 V to 2.4 V with the 20 dB/V

scale. Below and above this gain control range, the gain begins

to deviate from the ideal linear-in-dB control law. The gain

control region below 0.1 V is not used for gain control. When

the gain control voltage is <50 mV, the amplifier channel is

powered down to 1.9 mA.

The AD604 is available in 24-lead SSOP, SOIC, and PDIP

packages and is guaranteed for operation over the -40°C to

+85°C temperature range.

Rev. E

Information furnished by Analog Devices is belic^ad to be accurate and reliable. Howe^, no

responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other

rights of third parties that may result from its use. Specifications subject to change without notice No

license is granted by implication or otherw^ under any patent or patent rights of Analog Devices.

Trademarks and registered trademarks are the property of their r^pective owners.

One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.

Tel: 781.329.4700

www.analog.com

DSXx VGNx

VREF

OUTx

VOCM

1 2 3 4 5 6 ... 31 32

Inhaltsverzeichnis

Seite 1 - .BDTIC., c::pi:iii

►ANALOGDEVICESDual, Ultralow Noise Variable Gain AmplifierAD604FEATURESUltralow input noise at maximum gain 0.80 nV/VHz, 3.0 pA/VHz 2 independent line

Seite 2 - TABLE OF CONTENTS

AD6041M 10MFREQUENCY (Hz)Figure 21. Harmonic Distortion vs. Frequency-20-30-40-50-60-70-80-90-100-110-120Vo = 1Vp-p—I— VGN = 1V96 9.98 10.00 10.02

Seite 3 - SPECIFICATIONS

AD604>QÍX-2V' ' ' M ' ' ' M ' ' ' Vo = 2V p-p :1253ns 100ns/DIVFigure 27. Large Signal Pulse Response

Seite 4 - Rev. E

AD60410M10k 100k 1MFREQUENCY (Hz)Figure 33. Input Impedance vs. Frequency-40 -20 0 20 40 60 80 90TEMPERATURE (°C)Figure 35. Supply Current (O

Seite 5 - .com/ADI

AD604THEORY OF OPERATIONThe AD604 is a dual-channel VGA with an ultralow noise preamplifier. Figure 37 shows the simplified block diagram of one chann

Seite 6 - C.com/ADI

AD604PREAMPLIFIERThe input capability of the following single-supply DSX (2.5 ± 2 V for a +5 V supply) limits the maximum input voltage of the preampl

Seite 7 - Vss = ±5 V

AD604The larger portion of the input referred voltage noise comes from the amplifier with 0.63 nV/VHz. The current noise is independent of gain and de

Seite 8 - Rev. E

AD604AC COUPLINGThe DSX portion of the AD604 is a single-supply circuit and, therefore, its inputs need to be ac-coupled to accommodate ground-based s

Seite 9 - Rev. E

AD604The AFA offers the following additional features:• The ability to invert the signal by switching the positive and negative inputs to the ladder

Seite 10 - Rev. E

AD604APPLICATIONS INFORMATIONThe basic circuit in Figure 43 shows the connections for one channel of the AD604. The signal is applied at Pin 5. RGN is

Seite 11 - Rev. E

Figure 44. AGC Amplifier with 82 dB of Gain RangeULTRALOW NOISE AGC AMPLl96 gAI NRaI NG 'eWFigure 44 shows animplementálion ofaw^GcampHTter &apos

Seite 12 - Rev. E

AD604TABLE OF CONTENTSFeatures...Applications...Functional Block Diagram...

Seite 13 - THEORY OF OPERATION

AD604The 50 n termination resistor, in parallel with the 50 O source resistance of the signal generator, forms an effective resistance of 25 n as seen

Seite 14 - PREAMPLIFIER

AD604At 1 MHz, the attenuation is about -0.2 dB, increasing to -6 dB at 10 MHz and -28 dB at 100 MHz. Signals less than approximately 1 MHz are not si

Seite 15 - \ m~8"

AD604MEDICAL ULTRASOUND TGC DRIVING THE AD9050, A 10-BIT, 40 MSPS ADCThe AD604 is an ideal candidate for the time gain control (TGC) amplifier that is

Seite 16 - GAIN CONTROL INTERFACE

NOTES1. PAO1 AND PAO2 ARE USED TO MEASURE PREAMPS.2. RGN = 0 NOMINALLY; PREAMP GAIN = 5, RGN = OPEN; PREAMP GAIN = 10.3. WHEN MEASURING BW WITH 500

Seite 17 - Rev. E

AD604EVALUATION BOARDFigure 55 is a photograph of the AD604 evaluation board assembly. Multiple input connections, test points, jumper selectable opti

Seite 18 - APPLICATIONS INFORMATION

AD604Connecting the DSX Inputs to the PreamplifiersTo connect the DSX inputs to the preamplifiers, install jumpers in the JP6 lower position and in JP

Seite 19 - I NG '

AD604EVALUATION BOARD ARTWORK AND SCHEMATIC• •h••••••N««• H • •• •• r: •• •• •• •KFigure 59. Internn^l Grp^ndO O ®o oo oo ^8§l O ° ®^ CH) g CLD o°oS

Seite 20 - Rev. E

AD604J1CH1 VGA -DSX1 IN_(-) ^ JP5 C8gg t * aQCH1 VGA +DSX1 “IN (+) '? JP6Pa>AI1C90.1mFCH 1 PREAMP PAI1 INTJr+5VI R749.90TCH 2 PREAMP PAI2 I

Seite 21 - DIFFERENTIAL OUTPUT VGA

OUTLINE DIMENSIONS1.280 (32.51)----------1.250 (31.75)-------------------•1.230 (31.24)0.280 (7.11) 0.250 (6.35) 0.240 (6.10)0.100 (2.54) BSC0.210 (

Seite 22 - AD9050, A 10-BIT, 40 MSPS ADC

AD6040.25"0.098°J4°_l0.95 I I 0.75->| 0.55COMPLIANT TO JEDEC STANDARDS MO-150-AGFigure 64.24-Lead Shrink Small Outline Package [SSOP] (RS-24)D

Seite 23 - Figure 53. Basic Test Board

AD604SPECIFICATIONSEach amplifier channel at Ta = 25°C, Vs = ±5 V, Rs = 50 O, Rl = 500 O, Cl = 5 pF, Vref = 2.50 V (scaling = 20 dB/V), 0 dB to 48 dB

Seite 24 - EVALUATION BOARD

AD604NOTESwww.BDTIC.com/ADIRev. E | Page 30 of 32

Seite 25 - DC OPERATING CONDITIONS

AD604NOTESwww.BDTIC.com/ADIRev. E | Page 31 of 32

Seite 26 - ^ CH) g

Seite 27 - Rev. E

AD604Parameter Conditions Min Typ Max UnitACCURACYAbsolute Gain Error0 dB to 3 dB 0.25 V < VGN < 0.400 V -1.2 +0.75 +3 dB3 dB to 43 dB 0.400 V &

Seite 28 - OUTLINE DIMENSIONS

AD604ABSOLUTE MAXIMUM RATINGSTable 2.Parameter1,2RatingSupply Voltage ±VsPin 17 to Pin 20 (with Pin 16, Pin 22 = 0 V) Input Voltages±6.5 VPin 1, Pin 2

Seite 29 - ORDERING GUIDE

AD604PIN CONFIGURATION AND FUNCTION DESCRIPTIONS-DSX^T +DSX^T PAO^T FBK^T PAI^T COM^T COM^T PAI^T FBK^T PAO2 [io +DSX2 QT -DSX2 [122^VGN1I^VREF2^OUT

Seite 30 - Rev. E

AD604TYPICAL PERFORMANCE CHARACTERISTICSUnless otherwise noted, G (preamplifier) = 14 dB, VREF = 2.5 V (20 dB/V scaling), f = 1 MHz, Rl = 500 U, Cl =

Seite 31 - Rev. E

AD60450403020100-10-20-30-401 1_____1 J\1VGN = 2 9V1= 1.5V 1= 0.5VVNVGNSr1 1 1VGN = 0 1VNVGN = 0VFigure 9. Gain Error ^s. VGN for Two Gain Scaling Val

Seite 32 - Rev. E

AD6040.1 0.5 0.9 1.3 1.7 2.1 2.5 2.9VGN (V)Figure 15. Input Referred Noise vs. VGNVGN = 2. 9VRSOU ?CEA LONE10 100 rsource (^)Figure 18. Input R

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Analog-devices AD604 Bedienungsanleitung

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