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Details, datasheet, quote on part number:AD604AN
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Datasheet text preview:
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FEATURES Ultralow Input Noise at Maximum Gain: 0.80 nV/Hz, 3.0 pA/ Hz Two Independent Linear-in-dB Channels Absolute Gain Range per Channel Programmable: 0 dB to +48 dB (Preamp Gain = +14 dB), through +6 dB to +54 dB (Preamp Gain = +20 dB) 1.0 dB Gain Accuracy Bandwidth: 40 MHz (3 dB) 300 k Input Resistance 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 Can Drive A/D Converters Directly APPLICATIONS Ultrasound and Sonar Time-Gain Control High Performance AGC Systems Signal Measurement
Dual, Ultralow Noise Variable Gain Amplifier AD604
FUNCTIONAL BLOCK DIAGRAM
PAO DSX +DSX VGN GAIN CONTROL AND SCALING DIFFERENTIAL ATTENUATOR R-1.5R LADDER NETWORK 0 TO 48.4dB VOCM PROGRAMMABLE ULTRALOW NOISE PREAMPLIFIER G = 1420dB PRECISION PASSIVE INPUT ATTENUATOR
VREF
PAI
AFA
OUT
FIXED GAIN AMPLIFIER +34.4dB
PRODUCT DESCRIPTION
The AD604 is an ultralow noise, very accurate, dual channel, linear-in-dB variable gain amplifier (VGA) optimized for timebased variable gain control in ultrasound applications; however it will support any application requiring low noise, wide bandwidth variable gain control. Each channel of the AD604 provides a 300 k 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 application performance. Each channel of the AD604 utilizes a high performance preamplifier that provides an input referred noise voltage of 0.8 nV/Hz. The very accurate linear-in-dB response of the AD604 is achieved with the differential input exponential amplifier (DSX-AMP) architecture. Each of the DSX-AMPs comprise a variable attenuator of 0 dB to 48.36 dB followed by a high speed fixed gain amplifier. The attenuator is based on a seven stage R-1.5R ladder network. The attenuation between tap points is 6.908 dB and 48.36 dB for the ladder network. Each independent channel of the AD604 provides a gain range of 48 dB which can be optimized for the application by programming the preamplifier with a single external resistor in the preamp feedback path. The linear-in-dB gain response of the AD604 can be described by the equation: G (dB) = (Gain Scaling (dB/V ) × 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 2nd channel's preamplifier. However, in multiple channel systems, cascading the AD604 with other devices in the AD60x VGA family, which 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. The gain control interface provides an input resistance of approximately 2 M and scale factors from 20 dB/V to 30 dB/V for a VREF input voltage of 2.5 V to 1.67 V respectively. Note that scale factors up to 40 dB/V are achievable with reduced accuracy for scales above 30 dB/V. The gain scales linear-in-dB 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. In fact when the gain control voltage is <50 mV the amplifier channel is powered down to 1.9 mA. The AD604 is available in a 24-pin plastic SSOP, SOIC and DIP, and is guaranteed for operation over the 40°C to +85°C temperature range.
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Information furnished by Analog Devices is believed to be accurate and reliable. However, no responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other rights of third parties which may result from its use. No license is granted by implication or otherwise under any patent or patent rights of Analog Devices. One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A. Tel: 617/329-4700 World Wide Web Site: http://www.analog.com Fax: 617/326-8703 © Analog Devices, Inc., 1996
(Each Amplifier Channel at TA = +25 C, VS = 5 V, RS = 50 , RL = 500 , CL = 5 pF, VREF = 2.50 V (Scaling = 20 dB/V), 0 dB to +48 dB gain range (preamplifier gain = +14 dB), VOCM = 2.5 V, C1 and C2 = 0.1 F (see Figure 35) unless otherwise noted)
Parameter INPUT CHARACTERISTICS Preamplifier Input Resistance Input Capacitance Input Bias Current Peak Input Voltage Input Voltage Noise Input Current Noise Noise Figure DSX Input Resistance Input Capacitance Peak Input Voltage Input Voltage Noise Input Current Noise Noise Figure Common-Mode Rejection Ratio OUTPUT CHARACTERISTICS 3 dB Bandwidth Slew Rate Output Signal Range Output Impedance Output Short-Circuit Current Harmonic Distortion HD2 HD3 HD2 HD3 Two-Tone Intermodulation Distortion (IMD) 3rd Order Intercept 1 dB Compression Point Channel-to-Channel Crosstalk Group Delay Variation VOCM Input Resistance ACCURACY Absolute Gain Error 0 dB to +3 dB +3 dB to +43 dB +43 dB to +48 dB Gain Scaling Error Output Offset Voltage Output Offset Variation Conditions Min Typ Max Unit
AD604SPECIFICATIONS
Preamp Gain = +14 dB Preamp Gain = +20 dB VGN = 2.9 V, RS = 0 Preamp Gain = +14 dB Preamp Gain = +20 dB Independent of Gain RS = 50 , f = 1 MHz, VGN = 2.9 V RS = 200 , f =1 MHz, VGN = 2.9 V
300 8.5 27 ± 400 ± 200 0.8 0.73 3.0 2.3 1.1 175 3.0 2.5 ± 2 1.8 2.7 8.4 12 20 40 170 2.5 ± 1.5 2 ± 40 54 67 43 48 74 71 12.5 +15 30 ±2 45
k pF µA mV mV nV/ H z nV/ H z pA/H z dB dB pF V nV/H z pA/Hz dB dB dB MHz V/µs V mA dBc dBc dBc dBc dBc dBc dBm dBm dB dB ns k
VGN = 2.9 V VGN = 2.9 V RS = 50 , f = 1 MHz, VGN = 2.9 V RS = 200 , f =1 MHz, VGN = 2.9 V f = 1 MHz, VGN = 2.65 V Constant with Gain VGN = 1.5 V, Output = 1 V Step RL 500 f = 10 MHz VGN = 1 V, VOUT = 1 V p-p f = 1 MHz f = 1 MHz f = 10 MHz f = 10 MHz VGN = 2.9 V, VOUT = 1 V p-p f = 1 MHz f = 10 MHz f = 10 MHz, VGN = 2.65 V, VOUT = 1 V p-p, Input Referred f = 1 MHz, VGN = 2.9 V, Output Referred VOUT = 1 V p-p, f = 1 MHz Ch #1: VGN = 2.65 V, Inputs Shorted Ch #2: VGN = 1.5 V (Mid Gain) 1 MHz < f < 10 MHz, Full Gain Range
0.25 V < VGN < 0.400 V 0.400 V < VGN < 2.400 V 2.400 V < VGN < 2.65 V 0.400 V < VGN < 2.400 V VREF = 2.500 V, VOCM = 2.500 V VREF = 2.500 V, VOCM = 2.500 V
1.2 1.0 3.5 50
+0.75 ± 0.3 1.25 ± 0.25 ± 30 30
+3 +1.0 +1.2 +50 50
dB dB dB dB/V mV mV
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AD604
Parameter GAIN CONTROL INTERFACE Gain Scaling Factor Gain Range Input Voltage (VGN) Range Input Bias Current Input Resistance Response Time VREF Input Resistance POWER SUPPLY Specified Operating Range Power Dissipation Quiescent Supply Current Powered Down Power-Up Response Time Power-Down Response Time Conditions VREF = 2.5 V, 0.4 V < VGN < 2.4 V VREF = 1.67 V Preamp Gain = +14 dB Preamp Gain = +20 dB 20 dB/V, VREF = 2.5 V 48 dB Gain Change Min 19 Typ Max Unit dB/V dB/V dB dB V µA M µs k V V mW mW mA mA mA mA µA µs µs 20 21 30 0 to +48 +6 to +54 0.1 to 2.9 0.4 2 0.2 10 ±5 +5 220 95 32 19 12 1.9 150 0.6 0.4
One Complete Channel One DSX Only One Complete Channel One DSX Only VPOS, One Complete Channel VPOS, One DSX Only VNEG, One Preamplifier Only VPOS, VGN < 50 mV, One Channel VNEG, VGN < 50 mV, One Channel 48 dB Gain Change, VOUT = 2 V p-p
36 23 3.0
15
Supply Voltage ± VS Pins 17, 18, 19, 20 (with Pins 16, 22 = 0 V) . . . . . . ± 6.5 V Input Voltages Pins 1, 2, 11, 12 . . . . . . . . . . . . . VPOS/2 ± 2 V Continuous Pins 4, 9 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ± 2 V Pins 5, 8 . . . . . . . . . . . . . . . . . . . . . . . . . . . . VPOS, VNEG Pins 6, 7, 13, 14, 23, 24 . . . . . . . . . . . . . . . . . . . . VPOS, 0 Internal Power Dissipation Plastic (N) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.2 W Small Outline (R) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.7 W Shrink Small Outline (RS) . . . . . . . . . . . . . . . . . . . . . 1.1 W Operating Temperature Range . . . . . . . . . . . 40°C to +85°C Storage Temperature Range . . . . . . . . . . . . 65°C to +150°C Lead Temperature, Soldering 60 seconds . . . . . . . . . +300°C
NOTES 1 Stresses above those listed under "Absolute Maximum Ratings" may cause permanent damage to the device. This is a stress rating only and functional operation of the device at these or any other conditions above those indicated in the operational section of this specification is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. 2 Pins 1, 2, 11, 12, 13, 14, 23, 24 are part of a single-supply circuit and the part will most likely be damaged if any of these pins are accidentally connected to VN. 3 When driven from an external low impedance source.
ABSOLUTE MAXIMUM RATINGS
ORDERING GUIDE
Model AD604AN AD604AR AD604ARS
Temperature Range 40°C to +85°C 40°C to +85°C 40°C to +85°C
JA 57 °C/W 70 °C/W 112°C/W
Package Option* N-24 R-24 R-24
*N = Plastic DIP, R = Small Outline IC (SOIC), RS = Shrink Small Outline Package (SSOP).
CAUTION ESD (electrostatic discharge) sensitive device. Electrostatic charges as high as 4000 V readily accumulate on the human body and test equipment and can discharge without detection. Although the AD604 features proprietary ESD protection circuitry, permanent damage may occur on devices subjected to high energy electrostatic discharges. Therefore, proper ESD precautions are recommended to avoid performance degradation or loss of functionality.
WARNING!
ESD SENSITIVE DEVICE
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AD604
PIN DESCRIPTIONS
Pin No. Pin 1 Pin 2 Pin 3 Pin 4 Pin 5 Pin 6 Pin 7 Pin 8 Pin 9 Pin 10 Pin 11 Pin 12 Pin 13 Pin 14 Pin 15 Pin 16 Pin 17 Pin 18 Pin 19 Pin 20 Pin 21 Pin 22 Pin 23 Pin 24
Mnemonic DSX1 +DSX1 PAO1 FBK1 PAI1 COM1 COM2 PAI2 FBK2 PAO2 +DSX2 DSX2 VGN2 VOCM OUT2 GND2 VPOS VNEG VNEG VPOS GND1 OUT1 VREF VGN1
Description CH1 Negative Signal Input to DSX1. CH1 Positive Signal Input to DSX1. CH1 Preamplifier Output. CH1 Preamplifier Feedback Pin. CH1 Preamplifier Positive Input. CH1 Signal Ground; when connected to positive supply, Preamplifier1 will shut down. CH2 Signal Ground; when connected to positive supply, Preamplifier2 will shut down. CH2 Preamplifier Positive Input. CH2 Preamplifier Feedback Pin. CH2 Preamplifier Output. CH2 Positive Signal Input to DSX2. CH2 Negative Signal Input to DSX2. CH2 Gain-Control Input and Power-Down Pin. If grounded, device is off, otherwise positive voltage increases gain. Input to this pin defines common-mode of output at OUT1 and OUT2. CH2 Signal Output. Ground. Positive Supply. Negative Supply. Negative Supply. Positive Supply. Ground. CH1 Signal Output. Input to this pin sets gain-scaling for both channels +2.5 V = 20 dB/V, +1.67 V = 30 dB/V. CH1 Gain-Control Input and Power-Down Pin. If grounded, device is off; otherwise positive voltage increases gain.
PIN CONFIGURATION
DSX1 1 +DSX1 2 PAO1 3 FBK1 4 PAI1 5 COM1 6 24 VGN1 23 VREF 22 OUT1 21 GND1
AD604
20 VPOS
TOP VIEW 19 VNEG (Not to Scale) COM2 7 18 VNEG PAI2 8 FBK2 9 PAO2 10 +DSX2 11 DSX2 12 17 VPOS 16 GND2 15 OUT2 14 VOCM 13 VGN2
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Typical Performance Characteristics (per Channel)AD604
(Unless otherwise noted G (preamp) = +14 dB, VREF = 2.5 V (20 dB/V Scaling), f = 1 MHz, RL = 500
50 40 3 CURVES 40°C, +25°C, +85°C
60 50 40 G (PREAMP) = +14dB (0dB +48dB)
, CL = 5 pF, TA = +25 C, VSS =
5 V)
50 ACTUAL 30dB/V VREF = 1.67V ACTUAL
40
G (PREAMP) = +20dB (+6dB +54dB)
30
30
GAIN dB
GAIN dB
20
GAIN dB
30 20 10 0
20 20dB/V VREF = 2.50V 10
10
0 10 0.1
DSX ONLY (14dB +34dB)
0
10
0.5
0.9
1.3 1.7 2.1 VGN Volts
2.5
2.9
20 0.1
0.5
0.9
1.3 1.7 2.1 VGN Volts
2.5
2.9
10 0.1
0.5
0.9
1.3 1.7 2.1 VGN Volts
2.5
2.9
Figure 1. Gain vs. VGN
Figure 2. Gain vs. VGN for Different Preamp Gains
Figure 3. Gain vs. VGN for Different Gain Scalings
40 37.5 THEORETICAL
GAIN SCALING dB/V
2.0 1.5 1.0
GAIN ERROR dB
2.0 1.5 1.0
35 32.5 30 27.5 25 22.5 20 1.25 ACTUAL
GAIN ERROR dB
0.5 0 0.5 1.0 1.5 2.0 0.2
40°C
+25°C
0.5 0 0.5 1.0
FREQ = 1MHz
+85°C
FREQ = 5MHz FREQ = 10MHz
1.5 2.0 0.2
1.5
1.75 2 VREF Volts
2.25
2.5
0.7
1.2 1.7 VGN Volts
2.2
2.7
0.7
1.2 1.7 VGN Volts
2.2
2.7
Figure 4. Gain Scaling vs. VREF
Figure 5. Gain Error vs. VGN at Different Temperatures
Figure 6. Gain Error vs. VGN at Different Frequencies
2.0 1.5
25 N = 50 VGN1 = 1.0V VGN2 = 1.0V G(dB) = G(CH1) G(CH2)
25 N = 50 VGN1 = 2.50V VGN2 = 2.50V G(dB) = G(CH1) G(CH2)
20
1.0
20 PERCENTAGE
GAIN ERROR dB
PERCENTAGE
0.5 0 0.5 1.0 1.5 2.0 0.2 30dB/V VREF = 1.67V
20dB/V VREF = 2.50V
15
15
10
10
5
5
0.7
1.2 1.7 VGN Volts
2.2
2.7
0 1.0 0.8 0.6 0.4 0.2 0.1 0.3 0.5 0.7 0.9 DELTA GAIN dB
0 1.0 0.8 0.6 0.4 0.2 0.1 0.3 0.5 0.7 0.9 DELTA GAIN dB
Figure 7. Gain Error vs. VGN for Different Gain Scalings
Figure 8. Gain Match; VGN1 = VGN2 = 1.0 V
Figure 9. Gain Match: VGN1 = VGN2 = 2.50 V
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