AD605BRZ-REEL7 [ADI]

SPECIALTY ANALOG CIRCUIT, PDSO16, MS-012-AC, SOIC-16;
AD605BRZ-REEL7
型号: AD605BRZ-REEL7
厂家: ADI    ADI
描述:

SPECIALTY ANALOG CIRCUIT, PDSO16, MS-012-AC, SOIC-16

光电二极管
文件: 总25页 (文件大小:661K)
中文:  中文翻译
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Dual, Low Noise, Single-Supply  
Variable Gain Amplifier  
AD605  
FUNCTIONAL BLOCK DIAGRAM  
FEATURES  
2 independent linear-in-dB channels  
Input noise at maximum gain: 1.8 nV/√Hz, 2.7 pA/√Hz  
Bandwidth: 40 MHz (−3 dB)  
FIXED GAIN  
AMPLIFIER  
+34.4dB  
PRECISION PASSIVE  
INPUT ATTENUATOR  
VGN  
GAIN  
CONTROL  
AND  
OUT  
FBK  
Differential input  
SCALING  
VREF  
Absolute gain range programmable  
−14 dB to +34 dB (FBK shorted to OUT) through  
0 dB to 48 dB (FBK open)  
VOCM  
+IN  
–IN  
Variable gain scaling: 20 dB/V through 40 dB/V  
Stable gain with temperature and supply variations  
Single-ended unipolar gain control  
Output common mode independently set  
Power shutdown at lower end of gain control  
Single 5 V supply  
DIFFERENTIAL  
ATTENUATOR  
0 TO –48.4dB  
AD605  
Figure 1.  
Low power: 90 mW/channel  
Drives ADCs directly  
APPLICATIONS  
Ultrasound and sonar time-gain controls  
High performance AGC systems  
Signal measurement  
GENERAL DESCRIPTION  
The AD605 is a low noise, accurate, dual-channel, linear-in-dB  
variable gain amplifier (VGA), optimized for any application  
requiring high performance, wide bandwidth variable gain  
control. Operating from a single 5 V supply, the AD605 provides  
differential inputs and unipolar gain control for ease of use.  
Added flexibility is achieved with a user-determined gain range  
and an external reference input that provide user-determined  
gain scaling (dB/V).  
Each independent channel of the AD605 provides a gain range  
of 48 dB that can be optimized for the application. Gain ranges  
between −14 dB to +34 dB and 0 dB to +48 dB can be selected  
by a single resistor between Pin FBK and Pin OUT. The lower  
and upper gain ranges are determined by shorting Pin FBK to  
Pin OUT or leaving Pin FBK unconnected, respectively. The  
two channels of the AD605 can be cascaded to provide 96 dB  
of very accurate gain range in a monolithic package.  
The high performance linear-in-dB response of the AD605 is  
achieved with the differential input, single-supply, exponential  
amplifier (DSX-AMP) architecture. Each of the DSX-AMPs  
comprises a variable attenuator of 0 dB to −48.4 dB followed by  
a high speed, fixed-gain amplifier. The attenuator is based on a  
7-stage R-1.5R ladder network. The attenuation between tap  
points is 6.908 dB, and 48.360 dB for the entire ladder network.  
The DSX-AMP architecture results in 1.8 nV/√Hz input noise  
spectral density and accepts a 2.0 V input signal when VOCM  
is biased at VP/2.  
The gain control interface provides an input resistance of  
approximately 2 MΩ 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 linearly in dB  
with control voltages (VGN) of 0.4 V to 2.4 V for the 20 dB/V  
scale and 0.20 V to 1.20 V for the 40 dB/V scale. When VGN is  
<50 mV, the amplifier is powered down to draw 1.9 mA. Under  
normal operation, the quiescent supply current of each amplifier  
channel is only 18 mA.  
The AD605 is available in a 16-lead PDIP and a 16-lead SOIC_N  
package and is guaranteed for operation over the −40°C to +85°C  
temperature range.  
Rev. F  
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 that may result from its use. Specifications subject to change without notice. No  
license is granted by implication or otherwise under any patent or patent rights of Analog Devices.  
Trademarks and registeredtrademarks arethe property of their respective owners.  
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.  
Tel: 781.329.4700  
www.analog.com  
Fax: 781.461.3113 ©1996–2008 Analog Devices, Inc. All rights reserved.  
 
IMPORTANT LINKS for the AD605*  
Last content update 09/09/2013 12:26 am  
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DOCUMENTATION  
Design and Operation of Automatic Gain Control Loops for Receivers  
in Modern Communication Systems  
Choosing High-Speed Signal Processing Components for Ultrasound  
Systems  
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View the Evaluation Boards and Kits page for documentation and  
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This content may be frequently modified.  
AD605  
TABLE OF CONTENTS  
Features .............................................................................................. 1  
Gain Control Interface............................................................... 14  
Applications....................................................................................... 1  
Functional Block Diagram .............................................................. 1  
General Description......................................................................... 1  
Revision History ............................................................................... 2  
Specifications..................................................................................... 3  
Absolute Maximum Ratings............................................................ 5  
ESD Caution.................................................................................. 5  
Pin Configuration and Function Descriptions............................. 6  
Typical Performance Characteristics (per Channel) ................... 7  
Theory of Operation ...................................................................... 13  
Differential Ladder (Attenuator).............................................. 14  
AC Coupling ............................................................................... 14  
Fixed Gain Amplifier and Interpolator Circuits—Applying an  
Active Feedback Amplifier........................................................ 15  
Applications Information.............................................................. 16  
Connecting Two Amplifiers to Double the Gain Range....... 16  
Evaluation Board ............................................................................ 18  
Input Connections ..................................................................... 18  
Adjusting Gain, Common-Mode, and Reference Levels ...... 18  
Output Connections .................................................................. 18  
Outline Dimensions....................................................................... 21  
Ordering Guide .......................................................................... 22  
REVISION HISTORY  
6/08—Rev. E to Rev. F  
7/04—Rev. B to Rev. C  
Added Evaluation Board Section ................................................. 18  
Added Figure 42 and Table 4......................................................... 18  
Added Figure 43 and Figure 44..................................................... 19  
Added Figure 45 to Figure 50........................................................ 20  
Edits to General Description ...........................................................1  
Edits to Specifications.......................................................................2  
Edits to Ordering Guide ...................................................................3  
Change to TPC 22 .............................................................................6  
Updated Outline Dimensions....................................................... 12  
5/07—Rev. D to Rev. E  
Changes to Table 1............................................................................ 5  
Changes to Fixed Gain Amplifier and Interpolator Circuits—  
Applying an Active Feedback Amplifier Section........................ 15  
Updated Outline Dimensions....................................................... 18  
Changes to Ordering Guide .......................................................... 19  
1/06—Rev. C to Rev. D  
Updated Format..................................................................Universal  
Changes to Table 2............................................................................ 5  
Changes to Differential Ladder (Attenuator) Section ............... 14  
Updated the Outline Dimensions ................................................ 18  
Changes to the Ordering Guide.................................................... 19  
Rev. F | Page 2 of 24  
 
AD605  
SPECIFICATIONS  
Each channel @ TA = 25°C, VS = 5 V, RS = 50 Ω, RL = 500 Ω, CL = 5 pF, VREF = 2.5 V (scaling = 20 dB/V), −14 dB to +34 dB gain range,  
unless otherwise noted.  
Table 1.  
AD605A  
Min Typ  
AD605B  
Max Min Typ  
Parameter  
Conditions  
Max Unit  
INPUT CHARACTERISTICS  
Input Resistance  
Input Capacitance  
Peak Input Voltage  
Input Voltage Noise  
Input Current Noise  
Noise Figure  
175 4ꢀ  
3.ꢀ  
2.5 2.5  
1.8  
2.7  
8.4  
175 4ꢀ  
3.ꢀ  
2.5 2.5  
1.8  
2.7  
8.4  
Ω
pF  
V
nV/√Hz  
pA/√Hz  
dB  
At minimum gain  
VGN = 2.9 V  
VGN = 2.9 V  
RS = 5ꢀ Ω, f = 1ꢀ MHz, VGN = 2.9 V  
RS = 2ꢀꢀ Ω, f = 1ꢀ MHz, VGN = 2.9 V  
12  
12  
dB  
Common-Mode Rejection Ratio f = 1 MHz, VGN = 2.65 V  
OUTPUT CHARACTERISTICS  
−2ꢀ  
−2ꢀ  
dB  
−3 dB Bandwidth  
Slew Rate  
Constant with gain  
VGN = 1.5 V, output = 1 V step  
RL ≥ 5ꢀꢀ Ω  
4ꢀ  
17ꢀ  
2.5 1.5  
2
4ꢀ  
17ꢀ  
2.5 1.5  
2
MHz  
V/μs  
V
Ω
mA  
Output Signal Range  
Output Impedance  
Output Short-Circuit Current  
Harmonic Distortion  
HD2  
HD3  
HD2  
HD3  
f = 1ꢀ MHz  
4ꢀ  
4ꢀ  
VGN = 1 V, VOUT = 1 V p-p  
f = 1 MHz  
f = 1 MHz  
f = 1ꢀ MHz  
f = 1ꢀ MHz  
−64  
−68  
−51  
−53  
−64  
−68  
−51  
−53  
dBc  
dBc  
dBc  
dBc  
Two-Tone Intermodulation  
Distortion (IMD)  
RS = ꢀ Ω, VGN = 2.9 V, VOUT = 1 V p-p  
f = 1 MHz  
f = 1ꢀ MHz  
f = 1ꢀ MHz, VGN = 2.9 V, output referred  
f = 1ꢀ MHz, VGN = 2.9 V,  
−72  
−6ꢀ  
15  
−72  
−6ꢀ  
15  
dBc  
dBc  
dBm  
dBm  
1 dB Compression Point  
Third-Order Intercept  
−1  
−1  
V
OUT = 1 V p-p, input referred  
Channel-to-Channel Crosstalk  
Ch1: VGN = 2.65 V, inputs shorted,  
Ch2: VGN = 1.5 V (mid gain),  
f = 1 MHz, VOUT = 1 V p-p  
−7ꢀ  
−7ꢀ  
dB  
Group Delay Variation  
VOCM Input Resistance  
ACCURACY  
1 MHz < f < 1ꢀ MHz, full gain range  
2.ꢀ  
45  
2.ꢀ  
45  
ns  
kΩ  
Absolute Gain Error  
−14 dB to −11 dB  
−11 dB to +29 dB  
ꢀ.25 V < VGN < ꢀ.4ꢀ V  
ꢀ.4ꢀ V < VGN < 2.4ꢀ V  
2.4ꢀ V < VGN < 2.65 V  
ꢀ.4 V < VGN < 2.4 V  
VREF = 2.5ꢀꢀ V, VOCM = 2.5ꢀꢀ V  
VREF = 2.5ꢀꢀ V, VOCM = 2.5ꢀꢀ V  
−1.2 +1.ꢀ  
−1.ꢀ ꢀ.3  
−3.5 −1.25  
ꢀ.25  
+3.ꢀ –1.2 +ꢀ.75  
+1.ꢀ –1.ꢀ ꢀ.2  
+1.2 –3.5 −1.25  
ꢀ.25  
+3.ꢀ dB  
+1.ꢀ dB  
+1.2 dB  
dB/V  
+3ꢀ mV  
5ꢀ mV  
+29 dB to +34 dB  
Gain Scaling Error  
Output Offset Voltage  
Output Offset Variation  
−3ꢀ  
2ꢀ  
3ꢀ  
+3ꢀ –3ꢀ  
57  
2ꢀ  
3ꢀ  
Rev. F | Page 3 of 24  
 
AD605  
AD605A  
Min Typ  
AD605B  
Max Min Typ  
Parameter  
Conditions  
Max Unit  
GAIN CONTROL INTERFACE  
Gain Scaling Factor  
VREF = 2.5 V, ꢀ.4 V < VGN < 2.4 V  
VREF = 1.67 V  
FBK short to OUT  
FBK open  
19  
2ꢀ  
3ꢀ  
21  
19  
2ꢀ  
3ꢀ  
21  
dB/V  
dB/V  
dB  
dB  
V
Gain Range  
−14 to +34  
ꢀ to 48  
ꢀ.1 to 2.9  
−ꢀ.4  
−14 to +34  
ꢀ to 48  
ꢀ.1 to 2.9  
−ꢀ.4  
Input Voltage (VGN) Range  
Input Bias Current  
2ꢀ dB/V, VREF = 2.5 V  
ꢁA  
Input Resistance  
Response Time  
2
ꢀ.2  
2
ꢀ.2  
MΩ  
ꢁs  
48 dB gain change  
POWER SUPPLY  
Supply Voltage  
Power Dissipation  
4.5  
5.ꢀ  
9ꢀ  
1ꢀ  
5.5  
4.5  
5.ꢀ  
9ꢀ  
1ꢀ  
5.5  
V
mW  
kΩ  
mA  
mA  
ꢁs  
VREF Input Resistance  
Quiescent Supply Current  
Power-Down  
Power-Up Response Time  
Power-Down Response Time  
VPOS  
18  
23  
3.ꢀ  
18  
23  
3.ꢀ  
VPOS, VGN < 5ꢀ mV  
48 dB gain, VOUT = 2 V p-p  
1.9  
ꢀ.6  
ꢀ.4  
1.9  
ꢀ.6  
ꢀ.4  
ꢁs  
Rev. F | Page 4 of 24  
AD605  
ABSOLUTE MAXIMUM RATINGS  
Stresses above those listed under Absolute Maximum Ratings  
Table 2.  
Parameter  
may cause permanent damage to the device. This is a stress  
rating only; 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.  
Rating  
Supply Voltage +VS  
Pin 12, Pin 13 (with Pin 4, Pin 5 = ꢀ V)  
Input Voltage Pin 1 to Pin 3, Pin 6 to Pin 9, Pin 16  
Internal Power Dissipation  
16-Lead PDIP  
6.5 V  
VPOS, ꢀ V  
1.4 W  
16-Lead SOIC_N  
1.2 W  
ESD CAUTION  
Operating Temperature Range  
Storage Temperature Range  
Lead Temperature, Soldering 6ꢀ sec  
Thermal Resistance θJA  
16-Lead PDIP  
−4ꢀ°C to +85°C  
−65°C to +15ꢀ°C  
3ꢀꢀ°C  
85°C/W  
16-Lead SOIC_N  
1ꢀꢀ°C/W  
Rev. F | Page 5 of 24  
 
AD605  
PIN CONFIGURATION AND FUNCTION DESCRIPTIONS  
VGN1  
–IN1  
16  
15  
1
2
3
4
5
6
7
8
VREF  
OUT1  
+IN1  
14 FBK1  
AD605  
GND1  
GND2  
+IN2  
VPOS  
13  
TOP VIEW  
12  
11  
10  
9
VPOS  
FBK2  
OUT2  
(Not to Scale)  
–IN2  
VGN2  
VOCM  
Figure 2. Pin Configuration  
Table 3. Pin Function Descriptions  
Pin No. Mnemonic Description  
1
2
VGN1  
−IN1  
CH1 Gain Control Input and Power-Down Pin. If grounded, device is off; otherwise, positive voltage increases gain.  
CH1 Negative Input.  
3
+IN1  
CH1 Positive Input.  
4
5
6
GND1  
GND2  
+IN2  
Ground.  
Ground.  
CH2 Positive Input.  
7
−IN2  
CH2 Negative Input.  
8
9
VGN2  
VOCM  
OUT2  
FBK2  
VPOS  
VPOS  
FBK1  
OUT1  
VREF  
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 Voltage for OUT1 and OUT2.  
CH2 Output.  
Feedback Pin That Selects Gain Range of CH2.  
Positive Supply.  
Positive Supply.  
Feedback Pin That Selects Gain Range of CH1.  
CH1 Output.  
Input to This Pin Sets Gain Scaling for Both Channels: 2.5 V = 2ꢀ dB/V and 1.67 V = 3ꢀ dB/V.  
1ꢀ  
11  
12  
13  
14  
15  
16  
Rev. F | Page 6 of 24  
 
AD605  
TYPICAL PERFORMANCE CHARACTERISTICS (PER CHANNEL)  
VREF = 2.5 V (20 dB/V scaling), f = 1 MHz, RL = 500 Ω, CL = 5 pF, TA = 25°C, VSS = 5 V.  
40  
40.0  
37.5  
35.0  
32.5  
30.0  
27.5  
25.0  
22.5  
20.0  
THEORETICAL  
30  
–40°C, +25°C, +85°C  
20  
ACTUAL  
10  
0
–10  
–20  
1.25  
1.50  
1.75  
2.00  
2.25  
2.50  
0.1  
0.5  
0.9  
1.3  
1.7  
2.1  
2.5  
2.9  
VGN (V)  
V
(V)  
REF  
Figure 3. Gain vs. VGN  
Figure 6. Gain Scaling vs. VREF  
50  
40  
3.0  
2.5  
2.0  
1.5  
30  
FBK (OPEN)  
1.0  
–40°C  
0.5  
20  
FBK (SHORT)  
0
10  
–0.5  
–1.0  
–1.5  
–2.0  
–2.5  
–3.0  
+25°C  
+85°C  
0
–10  
–20  
0.1  
0.5  
0.9  
1.3  
1.7  
2.1  
2.5  
2.9  
0.2  
0.7  
1.2  
1.7  
2.2  
2.7  
VGN (V)  
VGN (V)  
Figure 4. Gain vs. VGN for Different Gain Ranges  
Figure 7. Gain Error vs. VGN at Three Temperatures  
40  
30  
2.0  
1.5  
1.0  
0.5  
0
ACTUAL  
ACTUAL  
30dB/V  
= 1.67V)  
(V  
REF  
f = 1MHz  
20  
20dB/V  
= 2.50V)  
10  
(V  
REF  
f = 5MHz  
–0.5  
–1.0  
f = 10MHz  
0
–10  
–20  
–1.5  
–2.0  
0.2  
0.7  
1.2  
1.7  
2.2  
2.7  
0.1  
0.5  
0.9  
1.3  
VGN (V)  
1.7  
2.1  
2.5  
2.9  
VGN (V)  
Figure 5. Gain vs. VGN for Different Gain Scalings  
Figure 8. Gain Error vs. VGN at Three Frequencies  
Rev. F | Page 7 of 24  
 
AD605  
2.0  
1.5  
1.0  
0.5  
0
60  
40  
20  
VGN = 2.9V (FBK = OPEN)  
VGN = 2.9V (FBK = SHORT)  
VGN = 1.5V (FBK = OPEN)  
20dB/V  
= 2.50V  
VGN = 1.5V (FBK = SHORT)  
VGN = 0.1V (FBK = OPEN)  
V
REF  
0
VGN = 0.1V (FBK = SHORT)  
30dB/V  
= 1.67V  
–0.5  
–1.0  
V
REF  
–20  
VGN = 0.0V  
–40  
–60  
–1.5  
–2.0  
0.2  
0.7  
1.2  
1.7  
2.2  
2.7  
100k  
1M  
10M  
100M  
VGN (V)  
FREQUENCY (Hz)  
Figure 12. AC Response for Three Values of VGN  
Figure 9. Gain Error vs. VGN for Two Gain Scale Values  
2.525  
2.520  
20  
18  
16  
14  
12  
10  
8
V
= 2.50V  
N = 50  
OCM  
ΔG(dB) = G(CH1) – G(CH2)  
–40°C  
+25°C  
2.515  
2.510  
2.505  
2.500  
2.495  
2.490  
2.485  
+85°C  
6
4
2.480  
2.475  
2
0
0
0.5  
1.0  
1.5  
VGN (V)  
2.0  
2.5  
3.0  
–0.8 –0.6 –0.4 –0.2  
0
0.2  
0.4  
0.6  
0.8  
DELTA GAIN (dB)  
Figure 10. Gain Match, VGN1 = VGN2 = 1.0 V  
Figure 13. Output Offset vs. VGN at Three Temperatures  
20  
18  
16  
14  
12  
10  
8
130  
N = 50  
+85°C  
+25°C  
ΔG(dB) = G(CH1) – G(CH2)  
125  
120  
115  
110  
105  
100  
95  
–40°C  
6
4
2
0
90  
–0.8 –0.6 –0.4 –0.2  
0
0.2  
0.4  
0.6  
0.8  
0
0.5  
1.0  
1.5  
2.0  
2.5  
3.0  
DELTA GAIN (dB)  
VGN (V)  
Figure 14. Output Referred Noise vs. VGN at Three Temperatures  
Figure 11. Gain Match, VGN1 = VGN2 = 2.50 V  
Rev. F | Page 8 of 24  
AD605  
1000  
100  
10  
VGN = 2.9V  
100  
10  
1
1.0  
R
ALONE  
SOURCE  
0.1  
1
0.1  
0.5  
0.9  
1.3  
1.7  
2.1  
2.5  
2.9  
10  
100  
1k  
VGN (V)  
R
()  
SOURCE  
Figure 18. Input Referred Noise vs. RSOURCE  
Figure 15. Input Referred Noise vs. VGN  
30  
25  
20  
15  
2.00  
1.95  
1.90  
VGN = 2.9V  
VGN = 2.9V  
1.85  
1.80  
1.75  
1.70  
1.65  
1.60  
10  
5
–40 –30 –20 –10  
0
10 20 30 40 50 60 70 80 90  
TEMPERATURE (°C)  
1
10  
100  
1k  
R
()  
SOURCE  
Figure 19. Noise Figure vs. RSOURCE  
Figure 16. Input Referred Noise vs. Temperature  
60  
50  
40  
30  
20  
10  
0
1.90  
1.85  
1.80  
1.75  
1.70  
1.65  
1.60  
VGN = 2.9V  
R
= 50  
S
0.1  
0.5  
0.9  
1.3  
1.7  
2.1  
2.5  
2.9  
100k  
1M  
10M  
VGN (V)  
FREQUENCY (Hz)  
Figure 17. Input Referred Noise vs. Frequency  
Figure 20. Noise Figure vs. VGN  
Rev. F | Page 9 of 24  
AD605  
–30  
–35  
–40  
–45  
–50  
–55  
–60  
–65  
–70  
15  
V
= 1V p-p  
OUT  
10  
VGN = 1.0V  
INPUT GENERATOR  
LIMIT = 21dBm  
5
0
–5  
HD3  
HD2  
–10  
–15  
–20  
FREQ = 10MHz  
FREQ = 1MHz  
100k  
1M  
10M  
FREQUENCY (Hz)  
100M  
0.1  
0.5  
0.9  
1.3  
1.7  
2.1  
2.5  
2.9  
VGN (V)  
Figure 21. Harmonic Distortion vs. Frequency  
Figure 24. 1 dB Compression vs. VGN  
35  
30  
25  
20  
15  
10  
5
–35  
–40  
–45  
–50  
–55  
–60  
–65  
–70  
–75  
V
= 1V p-p  
OUT  
HD3  
(10MHz)  
f = 1MHz  
HD2  
(1MHz)  
HD2  
f = 10MHz  
(10MHz)  
0
HD3  
(1MHz)  
–5  
0.6  
1.0  
1.4  
1.8  
2.2  
2.6  
3.0  
0.5  
0.8  
1.1  
1.4  
1.7  
2.0  
2.3  
2.6  
2.9  
VGN (V)  
VGN (V)  
Figure 22. Harmonic Distortion vs. VGN at 1 MHz and 10 MHz  
Figure 25. Third-Order Intercept vs. VGN at 1 MHz and 10 MHz  
–20  
2V  
f = 10MHz  
V
= 2V p-p  
OUT  
VGN = 1.5V  
–30  
–40  
V
= 1V p-p  
OUT  
VGN = 1.0V  
–50  
–60  
–70  
–80  
–90  
TRIG'D  
2V  
–100  
–110  
–120  
9.92  
9.96  
10.00  
FREQUENCY (MHz)  
10.02  
10.04  
1.253µs  
253ns  
100ns/DIV  
Figure 23. Intermodulation Distortion  
Figure 26. Large Signal Pulse Response  
Rev. F | Page 1ꢀ of 24  
AD605  
–30  
–40  
200  
VGN1 = 1V  
V
= 200mV p-p  
OUT  
VGN = 1.5V  
V
= 1V p-p  
OUT1  
V
= GND  
IN2  
–50  
–60  
–70  
VGN2 = 2.9V  
TRIG'D  
–200  
VGN2 = 2.5V  
VGN2 = 2.0V  
VGN2 = 0.1V  
–80  
–90  
100k  
1M  
10M  
100M  
1.253µs  
253ns  
FREQUENCY (Hz)  
100ns/DIV  
Figure 27. Small Signal Pulse Response  
Figure 30. Crosstalk (CH1 to CH2) vs. Frequency for Four Values of VGN2  
0
V
= 0dBm  
IN  
500mV  
–10  
–20  
–30  
–40  
–50  
–60  
2.9V  
100  
90  
VGN = 2.9V  
VGN = 2.5V  
VGN = 2.0V  
10  
VGN = 0.1V  
0%  
0.0V  
500mV  
200ns  
100k  
1M  
10M  
100M  
FREQUENCY (Hz)  
Figure 31. CMRR vs. Frequency for Four Values of VGN  
Figure 28. Power-Up/Power-Down Response  
180  
VGN = 2.9V  
500mV  
175  
170  
165  
160  
2.9V  
100  
90  
155  
150  
10  
0%  
145  
140  
0.1V  
500mV  
100ns  
100k  
1M  
10M  
100M  
FREQUENCY (Hz)  
Figure 29. Gain Response  
Figure 32. Input Impedance vs. Frequency  
Rev. F | Page 11 of 24  
AD605  
25  
20  
15  
10  
5
16  
+I (AD605)  
S
14  
12  
10  
8
6
VGN = 0.1V  
VGN = 2.9V  
+I (VGN = 0)  
S
4
100k  
0
–40 –30 –20 –10  
0
10 20 30 40 50 60 70 80 90  
TEMPERATURE (°C)  
1M  
10M  
100M  
FREQUENCY (Hz)  
Figure 34. Group Delay vs. Frequency  
Figure 33. Supply Current (One Channel) vs. Temperature  
Rev. F | Page 12 of 24  
AD605  
THEORY OF OPERATION  
The AD605 is a dual-channel, low noise VGA. Figure 35 shows  
the simplified block diagram of one channel. Each channel consists  
of a single-supply X-AMP® (hereafter called DSX, differential  
single-supply X-AMP) comprising the following:  
The desired gain can then be achieved by setting the unipolar  
gain control (VGN) to a voltage within its nominal operating  
range of 0.25 V to 2.65 V (for 20 dB/V gain scaling). The gain is  
monotonic for a complete gain control range of 0.1 V to 2.9 V.  
Maximum gain can be achieved at a VGN of 2.9 V.  
Precision passive attenuator (differential ladder)  
Gain control block  
Because the two channels are identical, only Channel 1 is used  
to describe their operation. VREF and VOCM are the only inputs  
that are shared by the two channels, and because they are normally  
ac grounds, crosstalk between the two channels is minimized.  
For the highest gain scaling accuracy, VREF should have an  
external low impedance voltage source. For low accuracy 20 dB/V  
applications, the VREF input can be decoupled with a capacitor  
to ground. In this mode, the gain scaling is determined by the  
midpoint between +VCC and GND; therefore, care should be  
taken to control the supply voltage to 5 V. The input resistance  
looking into the VREF pin is 10 kΩ 20ꢀ.  
VOCM buffer with supply splitting resistors R3 and R4  
Active feedback amplifier1 (AFA) with gain setting resistors  
R1 and R2  
The linear-in-dB gain response of the AD605 can generally be  
described by Equation 1.  
G (dB) = (Gain Scaling (dB/V)) × (Gain Control (V)) −  
(19 dB − (14 dB) × (FB))  
(1)  
where:  
FB = 0, if FBK to OUT is shorted.  
FB = 1, if FBK to OUT is open.  
The AD605 is a single-supply circuit, and the VOCM pin is used  
to establish the dc level of the midpoint of this portion of the  
circuit. VOCM needs only an external decoupling capacitor to  
ground to center the midpoint between the supply voltages (5 V,  
GND). However, if the dc level of the output is important to the  
user (see the Applications Information section of the AD9050  
data sheet for an example), VOCM can be specifically set. The  
input resistance looking into the VOCM pin is 45 kΩ 20ꢀ.  
Each channel provides between −14 dB to +34.4 dB through  
0 dB to +48.4 dB of gain, depending on the value of the resistance  
connected between Pin FBK and Pin OUT. The center 40 dB of  
gain is exactly linear-in-dB while the gain error increases at the top  
and bottom of the range. The gain is set by the gain control voltage  
(VGN). The VREF input establishes the gain scaling. The useful  
gain scaling range is between 20 dB/V and 40 dB/V for a VREF  
voltage of 2.5 V and 1.25 V, respectively. For example, if FBK to  
OUT is shorted and VREF is set to 2.50 V (to establish a gain  
scaling of 20 dB/V), the gain equation simplifies to  
1 To understand the active-feedback amplifier topology, refer to the AD83ꢀ  
data sheet. The AD83ꢀ is a practical implementation of the idea.  
G (dB) = (20 (dB/V)) × (VGN (V)) – 19 dB  
(2)  
VREF  
VGN  
GAIN  
CONTROL  
DISTRIBUTED g  
175  
175Ω  
m
C1  
+IN  
+
G1  
DIFFERENTIAL  
ATTENUATOR  
EXT  
C2  
+
Ao  
–IN  
OUT  
3.36kΩ  
VPOS  
G2  
+
R3  
200kΩ  
R2  
20Ω  
R1  
820Ω  
VOCM  
+
FBK  
R4  
C3  
200kΩ  
EXT  
Figure 35. Simplified Block Diagram of a Single Channel of the AD605  
Rev. F | Page 13 of 24  
 
 
AD605  
R
R
–6.908dB  
1.5R  
R
R
–13.82dB  
1.5R  
R
R
–20.72dB  
1.5R  
R
R
–27.63dB  
1.5R  
R
R
–34.54dB  
1.5R  
R
R
–41.45dB  
1.5R  
R
R
–48.36dB  
1.5R  
+IN  
175  
175Ω  
MID  
–IN  
1.5R  
1.5R  
1.5R  
1.5R  
1.5R  
1.5R  
1.5R  
NOTE: R = 96Ω  
1.5R = 144Ω  
Figure 36. R-1.5R Dual Ladder Network  
DIFFERENTIAL LADDER (ATTENUATOR)  
AC COUPLING  
The attenuator before the fixed gain amplifier is realized by a  
differential, 7-stage, R-1.5R resistive ladder network with an  
untrimmed input resistance of 175 Ω single ended or 350 Ω  
differentially. The signal applied at the input of the ladder  
network is attenuated by 6.908 dB per tap; therefore, the  
attenuation at the first tap is 6.908 dB, at the second, 13.816 dB,  
and so on all the way to the last tap where the attenuation is  
48.356 dB (see Figure 36). A unique circuit technique is used to  
interpolate continuously between the tap points, thereby providing  
continuous attenuation from 0 dB to −48.36 dB. One can think  
of the ladder network together with the interpolation mechanism  
as a voltage-controlled potentiometer.  
The DSX is a single-supply circuit; therefore, its inputs need to  
be ac-coupled to accommodate ground-based signals. External  
Capacitor C1 and Capacitor C2 in Figure 35 level-shift the input  
signal from ground to the dc value established by VOCM (nominal  
2.5 V). C1 and C2, together with the 175 Ω looking into each of  
DSX inputs (+IN and −IN), act as high-pass filters with corner  
frequencies depending on the values chosen for C1 and C2. For  
example, if C1 and C2 are 0.1 μF, together with the 175 Ω input  
resistance of each side of the differential ladder of the DSX, a −3 dB  
high-pass corner at 9.1 kHz is formed.  
If the DSX output needs to be ground referenced, another ac  
coupling capacitor is required for level shifting. This capacitor also  
eliminates any dc offsets contributed by the DSX. With a nominal  
load of 500 Ω and a 0.1 μF coupling capacitor, this adds a high-pass  
filter with −3 dB corner frequency at about 3.2 kHz.  
Because the DSX is a single-supply circuit, some means of  
biasing its inputs must be provided. Node MID together with  
the VOCM buffer performs this function. Without internal  
biasing, external biasing is required. If not done carefully, the  
biasing network can introduce additional noise and offsets. By  
providing internal biasing, the user is relieved of this task and  
only needs to ac couple the signal into the DSX. It should be  
made clear again that the input to the DSX is still fully differential if  
driven differentially, that is, Pin +IN and Pin −IN see the same  
signal but with opposite polarity. What changes is the load seen  
by the driver; it is 175 Ω when each input is driven single ended,  
but 350 Ω when driven differentially. This can be easily explained  
when thinking of the ladder network as two 175 Ω resistors  
connected back-to-back with the middle node, MID, being  
biased by the VOCM buffer. A differential signal applied between  
nodes +IN and −IN results in zero current into Node MID, but  
a single-ended signal applied to either input +IN or −IN, while the  
other input is ac grounded, causes the current delivered by the  
source to flow into the VOCM buffer via Node MID.  
The choice for all three of these coupling capacitors depends on  
the application. They should allow the signals of interest to pass  
unattenuated, while at the same time, they can be used to limit  
the low frequency noise in the system.  
GAIN CONTROL INTERFACE  
The gain control interface provides an input resistance of  
approximately 2 MΩ at Pin VGN1 and gain scaling factors from  
20 dB/V to 40 dB/V for VREF input voltages of 2.5 V to 1.25 V,  
respectively. The gain varies linearly in decibels for the center  
40 dB of gain range, that is, for VGN equal to 0.4 V to 2.4 V for  
the 20 dB/V scale and 0.25 V to 1.25 V for the 40 dB/V scale.  
Figure 37 shows the ideal gain curves when the FBK-to-OUT  
connection is shorted as described by the following equations:  
G (20 dB/V) = 20 × VGN − 19, VREF = 2.500 V  
G (30 dB/V) = 30 × VGN − 19, VREF = 1.6666 V  
G (40 dB/V) = 40 × VGN − 19, VREF = 1.250 V  
(3)  
(4)  
(5)  
A feature of the X-AMP architecture is that the output-referred  
noise is constant vs. gain over most of the gain range. Referring  
to Figure 36, the tap resistance is approximately equal for all  
taps within the ladder, excluding the end sections. The resistance  
seen looking into each tap is 54.4 Ω, which makes 0.95 nV/√Hz of  
Johnson noise spectral density. Because there are two attenuators,  
the overall noise contribution of the ladder network is √2 times  
0.95 nV/√Hz or 1.34 nV/√Hz, a large fraction of the total DSX  
noise. The rest of the DSX circuit components contribute another  
1.20 nV/√Hz, which together with the attenuator produces  
1.8 nV/√Hz of total DSX input referred noise.  
The equations show that all gain curves intercept at the same  
−19 dB point; this intercept is 14 dB higher (−5 dB) if the FBK-  
to-OUT connection is left open. Outside the central linear  
range, the gain starts to deviate from the ideal control law but  
still provides another 8.4 dB of range. For a given gain scaling,  
one can calculate VREF as  
2.500 V×20 dB/V  
VREF  
=
(6)  
Gain Scale  
Rev. F | Page 14 of 24  
 
 
 
AD605  
40dB/V  
30dB/V  
20dB/V  
The AFA makes a differential input structure possible because  
one of its inputs (G1) is fully differential; this input is made  
up of a distributed gm stage. The second input (G2) is used for  
feedback. The output of G1 is some function of the voltages  
sensed on the attenuator taps that is applied to a high gain  
amplifier (A0). Because of negative feedback, the differential  
input to the high gain amplifier is zero; this in turn implies that  
the differential input voltage to G2 times gm2 (the transconductance  
of G2) is equal to the differential input voltage to G1 times gm1  
(the transconductance of G1). Therefore, the overall gain  
function of the AFA is  
35  
30  
25  
20  
15  
10  
5
LINEAR-IN-dB RANGE  
OF AD605  
0
0.5  
1.0  
1.5  
2.0  
2.5  
3.0  
–5  
–10  
GAIN CONTROL VOLTAGE  
gm  
VOUT  
R1×R2  
R2  
1
2
=
×
(7)  
VATTEN gm  
–15  
–20  
where:  
VOUT is the output voltage.  
V
ATTEN is the effective voltage sensed on the attenuator.  
Figure 37. Ideal Gain Curves vs. VREF  
(R1 + R2)/R2 = 42.  
Usable gain control voltage ranges are 0.1 V to 2.9 V for the  
20 dB/V scale and 0.1 V to 1.45 V for the 40 dB/V scale. VGN  
voltages of less than 0.1 V are not used for gain control because  
below 50 mV the channel is powered down. This can be used to  
conserve power and at the same time gate-off the signal. The  
supply current for a powered-down channel is 1.9 mA, and the  
response time to power the device on or off is less than 1 μs.  
gm1/gm2 = 1.25; the overall gain is therefore 52.5 (34.4 dB).  
The AFA has additional features that include the following:  
inverting the output signal by switching the positive and negative  
input to the ladder network; the possibility of using the −IN  
input as a second signal input; and independent control of the  
DSX common-mode voltage. Under normal operating conditions,  
it is best to connect a decoupling capacitor to Pin VOCM, in  
which case, the common- mode voltage of the DSX is half of  
the supply voltage; this allows for maximum signal swing.  
Nevertheless, the common-mode voltage can be shifted up or  
down by directly applying a voltage to VOCM. It can also be  
used as another signal input, the only limitation being the  
rather low slew rate of the VOCM buffer.  
FIXED GAIN AMPLIFIER AND INTERPOLATOR  
CIRCUITS—APPLYING AN ACTIVE FEEDBACK  
AMPLIFIER  
A typical X-amp architecture is powered by a dual polarity  
power supply. Because the AD605 operates from a single supply, a  
supply common equal to half the value of the supply voltage is  
required. An active feedback amplifier (AFA) is used to provide  
a differential input and to implement the feedback loop. The  
AFA in the AD605 is an op amp with two gm stages; one is used  
in the feedback path, and the other is used as a highly linear  
differential input.  
If the dc level of the output signal is not critical, another coupling  
capacitor is normally used at the output of the DSX; again, this  
is done for level shifting and to eliminate any dc offsets contributed  
by the DSX (see the AC Coupling section).  
The gain range of the DSX is programmable by a resistor connected  
between Pin FBK and Pin OUT. The possible ranges are −14 dB to  
+34.4 dB when the pins are shorted together or 0 dB to +48.4 dB  
when FBK is left open. For the higher gain range, the bandwidth  
of the amplifier is reduced by a factor of five to about 8 MHz  
because the gain increased by 14 dB. This is the case for any  
constant gain bandwidth product amplifier that includes the  
active feedback amplifier.  
A multisection distributed gm stage senses the voltages on the  
ladder network, one stage for each of the ladder nodes. Only a  
few of the stages are active at any time and are dependent on the  
gain control voltage.  
Rev. F | Page 15 of 24  
 
 
AD605  
APPLICATIONS INFORMATION  
The basic circuit in Figure 38 shows the connections for one  
channel of the AD605 with a gain range of −14 dB to +34.4 dB.  
The signal is applied at +IN1. The ac coupling capacitors before  
Pin −IN1 and Pin +IN1 should be selected according to the  
required lower cutoff frequency. In this example, the 0.1 μF  
capacitors, together with the 175 Ω of each of the DSX input  
pins, provide a −3 dB high-pass corner of about 9.1 kHz. The  
upper cutoff frequency is determined by the amplifier and is  
40 MHz.  
VGN  
C1  
1
2
3
4
5
6
7
8
16  
15  
14  
13  
12  
11  
10  
9
2.500V  
VREF  
VGN1  
–IN1  
0.1µF  
AD605OUT1  
R1  
R2  
V
IN  
+IN1  
FBK1  
C2  
GND1  
GND2  
+IN2  
0.1µF  
VPOS  
VPOS  
FBK2  
OUT2  
VOCM  
5V  
C3  
0.1µF  
C5  
0.1µF  
–IN2  
OUT  
C4  
0.1µF  
VGN2  
C6  
0.1µF  
VGN  
16  
15  
14  
13  
12  
11  
10  
9
1
2
3
4
5
6
7
8
2.500V  
OUT  
VREF  
VGN1  
–IN1  
0.1µF  
Figure 39. Doubling the Gain Range with Two Amplifiers  
AD605OUT1  
0.1µF  
5V  
Two other easy combinations are possible to provide a gain  
range of −14 dB to +82.8 dB: make R1 a short and R2 an open,  
or make R1 an open and R2 a short. The bandwidth for both of  
these cases is dominated by the channel that is set to the higher  
gain and is about 8 MHz. From a noise standpoint, the second  
choice is the best because by increasing the gain of the first  
amplifier, the noise of the second amplifier has less of an impact  
on the total output noise. One further observation regarding  
noise is that by increasing the gain, the output noise increases  
proportionally; therefore, there is no increase in signal-to-noise  
ratio. It actually stays fixed.  
V
IN  
+IN1  
FBK1  
0.1µF  
GND1  
GND2  
+IN2  
VPOS  
VPOS  
FBK2  
OUT2  
VOCM  
–IN2  
VGN2  
0.1µF  
Figure 38. Basic Connections for a Single Channel  
As shown in Figure 38, the output is ac-coupled for optimum  
performance. In the case of connecting to the 10-bit, 40 MSPS  
ADC, AD9050, ac coupling can be eliminated as long as  
Pin VOCM is biased by the same 3.3 V common-mode voltage  
as the AD9050.  
It should be noted that by selecting the appropriate values of R1  
and R2, any gain range between −28 dB to +68.8 dB and 0 dB to  
+96.8 dB can be achieved with the circuit in Figure 39. When  
using any value other than shorts and opens for R1 and R2, the  
final value of the gain range depends on the external resistors  
matching the on-chip resistors. Because the internal resistors  
can vary by as much as 20ꢀ, the actual values for a particular  
gain have to be determined empirically. Note that the two channels  
within one part match quite well; therefore, R1 tracks R2 in  
Figure 39.  
Pin VREF requires a voltage of 1.25 V to 2.5 V, with gain scaling  
between 40 dB/V and 20 dB/V, respectively. Voltage VGN controls  
the gain; its nominal operating range is from 0.25 V to 2.65 V  
for 20 dB/V gain scaling and 0.125 V to 1.325 V for 40 dB/V  
scaling. When this pin is taken to ground, the channel powers  
down and disables its output.  
CONNECTING TWO AMPLIFIERS TO DOUBLE THE  
GAIN RANGE  
C3 is not required because the common-mode voltage at  
Pin OUT1 should be identical to the one at Pin +IN2 and  
Pin −IN2. However, because only 1 mV of offset at the output  
of the first DSX introduces an offset of 53 mV when the second  
DSX is set to the maximum gain of the lowest gain range (34.4 dB),  
and 263 mV when set to the maximum gain of the highest gain  
range (48.4 dB), it is important to include ac coupling to get the  
maximum dynamic range at the output of the cascaded amplifiers.  
C5 is necessary if the output signal needs to be referenced to any  
common-mode level other than half of the supply as is provided  
by Pin OUT2.  
Figure 39 shows the two channels of the AD605 connected in  
series to provide a total gain range of 96.8 dB. When R1 and R2  
are shorts, the gain range is from −28 dB to +68.8 dB with a  
slightly reduced bandwidth of about 30 MHz. The reduction in  
bandwidth is due to two identical low-pass circuits being connected  
in series; in the case of two identical single-pole, low-pass filters,  
the bandwidth is reduced by exactly √2. If R1 and R2 are  
replaced by open circuits, that is, Pin FBK1 and Pin FBK2 are left  
unconnected, the gain range shifts up by 28 dB to 0 dB to 96.8 dB.  
As previously noted, the bandwidth of each individual channel is  
reduced by a factor of 5 to about 8 MHz because the gain increased  
by 14 dB. In addition, there is still the √2 reduction because the  
series connection of the two channels results in a final  
bandwidth of the higher gain version of about 6 MHz.  
Rev. F | Page 16 of 24  
 
 
 
 
AD605  
4
3
Figure 40 shows the gain vs. VGN for the circuit in Figure 39  
at 1 MHz and the lowest gain range (−14 dB to +34.4 dB). Note  
that the gain scaling is 40 dB/V, double the 20 dB/V of an  
individual DSX; this is the result of the parallel connection of  
the gain control inputs, VGN1 and VGN2. The gain can also be  
sequentially increased by first increasing the gain of Channel 1  
and then Channel 2. In this case, VGN1 and VGN2 are driven  
from separate voltage sources, for instance two separate DACs.  
Figure 41 shows the gain error of Figure 39.  
f = 1MHz  
2
1
0
–1  
–2  
–3  
–4  
80  
THEORETICAL  
f = 1MHz  
70  
60  
50  
40  
30  
20  
10  
0
ACTUAL  
0.2  
0.7  
1.2  
1.7  
2.2  
2.7  
VGN (V)  
Figure 41. Gain Error vs. VGN for the Circuit in Figure 39  
–10  
–20  
–30  
–40  
0.1  
0.5  
0.9  
1.3  
1.7  
2.1  
2.5  
2.9  
VGN (V)  
Figure 40. Gain vs. VGN for the Circuit in Figure 39  
Rev. F | Page 17 of 24  
 
 
AD605  
EVALUATION BOARD  
The AD605-EVALZ provides a platform for the circuit designer  
to become familiar with the many operating and performance  
features of the AD605 variable gain amplifier. It is a factory-  
designed, surface-mount assembly fully tested and ready for  
service. Figure 42 is a photograph of the AD605-EVALZ. Multiple  
inputs, test points, and jumpers provide circuit configurations that  
support any of the operating options of the device. Figure 43 is a  
schematic of the board.  
INPUT CONNECTIONS  
The AD605 VGA accepts differential or single-ended input  
signals and provides single-ended outputs. The SMA connectors  
enable either configuration to be used, as well as the output and  
gain control signals. Each of the I/O ports is also available at a  
test-loop labeled for easy identification.  
The input resistance at each of the four input SMA connectors is  
50 ꢁ, consisting of the 175 Ω, 40 Ω resistance of the attenuator  
ladder network in parallel with the external 69.8 Ω resistors. For  
single-ended operation, unused inputs can be left disconnected  
or optional jumpers installed. Either VGA input is usable; for  
noninverting operation, the INPx is used, and for signal inversion,  
the INMx is used.  
Power is required from only a single 5 V supply capable of  
supplying 55 mA to 60 mA quiescent current.  
ADJUSTING GAIN, COMMON-MODE, AND  
REFERENCE LEVELS  
The gain of each channel is adjusted with trimmers, GN1ADJ and  
GN2ADJ. Trimmer VREF ADJ adjusts the gain scaling in dB/V (or  
gain slope), and VOCM ADJ adjusts the output common-mode  
voltage for both channels. For dynamic gain control, JP1 and  
JP4 can be removed and the signal applied at the SMA  
connectors, GN1 and GN2.  
OUTPUT CONNECTIONS  
SMA connectors, OUT1 and OUT2, are the output connectors.  
Series resistors and capacitors are included for termination and  
dc blocking purposes. The output of the AD605 has a common-  
mode value of one-half the supply (unless amended by a voltage  
applied to the VCM pin).  
Table 4 lists jumpers and their functions, and Figure 44 shows  
the evaluation board in a typical test configuration.  
Figure 42. AD605–EVALZ Evaluation Board  
Table 4. Table of Jumpers  
Jumper Function  
Default Configuration  
JP1  
JP2  
JP3  
JP4  
JP5  
JP6  
JP7  
JP8  
Connects trimmer GN1ADJ to pin VGN1. This jumper can be removed for an ac signal at VGN1.  
Grounds the IN1 pin via C2.  
Grounds the IN2 pin via C5.  
Connects trimmer GN2ADJ to Pin VGN2. This jumper can be removed for an ac signal at VGN2.  
Connects trimmer VOCMADJ to the VOCM pin. This jumper can be removed for the half supply default VOCM. Installed  
Shifts the gain of Channel 2 up or down by 14 dB.  
Shifts the gain of Channel 1 up or down by 14 dB.  
Connects trimmer VREFADJ to the VREF pin to change the gain slope.  
Installed  
User supplied  
User supplied  
Installed  
Installed  
Installed  
Installed  
Rev. F | Page 18 of 24  
 
 
 
AD605  
VREF  
ADJ  
+5V  
+5V  
CH1_GN  
R1  
DNI  
R2  
JP1  
10k  
GN1  
ADJ  
J1  
GN1  
R14  
10kΩ  
C1  
C14  
0.1µF  
1nF  
JP8  
VGA1_NEG  
AD605  
VREF  
C2  
0.1µF  
1
2
3
4
5
6
16  
15  
14  
13  
J2  
VGN1  
VREF  
C13  
OUT1  
INM1  
R4  
69.8Ω  
VGA1_POS  
R13  
0.1µF  
JP2  
49.9Ω  
J8  
–IN1  
OUT1  
FBK1  
VPOS  
VPOS  
FBK2  
OUT2  
VOCM  
+5V  
C3  
OUT1  
R12  
DNI  
0.1µF  
JP7  
J3  
INP1  
+IN1  
+5V  
C12 C11  
0.1µF 0.1µF  
R3  
69.8Ω  
GND1  
GND2  
+IN2  
+5V  
+
C7  
0.1µF  
C8  
10µF  
10V  
12  
11  
GND1  
C4  
0.1µF  
VGA2_POS  
J4  
INP2  
C10  
0.1µF  
R10  
49.9Ω  
R11  
DNI  
R6  
69.8Ω  
JP6  
7
8
10  
9
J7  
OUT2  
–IN2  
C5  
0.1µF  
VGA2_NEG  
VOCM  
J5  
INM2  
OUT2  
+5V  
VGN2  
R5  
69.8Ω  
VOCM  
ADJ  
JP3  
JP5  
CH2_GN  
R8  
R9  
10kΩ  
JP4  
10kΩ  
GN2  
ADJ  
J6  
GN2  
C9  
0.1µF  
C6  
1nF  
R7  
DNI  
GND2 GND3 GND4  
NOTES  
1. PARTS IN GRAY ARE NOT INSTALLED.  
Figure 43. Schematic Diagram of the AD605-EVALZ Evaluation Board  
OSCILLOSCOPE  
POWER SUPPLY  
GND  
5V  
FUNCTION GENERATOR  
SINGLE-ENDED  
INPUT  
VGA OUTPUT  
(TO SCOPE)  
Figure 44. Typical Test Configuration of the AD605-EVALZ  
Rev. F | Page 19 of 24  
 
 
AD605  
Figure 48. AD605-EVALZ Internal Ground Plane  
Figure 45. AD605-EVALZ Assembly  
Figure 46. AD605-EVALZ Primary Side Copper  
Figure 49. AD605-EVALZ Internal Power Plane  
Figure 47. AD605-EVALZ Secondary Side Copper  
Figure 50. AD605-EVALZ Primary Side Silkscreen  
Rev. F | Page 2ꢀ of 24  
AD605  
OUTLINE DIMENSIONS  
0.800 (20.32)  
0.790 (20.07)  
0.780 (19.81)  
16  
1
9
8
0.280 (7.11)  
0.250 (6.35)  
0.240 (6.10)  
0.325 (8.26)  
0.310 (7.87)  
0.300 (7.62)  
0.100 (2.54)  
BSC  
0.060 (1.52)  
MAX  
0.195 (4.95)  
0.130 (3.30)  
0.115 (2.92)  
0.210 (5.33)  
MAX  
0.015  
(0.38)  
MIN  
0.150 (3.81)  
0.130 (3.30)  
0.115 (2.92)  
0.015 (0.38)  
GAUGE  
0.014 (0.36)  
0.010 (0.25)  
0.008 (0.20)  
PLANE  
SEATING  
PLANE  
0.022 (0.56)  
0.018 (0.46)  
0.014 (0.36)  
0.430 (10.92)  
MAX  
0.005 (0.13)  
MIN  
0.070 (1.78)  
0.060 (1.52)  
0.045 (1.14)  
COMPLIANT TO JEDEC STANDARDS MS-001-AB  
CONTROLLING DIMENSIONS ARE IN INCHES; MILLIMETER DIMENSIONS  
(IN PARENTHESES) ARE ROUNDED-OFF INCH EQUIVALENTS FOR  
REFERENCE ONLY AND ARE NOT APPROPRIATE FOR USE IN DESIGN.  
CORNER LEADS MAY BE CONFIGURED AS WHOLE OR HALF LEADS.  
Figure 51. 16-Lead Plastic Dual In-Line Package [PDIP]  
(N-16)  
Dimensions shown in inches and (millimeters)  
10.00 (0.3937)  
9.80 (0.3858)  
9
8
16  
1
6.20 (0.2441)  
5.80 (0.2283)  
4.00 (0.1575)  
3.80 (0.1496)  
1.27 (0.0500)  
0.50 (0.0197)  
0.25 (0.0098)  
45°  
BSC  
1.75 (0.0689)  
1.35 (0.0531)  
0.25 (0.0098)  
0.10 (0.0039)  
8°  
0°  
COPLANARITY  
0.10  
SEATING  
PLANE  
1.27 (0.0500)  
0.40 (0.0157)  
0.51 (0.0201)  
0.31 (0.0122)  
0.25 (0.0098)  
0.17 (0.0067)  
COMPLIANT TO JEDEC STANDARDS MS-012-AC  
CONTROLLING DIMENSIONS ARE IN MILLIMETERS; INCH DIMENSIONS  
(IN PARENTHESES) ARE ROUNDED-OFF MILLIMETER EQUIVALENTS FOR  
REFERENCE ONLY AND ARE NOT APPROPRIATE FOR USE IN DESIGN.  
Figure 52. 16-Lead Standard Small Outline Package [SOIC_N]  
Narrow Body  
(R-16)  
Dimensions shown in millimeters and (inches)  
Rev. F | Page 21 of 24  
 
AD605  
ORDERING GUIDE  
Model  
AD6ꢀ5AN  
AD6ꢀ5ANZ1  
Temperature Range  
−4ꢀ°C to +85°C  
−4ꢀ°C to +85°C  
−4ꢀ°C to +85°C  
−4ꢀ°C to +85°C  
−4ꢀ°C to +85°C  
−4ꢀ°C to +85°C  
−4ꢀ°C to +85°C  
−4ꢀ°C to +85°C  
−4ꢀ°C to +85°C  
−4ꢀ°C to +85°C  
−4ꢀ°C to +85°C  
−4ꢀ°C to +85°C  
−4ꢀ°C to +85°C  
−4ꢀ°C to +85°C  
−4ꢀ°C to +85°C  
Package Description  
16-Lead PDIP  
16-Lead PDIP  
Package Option  
N-16  
N-16  
R-16  
R-16  
R-16  
R-16  
R-16  
R-16  
N-16  
R-16  
R-16  
R-16  
R-16  
R-16  
R-16  
AD6ꢀ5AR  
16-Lead SOIC_N  
AD6ꢀ5AR-REEL  
AD6ꢀ5AR-REEL7  
AD6ꢀ5ARZ1  
AD6ꢀ5ARZ-RL1  
AD6ꢀ5ARZ-R71  
AD6ꢀ5BN  
16-Lead SOIC_N, 13" Tape and Reel  
16-Lead SOIC_N, 7" Tape and Reel  
16-Lead SOIC_N  
16-Lead SOIC_N, 13" Tape and Reel  
16-Lead SOIC_N, 7" Tape and Reel  
16-Lead PDIP  
AD6ꢀ5BR  
16-Lead SOIC_N  
AD6ꢀ5BR-REEL  
AD6ꢀ5BR-REEL7  
AD6ꢀ5BRZ1  
AD6ꢀ5BRZ-RL1  
AD6ꢀ5BRZ-R71  
AD6ꢀ5-EVALZ1  
AD6ꢀ5ACHIPS  
16-Lead SOIC_N, 13" Tape and Reel  
16-Lead SOIC_N, 7" Tape and Reel  
16-Lead SOIC_N  
16-Lead SOIC_N, 13" Tape and Reel  
16-Lead SOIC_N, 7" Tape and Reel  
Evaluation Board  
DIE  
1 Z = RoHS Compliant Part.  
Rev. F | Page 22 of 24  
 
 
AD605  
NOTES  
Rev. F | Page 23 of 24  
AD605  
NOTES  
©1996–2008 Analog Devices, Inc. All rights reserved. Trademarks and  
registered trademarks are the property of their respective owners.  
D00541-0-6/08(F)  
Rev. F | Page 24 of 24  
 

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