AD8366ACPZ-R7 [ADI]

DC to 600 MHz, Dual-Digital Variable Gain Amplifiers; DC至600 MHz的双数字可变增益放大器
AD8366ACPZ-R7
型号: AD8366ACPZ-R7
厂家: ADI    ADI
描述:

DC to 600 MHz, Dual-Digital Variable Gain Amplifiers
DC至600 MHz的双数字可变增益放大器

电信集成电路 蜂窝电话电路 电信电路 放大器
文件: 总28页 (文件大小:894K)
中文:  中文翻译
下载:  下载PDF数据表文档文件
DC to 600 MHz,  
Dual-Digital Variable Gain Amplifiers  
AD8366  
FUNCTIONAL BLOCK DIAGRAM  
FEATURES  
Matched pair of differential, digitally controlled VGAs  
Gain range: 4.5 dB to 20.25 dB  
0.25 dB gain step size  
Operating frequency  
VPSIA  
IPPA  
BIT0/CS  
BIT1/SDAT  
BIT2/SCLK  
BIT3  
DC to 150 MHz (2 V p-p)  
3 dB bandwidth: 600 MHz  
Noise figure (NF)  
11.4 dB at 10 MHz at maximum gain  
18 dB at 10 MHz at minimum gain  
OIP3: 45 dBm at 10 MHz  
IPMA  
ENBL  
ICOM  
IPMB  
IPPB  
DIGITAL GAIN  
CONTROL LOGIC  
OCOM  
BIT4  
HD2/HD3  
Better than −90 dBc for 2 V p-p output at 10 MHz at  
maximum gain  
BIT 5  
VPSIB  
DENA  
Differential input and output  
Adjustable output common-mode  
Optional dc output offset correction  
Serial/parallel mode gain control  
Power-down feature  
Figure 1.  
Single 5 V supply operation  
APPLICATIONS  
Baseband I/Q receivers  
Diversity receivers  
Wideband ADC drivers  
GENERAL DESCRIPTION  
The AD8366 is a matched pair of fully differential, low noise and  
low distortion, digitally programmable variable gain amplifiers  
(VGAs). The gain of each amplifier can be programmed separately  
or simultaneously over a range of 4.5 dB to 20.25 dB in steps of  
0.25 dB. The amplifier offers flat frequency performance from dc  
to 70 MHz, independent of gain code.  
The output common-mode voltage defaults to VPOS/2 but can  
be programmed via the VCMA and VCMB pins over a range  
of voltages. The input common-mode voltage also defaults  
to VPOS/2 but can be driven down to 1.5 V. A built-in, dc offset  
compensation loop can be used to eliminate dc offsets from prior  
stages in the signal chain. This loop can also be disabled if dc-  
coupled operation is desired.  
The AD8366 offers excellent spurious-free dynamic range, suitable  
for driving high resolution analog-to-digital converters (ADCs).  
The NF at maximum gain is 11.4 dB at 10 MHz and increases  
~2 dB for every 4 dB decrease in gain. Over the entire gain range,  
the HD3/HD2 are better than −90 dBc for 2 V p-p at the output at  
10 MHz into 200 Ω. The two-tone intermodulation distortion of  
−90 dBc into 200 Ω translates to an OIP3 of 45 dBm (38 dBVrms).  
The differential input impedance of 200 ꢀ provides a well-defined  
termination. The differential output has a low impedance of ~25 ꢀ.  
The digital interface allows for parallel or serial mode gain  
programming. The AD8366 operates from a 4.75 V to 5.25 V  
supply and consumes typically 180 mA. When disabled, the  
part consumes roughly 3 mA. The AD8366 is fabricated using  
Analog Devices, Inc., advanced silicon-germanium bipolar  
process, and it is available in a 32-lead exposed paddle LFCSP  
package. Performance is specified over the −40°C to +85°C  
temperature range.  
Rev. A  
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 ©2010-2011 Analog Devices, Inc. All rights reserved.  
 
AD8366  
TABLE OF CONTENTS  
Features .............................................................................................. 1  
Output Differential Offset Correction .................................... 15  
Output Common-Mode Control ............................................. 15  
Gain Control Interface............................................................... 16  
Applications Information.............................................................. 17  
Basic Connections...................................................................... 17  
Direct Conversion Receiver Design......................................... 18  
Quadrature Errors and Image Rejection................................. 18  
Low Frequency IMD3 Performance ........................................ 19  
Baseband Interface..................................................................... 21  
Characterization Setups................................................................. 22  
Evaluation Board ............................................................................ 25  
Outline Dimensions....................................................................... 28  
Ordering Guide .......................................................................... 28  
Applications....................................................................................... 1  
Functional Block Diagram .............................................................. 1  
General Description......................................................................... 1  
Revision History ............................................................................... 2  
Specifications..................................................................................... 3  
Parallel and Serial Interface timing............................................ 5  
Absolute Maximum Ratings............................................................ 6  
ESD Caution.................................................................................. 6  
Pin Configuration and Function Descriptions............................. 7  
Typical Performance Characteristics ............................................. 8  
Circuit Description......................................................................... 15  
Inputs ........................................................................................... 15  
Outputs ........................................................................................ 15  
REVISION HISTORY  
3/11—Rev. 0 to Rev. A  
Changes to Table 2, Internal Power Dissipation Value................ 6  
10/10—Revision 0: Initial Version  
Rev. A | Page 2 of 28  
 
AD8366  
SPECIFICATIONS  
VS = 5 V, TA = 25°C, ZS = 200 Ω, ZL = 200 Ω, f = 10 MHz, unless otherwise noted.  
Table 1.  
Parameter  
Test Conditions/Comments  
Min Typ  
Max Unit  
DYNAMIC PERFORMANCE  
Bandwidth  
3 dB; all gain codes  
1 dB; all gain codes  
Maximum gain  
Minimum gain  
600  
200  
1100  
1500  
MHz  
MHz  
V/μs  
V/μs  
Slew Rate  
INPUT STAGE  
Linear Input Swing  
IPPA, IPMA, IPPB, IPMB  
At minimum gain AV = 4.5 dB, 1 dB gain compression  
3.6  
217  
1.5  
VPOS/2 + 0.075  
VPOS/2  
V p-p  
Differential Input Impedance  
Minimum Input Common-Mode Voltage  
Maximum Input Common-Mode Voltage  
Ω
V
V
V
Input pins left floating  
GAIN  
Minimum Voltage Gain  
Maximum Voltage Gain  
Gain Step Size  
Gain Step Accuracy  
Gain Flatness  
Gain Mismatch  
Group Delay Flatness  
Mismatch  
4.5  
dB  
dB  
dB  
dB  
dB  
dB  
ns  
ps  
ns  
ns  
20.25  
0.25  
0.25  
0.1  
0.1  
<0.5  
2
All gain codes  
All gain codes  
Maximum gain, DC to 70 MHz  
Channel A/Channel B at minimum/maximum gain code  
All gain codes, 20% fractional bandwidth, fC < 100 MHz  
Channel A and Channel B at same gain code  
Maximum gain to minimum gain  
Minimum gain to maximum gain  
Gain Step Response  
30  
60  
Common-Mode Rejection Ratio  
OUTPUT STAGE  
Linear Output Swing  
Differential Output Impedance  
Output DC Offset  
−66.2  
dB  
OPPA, OPMA, OPPB, OPMB, VCMA, VCMB  
1 dB gain compression  
6
28  
−10/−30  
V p-p  
Ω
mV  
Inputs shorted, offset loop disabled at  
minimum/maximum gain  
Inputs shorted, offset loop enabled (across all gain codes)  
HD3, HD2 > −90 dBc, 2 V p-p output  
HD3, HD2 > −90 dBc, 2 V p-p output  
VCMA and VCMB left floating  
10  
1.6  
3
VPOS/2  
4
mV  
V
V
V
kΩ  
Minimum Output Common-Mode Voltage  
Maximum Output Common-Mode Voltage  
Common-Mode Setpoint Input Impedance  
NOISE/DISTORTION  
3 MHz  
Noise Figure  
Maximum gain  
Minimum gain  
11.3  
18.2  
−82  
−82  
−87  
−90  
34  
35  
76  
76  
6.7  
dB  
dB  
dBc  
dBc  
dBc  
dBc  
dBVrms  
dBVrms  
dBVrms  
dBVrms  
dBVrms  
dBVrms  
Second Harmonic  
Third Harmonic  
OIP31  
2 V p-p output, maximum gain  
2 V p-p output, minimum gain  
2 V p-p output, maximum gain  
2 V p-p output, minimum gain  
2 V p-p composite, maximum gain  
2 V p-p composite, minimum gain  
2 V p-p composite, maximum gain  
2 V p-p composite, minimum gain  
Maximum gain  
OIP21  
Output 1 dB Compression Point1  
Minimum gain  
6.9  
Rev. A | Page 3 of 28  
 
 
AD8366  
Parameter  
Test Conditions/Comments  
Min Typ  
Max Unit  
10 MHz  
Noise Figure  
Maximum gain  
Minimum gain  
11.4  
18  
dB  
dB  
Second Harmonic  
Third Harmonic  
OIP31  
2 V p-p output, maximum gain  
2 V p-p output, minimum gain  
2 V p-p output, maximum gain  
2 V p-p output, minimum gain  
2 V p-p composite, maximum gain  
2 V p-p composite, minimum gain  
2 V p-p composite, maximum gain  
2 V p-p composite, minimum gain  
Maximum gain  
−97  
−96  
−97  
−90  
38  
36  
72  
76  
7
dBc  
dBc  
dBc  
dBc  
dBVrms  
dBVrms  
dBVrms  
dBVrms  
dBVrms  
dBVrms  
OIP21  
Output 1 dB Compression Point1  
Minimum gain  
6.7  
50 MHz  
Noise Figure  
Maximum gain  
Minimum gain  
11.8  
18.2  
−82  
−84  
−80  
−71  
32  
26  
71  
78  
6.7  
dB  
dB  
dBc  
dBc  
dBc  
dBc  
dBVrms  
dBVrms  
dBVrms  
dBVrms  
dBVrms  
dBVrms  
Second Harmonic  
Third Harmonic  
OIP31  
2 V p-p output, maximum gain  
2 V p-p output, minimum gain  
2 V p-p output, maximum gain  
2 V p-p output, minimum gain  
2 V p-p composite, maximum gain  
2 V p-p composite, minimum gain  
2 V p-p composite, maximum gain  
2 V p-p composite, minimum gain  
Maximum gain  
OIP21  
Output 1 dB Compression Point1  
Minimum gain  
6.7  
DIGITAL LOGIC  
SENB, DENA, DENB, BIT0, BIT1, BIT2, BIT3, BIT4, BIT5  
Input High Voltage, VINH  
Input Low Voltage, VINL  
Input Capacitance, CIN  
Input Resistance, RIN  
2.2  
1.2  
1
V
V
pF  
kΩ  
50  
SPI INTERFACE TIMING  
SENB = high  
fSCLK  
t1  
t2  
t3  
t4  
t5  
t6  
Serial clock frequency (maximum)  
CS rising edge to first SCLK rising edge (minimum)  
SCLK high pulse width (minimum)  
SCLK low pulse width (minimum)  
SCLK falling edge to CS low (minimum)  
SDAT setup time (minimum)  
44.4  
7.5  
7.5  
15  
7.5  
7.5  
15  
MHz  
ns  
ns  
ns  
ns  
ns  
ns  
SDAT hold time (minimum)  
PARALLEL PORT TIMING  
SENB = low  
t7  
t8  
t9  
t10  
DENA/DENB high pulse width (minimum)  
DENA/DENB low pulse width (minimum)  
BITx setup time (minimum)  
7.5  
15  
7.5  
7.5  
ns  
ns  
ns  
ns  
BITx hold time (minimum)  
POWER AND ENABLE  
Supply Voltage Range  
Total Supply Current  
Disable Current  
Disable Threshold  
Enable Response Time  
VPSIA, VPSIB, VPSOA, VPSOB, ICOM, OCOM, ENBL  
4.75  
180  
3.2  
5.25  
V
ENBL = 5 V  
ENBL = 0 V  
mA  
mA  
V
1.65  
150  
Delay following high-to-low transition until device  
meets full specifications  
ns  
Disable Response Time  
Delay following low-to-high transition until device  
produces full attenuation  
3
μs  
1 To convert to dBm for a 200 Ω load impedance, add 7 dB to the dBVrms value.  
Rev. A | Page 4 of 28  
 
AD8366  
PARALLEL AND SERIAL INTERFACE TIMING  
CS  
t3  
t4  
t2  
t1  
SCLK  
t5  
B-LSB  
t6  
X
B-MSB  
A-LSB  
A-MSB  
X
SDAT  
SENB  
ALWAYS HIGH  
Figure 2. SPI Port Timing Diagram  
BIT[5:0]  
DENA  
DENB  
SENB  
GAIN A  
t10  
GAIN B  
GAIN A, GAIN B  
t9  
t8  
t7  
ALWAYS LOW  
Figure 3. Parallel Port Timing Diagram  
Rev. A | Page 5 of 28  
 
AD8366  
ABSOLUTE MAXIMUM RATINGS  
Table 2.  
Stresses above those listed under Absolute Maximum Ratings  
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.  
Parameter  
Rating  
5.5 V  
Supply Voltages, VPSIx and VPSOx  
ENBL, SENB, DENA, DENB, BIT0, BIT1, BIT2,  
BIT3, BIT4, BIT5  
5.5 V  
IPPA, IPMA, IPPB, IPMB  
5.5 V  
OPPA, OPMA, OPPB, OPMB  
OFSA, OFSB  
5.5 V  
5.5 V  
DECA, DECB, VCMA, VCMB, CCMA, CCMB  
Internal Power Dissipation  
θJA (With Pad Soldered to Board)  
Maximum Junction Temperature  
Operating Temperature Range  
Storage Temperature Range  
Lead Temperature (Soldering, 60 sec)  
5.5 V  
1.4 W  
ESD CAUTION  
45.4°C/W  
150°C  
−40°C to +85°C  
−65°C to +150°C  
300°C  
Rev. A | Page 6 of 28  
 
AD8366  
PIN CONFIGURATION AND FUNCTION DESCRIPTIONS  
BIT0/CS  
BIT1/SDAT  
BIT2/SCLK  
BIT3  
OCOM  
BIT4  
VPSIA  
IPPA  
1
2
3
4
5
6
7
8
24  
23  
22  
21  
20  
19  
18  
17  
PIN 1  
INDICATOR  
IPMA  
ENBL  
ICOM  
IPMB  
IPPB  
AD8366  
TOP VIEW  
(Not to Scale)  
BIT5  
DENA  
VPSIB  
NOTES  
1. THE EXPOSED PAD MUST BE CONNECTED  
TO GROUND.  
Figure 4. Pin Configuration  
Table 3. Pin Function Descriptions  
Pin No.  
Mnemonic  
Description  
1, 8, 13, 28  
VPSIA, VPSIB, VPSOB, Input and Output Stage Positive Supply Voltage (4.75 V to 5.25 V).  
VPSOA  
2, 3, 6, 7  
IPPA, IPMA, IPMB,  
IPPB  
Differential Inputs.  
4
ENBL  
Chip Enable. Pull this pin high to enable.  
5, 20  
ICOM, OCOM  
Input and Output Ground Pins. Connect these pins via the lowest possible impedance to  
ground.  
9, 32  
DECB, DECA  
OFSB, OFSA  
VPOS/2 Reference Decoupling Node. Connect a decoupling capacitor from these nodes to  
ground.  
Output Offset Correction Loop Compensation. Connect a capacitor from these nodes to  
ground to enable the correction loop. Tie this pin to ground to disable.  
10, 31  
11, 30  
12, 29  
CCMB, CCMA  
VCMB, VCMA  
Connect These Nodes to Ground.  
Output Common-Mode Setpoint. These pins default to VPOS/2 if left open. Drive these pins  
from a low impedance source to change the output common-mode voltage.  
14, 15, 26, 27  
16, 17  
OPPB, OPMB, OPMA,  
OPPA  
DENB, DENA  
Differential Outputs.  
Data Enable. Pull these pins high to address each or both channels for parallel gain  
programming. These pins are not used in serial mode.  
18, 19, 21, 22, 23, 24 BIT5, BIT4, BIT3,  
Parallel Data Path (When SENB Is Low). When SENB is high, BIT0 becomes a chip select (CS),  
BIT2/SCLK, BIT1/SDAT, BIT1 becomes a serial data input (SDAT), and BIT2 becomes a serial clock (SCLK). BIT3 to BIT5  
BIT0/CS  
are not used in serial mode.  
25  
SENB  
Serial Interface Enable. Pull this pin high for serial gain programming mode and pull this pin low  
for parallel gain programming mode.  
EPAD  
The exposed pad must be connected to ground.  
Rev. A | Page 7 of 28  
 
AD8366  
TYPICAL PERFORMANCE CHARACTERISTICS  
VS = 5 V, TA = 25°C, ZS = 200 Ω, ZL = 200 Ω, f = 10 MHz, unless otherwise noted.  
22  
20  
18  
16  
14  
12  
10  
8
0.5  
FREQUENCY = 3MHz  
FREQUENCY = 50MHz  
T
T
T
= +85°C  
= +25°C  
= –40°C  
A
A
A
0.4  
0.3  
T
T
T
= +85°C  
= +25°C  
= –40°C  
A
A
A
0.2  
0.1  
0
–0.1  
–0.2  
–0.3  
–0.4  
–0.5  
6
4
0
5
10 15 20 25 30 35 40 45 50 55 60  
GAIN CODE  
0
5
10 15 20 25 30 35 40 45 50 55 60  
GAIN CODE  
Figure 8. Gain Error vs. Gain Code, Error Normalized to 10 MHz  
Figure 5. Gain vs. Gain Code at 500 kHz, 3 MHz, 10 MHz, and 50 MHz  
21.0  
20.8  
20.6  
20.4  
20.2  
20.0  
19.8  
19.6  
19.4  
19.2  
19.0  
25  
GAIN CODE 63  
20  
GAIN CODE 48  
15  
GAIN CODE 32  
10  
GAIN CODE 16  
GAIN CODE 00  
5
0
5
–10  
100k  
–40 –30 –20 –10  
0
10 20 30 40 50 60 70 80  
TEMPERATURE (°C)  
1M  
10M  
100M  
1G  
FREQUENCY (Hz)  
Figure 9. Gain vs. Temperature at Maximum Gain at 10 MHz  
Figure 6. Frequency Response vs. Gain Code  
1.0  
0.9  
0.8  
0.7  
0.6  
0.5  
0.4  
0.3  
0.2  
1.0  
0.9  
0.8  
0.7  
0.6  
0.5  
0.4  
0.3  
0.2  
0.1  
0
0.1  
0
–0.1  
–0.2  
–0.3  
–0.4  
–0.5  
–0.6  
–0.7  
–0.8  
–0.9  
–1.0  
–0.1  
–0.2  
–0.3  
–0.4  
–0.5  
–0.6  
–0.7  
–0.8  
–0.9  
–1.0  
0
10  
20  
30  
40  
50  
60  
0
10  
20  
30  
40  
50  
60  
GAIN CODE  
GAIN CODE  
Figure 10. Channel A-to-Channel B Phase Mismatch vs. Gain Code,  
2 V p-p Output  
Figure 7. Channel A-to-Channel B Amplitude Mismatch vs. Gain Code,  
2 V p-p Output  
Rev. A | Page 8 of 28  
 
 
 
AD8366  
20  
18  
16  
14  
12  
10  
8
20  
18  
16  
14  
12  
10  
8
20  
18  
16  
14  
12  
10  
8
20  
18  
16  
14  
12  
10  
8
T
T
T
= +85°C  
= +25°C  
= –40°C  
GAIN CODE 0  
GAIN CODE 63  
T
T
T
= +85°C  
= +25°C  
= –40°C  
A
A
A
A
A
A
6
6
6
6
4
4
4
4
2
2
2
2
0
0
0
0
0
10 20 30 40 50 60 70 80 90 100 110 120 130 140 150  
0
5
10 15 20 25 30 35 40 45 50 55 60  
GAIN CODE  
FREQUENCY (MHz)  
Figure 14. OP1dB vs. Frequency at Gain Code 0 and Gain Code 63  
Figure 11. OP1dB vs. Gain Code at 500 kHz, 3 MHz, 10 MHz, and 50 MHz  
50  
50  
45  
40  
35  
30  
25  
20  
15  
10  
5
60  
55  
50  
45  
40  
35  
30  
25  
20  
15  
10  
45  
GAIN CODE 63  
GAIN CODE 32  
40  
35  
30  
25  
20  
15  
10  
5
GAIN CODE 0  
T
T
= +85°C  
= +25°C  
= –40°C  
T
T
T
= +85°C  
= +25°C  
= –40°C  
A
A
A
A
A
A
FREQUENCY = 10MHz  
FREQUENCY = 50MHz  
CHANNEL A  
CHANNEL B  
T
0
0
0
10 20 30 40 50 60 70 80 90 100 110 120 130 140 150  
FREQUENCY (MHz)  
0
5
10 15 20 25 30 35 40 45 50 55 60  
GAIN CODE  
Figure 15. OIP3 vs. Frequency, Gain Code 0, Gain Code 32, and Gain Code 63,  
2 V p-p Composite Output  
Figure 12. OIP3 vs. Gain Code at 10 MHz and 50 MHz Frequency, 2 V p-p  
Composite Output  
0
CHANNEL A  
CHANNEL B  
T
T
T
= +85°C  
= +25°C  
= –40°C  
A
A
A
T
T
= +85°C  
= +25°C  
= –40°C  
FREQUENCY = 10MHz  
FREQUENCY = 50MHz  
A
A
A
–10  
–30  
–10  
–20  
–30  
–40  
–50  
–60  
–70  
–80  
–90  
–100  
–110  
T
GAIN CODE 0  
–50  
–70  
GAIN CODE 32  
GAIN CODE 63  
–90  
–110  
10 20 30 40 50 60 70 80 90 100 110 120 130 140 150  
FREQUENCY (MHz)  
0
5
10 15 20 25 30 35 40 45 50 55 60  
GAIN CODE  
Figure 16. Two-Tone Output IMD3 vs. Frequency at Gain Code 0,  
Gain Code 32, and Gain Code 63, 2 V p-p Composite Output  
Figure 13. Two-Tone Output IMD3 vs. Gain Code at 10 MHz and 50 MHz  
Frequency, 2 V p-p Composite Output  
Rev. A | Page 9 of 28  
AD8366  
100  
90  
80  
70  
60  
50  
40  
30  
20  
100  
90  
80  
70  
60  
50  
40  
30  
20  
10  
0
100  
90  
80  
70  
60  
50  
40  
30  
20  
10  
0
GAIN CODE 63  
GAIN CODE 0  
T
= +85°C  
= +25°C  
= –40°C  
T
T
T
= +85°C  
= +25°C  
= –40°C  
A
A
A
A
10  
FREQUENCY = 10MHz  
FREQUENCY = 50MHz  
T
A
CHANNEL A  
CHANNEL B  
T
A
0
0
5
10 15 20 25 30 35 40 45 50 55 60  
GAIN CODE  
10 20 30 40 50 60 70 80 90 100 110 120 130 140 150  
FREQUENCY (MHz)  
Figure 17. OIP2 vs. Gain Code at 10 MHz and 50 MHz Frequency,  
2 V p-p Composite Output  
Figure 20. OIP2 vs. Frequency at Gain Code 0 and Gain Code 63, 2 V p-p  
Composite Output  
0
0
T
T
T
= +85°C  
= +25°C  
= –40°C  
CHANNEL A  
CHANNEL B  
T
T
T
= +85°C  
= +25°C  
= –40°C  
A
A
A
FREQUENCY = 10MHz  
FREQUENCY = 50MHz  
A
A
A
–10  
–20  
–30  
–40  
–50  
–60  
–70  
–80  
–90  
–100  
–10  
–20  
–30  
–40  
–50  
–60  
–70  
–80  
–90  
–100  
GAIN CODE 0  
GAIN CODE 63  
0
5
10 15 20 25 30 35 40 45 50 55 60  
GAIN CODE  
0
10 20 30 40 50 60 70 80 90 100 110 120 130 140 150  
FREQUENCY (MHz)  
Figure 18. Two-Tone Output IMD2 vs. Gain Code at 10 MHz and 50 MHz  
Frequency, 2 V p-p Composite Output  
Figure 21. Two-Tone Output IMD2 vs. Frequency,  
Gain Code 0 and Gain Code 63, 2 V p-p Composite Output  
0
0
–10  
–20  
–30  
–40  
–50  
–60  
–70  
–80  
–90  
–100  
–110  
0
CHANNEL A  
T
T
T
= +85°C  
= +25°C  
= –40°C  
GAIN CODE 0  
GAIN CODE 32  
GAIN CODE 63  
HD2  
HD3  
A
A
A
CHANNEL B  
–10  
–20  
–10  
–20  
–30  
–40  
–50  
–60  
–70  
–80  
–90  
–100  
–30  
–40  
–50  
–60  
–70  
–80  
–90  
–100  
–110  
–120  
1.0  
1.2  
1.4  
1.6  
1.8  
2.0  
2.2  
2.4  
2.6  
2.8  
3.0  
1
10  
100  
1000  
VCMA, VCMB (V)  
FREQUENCY (MHz)  
Figure 22. HD3/HD2 vs. VOCM at 10 MHz, Gain Code 0, 2 V p-p Output  
Figure 19. Harmonic Distortion vs. Frequency at Gain Code 0, Gain Code 32,  
and Gain Code 63, 2 V p-p Output  
Rev. A | Page 10 of 28  
AD8366  
0
–10  
–20  
–30  
–40  
–50  
–60  
–70  
–80  
–90  
–100  
–110  
60  
50  
40  
30  
20  
10  
0
T
T
T
= +85°C  
= +25°C  
= –40°C  
GAIN CODE 0  
GAIN CODE 63  
A
A
A
T
T
T
= +85°C  
= +25°C  
= –40°C  
A
A
A
GAIN CODE 0  
GAIN CODE 63  
–3  
–2  
–1  
0
1
2
3
4
5
–3  
–2  
–1  
0
1
2
3
4
5
P
PER TONE (dBm)  
P
PER TONE (dBm)  
OUT  
OUT  
Figure 26. IMD3 vs. Output Power (POUT) at Minimum-to-Maximum Gain  
Codes, 10 MHz Frequency  
Figure 23. OIP3 vs. Output Power (POUT) at Minimum and Maximum Gain  
Codes, 10 MHz Frequency  
0
100  
90  
80  
70  
60  
50  
40  
30  
20  
GAIN CODE 0  
GAIN CODE 63  
T
T
T
= +85°C  
= +25°C  
= –40°C  
A
A
A
–10  
–20  
–30  
–40  
–50  
–60  
–70  
–80  
–90  
–100  
T
T
T
= +85°C  
= +25°C  
= –40°C  
A
A
A
10  
0
GAIN CODE 0  
GAIN CODE 63  
–8 –7 –6 –5 –4 –3 –2 –1  
0
1
2
3
4
5
–8 –7 –6 –5 –4 –3 –2 –1  
0
1
2
3
4
5
P
PER TONE (dBm)  
P
PER TONE (dBm)  
OUT  
OUT  
Figure 27. IMD2 vs. Output Power (POUT) at Minimum and Maximum Gain  
Codes, 10 MHz Frequency  
Figure 24. OIP2 vs. Output Power (POUT) at Minimum and Maximum Gain  
Codes, 10 MHz Frequency  
–60  
–60  
T
T
T
= +85°C  
= +25°C  
= –40°C  
GAIN CODE 0  
GAIN CODE 63  
A
A
A
T
T
T
= +85°C  
= +25°C  
= –40°C  
GAIN CODE 0  
GAIN CODE 63  
A
A
A
–65  
–70  
–65  
–70  
–75  
–75  
–80  
–80  
–85  
–90  
–85  
–95  
–90  
–100  
–105  
–110  
–115  
–120  
–95  
–100  
–105  
–110  
–5  
–4  
–3  
–2  
–1  
0
1
2
3
4
5
–5 –4 –3 –2 –1  
0
1
2
3
4
5
6
7
8
P
(dBm)  
P
(dBm)  
OUT  
OUT  
Figure 28. HD3 vs. Output Power (POUT) for Gain Code 0 and Gain Code 63,  
10 MHz Frequency  
Figure 25. HD2 vs. Output Power (POUT) at Gain Code 0 and Gain Code 63,  
10 MHz Frequency  
Rev. A | Page 11 of 28  
AD8366  
60  
55  
50  
45  
40  
35  
30  
25  
20  
15  
10  
300  
280  
260  
240  
220  
200  
180  
160  
140  
120  
CHANNEL A  
CHANNEL B  
T
T
T
= +85°C  
= +25°C  
= –40°C  
A
A
A
GAIN CODE 63  
GAIN CODE 47  
GAIN CODE 48  
GAIN CODE 31  
GAIN CODE 32  
GAIN CODE 15  
GAIN CODE 16  
GAIN CODE 0  
100  
0
0.1  
1
10  
100  
1000  
5
10 15 20 25 30 35 40 45 50 55 60  
GAIN CODE  
FREQUENCY (kHz)  
Figure 32. Noise Spectral Density vs. Frequency  
Figure 29. Supply Current vs. Gain Code at 10 MHz  
30  
28  
26  
24  
22  
20  
18  
16  
14  
12  
10  
30  
28  
26  
24  
22  
20  
18  
16  
14  
12  
10  
CHANNEL A  
CHANNEL B  
CHANNEL B, FREQUENCY = 0.5MHz  
CHANNEL A, FREQUENCY = 0.5MHz  
CHANNEL B, FREQUENCY = 3MHz  
CHANNEL A, FREQUENCY = 3MHz  
CHANNEL B, FREQUENCY = 10MHz  
CHANNEL A, FREQUENCY = 10MHz  
CHANNEL B, FREQUENCY = 50MHz  
CHANNEL A, FREQUENCY = 50MHz  
GAIN CODE 0  
GAIN CODE 15  
GAIN CODE 16  
GAIN CODE 31  
GAIN CODE 32  
GAIN CODE 47  
GAIN CODE 48  
GAIN CODE 63  
0.1  
1
10  
100  
1000  
0
5
10 15 20 25 30 35 40 45 50 55 60  
GAIN CODE  
FREQUENCY (kHz)  
Figure 33. Noise Figure vs. Frequency  
Figure 30. Noise Figure vs. Gain Code at 0.5 MHz, 3 MHz, 10 MHz, and 50 MHz  
40  
37  
34  
31  
28  
25  
22  
19  
16  
13  
10  
7.5  
7.2  
6.9  
6.6  
6.3  
6.0  
5.7  
5.4  
5.1  
4.8  
4.5  
280  
270  
260  
250  
240  
230  
220  
210  
200  
190  
180  
3.0  
2.7  
2.4  
2.1  
1.8  
1.5  
1.2  
0.9  
0.6  
0.3  
0
CHANNEL A: R  
, GAIN CODE 0  
, GAIN CODE 63  
, GAIN CODE 32  
, GAIN CODE 0  
, GAIN CODE 63  
, GAIN CODE 32  
, GAIN CODE 32  
, GAIN CODE 0  
OUT  
OUT  
OUT  
CHANNEL A: R , GAIN CODE 0  
IN  
CHANNEL A: R  
CHANNEL B: R  
CHANNEL A: L  
CHANNEL A: L  
CHANNEL B: L  
CHANNEL A: R  
CHANNEL A: R  
CHANNEL A: R , GAIN CODE 63  
IN  
CHANNEL B: R , GAIN CODE 32  
IN  
OUT  
OUT  
OUT  
OUT  
OUT  
CHANNEL A: C , GAIN CODE 0  
IN  
CHANNEL A: C , GAIN CODE 63  
IN  
CHANNEL B: C , GAIN CODE 32  
IN  
CHANNEL A: R , GAIN CODE 32  
IN  
CHANNEL A: R , GAIN CODE 0  
IN  
CHANNEL B: R , GAIN CODE 63  
IN  
CHANNEL B: R  
, GAIN CODE 63  
OUT  
CHANNEL A: C , GAIN CODE 32  
IN  
CHANNEL A: L  
CHANNEL B: L  
CHANNEL B: L  
, GAIN CODE 32  
, GAIN CODE 0  
, GAIN CODE 63  
OUT  
OUT  
OUT  
CHANNEL B: C , GAIN CODE 0  
IN  
CHANNEL B: C , GAIN CODE 63  
IN  
0
20  
40  
60  
80  
100 120 140 160 180 200  
0
20  
40  
60  
80  
100 120 140 160 180 200  
FREQUENCY (MHz)  
FREQUENCY (MHz)  
Figure 34. Differential Series Output Resistance and Inductance vs.  
Frequency  
Figure 31. Differential Parallel Input Resistance and Capacitance vs.  
Frequency  
Rev. A | Page 12 of 28  
AD8366  
0
–10  
–20  
–30  
–40  
–50  
–60  
–70  
–80  
–90  
140  
130  
120  
110  
100  
90  
PSRR GAIN CODE 0  
PSRR GAIN CODE 63  
80  
70  
60  
50  
40  
30  
20  
T
T
T
= +85°C  
= +25°C  
= –40°C  
A
A
A
FREQUENCY = 10MHz  
FREQUENCY = 50MHz  
10  
0
10 20 30 40 50 60 70 80 90 100 110 120 130 140 150  
0
5
10 15 20 25 30 35 40 45 50 55 60  
GAIN CODE  
FREQUENCY (MHz)  
Figure 35. Power Supply Rejection Ratio (PSRR) vs. Frequency  
Figure 38. SFDR vs. Gain Code at 10 MHz and 50 MHz,  
1 Hz Analysis Bandwidth  
2.0  
90  
80  
70  
60  
50  
40  
30  
20  
10  
0
GAIN CODE 32  
GAIN CODE 0  
1.8  
GAIN CODE 63  
GAIN CODE 63  
1.6  
1.4  
1.2  
1.0  
0.8  
0.6  
0.4  
0.2  
GAIN CODE 32  
GAIN CODE 0  
0
10 20 30 40 50 60 70 80 90 100 110 120 130 140 150  
1M  
10M  
100M  
1G  
FREQUENCY (MHz)  
FREQUENCY (Hz)  
Figure 36. Group Delay vs. Frequency at Gain Code 0, Gain Code 32, and  
Gain Code 63  
Figure 39. Common-Mode Rejection Ratio (CMRR) vs. Frequency  
0
0
P
P
P
P
P
= +10dBm  
= +5dBm  
= 0dBm  
= –5dBm  
= –10dBm  
MEASURED CHANNEL AT GAIN CODE 63  
MEASURED CHANNEL AT GAIN CODE 32  
MEASURED CHANNEL AT GAIN CODE 0  
–20  
IN  
IN  
IN  
IN  
IN  
–20  
–40  
–40  
–60  
–60  
–80  
–100  
–120  
–140  
–160  
–80  
–100  
DRIVEN CHANNEL AT GAIN CODE 0  
–120  
1
10  
100  
1000  
1
10  
100  
1000  
FREQUENCY (MHz)  
FREQUENCY (MHz)  
Figure 37. Channel-to-Channel Isolation vs. Frequency,  
Channel A Driven, Channel B Measured  
Figure 40. Forward Leakage vs. Frequency, Part Disabled  
Rev. A | Page 13 of 28  
AD8366  
1.2  
1.0  
1.4  
1.2  
0pF  
0pF  
1.0  
0.8  
0.8  
0.6  
10pF  
10pF  
0.6  
0.4  
0.4  
0.2  
0.2  
0
0
–0.2  
–0.4  
–0.6  
–0.8  
–1.0  
–0.2  
–0.4  
–0.6  
–0.8  
–1.0  
–1.2  
–1.2  
–5  
–4  
–3  
–2  
–1  
0
1
2
3
4
5
–5  
–4  
–3  
–2  
–1  
0
1
2
3
4
5
TIME (ns)  
TIME (ns)  
Figure 41. Large Signal Pulse Response, Gain Code 0, Input Signal 1.2 V p-p,  
0 pF and 10 pF Capacitive Loading Conditions  
Figure 44. Large Signal Pulse Response, Gain Code 63, Input Signal 240 mV p-p,  
0 pF and 10 pF Capacitive Loading Conditions  
1
2
3
T
CH1 1V  
CH2 100mV  
M1µs  
4.02µs  
5GS/s A CH1  
100k pts  
1.60V  
M 200ns 250MS/s  
CH4 1V  
4.0ns/pt  
A CH4  
2.48V  
CH3 50mV  
Figure 42. ENBL Time Domain Response  
Figure 45. Gain Step Time Domain Response, Minimum-to-Maximum Gain  
(Time Scale 200 ns/division), CH4 = Digital Control Inputs  
0
–20  
–40  
–60  
–80  
–100  
–120  
0.1  
1
10  
100  
1000  
FREQUENCY (MHz)  
Figure 43. Reverse Isolation (S12) vs. Frequency  
Rev. A | Page 14 of 28  
AD8366  
CIRCUIT DESCRIPTION  
The AD8366 is a dual, differential, digitally controlled VGA  
with 600 MHz of 3 dB bandwidth and a gain range of 4.5 dB to  
20.25 dB adjustable in 0.25 dB steps. Using a proprietary variable  
gain architecture, the AD8366 is able to achieve excellent linearity  
(45 dBm) and noise performance (11.7 nV/√Hz) at 10 MHz at  
minimum gain. Intended for use in direct conversion systems, the  
part also includes dc offset correction that can be disabled easily  
by grounding either OFSA or OFSB. In addition, the part offers  
an adjustable output common-mode range of 1.6 V to 3 V.  
OUTPUT DIFFERENTIAL OFFSET CORRECTION  
To prevent significant levels of offset from appearing at the  
outputs of the AD8366, each digitally controlled VGA has a  
differential offset correction loop, as shown in Figure 47. This  
loop senses any differential offset at the output and corrects for  
it by injecting an opposing current at the input differential ground.  
The loop is able to correct for input dc offsets of up to 20 mV.  
Because the loop automatically nulls out any dc or low frequency  
offset, the effect of the loop is to introduce a high-pass corner into  
the transfer function of the digitally controlled VGA. The  
location of this high-pass corner depends on both the gain  
setting and the value of the capacitor connected to the OFSx pin  
(OFSA for DVGA A and OFSB for DVGA B) and is given by  
The main signal path is shown in Figure 46. It consists of an  
input transconductance, a variable-gain cell, and an output  
transimpedance amplifier.  
VARIABLE  
CURRENT-GAIN OUTPUT  
STAGE  
BUFFER  
GC  
100  
100Ω  
12.5Ω  
12.5Ω  
4300  
(
1.037  
)
+ 4000  
INP  
INM  
OUTP  
OUTM  
f3dB,HP kHz =  
( )  
2π  
(
COFS +10  
)
A
Z
I
VIRTUAL  
GROUND  
VIRTUAL  
GROUND  
where:  
GC is the gain code (a value from 0 to 63).  
OFS is the value of the capacitance connected to OFSA or OFSB,  
Figure 46. Main Signal Path  
C
The input transconductance provides a broadband 200 Ω  
differential termination and converts the input voltage to a  
current. This current is fed into the variable current-gain cell.  
The output of this cell goes into the transimpedance stage, which  
generates the output voltage. The transimpedance is fixed at 500 Ω,  
with a roughly 25 Ω differential output impedance.  
in picofarads (pF).  
The offset correction loop can be disabled by grounding either  
OFSA or OFSB.  
VARIABLE-GAIN OUTPUT  
STAGE  
BUFFER  
OUTP  
OUTM  
A
Z
I
INPUTS  
The inputs to the digitally-controlled VGAs in the AD8366 are  
differential and can be either ac- or dc-coupled. The AD8366  
synthesizes a 200 Ω (differential) input impedance, with a return  
loss (re: 200 Ω) of better than 10 dB to 200 MHz. The nominal  
common-mode input voltage to the part is VPOS/2, but the AD8366  
can be dc-coupled to parts with lower common modes if these  
parts can sink current. The amount of current sinking required  
depends on the input common-mode level and is given by  
INP  
INM  
gm2  
gm1  
C
OFFSET  
OFS  
COMPENSATION  
LOOP  
Figure 47. Differential Offset Correction Loop  
OUTPUT COMMON-MODE CONTROL  
I
SINK (per leg) = (VPOS/2 − VICM)/100  
To interface to ADCs that require different input common-mode  
voltages, the AD8366 has an adjustable output common-mode  
level. The output common-mode level is normally set to VPOS/2;  
however, it can be changed between 1.6 V and 3 V by driving  
the VCMA pin or the VCMB pin. The input equivalent circuit  
for the VCMA pin is shown in Figure 48; the VCMB pin has the  
same input equivalent circuit.  
The input common-mode range is 1.5 V to VPOS/2.  
OUTPUTS  
The outputs of the digitally-controlled VGAs are differential and  
can be either ac- or dc-coupled. The AD8366 synthesizes a 25 Ω  
differential output impedance, with a return loss (re: 25 Ω) of  
better than 10 dB to 120 MHz. The nominal common-mode  
output voltage is VPOS/2; however, it can be lowered or raised by  
driving the VCMA or VCMB pins.  
4k  
V
/2  
POS  
500Ω  
VCMA  
Figure 48. Input Equivalent Circuit for VCMA  
Rev. A | Page 15 of 28  
 
 
 
 
AD8366  
25.0  
22.5  
20.0  
17.5  
15.0  
12.5  
10.0  
7.5  
1.0  
GAIN CONTROL INTERFACE  
0.8  
The AD8366 provides two methods of digital gain control:  
serial or parallel. When the SENB pin is pulled low, the part  
is in parallel gain control mode. In this mode, the two digitally  
controlled VGAs can be programmed simultaneously, or one at  
a time, depending on the levels at DENA and DENB. If the SENB  
pin is pulled high, the part is in serial gain control mode, with  
Pin 24, Pin 23, and Pin 22 corresponding to the CS, SDAT, and  
SCLK signals, respectively.  
0.6  
0.4  
0.2  
0
–0.2  
–0.4  
–0.6  
–0.8  
–1.0  
5.0  
The voltage gain of the AD8366 is well approximated by  
2.5  
Gain (dB) = GainCode × 0.253 + 4.5  
0
0
5
10 15 20 25 30 35 40 45 50 55 60  
GAIN CODE  
Note that at several major transitions (15 to 16, 31 to 32, and 47 to  
48), the gain changes significantly less (0 dB step) or significantly  
more (0.5 dB step) than the desired 0.25 dB step. This is inherent  
in the design of the part and is related to the partitioning of the  
variable gain block into a fine-gain and a coarse-gain section.  
Figure 49. Gain and Gain Step Error vs. Gain Code at 10 MHz  
Rev. A | Page 16 of 28  
 
AD8366  
APPLICATIONS INFORMATION  
The output buffers of the AD8366 are low impedance around  
25 Ω designed to drive ADC inputs. The output common-mode  
voltage defaults to VPOS/2; however, it can be adjusted by applying a  
desired external voltage to VCMA/VCMB. The common-mode  
voltage can be adjusted from 1.6 V to 3.0 V without significant  
harmonic distortion degradation.  
BASIC CONNECTIONS  
Figure 50 shows the basic connections for operating the AD8366.  
A voltage from 4.75 V to 5.25 V should be applied to the supply  
pins. Each supply pin should be decoupled with at least one low  
inductance, surface-mount ceramic capacitor of 0.1 μF placed as  
close as possible to the device.  
To enable the AD8366, the ENBL pin must be pulled high. Taking  
ENBL low disables the device, reducing current consumption to  
approximately 3 mA at ambient temperature.  
The differential input impedance is 200 Ω and sits at a nominal  
common-mode voltage of VPOS/2. The inputs can be dc-coupled  
or ac-coupled. If using direct dc coupling, the common-mode  
voltage, VCM, can range from 1.5 V to VPOS/2.  
VPOS  
0.01µF  
8200pF  
0.01µF  
CHANNEL A  
OUTPUT  
0.01µF  
VPOS  
0.1µF  
0.1µF  
0.1µF  
0.1µF  
VPSIA  
IPPA  
BIT0/CS  
BIT1/SDAT  
BIT2/SCLK  
CHANNEL A  
INPUT  
IPMA  
ENBL  
ICOM  
IPMB  
IPPB  
VPOS  
BIT3  
AD8366  
OCOM  
0.1µF  
BIT4  
BIT5  
CHANNEL B  
INPUT  
VPSIB  
DENA  
VPOS  
0.1µF  
0.01µF  
0.01µF  
CHANNEL B  
OUTPUT  
0.01µF  
0.01µF  
8200pF  
VPOS  
Figure 50. Basic Connections  
Rev. A | Page 17 of 28  
 
 
AD8366  
LC LOW-  
PASS  
FILTER  
LC LOW-  
PASS  
FILTER  
PAD  
FILTER  
BALUN  
0
LO  
MATCHING  
NETWORK  
RF  
TO  
90  
ADC  
ADF4350  
ADL5523  
ADL5523  
LC LOW-  
PASS  
FILTER  
LC LOW-  
PASS  
FILTER  
ADL5380  
Figure 51. Direct Conversion Receiver Block Diagram  
AD8366  
The image rejection ratio is the ratio of the intermediate frequency  
(IF) signal level produced by the desired input frequency to that  
produced by the image frequency. The image rejection ratio is  
expressed in decibels (dB). Appropriate image rejection is critical  
because the image power can be much higher than that of the  
desired signal, thereby plaguing the downconversion process.  
Amplitude and phase balance between the I/Q channels are  
critical for high levels of image rejection. Image rejection of  
greater than 47 dB was measured for the combined ADL5380  
and the AD8366 for a 5 MHz baseband frequency, as seen in  
Figure 53. This level of image rejection corresponds to a 0.5°  
phase mismatch and a 0.05 dB of amplitude mismatch for the  
combined ADL5380 and AD8366. Looking back to Figure 7 and  
Figure 10, the AD8366 exhibits only 0.05 dB of amplitude mismatch  
and 0.05o of phase mismatch, thus implying that the AD8366  
does not introduce additional amplitude and phase imbalance.  
55  
DIRECT CONVERSION RECEIVER DESIGN  
A direct conversion receiver directly demodulates an RF modulated  
carrier to baseband frequencies, where the signals can be detected  
and the conveyed information recovered. Eliminating the IF  
stages and directly converting the signal to effectively zero IF  
results in reduced component count. The image problems  
associated with the traditional superheterodyne architectures  
can be ignored as well. However, there are different challenges  
associated with direct conversion that include LO leakage, dc  
offsets, quadrature imperfections, and image rejection. LO  
leakage causes self mixing that results in squaring of the LO  
waveform which generates a dc offset that falls in band for the  
direct conversion receiver. Residual dc offsets create a similar  
interfering signal that falls in band. I/Q amplitude and phase  
mismatch lead to degraded SNR performance and poor image  
rejection in the direct conversion system. Figure 51 shows the  
block diagram for a direct conversion receiver system.  
QUADRATURE ERRORS AND IMAGE REJECTION  
50  
45  
40  
35  
30  
An overall RF-to-baseband EVM performance was measured  
with the ADL5380 IQ demodulator preceding the AD8366, as  
shown in Figure 56. In this setup, no LC low-pass filters were used  
between the ADL5380 and AD8366. A 1900 MHz W-CDMA RF  
signal with a 3.84 MHz symbol rate was used. The local oscillator  
(LO) is set at 1900 MHz to obtain a zero IF baseband signal.  
The gain of the AD8366 is set to maximum gain (~20.25 dB).  
Figure 52 shows the SNR vs. the input power of the cascaded  
system for a 5 MHz analysis bandwidth. The broad input power  
range over which the system exhibits strong SNR performance  
reflects the superior dynamic range of the AD8366.  
45  
25  
900 1100 1300 1500 1700 1900 2100 2300 2500 2700 2900  
RF FREQUENCY (MHz)  
Figure 53. Image Rejection vs. RF Frequency  
40  
35  
30  
25  
20  
15  
10  
5
0
–75  
–65  
–55  
–45  
–35  
–25  
–15  
–5  
5
INPUT POWER (dBm)  
Figure 52. SNR vs. RF Input Power Level  
Rev. A | Page 18 of 28  
 
 
 
 
AD8366  
–20  
–30  
–40  
–50  
–60  
–70  
–80  
–90  
LOW FREQUENCY IMD3 PERFORMANCE  
GC63  
GC0  
To measure the IMD3 data at low frequencies, wideband  
transformer baluns from North Hills Signal Processing Corp.  
were used, specifically the 0301BB and the 0520BB. Figure 55  
shows the IMD3 performance vs. frequency for a 2 V p-p  
composite output. The IMD3 performance was also measured  
for the combined ADL5380 and AD8366 system, as shown in  
Figure 56, with an FFT spectrum analyzer. An FFT spectrum  
analyzer works very similar to a typical ADC, the input signal  
is digitized at a high sampling rate that is then passed through an  
antialiasing filter. The resulting signal is transformed to the  
frequency domain using fast Fourier transforms (FFT).  
0.5  
1.0  
1.5  
2.0  
2.5  
3.0  
3.5  
4.0  
4.5  
5.0  
The single-ended RF signal from the source generator is converted  
to a differential signal using a balun that gets demodulated and  
down converted to differential IF signals through the ADL5380.  
This differential IF signal drives the AD8366, thus eliminating  
the need for low frequency baluns. Figure 54 shows the IMD3  
performance vs. frequency over the 500 kHz to 5 MHz range  
for minimum and maximum gain code setting on the AD8366.  
During the measurements, the output was set to 2 V p-p composite.  
FREQUENCY (MHz)  
Figure 54. System IMD3 vs. Frequency, 2 V p-p Composite at  
the Output of the AD8366  
50  
45  
40  
35  
30  
25  
20  
15  
10  
5
0
FREQUENCY = 1MHz  
FREQUENCY = 3MHz  
–10  
–20  
–30  
–40  
–50  
–60  
–70  
–80  
–90  
–100  
0
0
5
10 15 20 25 30 35 40 45 50 55 60  
GAIN CODE  
Figure 55. OIP3 on Low Frequency, 2 V p-p Composite  
Rev. A | Page 19 of 28  
 
 
 
AD8366  
RFIN  
BALUN  
100pF  
100pF  
V
VPOS  
POS  
0.1µF  
100pF  
24  
23  
22  
21  
20  
19  
1
2
3
4
5
6
18  
17  
16  
15  
GND  
GND  
GND  
IHI  
GND  
QHI  
ADL5380  
QLO  
ILO  
GND 14  
VCC  
GND  
VCC  
V
POS  
13  
V
POS  
0.1µF  
100pF  
100pF  
0.1µF  
7
8
9
10  
11  
12  
100pF  
100pF  
BALUN  
LO  
V
V
POS  
POS  
V
POS  
0.1µF  
0.1µF  
0.1µF  
0.01µF  
0.01µF  
C
C
OFS  
OFS  
0.01µF  
0.1µF  
0.01µF  
OFSB  
CCMB  
VCMB  
VPSOB  
OPPB  
OPMB  
OFSA  
CCMA  
VCMA  
VPSOA  
OPPA  
AD8366  
V
V
POS  
POS  
0.01µF  
0.01µF  
0.1µF  
OPMA  
200  
200Ω  
Q CHANNEL  
I CHANNEL  
PARALLEL/SERIAL  
CONTROL INTERFACE  
Figure 56. ADL5380 and AD8366 Interface Block Diagram  
Rev. A | Page 20 of 28  
 
AD8366  
The order and type of filter network depends on the desired high  
frequency rejection required, pass-band ripple, and group delay.  
BASEBAND INTERFACE  
In most direct-conversion receiver designs, it is desirable to select a  
wanted carrier within a specified band. The desired channel can be  
demodulated by tuning the LO to the appropriate carrier frequency.  
If the desired RF band contains multiple carriers of interest, the  
adjacent carriers would also be down converted to a lower IF  
frequency. These adjacent carriers can be a problem if they are  
large relative to the desired carrier because they can overdrive  
the baseband signal detection circuitry. As a result, it is often  
necessary to insert a filter to provide sufficient rejection of the  
adjacent carriers.  
Figure 57 shows the schematic for a typical fourth-order, Chebyshev,  
low-pass filter. Table 4 shows the typical values of the filter  
components for a fourth-order, Chebyshev, low-pass filter with  
a differential source impedance of 25 ꢀ and a differential load  
impedance of 200 ꢀ.  
L1  
L3  
C1  
C2  
Z
Z
SOURCE  
LOAD  
It is necessary to consider the overall source and load impedance  
presented by the AD8366 and the ADC input to design the  
filter network. The differential baseband output impedance of  
the AD8366 is 25 Ω and is designed to drive a high impedance  
ADC input. It may be desirable to terminate the ADC input down  
to the lower impedance by using a terminating resistor, such as  
500 Ω. The terminating resistor helps to better define the input  
impedance at the ADC input at the cost of a slightly reduced gain.  
L2  
L4  
Figure 57. Schematic of a Fourth-Order, Chebyshev, Low-Pass Filter  
Table 4. Typical Values for Fourth-Order, Chebyshev, Low-Pass Filter  
3 dB Corner (MHz)  
ZSOURCE (Ω)  
ZLOAD (Ω)  
L1 (μH)  
L2 (μH)  
6.6  
3.3  
L3 (μH)  
L4 (μH)  
C1 (pF)  
220  
110  
C2 (pF)  
180  
90  
5
10  
28  
25  
25  
25  
200  
200  
200  
6.6  
3.3  
1.2  
6.0  
3
1
6.0  
3
1
1.2  
39  
33  
Rev. A | Page 21 of 28  
 
 
 
AD8366  
CHARACTERIZATION SETUPS  
Figure 58 and Figure 59 are characterization setups used  
extensively to characterize the AD8366. Characterization was  
done on single-ended and differential evaluation boards. The  
bulk of the characterization was done using an automated VEE  
program to control the equipment as shown in Figure 58. This  
setup was used to measure P1dB, OIP3, OIP2, IMD2, IMD3,  
harmonic distortion, gain, gain error, supply current, and noise  
density. All measurements were done with a 200 Ω load. All balun,  
output matching network, and filter losses were de-embedded.  
Gain error was measured with constant input power. All other  
measurements were done on 2 V p-p (4 dBm, re: 200 Ω) on  
the output of the device under test (DUT), and 2 V p-p composite  
output for two-tone measurements. To measure harmonic  
distortion, band-pass and band-reject filters were used on  
the input and output of the DUT.  
Figure 59 shows the setup used to make differential measurements.  
All measurements on this setup were done in a 50 Ω system and  
post processed to reference the measurements to a 200 Ω system.  
Gain and phase mismatch were measured with 2 V p-p on the  
output, and small signal frequency responses were measured  
with −30 dBm on the input of the DUT.  
Rev. A | Page 22 of 28  
 
AD8366  
AGILENT E8251D  
SIGNAL GENERATOR  
AGILENT E8251A  
SIGNAL GENERATOR  
AGILENT E4440A  
SPECTRUM ANALYZER  
COMBINER  
RF SWITCH  
MATRIX  
KEITHLEY  
IEEE  
RF SWITCH  
MATRIX  
KEITHLEY  
IEEE  
BAND PASS  
BAND REJECT  
CH2  
RF IN  
CH1  
RF IN  
CH2  
RF OUT  
CH1  
RF OUT  
AD8366  
EVALUATION BOARD  
AGILENT E3631A POWER  
SUPPLY  
AGILENT 34401A DMM  
(IN DC I MODE FOR SUPPLY  
CURRENT MEASUREMENT)  
AGILENT 34980A  
MULTIFUNCTION SWITCH  
(WITH 34950 AND 34921 MODULES)  
Figure 58. Characterization Setup, Single-Ended Measurements  
Rev. A | Page 23 of 28  
 
AD8366  
Rohde & Schwarz ZVA8  
RF SWITCH  
MATRIX  
KEITHLEY  
CH2  
IP  
CH2  
IP  
AD8366  
EVALUATION BOARD  
CH2  
IM  
CH2  
IM  
CH1  
OP  
CH1  
OM  
CH2  
OP  
CH2  
OM  
AGILENT E3631A  
POWER SUPPLY  
Figure 59. Characterization Setup, Differential Measurements  
Rev. A | Page 24 of 28  
 
AD8366  
EVALUATION BOARD  
The schematic for the AD8366 evaluation board is shown in Figure 60. The board can be used for single-ended or differential baseband  
analysis. The default configuration of the board is for single-ended baseband analysis.  
C26  
T3  
C27  
T4  
R39  
R29  
R38  
R31  
R35  
R34  
R37  
R36  
R30  
R67  
R33  
R80  
C24  
C25  
R71  
R70  
R69  
R74  
R73  
R72  
R65  
R68  
C33  
C29  
C31  
OPMA  
OPPA  
VPSOA  
VCMA  
CCMA  
OFSA  
OPMB  
OPPB  
VPSOB  
VCMB  
CCMB  
OFSB  
C28  
VPSO_A  
VPSO_B  
AD8366  
VCMA  
C9  
VCMB  
C10  
S12  
S11  
C12  
C3  
C2  
C11  
VPSI_A  
VPSI_B  
C22  
C15  
C16  
R54  
R50  
C20  
R48 R63  
R62  
C5  
R58  
R45  
R13  
R44  
R14  
R46  
R47  
R15  
T1  
T2  
C23  
R16  
R17  
R20  
R18  
R21  
R12  
R19  
C30  
C13  
C1  
C14  
C18  
C21  
S1  
Figure 60. Evaluation Board Schematic  
Rev. A | Page 25 of 28  
 
 
AD8366  
Figure 61. AD8366 Evaluation Board Printed Circuit Board (PCB), Top Side  
Figure 62. AD8366 Evaluation Board PCB, Bottom Side  
Table 5. Evaluation Board Configuration Options  
Components  
Function  
Default Conditions  
C1, C13 to C16, R3 to R6  
Power supply decoupling. Nominal supply decoupling consists of a  
0.1 μF capacitor to ground followed by 0.01 μF capacitors to ground  
positioned as close to the device as possible.  
C1 = 0.1 μF (size 0603),  
C13 to C16 = 0.01 μF (size 0402),  
R3 to R6 = 0 Ω (size 0603)  
T1, T2, C5, C18, C20, C21,  
R12 to R21, R44 to R48,  
R50, R54, R58, R62, R63  
Input interface. The default configuration of the evaluation board is  
for single-ended operation. T1 and T2 are 4:1 impedance ratio baluns to  
transform a 50 Ω single-ended input into a 200 Ω balanced differential  
signal. R12 to R14 and R15, R16, and R19 are populated for appropriate  
balun interface. R44 to R48 and R50, R54, R58, R62, and R63 are  
provided for generic placement of matching components. C5, C18,  
C20, and C21 are balun decoupling capacitors. R17, R18, R20, and  
R21 can be populated with 0 Ω, and the balun interfacing resistors  
can be removed to bypass T1 and T2 for differential interfacing.  
T1, T2 = ADT4-6T+ (Mini-Circuits),  
C5, C20 = 0.1 μF (size 0402),  
C18, C21 = do not install,  
R12 to R16, R19, R44 to R47 = 0 Ω  
(size 0402),  
R17, R18, R20, R21,R48, R50, R54,  
R58, R62, and R63 = open (size 0402)  
T3, T4, C24 to C27, R29 to  
R31, R33 to R39, R65, R67  
to R74, R80  
Output interface. The default configuration of the evaluation board  
is for single-ended operation. T3 and T4 are 4:1 impedance ratio  
baluns to transform a 50 Ω single-ended output into a 200 Ω balanced  
differential load. R29 to R31, R33, R38, and R39 are populated for  
appropriate balun interface. R65, R67 to R74, and R80 are provided  
for generic placement of matching components. C24, C25, C26, and  
C27 are balun decoupling capacitors. R34 to R37 can be populated  
with 0 Ω, and the balun interfacing resistors can be removed to  
bypass T3 and T4 for differential interfacing.  
T3, T4 = ADT4-6T+ (Mini-Circuits),  
C24, C25 = 0.1 μF (size 0402),  
C26, C27 = do not install,  
R29 to R31, R33, R38, R39, R65, R67,  
R68, R80 = 0 Ω (size 0402),  
R34 to R37, R69 to R74 = open (size 0402)  
Rev. A | Page 26 of 28  
AD8366  
Components  
Function  
Default Conditions  
S1, S5, S7, R53, R57, R79,  
C29, C30, C31  
Enable interface includes device enable and data enable.  
S1, S5, S7 = installed,  
R53, R57 = 5.1 kΩ (size 0603),  
R79 = 10 kΩ (size 0402),  
C30 = 0.01 μF (size 0402),  
C29, C31 = 1500 pF (size 0402)  
Device enable. The AD8366 is enabled by applying a logic high  
voltage to the ENBL pin. The device is enabled when the S1 switch is  
set in the down position (high), connecting the ENBL pin to VPSI_A.  
Data enable. DENA and DENB are used to enable the data path for  
Channel A and Channel B, respectively. Channel A is enabled when  
the S5 switch is set in the down position (high), connecting the DENA  
pin to VPSI_A. Likewise, Channel B is enabled when the S7 switch is  
set in the down position (high), connecting the DENB pin to VPSI_A.  
Both channels are disabled by setting the switches to the up position,  
connecting the DENA and DENB pins to GND.  
S2, S3, S4, S6, S8, S9, S10  
R26, R32, R40 to R43, R61, either in parallel or serial mode. The parallel interface is enabled when  
Serial/parallel interface control. SENB is used to set the data control  
S2, S3, S4, S6, S8, S9, S10 = installed,  
R26 = 698 kΩ (size 0603),  
R64, C23, C33, U1  
S4 is in the up position (low). The serial interface is enabled when S4  
is in the down position (high).  
R32, R40 to R43, R61, R64 = 5.1 kΩ  
(size 0603),  
C23, C33 = 1500 pF (size 0603),  
U1 = SN74LVC2G14 inverter chip  
For SENB pulled low, BIT0 (S9) sets 0.25 dB gain, BIT1 (S2) sets 0.5 dB  
gain, BIT2 (S3) sets 1 dB gain, BIT3 (S6) sets 2 dB gain, BIT4 (S8) sets  
4 dB gain, and BIT5 (S10) sets 8 dB gain.  
For SENB pulled high, BIT0 becomes a chip select (CS), BIT1 becomes  
a serial data input (SDAT), and BIT2 becomes serial clock (SCLK). BIT3 to  
BIT5 are not used in serial mode. U1 is used to deglitch the SCLK signal.  
S11, S12, C9, C10  
DC offset correction loop compensation.  
S11, S12 = installed,  
C9, C10 = 8200 pF (size 0402)  
The dc offset correction loop is enabled (high) with S11 and S12 for  
Channel A and Channel B, respectively, when the enabled pins, OFSA/  
OFSB, are connected to ground through the C9 and C10 capacitors.  
When disabled (low), OFSA/OFSB are connected to ground directly.  
R10, R22, R24, R28, C22,  
C28  
Output common-mode setpoint. The output common mode on  
Channel A and Channel B can be set externally when applied to  
VCMA and VCMB. The resistive change through the potentiometer  
sets a variable VCMA voltage. If left open, the output common mode  
defaults to VPOS/2.  
R10, R24 = 10 kΩ potentiometers,  
R22, R28 = 0 Ω,  
C22, C28 = 0.1 μF (size 0402)  
C2, C3, C11, C12  
Reference output decoupling capacitor to circuit common.  
C2, C3 = 0.1 μF (size 0402),  
C11, C12 = 0.01 μF (size 0402)  
Rev. A | Page 27 of 28  
AD8366  
OUTLINE DIMENSIONS  
5.00  
BSC SQ  
0.60 MAX  
0.60 MAX  
PIN 1  
INDICATOR  
25  
32  
1
24  
0.50  
BSC  
PIN 1  
INDICATOR  
TOP  
VIEW  
2.85  
2.70 SQ  
2.55  
EXPOSED  
PAD  
(BOTTOM VIEW)  
4.75  
BSC SQ  
0.50  
0.40  
0.30  
17  
16  
8
9
0.20 MIN  
3.50 REF  
0.80 MAX  
1.00  
0.85  
0.80  
12° MAX  
0.65 TYP  
FOR PROPER CONNECTION OF  
THE EXPOSED PAD, REFER TO  
THE PIN CONFIGURATION AND  
FUNCTION DESCRIPTIONS  
0.05 MAX  
0.02 NOM  
0.30  
0.25  
0.18  
SEATING  
PLANE  
SECTION OF THIS DATA SHEET.  
COPLANARITY  
0.08  
0.20 REF  
COMPLIANT TO JEDEC STANDARDS MO-220-VHHD-2  
Figure 63. 32-Lead Lead Frame Chip Scale Package [LFCSP_VQ]  
5 mm × 5 mm Body, Very Thin Quad  
(CP-32-8)  
Dimensions shown in millimeters  
ORDERING GUIDE  
Model1  
Temperature Range  
Package Description  
Package Option  
AD8366ACPZ-R7  
AD8366-EVALZ  
−40°C to +85°C  
32-Lead Lead Frame Chip Scale Package [LFCSP_VQ]  
Evaluation Board  
CP-32-8  
1 Z = RoHS Compliant Part.  
©2010-2011 Analog Devices, Inc. All rights reserved. Trademarks and  
registered trademarks are the property of their respective owners.  
D07584-0-3/11(A)  
Rev. A | Page 28 of 28  
 
 
 
 

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