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1 MHz to 2.7 GHz RF Gain Block AD8353
FEATURES
Fixed gain of 20 dB Operational frequency of 1 MHz to 2.7 GHz Linear output power up to 9 dBm Input/output internally matched to 50 Temperature and power supply stable Noise figure: 5.3 dB Power supply: 3 V or 5 V
FUNCTIONAL BLOCK DIAGRAM
BIAS AND VREF VPOS
RFIN
RFOUT
COM1
AD8353
Figure 1.
COM2
APPLICATIONS
VCO buffers General Tx/Rx amplification Power amplifier predrivers Low power antenna drivers
GENERAL DESCRIPTION
The AD8353 is a broadband, fixed-gain, linear amplifier that operates at frequencies from 1 MHz up to 2.7 GHz. It is intended for use in a wide variety of wireless devices, including cellular, broadband, CATV, and LMDS/MMDS applications. By taking advantage of ADI's high performance, complementary Si bipolar process, these gain blocks provide excellent stability over process, temperature, and power supply. This amplifier is single-ended and internally matched to 50 with a return loss of greater than 10 dB over the full operating frequency range. The AD8353 provides linear output power of 9 dBm with 20 dB of gain at 900 MHz when biased at 3 V and an external RF choke is connected between the power supply and the output pin. The dc supply current is 42 mA. At 900 MHz, the output third-order intercept (OIP3) is greater than 23 dBm and is 19 dBm at 2.7 GHz. The noise figure is 5.3 dB at 900 MHz. The reverse isolation (S12) is -36 dB at 900 MHz and -30 dB at 2.7 GHz. The AD8353 can also operate with a 5 V power supply; in which case, no external inductor is required. Under these conditions, the AD8353 delivers 8 dBm with 20 dB of gain at 900 MHz. The dc supply current is 42 mA. At 900 MHz, the OIP3 is greater than 22 dBm and is 19 dBm at 2.7 GHz. The noise figure is 5.6 dB at 900 MHz. The reverse isolation (S12) is -35 dB. The AD8353 is fabricated on ADI's proprietary, high performance, 25 GHz, Si complementary, bipolar IC process. The AD8353 is available in a chip scale package that uses an exposed paddle for excellent thermal impedance and low impedance electrical connection to ground. It operates over a -40C to +85C temperature range, and an evaluation board is also available.
Rev. B
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 registered trademarks are the 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 (c) 2005 Analog Devices, Inc. All rights reserved.
02721-001
AD8353 TABLE OF CONTENTS
Features .............................................................................................. 1 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 ..............................................7 Theory of Operation ...................................................................... 13 Basic Connections...................................................................... 13 Applications..................................................................................... 14 Low Frequency Applications Below 100 MHz........................... 14 Evaluation Board ............................................................................ 15 Outline Dimensions ....................................................................... 16 Ordering Guide .......................................................................... 16
REVISION HISTORY
12/05--Rev. A to Rev. B Changes to Table 1............................................................................ 3 Changes to Table 2............................................................................ 4 Changes to Figure 16........................................................................ 9 Changes to Figure 32...................................................................... 11 Moved Figure 39 to Page 15; Renumbered Sequentially ........... 15 Changes to Ordering Guide .......................................................... 16 8/05--Rev. 0 to Rev. A Updated Format..................................................................Universal Changes to Product Title ................................................................. 1 Changes to Features, Figure 1, and General Description............ 1 Changes to Table 1............................................................................ 3 Changes to Table 2............................................................................ 4 Changes to Figure 2 and Table 4..................................................... 6 Changes to Figure 3 caption and Figure 6 caption....................... 7 Changes to Figure 17 caption and Figure 20 caption .................. 9 Changes to Basic Connections Section........................................ 13 Added Low Frequency Applications Below 100 MHz Section. 14 Changes to Table 5.......................................................................... 15 Changes to Ordering Guide .......................................................... 16 Updated Outline Dimensions ....................................................... 16 2/02--Revision 0: Initial Version
Rev. B | Page 2 of 16
AD8353 SPECIFICATIONS
VS = 3 V, TA = 25C, 100 nH external inductor between RFOUT and VPOS, ZO = 50 , unless otherwise noted. Table 1.
Parameter OVERALL FUNCTION Frequency Range Gain Conditions Min 1 f = 900 MHz f = 1.9 GHz f = 2.7 GHz f = 900 MHz, -40C TA +85C f = 1.9 GHz, -40C TA +85C f = 2.7 GHz, -40C TA +85C VPOS 10%, f = 900 MHz f = 1.9 GHz f = 2.7 GHz f = 900 MHz f = 1.9 GHz f = 2.7 GHz Pin RFIN f = 900 MHz f = 1.9 GHz f = 2.7 GHz Pin RFOUT f = 900 MHz, 1 dB compression f = 1.9 GHz f = 2.7 GHz f = 900 MHz, -40C TA +85C f = 1.9 GHz, -40C TA +85C f = 2.7 GHz, -40C TA +85C f = 900 MHz f = 1.9 GHz f = 2.7 GHz f = 900 MHz, f = 1 MHz, PIN = -28 dBm f = 1.9 GHz, f = 1 MHz, PIN = -28 dBm f = 2.7 GHz, f = 1 MHz, PIN = -28 dBm f = 900 MHz, f = 1 MHz, PIN = -28 dBm f = 900 MHz f = 1.9 GHz f = 2.7 GHz Pin VPOS 2.7 35 -40C TA +85C 19.8 17.7 15.6 -0.97 -1.15 -1.34 0.04 -0.004 -0.04 -35.6 -34.9 -30.3 22.3 20.9 11.2 9.1 8.4 7.6 -1.46 -1.17 -1 26.3 16.9 13.3 23.6 20.8 19.5 31.6 5.3 6 6.8 3 41 15.3 60 3.3 48 Typ Max 2700 Unit MHz dB dB dB dB dB dB dB/V dB/V dB/V dB dB dB dB dB dB dBm dBm dBm dB dB dB dB dB dB dBm dBm dBm dBm dB dB dB V mA mA/V A/C
Delta Gain
Gain Supply Sensitivity
Reverse Isolation (S12)
RF INPUT INTERFACE Input Return Loss
RF OUTPUT INTERFACE Output Compression Point
Delta Compression Point
Output Return Loss
DISTORTION/NOISE Output Third-Order Intercept
Output Second-Order Intercept Noise Figure
POWER INTERFACE Supply Voltage Total Supply Current Supply Voltage Sensitivity Temperature Sensitivity
Rev. B | Page 3 of 16
AD8353
VS = 5 V, TA = 25C, no external inductor between RFOUT and VPOS, ZO = 50 , unless otherwise noted. Table 2.
Parameter OVERALL FUNCTION Frequency Range Gain Conditions Min 1 f = 900 MHz f = 1.9 GHz f = 2.7 GHz f = 900 MHz, -40C TA +85C f = 1.9 GHz, -40C TA +85C f = 2.7 GHz, -40C TA +85C VPOS 10%, f = 900 MHz f = 1.9 GHz f = 2.7 GHz f = 900 MHz f = 1.9 GHz f = 2.7 GHz Pin RFIN f = 900 MHz f = 1.9 GHz f = 2.7 GHz Pin RFOUT f = 900 MHz f = 1.9 GHz f = 2.7 GHz f = 900 MHz, -40C TA +85C f = 1.9 GHz, -40C TA +85C f = 2.7 GHz, -40C TA +85C f = 900 MHz f = 1.9 GHz f = 2.7 GHz f = 900 MHz, f = 1 MHz, PIN = -28 dBm f = 1.9 GHz, f = 1 MHz, PIN = -28 dBm f = 2.7 GHz, f = 1 MHz, PIN = -28 dBm f = 900 MHz, f = 1 MHz, PIN = -28 dBm f = 900 MHz f = 1.9 GHz f = 2.7 GHz Pin VPOS 4.5 35 -40C TA +85C 19.5 17.6 15.7 -0.96 -1.18 -1.38 0.09 -0.01 -0.09 -35.4 -34.6 -30.2 22.9 21.7 11.5 8.3 8.1 7.5 -1.05 -1.49 -1.33 27 22 14.3 22.8 20.6 19.5 30.3 5.6 6.3 7.1 5 42 4.3 45.7 5.5 52 Typ Max 2700 Unit MHz dB dB dB dB dB dB dB/V dB/V dB/V dB dB dB dB dB dB dBm dBm dBm dB dB dB dB dB dB dBm dBm dBm dBm dB dB dB V mA mA/V A/C
Delta Gain
Gain Supply Sensitivity
Reverse Isolation (S12)
RF INPUT INTERFACE Input Return Loss
RF OUTPUT INTERFACE Output Compression Point
Delta Compression Point
Output Return Loss
DISTORTION/NOISE Output Third-Order Intercept
Output Second-Order Intercept Noise Figure
POWER INTERFACE Supply Voltage Total Supply Current Supply Voltage Sensitivity Temperature Sensitivity
Rev. B | Page 4 of 16
AD8353 ABSOLUTE MAXIMUM RATINGS
Table 3.
Parameter Supply Voltage, VPOS Input Power (re: 50 ) Equivalent Voltage Internal Power Dissipation Paddle Not Soldered Paddle Soldered JA (Paddle Soldered) JA (Paddle Not Soldered) Maximum Junction Temperature Operating Temperature Range Storage Temperature Range Lead Temperature (Soldering 60 sec) Rating 5.5 V 10 dBm 700 mV rms 325 mW 812 mW 80C/W 200C/W 150C -40C to +85C -65C to +150C 240C
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.
ESD CAUTION
ESD (electrostatic discharge) sensitive device. Electrostatic charges as high as 4000 V readily accumulate on the human body and test equipment and can discharge without detection. Although this product features proprietary ESD protection circuitry, permanent damage may occur on devices subjected to high energy electrostatic discharges. Therefore, proper ESD precautions are recommended to avoid performance degradation or loss of functionality.
Rev. B | Page 5 of 16
AD8353 PIN CONFIGURATION AND FUNCTION DESCRIPTIONS
COM1 1 NC 2
8 COM1
7 RFOUT TOP VIEW RFIN 3 (Not to Scale) 6 VPOS 5 COM2 COM2 4
04862-002
AD8353
NC = NO CONNECT
Figure 2. Pin Configuration
Table 4. Pin Function Descriptions
Pin No. 1, 8 2 3 4, 5 6 7 Mnemonic COM1 NC RFIN COM2 VPOS RFOUT Description Device Common. Connect to low impedance ground. No Connection. RF Input Connection. Must be ac-coupled. Device Common. Connect to low impedance ground. Positive Supply Voltage. RF Output Connection. Must be ac-coupled.
Rev. B | Page 6 of 16
AD8353 TYPICAL PERFORMANCE CHARACTERISTICS
90 120 60
120 90 60
150
30
150
30
180
180
210
330
210
330
02721-003
240 270
300
240 270
300
Figure 3. S11 vs. Frequency, VS = 3 V, TA = 25C, dc f 3 GHz
25 GAIN AT 3.3V 20
Figure 6. S22 vs. Frequency, VS = 3 V, TA = 25C, dc f 3 GHz
25 GAIN AT -40C 20
GAIN (dB)
GAIN (dB)
15 GAIN AT 2.7V 10 GAIN AT 3.0V
15 GAIN AT +25C 10 GAIN AT +85C
5
5
02721-004
0
500
1000
1500
2000
2500
3000
0
500
1000
1500
2000
2500
3000
FREQUENCY (MHz)
FREQUENCY (MHz)
Figure 4. Gain vs. Frequency, VS = 2.7 V, 3 V, and 3.3 V, TA = 25C
0 -5
Figure 7. Gain vs. Frequency, VS = 3 V, TA = -40C, +25C, and +85C
0 -5
REVERSE ISOLATION (dB)
REVERSE ISOLATION (dB)
-10 -15 -20 -25 -30 -35 -40 0 S12 AT 3.3V
02721-005
-10 -15 -20 -25 -30 -35
02721-008
S12 AT +25C S12 AT -40C
S12 AT 3.0V S AT 2.7V 12
-40
S12 AT +85C 0 500 1000 1500 2000 2500 3000
500
1000
1500
2000
2500
3000
FREQUENCY (MHz)
FREQUENCY (MHz)
Figure 5. Reverse Isolation vs. Frequency, VS = 2.7 V, 3 V, and 3.3 V, TA = 25C
Figure 8. Reverse Isolation vs. Frequency, VS = 3 V, TA = -40C, +25C, and +85C
Rev. B | Page 7 of 16
02721-007
0
0
02721-006
AD8353
12 12
P1dB AT -40C
10 10
P1dB AT 3.3V
8 8
P1dB (dBm)
P1dB (dBm)
6
P1dB AT 3.0V
P1dB AT 2.7V
6
P1dB AT +25C
P1dB AT +85C
4
4
2
2
02721-009
0
500
1000
1500
2000
2500
3000
0
500
1000
1500
2000
2500
3000
FREQUENCY (MHz)
FREQUENCY (MHz)
Figure 9. P1dB vs. Frequency, VS = 2.7 V, 3 V, and 3.3 V, TA = 25C
45 40
Figure 12. P1dB vs. Frequency, VS = 3 V, TA = -40C, +25C, and +85C
30
25
35 PERCENTAGE (%)
PERCENTAGE (%)
30 25 20 15 10
20
15
10
5
5
02721-010
0 7.0
0 19.1 19.5 19.9 20.3 20.7 OIP3 (dBm) 21.1 21.5 21.9
7.2
7.4 7.6 7.8 8.0 8.2 8.4 8.6 8.8 OUTPUT 1dB COMPRESSION POINT (dBm)
9.0
Figure 10. Distribution of P1dB, VS = 3 V, TA = 25C, f = 2.2 GHz
28 26 24 22 OIP3 AT 3.3V
OIP3 (dBm)
Figure 13. Distribution of OIP3, VS = 3 V, TA = 25C, f = 2.2 GHz
28 26 24 22 20 18 16 14 12
02721-011
OIP3 AT -40C
OIP3 (dBm)
20 18 16 14 12 10 0 500 1000 1500 2000 2500 3000 OIP3 AT 3.0V OIP3 AT 2.7V
OIP3 AT +85C OIP3 AT +25C
10
0
500
1000
1500
2000
2500
3000
FREQUENCY (MHz)
FREQUENCY (MHz)
Figure 11. OIP3 vs. Frequency, VS = 2.7 V, 3 V, and 3.3 V, TA = 25C
Figure 14. OIP3 vs. Frequency, VS = 3 V, TA = -40C, +25C, and +85C
Rev. B | Page 8 of 16
02721-014
02721-013
02721-012
0
0
AD8353
8.0 7.5 7.0
NOISE FIGURE (dBm) NOISE FIGURE (dB)
8.5 8.0 7.5 7.0 6.5 6.0 NF AT +25C 5.5 5.0 4.5
02721-015
6.5 NF AT 3.3V 6.0 5.5 5.0 NF AT 2.7V 4.5 4.0 0 500 1000 1500 2000 FREQUENCY (MHz) 2500 3000 NF AT 3.0V
NF AT +85C
NF AT -40C
4.0 0 500 1000 1500 2000 FREQUENCY (MHz) 2500 3000
Figure 15. Noise Figure vs. Frequency, VS = 2.7 V, 3 V, and 3.3 V, TA = 25C
35 30
Figure 18. Noise Figure vs. Frequency, VS = 3 V, TA = -40C, +25C, and +85C
50 45 40 IS AT 3.3V IS AT 3.0V IS AT 2.7V
25
PERCENTAGE (%)
SUPPLY CURRENT (mA)
35 30 25 20 15 10
20 15 10 5
5 0 -60 -40 -20 20 0 40 TEMPERATURE (C) 60 80 100
02721-019
02721-020
0 5.90 5.95 6.00 6.05 6.10 6.15 6.20 6.25 6.30 6.35 6.40 6.45 6.50 6.55 6.60 NOISE FIGURE (dB)
02721-016
Figure 16. Distribution of Noise Figure, VS = 3 V, TA = 25C, f = 2.2 GHz
90 120 60
Figure 19. Supply Current vs. Temperature, VS = 2.7 V, 3 V, and 3.3 V
90 120 60
150
30
150
30
180
0
180
0
02721-017
210
330
210
330
240 270
300
240 270
300
Figure 17. S11 vs. Frequency, VS = 5 V, TA = 25C, dc f 3 GHz
Figure 20. S22 vs. Frequency, VS = 5 V, TA = 25C, dc f 3 GHz
Rev. B | Page 9 of 16
02721-018
AD8353
25 GAIN AT 5.5V GAIN AT -40C 20 20 GAIN AT +85C 25
GAIN (dB)
GAIN AT 5.0V GAIN AT 4.5V
GAIN (dB)
15
15 GAIN AT +25C 10
10
5
5
02721-021
0
500
1000
1500
2000
2500
3000
0
500
1000
1500
2000
2500
3000
FREQUENCY (MHz)
FREQUENCY (MHz)
Figure 21. Gain vs. Frequency, VS = 4.5 V, 5 V, and 5.5 V, TA = 25C
0 -5
REVERSE ISOLATION (dB) REVERSE ISOLATION (dB)
Figure 24. Gain vs. Frequency, VS = 5 V, TA = -40C, +25C, and +85C
0 -5 -10 -15 -20 -25 -30 -35 S12 AT +25C
-10 -15 -20 -25 -30 -35 S12 AT 4.5V
02721-022
S12 AT 5V S12 AT 5.5V
S12 AT +85C
S12 AT -40C 3000 0 500 1000 1500 2000 FREQUENCY (MHz) 2500 3000
02721-025
02721-026
-40 0 500 1000 1500 2000 FREQUENCY (MHz) 2500
-40
Figure 22. Reverse Isolation vs. Frequency, VS = 4.5 V, 5 V, and 5.5 V, TA = 25C
10 9 8 7 P1dB AT 5.5V
Figure 25. Reverse Isolation vs. Frequency, VS = 5 V, TA = -40C, +25C, and +85C
12
10
P1dB AT +85C
P1dB AT +25C
P1dB (dBm)
6 5 4 3 2 1
P1dB AT 5.0V
P1dB (dBm)
P1dB AT 4.5V
8
6
P1dB AT -40C
4
2
02721-023
0
0 0 500 1000 1500 2000 FREQUENCY (MHz) 2500 3000
0
500
1000
1500
2000
2500
3000
FREQUENCY (MHz)
Figure 23. P1dB vs. Frequency, VS = 4.5 V, 5 V, and 5.5 V, TA = 25C
Figure 26. P1dB vs. Frequency, VS = 5 V, TA = -40C, +25C, and +85C
Rev. B | Page 10 of 16
02721-024
0
0
AD8353
45 40
30
25
35
PERCENTAGE (%)
PERCENTAGE (%)
30 25 20 15 10
20
15
10
5
5
02721-027
0 7.0
7.2
7.4 7.6 7.8 8.0 8.2 8.4 8.6 OUTPUT 1dB COMPRESSION POINT (dBm)
8.8
0 18.8
19.2
19.6
20.0 20.4 OIP3 (dBm)
20.8
21.2
21.6
Figure 27. Distribution of P1dB, VS = 3 V, TA = 25C, f = 2.2 GHz
26 24 22 20 18 OIP3 AT 5.0V 16 14 12
02721-028
Figure 30. Distribution of OIP3, VS = 5 V, TA = 25C, f = 2.2 GHz
26 24 22 20 18 16 14 12 10 0 500 1000 1500 2000 FREQUENCY (MHz) 2500 3000
02721-031
02721-032
OIP3 AT -40C
OIP3 AT 5.5V
OIP3 (dBm)
OIP3 (dBm)
OIP3 AT +25C
OIP3 AT 4.5V
OIP3 AT +85C
10 0 500 1000 1500 2000 FREQUENCY (MHz) 2500 3000
Figure 28. OIP3 vs. Frequency, VS = 4.5 V, 5 V, and 5.5 V, TA = 27C
9.0 8.5 8.0
Figure 31. OIP3 vs. Frequency, VS = 5 V, TA = -40C, +25C, and +85C
10
9
NOISE FIGURE (dB)
NOISE FIGURE (dBm)
7.5 7.0 NF AT 5.5V 6.5 6.0 NF AT 4.5V 5.5 5.0 NF AT 5.0V 4.5 4.0 0 500 1000 1500 2000 FREQUENCY (MHz) 2500 3000
02721-029
8
7 NF AT +85C 6 NF AT +25C 5 NF AT -40C 4 0 500 1000 1500 2000 2500 3000 FREQUENCY (MHz)
Figure 29. Noise Figure vs. Frequency, VS = 4.5 V, 5 V, and 5.5 V, TA = 25C
Figure 32. Noise Figure vs. Frequency, VS = 5 V, TA = -40C, +25C, and +85C
Rev. B | Page 11 of 16
02721-030
AD8353
30
15 20
25
10
19
PERCENTAGE (%)
20
POUT (dBm)
5
18
15
0
17
10
-5
16
5
-10
15
GAIN (dB) GAIN (dB)
02721-036 02721-035
0 6.10 6.15 6.20 6.25 6.30 6.35 6.40 6.45 6.50 6.55 6.60 6.65 6.70 NOISE FIGURE (dB)
02721-033
-15 -30
14 -25 -20 -15 -10 PIN (dBm) -5 0 5
Figure 33. Distribution of Noise Figure, VS = 5 V, TA = 25C, f = 2.2 GHz
50 45 40
SUPPLY CURRENT (mA)
Figure 35. Output Power and Gain vs. Input Power, VS = 3 V, TA = 25C, f = 900 MHz
15 20
IS AT 5.5V
10 19
IS AT 4.5V 35 30 25 20 15 10 5 0 -60 -40 -20 20 0 40 TEMPERATURE (C) 60 80 100
02721-034
POUT (dBm)
IS AT 5.0V
5
18
0
17
-5
16
-10
15
-15 -30
14 -25 -20 -15 -10 PIN (dBm) -5 0 5
Figure 34. Supply Current vs. Temperature, VS = 4.5 V, 5 V, and 5.5 V
Figure 36. Output Power and Gain vs. Input Power, VS = 5 V, TA = 25C, f = 900 MHz
Rev. B | Page 12 of 16
AD8353 THEORY OF OPERATION
The AD8353 is a 2-stage, feedback amplifier employing both shunt-series and shunt-shunt feedback. The first stage is degenerated and resistively loaded and provides approximately 10 dB of gain. The second stage is a PNP-NPN Darlington output stage, which provides another 10 dB of gain. Seriesshunt feedback from the emitter of the output transistor sets the input impedance to 50 over a broad frequency range. Shuntshunt feedback from the amplifier output to the input of the Darlington stage helps to set the output impedance to 50 . The amplifier can be operated from a 3 V supply by adding a choke inductor from the amplifier output to VPOS. Without this choke inductor, operation from a 5 V supply is also possible. It is critical to supply very low inductance ground connections to the ground pins (Pin 1, Pin 4, Pin 5, and Pin 8) as well as to the backside exposed paddle. This ensures stable operation. The AD8353 is designed to operate over a wide supply voltage range, from 2.7 V to 5.5 V. The output of the part, RFOUT, is taken directly from the collector of the output amplifier stage. This node is internally biased to approximately 2.2 V when the supply voltage is 5 V. Consequently, a dc blocking capacitor should be connected between the output pin, RFOUT, and the load that it drives. The value of this capacitor is not critical, but it should be 100 pF or larger. When the supply voltage is 3 V, it is recommended that an external RF choke be connected between the supply voltage and the output pin, RFOUT. This increases the dc voltage applied to the collector of the output amplifier stage, which improves performance of the AD8353 to be very similar to the performance produced when 5 V is used for the supply voltage. The inductance of the RF choke should be approximately 100 nH, and care should be taken to ensure that the lowest series self-resonant frequency of this choke is well above the maximum frequency of operation for the AD8353. For lower frequency operation, use a higher value inductor. Bypass the supply voltage input, VPOS, using a large value capacitance (approximately 0.47 F or larger) and a smaller, high frequency bypass capacitor (approximately 100 pF) physically located close to the VPOS pin. The recommended connections and components are shown in Figure 40.
BASIC CONNECTIONS
The AD8353 RF gain block is a fixed gain amplifier with single-ended input and output ports whose impedances are nominally equal to 50 over the frequency range 1 MHz to 2.7 GHz. Consequently, it can be directly inserted into a 50 system with no impedance matching circuitry required. The input and output impedances are sufficiently stable vs. variations in temperature and supply voltage that no impedance matching compensation is required. A complete set of scattering parameters is available at www.analog.com. The input pin (RFIN) is connected directly to the base of the first amplifier stage, which is internally biased to approximately 1 V; therefore, a dc blocking capacitor should be connected between the source that drives the AD8353 and the input pin, RFIN.
Rev. B | Page 13 of 16
AD8353 APPLICATIONS
The AD8353 RF gain block can be used as a general-purpose, fixed gain amplifier in a wide variety of applications, such as a driver for a transmitter power amplifier (see Figure 37). Its excellent reverse isolation also makes this amplifier suitable for use as a local oscillator buffer amplifier that would drive the local oscillator port of an upconverter or downconverter mixer (see Figure 38).
LOW FREQUENCY APPLICATIONS BELOW 100 MHz
The AD8353 RF gain block can be used below 100 MHz. To accomplish this, the series dc blocking capacitors, C1 and C2, need to be changed to a higher value that is appropriate for the desired frequency. C1 and C2 were changed to 0.1 F to accomplish the sweep in Figure 39.
21.0 dB-S21 20.5
AD8353
HIGH POWER AMPLIFIER
02721-037
20.0 19.5 19.0 18.5
Figure 37. AD8353 as a Driver Amplifier
MIXER
18.0 17.5
AD8353
04862-038
17.0 16.5 16.0 CH 1: START 300.000kHz STOP 100.000MHz
02721-042
LOCAL OSCILLATOR
Figure 38. AD8353 as a LO Driver Amplifier
Figure 39. Low Frequency Application from 300 kHz to 100 MHz at 5 V VPOS, -12 dBm Input Power
Rev. B | Page 14 of 16
AD8353 EVALUATION BOARD
Figure 40 shows the schematic of the AD8353 evaluation board. Note that L1 is shown as an optional component that is used to obtain maximum gain only when VP = 3 V. The board is powered by a single supply in the 2.7 V to 5.5 V range. The power supply is decoupled by a 0.47 F and a 100 pF capacitor.
AD8353
1
COM1
COM1 8 C2 1000pF OUTPUT
2
NC
RFOUT 7 L1
INPUT
C1 1000pF
3
RFIN
VPOS 6
04862-040
C3 100pF
4
C4 0.47F
02721-039
COM2
COM2 5
Figure 41. Silkscreen Top
NC = NO CONNECT
Figure 40. Evaluation Board Schematic
Table 5. Evaluation Board Configuration Options
Component C1, C2 C3 C4 L1 Function AC coupling capacitors. High frequency bypass capacitor. Low frequency bypass capacitor. Optional RF choke, used to increase current through output stage when VP = 3 V. Not recommended for use when VP = 5 V. Default Value 1000 pF, 0603 100 pF 0603 0.47 F, 0603 100 nH, 0603
04862-041
Figure 42. Component Side
Rev. B | Page 15 of 16
AD8353 OUTLINE DIMENSIONS
3.25 3.00 2.75 2.25 2.00 1.75 0.60 0.45 0.30 1.89 1.74 1.59
5 BOTTOM VIEW 8 * EXPOSED PAD 4 1
0.55 0.40 0.30
1.95 1.75 1.55
TOP VIEW
0.15 0.10 0.05 0.25 0.20 0.15
PIN 1 INDICATOR
2.95 2.75 2.55 12 MAX 0.80 MAX 0.65 TYP
0.50 BSC
1.00 0.85 0.80
0.05 MAX 0.02 NOM 0.30 0.23 0.18 0.20 REF
SEATING PLANE
Figure 43. 8-Lead Lead Frame Chip Scale Package [LFCSP_VD] 2 mm x 3 mm Body, Very Thin, Dual Lead CP-8-1 Dimensions shown in millimeters
ORDERING GUIDE
Model AD8353ACP-R2 AD8353ACP-REEL7 AD8353ACPZ-REEL7 1 AD8353-EVAL
1
Temperature Range -40C to +85C -40C to +85C -40C to +85C
Package Description 8-Lead LFCSP_VD 8-Lead LFCSP_VD, 7" Tape and Reel 8-Lead LFCSP_VD, 7" Tape and Reel Evaluation Board
Package Option CP-8-1 CP-8-1 CP-8-1
Branding JB JB 0E
Z = Pb-free part.
(c) 2005 Analog Devices, Inc. All rights reserved. Trademarks and registered trademarks are the property of their respective owners. C02721-0-12/05(B)
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Rev. B | Page 16 of 16

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