AD ADL5202ACPZ-R7

FEATURES
Dual independent, digitally controlled VGAs
−11.5 dB to +20 dB gain range
0.5 dB ± 0.1 dB step size
150 Ω differential input and output
7.5 dB noise figure at maximum gain
OIP3 > 50 dBm at 200 MHz
−3 dB upper frequency bandwidth of 700 MHz
Multiple control interface options
Parallel 6-bit control interface (with latch)
Serial peripheral interface (SPI) (with fast attack)
Gain up/down mode
Wide input dynamic range
Low power mode option
Power-down control
Single 5 V supply operation
40-lead, 6 mm × 6 mm LFCSP package
APPLICATIONS
Differential ADC drivers
High IF sampling receivers
High output power IF amplification
Instrumentation
FUNCTIONAL BLOCK DIAGRAM
SIDE A
SPI WITH FA,
PARALLEL WITH LATCH,
UP/DN
PWUPA
VPOS
LOGIC
VINA+
150Ω
0dB TO 31.5dB
VOUTA+
+20dB
150Ω
+20dB
150Ω
VOUTA–
VINA–
MODE0,
MODE1
CONTROL
CIRCUITRY
PM
VINB+
150Ω
0dB TO 31.5dB
VOUTB+
VOUTB–
VINB–
LOGIC
ADL5202
PWUPB
SIDE B
SPI WITH FA,
PARALLEL WITH LATCH,
UP/DN
GND
09387-001
Data Sheet
Wide Dynamic Range, High Speed,
Digitally Controlled VGA
ADL5202
Figure 1.
GENERAL DESCRIPTION
The ADL5202 is a digitally controlled, variable gain, wide bandwidth amplifier that provides precise gain control, high output
IP3, and low noise figure. The excellent distortion performance
and high signal bandwidth make the ADL5202 an excellent gain
control device for a variety of receiver applications. The
ADL5202 also incorporates a low power mode option that
lowers the supply current.
The ADL5202 is powered on by applying the appropriate logic
level to the PWUPx pins. The quiescent current of the ADL5202
is typically 160 mA in low power mode. When configured in high
performance mode for more demanding applications, the quiescent
current is 210 mA. When powered down, the ADL5202 consumes
less than 14 mA and offers excellent input-to-output isolation.
The gain setting is preserved during power-down.
For wide input dynamic range applications, the ADL5202
provides a broad 31.5 dB gain range with 0.5 dB resolution. The
gain is adjustable through multiple gain control interface options:
parallel, serial peripheral interface, and up/down.
Fabricated on an Analog Devices, Inc., high speed SiGe process,
the ADL5202 provides precise gain adjustment capabilities with
good distortion performance and low phase error. The ADL5202
amplifier comes in a compact, thermally enhanced 40-lead,
6 mm × 6 mm LFCSP package and operates over a temperature
range of −40°C to +85°C.
Incorporating proprietary distortion cancellation techniques,
the ADL5202 achieves a better than 50 dBm output IP3 at
frequencies approaching 200 MHz for most gain settings.
Rev. 0
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
©2011 Analog Devices, Inc. All rights reserved.
ADL5202
Data Sheet
TABLE OF CONTENTS
Features .............................................................................................. 1 Gain Up/Down Interface........................................................... 16 Applications....................................................................................... 1 Truth Table .................................................................................. 17 Functional Block Diagram .............................................................. 1 Logic Timing............................................................................... 17 General Description ......................................................................... 1 Circuit Description......................................................................... 18 Revision History ............................................................................... 2 Basic Structure ............................................................................ 18 Specifications..................................................................................... 3 Applications Information .............................................................. 19 Absolute Maximum Ratings............................................................ 5 Basic Connections...................................................................... 19 ESD Caution.................................................................................. 5 ADC Driving............................................................................... 19 Pin Configuration and Functional Descriptions.......................... 6 Layout Considerations............................................................... 21 Typical Performance Characteristics ............................................. 8 Evaluation Board ............................................................................ 22 Characterization and Test Circuits............................................... 15 Evaluation Board Control Software......................................... 22 Theory of Operation ...................................................................... 16 Evaluation Board Schematics and Artwork............................ 23 Digital Interface Overview ........................................................ 16 Evaluation Board Configuration Options............................... 27 Parallel Digital Interface ............................................................ 16 Outline Dimensions ....................................................................... 29 Serial Peripheral Interface (SPI) ............................................... 16 Ordering Guide .......................................................................... 29 REVISION HISTORY
10/11—Revision 0: Initial Version
Rev. 0 | Page 2 of 32
Data Sheet
ADL5202
SPECIFICATIONS
VS = 5 V, TA = 25°C, RS = RL = 150 Ω at 100 MHz, high performance mode, 2 V p-p differential output, unless otherwise noted.
Table 1.
Parameter
DYNAMIC PERFORMANCE
−3 dB Bandwidth
Slew Rate
Input Return Loss (S11)
Output Return Loss (S22)
INPUT STAGE
Maximum Input Swing (Differential)
Differential Input Resistance
Common-Mode Input Voltage
CMRR
GAIN
Maximum Voltage Gain
Minimum Voltage Gain
Gain Step Size
Gain Flatness
Gain Temperature Sensitivity
Gain Step Response
Gain Conformance Error
Phase Conformance Error
OUTPUT STAGE
Output Voltage Swing
Differential Output Resistance
NOISE/HARMONIC PERFORMANCE
46 MHz
Second Harmonic
Third Harmonic
Output IP3
70 MHz
Second Harmonic
Third Harmonic
Output IP3
140 MHz
Noise Figure
Second Harmonic
Third Harmonic
Output IP3
Output 1 dB Compression Point
300 MHz
Second Harmonic
Third Harmonic
Output IP3
Test Conditions/Comments
VOUT < 2 V p-p (5.2 dBm)
100 MHz
100 MHz
Min
Typ
Max
Unit
700
5.5
−17.7
−16.5
MHz
V/ns
dB
dB
10.8
150
1.5
40
V p-p
Ω
V
dB
20
−11.5
0.5
0.285
0.012
15
±0.03
1.0
dB
dB
dB
dB
dB/°C
ns
dB
Degrees
10
150
V p-p
Ω
−92
−105
50
dBc
dBc
dBm
−96
−105
50
dBc
dBc
dBm
7.5
−86
−105
50
19.5
dB
dBc
dBc
dBm
dBm
−77
−91
47
dBc
dBc
dBm
VINA+, VINB+ and VINA−, VINB− pins
Gain code = 111111
Gain code = 000000
Gain code = 000000
Gain code = 111111
30 MHz < fC < 200 MHz
Gain code = 000000
For VIN = 0.2 V, gain code = 111111 to 000000
Over 10 dB gain range
Over 10 dB gain range
VOUTx+ and VOUTx− pins
At P1dB, gain code = 000000
Differential
Gain code = 000000, high performance mode
VOUT = 2 V p-p
VOUT = 2 V p-p
VOUT = 2 V p-p composite
Gain code = 000000, high performance mode
VOUT = 2 V p-p
VOUT = 2 V p-p
VOUT = 2 V p-p composite
Gain code = 000000, high performance mode
VOUT = 2 V p-p
VOUT = 2 V p-p
VOUT = 2 V p-p composite
Gain code = 000000, high performance mode
VOUT = 2 V p-p
VOUT = 2 V p-p
VOUT = 2 V p-p composite
Rev. 0 | Page 3 of 32
ADL5202
Data Sheet
Parameter
POWER-UP INTERFACE
Power-Up Threshold
Test Conditions/Comments
PWUPA, PWUPB pins
Minimum voltage to enable the device
Maximum voltage to enable the device
PWUPx Input Bias Current
GAIN CONTROL INTERFACE
VIH
VIL
Maximum Input Bias Current
SPI TIMING
fSCLK
tDH
tDS
tPW
POWER INTERFACE
Supply Voltage
Quiescent Current, Both Channels
Min
Typ
Max
Unit
3.3
V
V
μA
1.4
1
Minimum/Maximum voltage for a logic high
Maximum voltage for a logic low
1.4
3.3
0.8
LATCHA and LATCHB, SCLK, SDIO, data pins
1/tSCLK
Data hold time
Data setup time
SCLK high pulse width
1
μA
20
5
5
5
MHz
ns
ns
ns
4.5
5.5
High performance mode
TA = 85°C
Low power mode
TA = 85°C
PWUPx low
Power-Down Current, Both Channels
V
210
250
160
180
14
V
mA
mA
mA
mA
mA
Timing Diagrams
tPW
tSCLK
SCLK
tDH
tDS
___ ___
CSA, CSB
DNC
DNC
DNC
DNC
DNC
DNC
R/W
FA1
FA0
D5
D4
D3
Figure 2. SPI Interface Read/Write Mode Timing Diagram
tDS
tDS
tPW
UPDN_DAT
UPDN_CLK
UP
DN
tDS
RESET
tDH
Figure 3. Up/Down Mode Timing Diagram
LATCHA,
LATCHB
A5 TO A0
B5 TO B0
tDH
Figure 4. Parallel Mode Timing Diagram
Rev. 0 | Page 4 of 32
09387-104
DNC
09387-103
SDIO
D2
D1
D0
09387-002
tDS tDH
Data Sheet
ADL5202
ABSOLUTE MAXIMUM RATINGS
Table 2.
Parameter
Supply Voltage, VPOS
PWUPA, PWUPB, A0 to A5, B0 to B5,
MODE0, MODE1, PM, LATCHA, LATCHB
Input Voltage, VIN+ ,VIN−
Internal Power Dissipation
θJA (Exposed Paddle Soldered Down)
θJC (At Exposed Paddle)
Maximum Junction Temperature
Operating Temperature Range
Storage Temperature Range
Lead Temperature (Soldering, 60 sec)
Rating
5.5
3.6 V
+3.6 V to −1.2 V
1.6 W
34.6°C/W
3.6°C/W
140°C
−40°C to +85°C
−65°C to +150°C
240°C
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
Rev. 0 | Page 5 of 32
ADL5202
Data Sheet
40
39
38
37
36
35
34
33
32
31
FA_A/A2
UPDN_CLK_A/A1
UPDN_DAT_A/A0
LATCHA
VINA–
VINA+
PWUPA
GND
VOUTA–
VOUTA+
PIN CONFIGURATION AND FUNCTION DESCRIPTIONS
PIN 1
INDICATOR
ADL5202
TOP VIEW
(Not to Scale)
EXPOSED
PADDLE
30
29
28
27
26
25
24
23
22
21
VOUTA–
VOUTA+
VPOS
VPOS
VPOS
VPOS
VPOS
VPOS
VOUTB+
VOUTB–
NOTES
1. NC = NO CONNECT.
2. THE EXPOSED PADDLE (EP) MUST BE CONNECTED TO
A LOW IMPEDANCE GROUND PAD.
09387-003
GS0/FA_B/B2
UPDN_CLK_B/B1
UPDN_DAT_B/B0
LATCHB
VINB–
VINB+
PWUPB
GND
VOUTB–
VOUTB+
11
12
13
14
15
16
17
18
19
20
CSA/A3 1
A4 2
A5 3
MODE1 4
MODE0 5
PM 6
GND 7
SIDO/B5 8
SCLK/B4 9
GS1/CSB/B3 10
Figure 5. Pin Configuration
Table 3. Pin Function Descriptions
Pin No.
1
Mnemonic
CSA/A3
2
3
4
5
6
A4
A5
MODE1
MODE0
PM
7, 18, 33, EP
8
GND
SDIO/B5
9
SCLK/B4
10
GS1/CSB/B3
11
GS0/FA_B/B2
12
UPDN_CLK_B/B1
13
UPDN_DAT_B/B0
14
LATCHB
Description
Channel A Select (CSA). When serial mode is enabled, a logic low (0 V ≤ CSA ≤ 0.8 V) selects Channel A.
Bit 3 for Channel A Parallel Gain Control Interface (A3).
Bit 4 for Channel A Parallel Gain Control Interface.
Bit 5 (MSB) for Channel A Parallel Gain Control Interface.
MSB for Mode Control. With the MODE0 pin, selects parallel, SPI, or up/down interface mode.
LSB for Mode Control. With the MODE1 pin, selects parallel, SPI, or up/down interface mode.
Performance Mode. A logic low (0 V ≤ PM ≤ 0.8 V) enables high performance mode. A logic high
(1.4 V ≤ PM ≤ 3.3 V) enables low power mode.
Ground. The exposed paddle (EP) must be connected to a low impedance ground pad.
Serial Data Input/Output (SDIO). When CSA or CSB is pulled low, SDIO is used for reading and writing
to the SPI port.
Bit 5 for Channel B Parallel Gain Control Interface (B5).
Serial Clock Input in SPI Mode (SCLK).
Bit 4 for Channel B Parallel Gain Control Interface (B4).
MSB for Gain Step Size Control in Up/Down Mode (GS1).
Channel B Select (CSB). When serial mode is enabled, a logic low (0 V ≤ CSB≤ 0.8 V) selects Channel B.
Bit 3 for Channel B Parallel Gain Control Interface (B3).
LSB for Gain Step Size Control in Up/Down Mode (GS0).
Fast Attack (FA_B). In serial mode, a logic high (1.4 V ≤ FA_B ≤ 3.3 V) attenuates Channel B according to
the FA setting in the SPI word.
Bit 2 for Channel B Parallel Gain Control Interface (B2).
Clock Interface for Channel B Up/Down Function (UPDN_CLK_B).
Bit 1 for Channel B Parallel Gain Control Interface (B1).
Data Pin for Channel B Up/Down Function (UPDN_DAT_B).
Bit 0 for Channel B Parallel Gain Control Interface (B0).
Channel B Latch. A logic low (0 V ≤ LATCHB ≤ 0.8 V) allows gain changes on Channel B. A logic high
(1.4 V ≤ LATCHB ≤ 3.3 V) prevents gain changes on Channel B.
Rev. 0 | Page 6 of 32
Data Sheet
ADL5202
Pin No.
15
16
17
19, 21
20, 22
23, 24, 25,
26, 27, 28
29, 31
30, 32
34
35
36
37
Mnemonic
VINB−
VINB+
PWUPB
VOUTB−
VOUTB+
VPOS
Description
Channel B Negative Input.
Channel B Positive Input.
Channel B Power-Up. A logic high (1.4 V ≤ PWUPB ≤ 3.3 V) enables Channel B.
Channel B Negative Output.
Channel B Positive Output.
Positive Power Supply.
VOUTA+
VOUTA−
PWUPA
VINA+
VINA−
LATCHA
38
UPDN_DAT_A/A0
39
UPDN_CLK_A/A1
40
FA_A/A2
Channel A Positive Output.
Channel A Negative Output.
Channel A Power-Up. A logic high (1.4 V ≤ PWUPA ≤ 3.3 V) enables Channel A.
Channel A Positive Input.
Channel A Negative Input.
Channel A Latch. A logic low (0 V ≤ LATCHA ≤ 0.8 V) allows gain changes on Channel A. A logic high
(1.4 V ≤ LATCHA ≤ 3.3 V) prevents gain changes on Channel A.
Data Pin for Channel A Up/Down Function (UPDN_DAT_A).
Bit 0 for Channel A Parallel Gain Control Interface (A0).
Clock Interface for Channel A Up/Down Function (UPDN_CLK_A).
Bit 1 for Channel A Parallel Gain Control Interface (A1).
Fast Attack (FA_A). In serial mode, a logic high (1.4 V ≤ FA_A ≤ 3.3 V) attenuates Channel A according to
FA setting in the SPI word.
Bit 2 for Channel A Parallel Gain Control Interface (A2).
Rev. 0 | Page 7 of 32
ADL5202
Data Sheet
TYPICAL PERFORMANCE CHARACTERISTICS
VS = 5 V, TA = 25°C, RS = RL = 150 Ω at 200 MHz, high performance mode, 2 V p-p differential output, unless otherwise noted.
25
25
46MHz
140MHz
300MHz
20
GAIN (dB)
6dB
5dB
8dB
7dB
5
0
5
0
–5
–5
–10
–10
–15
20
30
40
50
60
70
GAIN CODE
–20
10
2dB
1dB
0dB
–1dB
–2dB
–3dB
–4dB
–5dB
–6dB
–7dB
–8dB
–9dB
–10dB
–11dB
100
1000
FREQUENCY (MHz)
Figure 9. Gain vs. Frequency Response (Every 1 dB Step)
Figure 6. Gain vs. Gain Code at 46 MHz, 140 MHz, and 300 MHz
50
40
45
35
40
NOISE FIGURE (dB)
45
30
25
20
15
10
TA = –40°C
TA = +25°C
TA = +85°C
MIN GAIN (–11.5dB)
35
30
MID GAIN (5dB)
25
20
15
MAX GAIN (20dB)
10
5
5
–10
–5
0
5
10
15
20
25
PROGRAMMED GAIN (dB)
0
09387-010
0
–15
4dB
3dB
09387-007
10
Figure 7. Noise Figure vs. Programmed Gain at 140 MHz
20
OP1dB (dBm)
20
15
10
–10
–5
300
400
500
600
TA = –40°C
TA = +25°C
TA = +85°C
15
10
5
0
5
10
15
20
PROGRAMMED GAIN (dB)
Figure 8. OP1dB vs. Programmed Gain at 140 MHz
25
0
09387-005
0
–15
200
Figure 10. Noise Figure vs. Frequency at Max, Mid, and Min Gain Outputs
25
INPUT
MAX RATINGS
BOUNDARY
100
FREQUENCY (MHz)
25
5
0
09387-013
0
09387-004
–15
0
50
100
150
200
250
FREQUENCY (MHz)
300
350
400
09387-008
GAIN (dB)
10dB
9dB
12dB
11dB
10
10
NOISE FIGURE (dB)
14dB
13dB
15
15
OP1dB (dBm)
16dB
15dB
18dB
17dB
20dB
19dB
20
Figure 11. OP1dB vs. Frequency at Maximum Gain, Three Temperatures
Rev. 0 | Page 8 of 32
Data Sheet
60
ADL5202
60
–11.5dB
0dB
10dB
20dB
55
55
–11.5dB
0dB
10dB
20dB
50
OIP3 (dBm)
OIP3 (dBm)
50
45
45
40
INPUT
MAX RATINGS
BOUNDARY
35
40
30
35
50
100
150
200
250
300
350
400
FREQUENCY (MHz)
Figure 12. Output Third-Order Intercept vs. Frequency
at Four Gain Codes
60
20
–4
55
1
2
3
4
5
6
TA = –40°C
TA = +25°C
TA = +85°C
45
45
40
40
35
35
50
100
150
200
250
300
350
400
Figure 13. Output Third-Order Intercept vs. Frequency,
Three Temperatures at 2 V p-p Composite
–60
30
–4
–60
–80
–80
IMD3 (dBc)
–70
–90
–100
–110
–110
5
10
15
20
25
–120
09387-018
0
PROGRAMMED GAIN (dB)
0
1
2
3
4
5
6
TA = –40°C
TA = +25°C
TA = +85°C
–90
–100
–5
–1
Figure 16. Output Third-Order Intercept vs. Power, Frequency = 140 MHz,
Three Temperatures
46MHz
140MHz
300MHz
–10
–2
POUT (dBm)
–70
–120
–15
–3
0
50
100
150
200
250
300
350
FREQUENCY (MHz)
Figure 14. Two-Tone Output IMD3 vs. Programmed Gain,
at 46 MHz, 140 MHz, 300 MHz
Figure 17. Two-Tone Output IMD3 vs. Frequency,
Three Temperatures
Rev. 0 | Page 9 of 32
400
09387-021
0
09387-019
OIP3 (dBm)
50
09387-016
OIP3 (dBm)
0
60
FREQUENCY (MHz)
IMD3 (dBc)
–1
Figure 15. Output Third-Order Intercept vs. Power at Four Gain Codes,
Frequency = 140 MHz at 2 V p-p Composite
50
30
–2
POUT (dBm)
TA = –40°C
TA = +25°C
TA = +85°C
55
–3
09387-014
0
09387-011
30
25
ADL5202
–90
–60
–100
–70
–110
–80
–120
–90
–130
–100
–140
–110
0
50
100
150
200
250
–120
350
300
FREQUENCY (MHz)
–60
–90
–70
–100
–80
–110
–90
–120
–100
–130
–110
–140
–6
–5
–90
–70
–100
–80
–110
–90
–120
–100
–130
–110
–140
50
100
150
200
250
–120
350
300
09387-028
0
HARMONIC DISTORTION HD2 (dBc)
–60
–80
HARMONIC DISTORTION HD3 (dBc)
–50
–80
FREQUENCY (MHz)
3
4
5
6
–120
–60
–70
–90
–120
–100
–130
–110
–140
–6
–5
–4
–3
–2
–1
0
1
2
3
4
5
6
–120
POUT (dBm)
Figure 22. Harmonic Distortion vs. Power, Frequency = 140 MHz,
Three Temperatures
OP1dB (dBm)
20
15
10
INPUT
MAX
RATINGS
BOUNDARY
TA = –40°C
TA = +25°C
TA = +85°C
15
10
5
0
5
10
PROGRAMMED GAIN (dB)
15
20
25
0
09387-006
–5
2
–110
20
–10
1
–80
25
0
–15
0
–100
25
5
–1
TA = –40°C
TA = +25°C
TA = +85°C
–90
Figure 19. Harmonic Distortion vs. Frequency, Three Temperatures
OP1dB (dBm)
HARMONIC DISTORTION HD2 (dBc)
–70
–2
POUT (dBm)
–40
TA = –40°C
TA = +25°C
TA = +85°C
–3
Figure 21. Harmonic Distortion vs. Power at Four Gains,
Frequency = 140 MHz
Figure 18. Harmonic Distortion vs. Frequency at Four Gain Codes
–60
–4
Figure 20. OP1dB vs. Programmed Gain at 140 MHz, Low Power Mode
0
50
100
150
200
250
FREQUENCY (MHz)
300
350
400
09387-009
–150
–80
HARMONIC DISTORTION HD3 (dBc)
–50
–50
HARMONIC DISTORTION HD3 (dBc)
–80
–70
09387-031
–40
–40
–11.5dB
0dB
10dB
20dB
09387-026
–30
HARMONIC DISTORTION HD2 (dBc)
–70
–60
HARMONIC DISTORTION HD3 (dBc)
–60
HARMONIC DISTORTION HD2 (dBc)
–20
–11.5dB
0dB
10dB
20dB
09387-023
–50
Data Sheet
Figure 23. OP1dB vs. Frequency at Maximum Gain, Three Temperatures,
Low Power Mode
Rev. 0 | Page 10 of 32
Data Sheet
ADL5202
60
60
–11.5dB
0dB
10dB
20dB
55
55
–11.5dB
0dB
10dB
20dB
50
OIP3 (dBm)
45
40
45
40
35
INPUT
MAX RATINGS
BOUNDRY
30
35
0
50
100
150
200
250
300
350
400
FREQUENCY (MHz)
–2
–1
0
1
2
3
4
5
6
POUT (dBm)
60
TA = –40°C
TA = +25°C
TA = +85°C
55
–3
Figure 27. Output Third-Order Intercept vs. Power at Four Gain Codes,
Frequency = 140 MHz, Low Power Mode
Figure 24. Output Third-Order Intercept vs. Frequency
at Four Gain Codes, Low Power Mode at 2 V p-p Composite
60
20
–4
09387-012
30
25
09387-015
OIP3 (dBm)
50
55
TA = –40°C
TA = +25°C
TA = +85°C
50
OIP3 (dBm)
OIP3 (dBm)
50
45
40
45
40
35
30
35
100
150
200
250
300
350
400
FREQUENCY (MHz)
20
–4
–70
–60
46MHz
140MHz
300MHz
0
1
2
3
4
5
6
TA = –40°C
TA = +25°C
TA = +85°C
–70
IMD3 (dBc)
–80
–90
–90
–100
–100
–110
–110
–10
–5
0
5
10
15
20
PROGRAMMED GAIN (dB)
25
09387-022
IMD3 (dBc)
–1
Figure 28. Output Third-Order Intercept vs. Power,
Three Temperatures, Low Power Mode at 2 V p-p Composite
–80
–120
–15
–2
POUT (dBm)
Figure 25. Output Third-Order Intercept vs. Frequency,
Three Temperatures, Low Power Mode
–60
–3
09387-020
50
Figure 26. Two-Tone Output IMD3 vs. Programmed Gain
at 46 MHz, 140 MHz, 300 MHz; Low Power Mode
–120
0
50
100
150
200
250
300
350
FREQUENCY (MHz)
Figure 29. Two-Tone Output IMD3 vs. Frequency,
Three Temperatures, Low Power Mode
Rev. 0 | Page 11 of 32
400
09387-025
0
09387-017
30
25
ADL5202
–90
–60
–100
–70
–110
–80
–120
–90
–130
–100
–140
–110
–150
0
50
100
150
200
250
300
–120
350
FREQUENCY (MHz)
–80
–60
–90
–70
–100
–80
–110
–90
–120
–100
–130
–110
–140
–6
–70
–80
–50
–90
–60
–100
–70
–110
–80
–120
–90
–130
–100
–140
–110
0
50
100
150
200
250
300
–120
350
FREQUENCY (MHz)
0
1
2
3
4
5
6
–120
–50
–80
–60
–90
–70
–100
–80
–110
–90
–120
–100
–130
–6
–5
–4
–3
–2
–1
0
1
2
3
4
5
6
–110
POUT (dBm)
Figure 34. Harmonic Distortion vs. Power, Frequency = 140 MHz, Three
Temperatures, Low Power Mode
VOLTAGE
Figure 31. Harmonic Distortion vs. Frequency, Three Temperatures,
Low Power Mode
–1
1
CH1 200mV/DIV
CH4 1V/DIV
4
CH1 200mV Ω
CH4 1mV
Ω
M 10ns 10GS/s
IT 4ps/pt
A CH4
1.12V
TIME (10ns/DIV)
Figure 35. Disable Time Domain Response
Figure 32. Enable Time Domain Response
Rev. 0 | Page 12 of 32
09387-033
–150
HARMONIC DISTORTION HD2 (dBc)
–40
HARMONIC DISTORTION HD3 (dBc)
–70
–2
TA = –40°C
TA = +25°C
TA = +85°C
–30
09387-036
HARMONIC DISTORTION HD2 (dBc)
–20
TA = –40°C
TA = +25°C
TA = +85°C
–3
Figure 33. Harmonic Distortion vs. Power at Four Gain Codes,
Frequency = 140 MHz, Low Power Mode
09387-029
–50
–4
POUT (dBm)
Figure 30. Harmonic Distortion vs. Frequency at Four Gain Codes,
Low Power Mode
–60
–5
HARMONIC DISTORTION HD3 (dBc)
–50
–50
HARMONIC DISTORTION HD3 (dBc)
–80
–70
09387-032
–40
–40
–11.5dB
0dB
10dB
20dB
09387-027
–30
HARMONIC DISTORTION HD2 (dBc)
–70
–60
HARMONIC DISTORTION HD3 (dBc)
–60
HARMONIC DISTORTION HD2 (dBc)
–20
–11.5dB
0dB
10dB
20dB
09387-024
–50
Data Sheet
Data Sheet
ADL5202
CH2 500mV/DIV
0pf
VOLTAGE
TIME (10ns/DIV)
TIME (1ns/DIV)
100
–30
50
–40
0
–50
–50
–60
–100
–150
250
–20
200
–30
150
–40
100
–50
50
–60
0
–70
–50
–90
–200
1000
100
300
–80
–100
10
09387-035
–80
10
MAGNITUDE MAX GAIN
MAGNITUDE MIN GAIN
PHASE MAX GAIN
PHASE MIN GAIN
0
–10
FREQUENCY (MHz)
–100
MAGNITUDE MAX GAIN
MAGNITUDE MIN GAIN
PHASE MAX GAIN
PHASE MIN GAIN
–150
–200
1000
100
FREQUENCY (MHz)
Figure 37. S11 Magnitude and Phase vs. Frequency
09387-038
–20
S11 PHASE (Degrees)
150
S22 MAGNITUDE (dB)
200
S22 PHASE (Degrees)
Figure 39. Large Signal Pulse Response, 0 pF and 5.6 pF, 2 V p-p Composite
–10
Figure 40. S22 Magnitude and Phase vs. Frequency
1.0
–60
0.8
–65
0.4
0.2
0
–0.2
–0.4
–0.6
CHANNEL A TO CHANNEL B
CHANNEL A = MAX GAIN
CHANNEL B = ALL GAINS
–75
–80
–85
–90
CHANNEL B TO CHANNEL A
CHANNEL B = MAX GAIN
CHANNEL A = ALL GAINS
–95
–10
–5
0
5
10
15
20
PROGRAMMED GAIN (dB)
25
09387-037
–0.8
–1.0
–15
–70
Figure 38. Gain Step Error, Frequency = 140 MHz
–100
0
100
200
300
400
500
600
700
800
FREQUENCY (MHz)
Figure 41. Channel Isolation vs. Frequency
Rev. 0 | Page 13 of 32
900
1000
09387-043
CHANNEL ISOLATION (dB)
0.6
GAIN ERROR (dB)
S11 MAGNITUDE (dB)
0
09387-034
200mV/DIV
Figure 36. Gain Step Time Domain Response
–70
INPUT
09387-030
VOLTAGE
CH3 50mV/DIV
5.6pf DIFFERENTIAL
Data Sheet
0
0
–10
–10
REVERSE ISOLATION (dB)
–20
–30
–40
–50
–20
–30
–40
100M
1G
FREQUENCY (Hz)
–60
10
09387-039
–60
10M
Figure 42. Reverse Isolation vs. Frequency
MIN
MID
MAX
GROUP DELAY (ns)
0.8
0.6
0.4
100
1000
FREQUENCY (MHz)
09387-040
0.2
0
10
Figure 43. Group Delay vs. Frequency at Max, Mid, and Min Gain Outputs
4.0
3.0
350MHz
300MHz
250MHz
200MHz
150MHz
100MHz
50MHz
2.0
1.5
1.0
0.5
0
0
10
20
30
40
50
GAIN CODE
60
70
09387-041
PHASE VARIATION (Degrees)
3.5
2.5
1000
Figure 45. Disable-State Reverse Isolation vs. Frequency
COMMON-MODE REJECTION RATIO, CMRR (dB)
1.0
100
FREQUENCY (MHz)
09387-042
–50
Figure 44. Phase Variation vs. Gain Code
Rev. 0 | Page 14 of 32
60
50
40
30
20
10
0
10M
100M
FREQUENCY (Hz)
Figure 46. Common-Mode Rejection Ratio vs. Frequency
1G
09387-044
REVERSE ISOLATION (dB)
ADL5202
Data Sheet
ADL5202
CHARACTERIZATION AND TEST CIRCUITS
+5V
L1
1µH
L2
1µH
0.1µF
50Ω
AC
0.1µF
1/2
50Ω TRACES
50Ω
50Ω
AC
50Ω TRACES
ADL5202
0.1µF
50Ω
0.1µF
09387-060
6
A0 TO A5
Figure 47. Test Circuit for S-Parameters on Dedicated 50 Ω Differential-to-Differential Board
+5V
AC
ADL5202
C2
0.1µF
6
C3
0.1µF
R1
62Ω
R4
25Ω
ETC1-1-13
PAD LOSS = 11dB
C4
0.1µF
R2
62Ω
T2
R3
25Ω
A0 TO A5
Figure 48. Test Circuit for Distortion, Gain, and Noise
09387-063
50Ω
1/2
T1
L2
1µH
Figure 49. Differential-to-Differential Characterization Board,
Circuit Side Layout
Rev. 0 | Page 15 of 32
50Ω
09387-062
TC3-1T
L1
1µH
C1
0.1µF
ADL5202
Data Sheet
THEORY OF OPERATION
DIGITAL INTERFACE OVERVIEW
The ADL5202 VGA has three digital gain control options:
the parallel control interface, serial peripheral interface, and gain
up/down interface. The desired gain control option is selected
via two control pins, MODE0 and MODE1 (see Table 4 for the
truth table for the mode control pins). The gain code is in a 6-bit
binary format. A voltage of between 1.4 V and 3.3 V is required
for a logic high.
Three pins are common to all gain control options: PM, PWUPA,
and PWUPB. PM allows the user to choose operation in nominal
mode or high performance mode. PWUPA and PWUPB are
power-up pins for Channel A and Channel B, respectively.
Physical pins are shared among the three interfaces, resulting in
as many as three different functions per digital pin (see Table 3).
Table 4. Digital Control Interface Selection Truth Table
MODE0
0
1
0
1
Interface
Parallel control
Serial peripheral (SPI)
Up/down
Up/down
The parallel digital interface uses six binary bits (Bits[A5:A0] or
Bits[B5:B0]) and a latch pin (LATCHA or LATCHB) per amplifier.
The latch pin controls whether the input data latch is transparent
or latched. In transparent mode, gain changes as input gain control
bits change. In latched mode, gain is determined by the latched
gain setting and does not change with changing input gain
control bits.
SERIAL PERIPHERAL INTERFACE (SPI)
The SPI uses three pins (SDIO, SCLK, and CSA or CSB). The
SPI data register consists of two bytes: six gain control bits, two
attenuation step size address bits, one read/write bit, and seven
don’t care bits. SDIO is the serial data input and output pin. The
SCLK pin is the serial clock, and CSA or CSB is the channel
select pin.
LSB
D0
MSB LSB MSB
D1
D2
D3
D4
D5
FA0 FA1 R/W DNC DNC DNC DNC DNC DNC DNC
DO NOT CARE
(7 BITS)
09387-046
GAIN CONTROL
Table 5. SPI 2-Bit Attenuation Step Size Truth Table
FA1
0
0
1
1
FA0
0
1
0
1
Step Size (dB)
2
4
8
16
GAIN UP/DOWN INTERFACE
The GS1 and GS0 pins control the up/down gain step function.
Gain is increased by a clock pulse on the UPDN_CLK_A pin or
the UPDN_CLK_B pin (rising and falling edges) when the
UPDN_DAT_A or UPDN_DAT_B pin is high. Gain is decreased
by a clock pulse on the UPDN_CLK_A or UPDN_CLK B pin
when the UPDN_DAT_A or UPDN_CLKB pin is low. The truth
table for the gain step function is shown in Table 6. Reset is
detected by a rising edge latching data having one polarity, with
the falling edge latching the opposite polarity. Reset results in
a minimum binary gain code of 111111.
Table 6. Step Size Control Truth Table
GS1
0
0
1
1
GS0
0
1
0
1
Step Size (dB)
0.5
1
2
4
The step size is selectable using the GS1 and GS0 pins. The gain
is limited by the top and bottom of the control range.
READ/WRITE
FAST ATTACK ATTENUATION
STEP SIZE ADDRESS
The fast attack feature, accessible via the SPI, allows the gain to be
reduced from its present gain setting by a predetermined step size.
Four different attenuation step sizes are available. The truth table
for fast attack is shown in Table 5.
SPI fast attack mode is controlled by the FA_A or FA_B pin.
A logic high on the FA_A or FA_B pin results in an attenuation
that is selected by Bits[FA1:FA0] in the SPI register.
PARALLEL DIGITAL INTERFACE
DATA
Fast Attack
Figure 50. 16-Bit SPI Register
UPDN_DAT
UPDN_CLK
To write to the SPI register, CSA or CSB must be pulled low and
16 clock pulses must be applied to SCLK. Individual channel
SPI registers can be selected by pulling CSA or CSB low. By
pulling the CSA and CSB pins low simultaneously, the same
data can be written to both SPI registers.
Rev. 0 | Page 16 of 32
UP
DN
Figure 51. Up/Down Timing
RESET
09387-045
MODE1
0
0
1
1
To read the SPI register value, the R/W bit must be set high,
CSA or CSB must be pulled low, and the part must be clocked.
After the register has been read out during the next 16 clock cycles,
the SPI is automatically put into write mode. Note that there is
only one SDIO pin. Readback from the registers should be performed individually.
Data Sheet
ADL5202
TRUTH TABLE
LOGIC TIMING
Table 7. Gain Code vs. Voltage Gain Lookup Table
To write to the ADL5202, refer to the timing shown in Figure 2
(reproduced in this section as Figure 52). The write mode uses
a 16-bit serial word on the SDIO pin. The R/W of the word must be
low to write Bits[D0:D5], which are the binary weighted codes for
the attenuation level (0 = minimum attenuation, 63 = maximum
attenuation). The FA0 and FA1 bits control the fast attack step size.
The DNC bits are nonfunctional, do not care bits. Reading the
ADL5202 SPI register requires the following two steps:
6-Bit Binary
Gain Code
000000
000001
000010
000011
000100
000101
000110
000111
001000
001001
001010
001011
001100
001101
001110
001111
010000
010001
010010
010011
010100
010101
010110
010111
011000
011001
011010
011011
011100
011101
011110
011111
Voltage
Gain (dB)
20
19.5
19
18.5
18
17.5
17
16.5
16
15.5
15
14.5
14
13.5
13
12.5
12
11.5
11
10.5
10
9.5
9
8.5
8
7.5
7
6.5
6
5.5
5
4.5
6-Bit Binary
Gain Code
100000
100001
100010
100011
100100
100101
100110
100111
101000
101001
101010
101011
101100
101101
101110
101111
110000
110001
110010
110011
110100
110101
110110
110111
111000
111001
111010
111011
111100
111101
111110
111111
Voltage
Gain (dB)
4
3.5
3
2.5
2
1.5
1
0.5
0
−0.5
−1
−1.5
−2
−2.5
−3
−3.5
−4
−4.5
−5
−5.5
−6
−6.5
−7
−7.5
−8
−8.5
−9
−9.5
−10
−10.5
−11
−11.5
1.
2.
Set the R/W bit high using a 16-bit word and the timing
described in this section and Figure 52. All other bits are
ignored when the R/W bit is high.
The SDIO is used as an output during the next sequence.
The written pattern is serially clocked out on SDIO using
16 clocks and the timing described in this section and
Figure 52. The R/W bit automatically returns low to the
write state following the read sequence.
tPW
tSCLK
SCLK
tDH
tDS
___ ___
CSA, CSB
SDIO
DNC
DNC
DNC
DNC
DNC
DNC
DNC
R/W
FA1
FA0
D5
Figure 52. SPI Interface Read/Write Mode Timing Diagram
Rev. 0 | Page 17 of 32
D4
D3
D2
D1
D0
09387-152
tDS tDH
ADL5202
Data Sheet
CIRCUIT DESCRIPTION
BASIC STRUCTURE
The ADL5202 is a dual, differential, variable gain amplifier,
with each amplifier consisting of a 150 Ω digitally controlled,
passive attenuator that is followed by a highly linear
transconductance amplifier with feedback.
1/2 OF
ADL5202
gm
AMP
ATTENUATOR
VIN–
VOUT+
VOUT–
LOGIC
REF
DIGITAL INPUTS
PARALLEL, SPI,
FAST ATTACK
UP/DOWN
09387-047
VIN+
Figure 53. Simplified Schematic
Input System
The dc voltage level at the inputs of each amplifier is set by two
independent internal voltage reference circuits to approximately
1.6 V. The references are not accessible and cannot be adjusted.
Each amplifier can be powered down by pulling the corresponding power-up pin down to ground (logic low). When powered
down, the total current of each amplifier reduces to 7 mA
(typical). The dc level at the inputs remains at approximately
1.6 V, regardless of the state of the PWUPA or PWUPB pin.
Output Amplifier
The gain of the output amplifier is set to 22 dB when driving
a 150 Ω load. The input and output resistance of this amplifier
is set to 150 Ω in matched condition. If the load or the source
resistance is different from 150 Ω, the following equations can
be used to determine the resulting gain and input/output
resistances.
Voltage Gain = AV = 0.09 × (2000)//RL
RIN = (2000 + RL)/(1 + 0.09 × RL)
S21 (Gain) = 2 × RIN/(RIN + RS) × AV
ROUT = (2000 + RS)/(1 + 0.09 × RS)
Note that at the maximum attenuation setting, RS, as seen by
the output amplifier, is the output resistance of the attenuator,
which is 150 Ω. However, at minimum attenuation, RS is the
source resistance that is connected to the input of the part.
The dc current to the outputs of each amplifier is supplied through
two external chokes. The inductance of the chokes and the
resistance of the load, in parallel with the output resistance of
the device, add a low frequency pole to the response. The parasitic capacitance of the chokes adds to the output capacitance of the
part. This total capacitance, in parallel with the load and output
resistance, sets the high frequency pole of the device. Generally,
the larger the inductance of the choke, the higher its parasitic
capacitance. Therefore, this trade-off must be considered when
the value and type of the choke are selected. For an operation
frequency of 15 MHz to 700 MHz driving a 150 Ω load, 1 μH
chokes with a self resonant frequency (SRF) of 160 MHz or
higher are recommended (such as the 0805LS-102XJBB from
Coilcraft). If higher value chokes are used, a 4 MHz zero, due to
the internal ac-coupled feedback, causes an increase in S21 of up
to 6 dB at frequencies below 4 MHz. The supply current of each
amplifier consists of about 35 mA through the VPOS pin and 50
mA through the two chokes combined. The latter increases with
temperature at approximately 2.5 mA per 10°C. The total choke
current increases to 75 mA for high performance mode. Each
amplifier has two output pins for each polarity, and they are
oriented in an alternating fashion. When designing the board,
care should be taken to minimize the parasitic capacitance due to
the routing that connects the corresponding outputs together.
To minimize the parasitic capacitance, a good practice is to
avoid any ground or power plane under this routing region and
under the chokes.
Gain Control
The gain of each amplifier can be adjusted using the parallel control
interface, the serial peripheral interface, or the gain up/down
interface. In general, the gain step size is 0.5 dB, but larger sizes
can be programmed using the various interfaces, as described in
the Digital Interface Overview section. Each amplifier has a
maximum gain of +20 dB (Code 0) to −11.5 dB (Code 63).
The noise figure of each amplifier is approximately 7.5 dB at
maximum gain setting, and it increases as the gain is reduced.
The increase in noise figure is equal to the reduction in gain.
The linearity of the part measured at the output is first-order
independent of the gain setting. From −4 dB to +20 dB gain,
OIP3 is approximately 50 dBm into 150 Ω load at 200 MHz
(0 dBm per tone). At gain settings below −4 dB, OIP3 drops to
approximately 40 dBm.
Rev. 0 | Page 18 of 32
Data Sheet
ADL5202
APPLICATIONS INFORMATION
To enable each channel of the ADL5202, the PWUPA or PWUPB
pin must be pulled high (1.4 V≤ PWUPA/PWUPB ≤ 3.3 V).
Taking PWUPA or PWUPB low puts the channels of the ADL5202
in sleep mode, reducing current consumption to approximately
7 mA per channel at ambient.
BASIC CONNECTIONS
Figure 54 shows the basic connections for operating the ADL5202.
A voltage between 4.5 V and 5.5 V should be applied to the VPOS
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.
ADC DRIVING
The outputs of the ADL5202 must be pulled up to the positive
supply with 1 μH RF chokes. The differential outputs are biased
to the positive supply and require ac coupling capacitors, preferably 0.1 μF. Similarly, the input pins are at bias voltages of
about 1.6 V above ground and should be ac-coupled as well.
The ac coupling capacitors and the RF chokes are the principle
limitations for operation at low frequencies.
The ADL5202 is a highly linear, variable gain amplifier that
is optimized for ADC interfacing. The output IMDs and noise
floor remain constant throughout the 31.5 dB gain range.
This is a valuable feature in a variable gain receiver where it is
desirable to maintain a constant instantaneous dynamic range
as the receiver range is modified. The output noise is 18 nV/√Hz,
which is compatible with 14- or 16-bit ADCs. The two-tone
IMDs are usually greater than −100 dB for −1 dBm into 150 Ω
or 2 V p-p output. The 150 Ω output impedance makes the task
of designing a filter for the high input impedance ADCs more
straightforward.
The digital pins (mode control pins, associated SPI and parallel
gain control pins, PM, PWUPA, and PWUPB) operate on a voltage
of 3.3 V.
BALANCED
SOURCE
RS
RS
AC
2
2
CHANNEL A
GAIN CONTROL INTERFACE
0.1µF
0.1µF
10
31
VOUTA+
32
VOUTA–
33
GND
35
34
PWUPA
VINA–
VINA+
36
37
39
38
UPDN_DAT_A/A0
LATCHA
VPOS
EXPOSED
PADDLE
VPOS
PM
GND
VPOS
SIDO/B5
VPOS
SCLK/B4
GS1/CSB/
B3
VOUTB+
VOUTB–
VOUTB+
9
ADL5202
VOUTB–
8
MODE0
GND
7
VPOS
PWUPB
6
MODE1
VINB+
3.3V
VPOS
VINB–
5
VOUTA+
LATCHB
4
VOUTA–
A5
UPDN_DAT_B/B0
3
GAIN MODE
INTERFACE
A4
UPDN_CLK_A/A1
2
CSA/A3
GS0/
FA_B/B2
UPDN_CLK_B/B1
1
FA_A/A2
40
3.3V
0.1µF
30
RL
29
0.1µF
28
27
26
25
0.1µF 1µH
22
21
1µH
0.1µF
0.1µF
0.1µF
VPOS
VPOS
24
23
BALANCED
LOAD
0.1µF
0.1µF
0.1µF
0.1µF
RL
BALANCED
LOAD
20
19
18
17
3.3V
CHANNEL B
GAIN CONTROL INTERFACE
0.1µF
1µH
0.1µF
VPOS
0.1µF
RS
RS
AC
2
2
BALANCED
SOURCE
Figure 54. Basic Connections
Rev. 0 | Page 19 of 32
09387-048
15
16
14
13
12
11
0.1µF
1µH
ADL5202
Data Sheet
5V
VREF
5V
1.0µH
0.1µF
1:3
0.1µF
75Ω
1/2
50Ω
56nH
ADL5202
75Ω
AC
0.1µF
33Ω
VREF
33Ω
4pF
AD9268
56nH
0.1µF
1.0µH
09387-049
DIGITAL
INTERFACE
5V
Figure 55. Wideband ADC Interfacing Example Featuring One-Half of the ADL5202 and the AD9268
0
–15
–30
–45
–60
–75
3
–90
+
4
5
2
6
–105
–1
–120
–2
–3
–150
–5
–6
0
6
12
18
24
30
36
42
48
54
60
FREQUENCY (MHz)
–7
09387-051
–135
–4
Figure 57. Measured Single-Tone Performance of the
Circuit in Figure 55 for a 100 MHz Input Signal
–8
–9
–10
–11
–12
–14
–15
20
40
60
80
100
120
140
160
180
FREQUENCY (MHz)
200
Figure 56. Measured Frequency Response of Wideband
ADC Interface, as Depicted in Figure 55
Figure 55 uses a 1:3 impedance transformer to provide the 150 Ω
input impedance of the ADL5202 with a matched input. The
outputs of the ADL5202 are biased through the two 1 μH
inductors, and the two 0.1 μf capacitors on the outputs decouple
the 5 V inductor voltage from the input common-mode voltage of
the AD9268. The two 75 Ω resistors provide the 150 Ω load to the
ADL5202 whose gain is load dependent. The 56 nH inductors
and 4 pF capacitor constitute the (100 MHz – 1 dB) low-pass
filter. The two 33 Ω isolation resistors suppress any switching
currents from the ADC input sample-and-hold circuitry. The
circuit depicted in Figure 55 provides variable gain, isolation,
filtering, and source matching for the AD9268. Using this circuit
with the ADL5202 in a gain of 20 dB (maximum gain), an SNR
of 69 dB, and an SFDR performance of >86 dBc is achieved at
100 MHz, as shown in Figure 57.
–30
AMPLITUDE (dBFS)
0
09387-050
–15
FUNDAMENTAL1 = –7.127dBFS
FUNDAMENTAL2 = –7.039dBFS
2F1 – F2 = –91.818dBc
2F2 – F1 = –87.083dBc
NOISE FLOOR = –109.57dB
0
–13
Rev. 0 | Page 20 of 32
–45
–60
–75
–90
+
2F2 – F1
F2 – F1
2F1 – F2
F1 + F2
2F1 + F2 2F2 + F1
–105
–120
–135
–150
0
6
12
18
24
30
36
42
48
54
FREQUENCY (MHz)
Figure 58. Measured Two-Tone Performance of the
Circuit in Figure 55 for a 100 MHz Input Signal
60
09387-052
INSERTION LOSS (dB)
SNR = 69dB
SFDR = 86dBc
NOISE FLOOR = –108dB
FUND = –1.035dBFS
SECOND = –89.17dBc
0
AMPLITUDE (dBFS)
Figure 55 shows one-half of the ADL5202 driving a two-pole,
100 MHz low-pass filter into the AD9268. The AD9268 is
a 16-bit, 125 MSPS analog-to-digital converter with a buffered
wideband input, which presents a 6 kΩ differential input impedance and requires between a 1 V or 2 V input swing to reach
full scale. This example uses the 2 V p-p input. For optimum
performance, the ADL5202 should be driven differentially,
using an impedance transformer or input balun.
Data Sheet
ADL5202
In addition, the L6 inductor shorts the ADC inputs at dc, which
introduces a zero into the transfer function. The ac coupling
capacitors and the bias chokes introduce additional zeros into the
transfer function. The final overall frequency response takes on
a band-pass characteristic, helping to reject noise outside of the
intended Nyquist zone. Table 8 provides initial suggestions for
prototyping purposes. Some empirical optimization may be
needed to help compensate for actual PCB parasitics.
An alternative narrow-band approach is presented in Figure 59.
By designing a narrow band-pass antialiasing filter between the
ADL5202 and the target ADC, the output noise of the ADL5202
outside of the intended Nyquist zone can be attenuated, helping
to preserve the available SNR of the ADC. In general, the SNR
improves by several decibels (dB) when including a reasonable
order antialiasing filter. In this example, a low loss 1:3 input
transformer is used to match the 150 Ω balanced input of the
ADL5202 to a 50 Ω unbalanced source, resulting in minimum
insertion loss at the input.
LAYOUT CONSIDERATIONS
Each amplifier has two output pins for each polarity, and they
are oriented in an alternating fashion. When designing the board,
care should be taken to minimize the parasitic capacitance due
to the routing that connects the corresponding outputs together.
A good practice is to avoid any ground or power plane under
this routing region and under the chokes to minimize the
parasitic capacitance.
Figure 59 is optimized for driving some of the Analog Devices
popular unbuffered ADCs, such as the AD9246, AD9640,
and AD6655. Table 8 includes antialiasing filter component
recommendations for popular IF sampling center frequencies.
Inductor L5 works in parallel with the on-chip ADC input
capacitance and a portion of the capacitance presented by C4 to
form a resonant tank circuit. The resonant tank helps to ensure
that the ADC input acts like a real resistance at the target center
frequency.
5V
5V
1:3
1µH
1nF
1nF
L1
1/2
50Ω
ADL5202
AC
1nF
1nF
L1
L3
L5
C2
4pF
C4
4pF
L3
L5
75Ω
75Ω
CML
AD9246
AD9640
AD6655
L6
1µH
09387-053
DIGITAL
INTERFACE
5V
Figure 59. Narrow-Band IF Sampling Solution for Unbuffered ADC Applications
Table 8. Interface Filter Recommendations for Various IF Sampling Frequencies
Center Frequency
96 MHz
140 MHz
170 MHz
211 MHz
1 dB Bandwidth
27 MHz
31 MHz
25 MHz
40 MHz
L1
68 nH
47 nH
39 nH
30 nH
C2
15 pF
11 pF
10 pF
7 pF
Rev. 0 | Page 21 of 32
L3
220 nH
150 nH
120 nH
100 nH
C4
15 pF
11 pF
10 pF
7.5 pF
L5
68 nH
47 nH
47 nH
30 nH
L6
150 nH
82 nH
51 nH
43 nH
ADL5202
Data Sheet
EVALUATION BOARD
EVALUATION BOARD CONTROL SOFTWARE
The ADL5202 evaluation board is configured with a USBfriendly interface to program the gain of the ADL5202. The
software graphic user interface (see Figure 60) lets users select
a particular gain mode and gain level to write to the device and
also to read back data from the SDIO pin, showing the currently
programmed gain setting. The software setup files can be
downloaded from the ADL5202 product page at
www.analog.com.
09387-054
The ADL5202 evaluation board is available with software to
program the variable gain control. It is a 4-layer board with a split
ground plane for analog and digital sections. Special care is
taken to place the power decoupling capacitors close to the
device pins. The board is designed for easy single-ended
(through a Mini-Circuits TC3-1T+ RF transformer) or
differential configuration for each channel.
Figure 60. Evaluation Control Software
Rev. 0 | Page 22 of 32
Data Sheet
ADL5202
EVALUATION BOARD SCHEMATICS AND ARTWORK
09387-055
Figure 61. Evaluation Board Schematic
Rev. 0 | Page 23 of 32
ADL5202
Data Sheet
09387-056
Figure 62. RF Output Detail
Rev. 0 | Page 24 of 32
Data Sheet
ADL5202
09387-057
Figure 63. Schematic for the USB Section of the Evaluation Board
Rev. 0 | Page 25 of 32
Data Sheet
09387-058
ADL5202
09387-059
Figure 64. Evaluation Board Top Layer
Figure 65. Evaluation Board Bottom Layer
Rev. 0 | Page 26 of 32
Data Sheet
ADL5202
EVALUATION BOARD CONFIGURATION OPTIONS
Configuration Options for the Main Section
Table 9. Bill of Materials for Main Section
Components
C24 to C27, C51
VPOS, 3V3
GND
DUT1
INA+, INA−
INB+, INB−
T1, T2, C18 to C23,
R8, R9, R20 to R29,
R88, R89
OUTA+, OUTA−
OUTB+, INB−
T3, T4, C36 to C45,
R63 to R82, L1 to L4
VXA, VXB
P1, P2, PWUPA, PWUPB,
R30
A0 to A5, B0 to B5,
LATCHA, LATCHB, PM,
MODE0, MODE1
R10 to R19, R31 to R62,
R84 to R87,
C28 to C35, C47 to C50
Function
Power supply decoupling. Nominal supply decoupling consists of a 0.1 μF
capacitor to ground.
Power supply connections.
Evaluation device.
Input interfaces. The INA+ and INA− input SMA connectors are used to
drive the Channel A balun in a single-ended fashion. The INB+ and INB−
input SMAs are used to drive the Channel B balun in a single-ended fashion.
The default configuration of the evaluation board is for single-ended
operation.
T1 and T2 are 3:1 impedance ratio RF transformers that are used to transform
a 50 Ω, single-ended input into a 150 Ω balanced differential signal.
C18 and C19 are balun decoupling capacitors. C20 to C23 are used for
dc blocking purposes.
R20 to R29 are provided for generic placement of matching components.
R88 and R89 are populated to ground on one side of the transformer
primary, creating the 50 Ω single-ended input.
Output interfaces. The OUTA+ and OUTA− output SMA connectors are used to
load the Channel A balun in a single-ended fashion. The default configuration
of the evaluation board is for single-ended operation. The OUTB+ and
OUTB− output SMAs are used to load the Channel B balun in a singleended fashion. The default configuration of the evaluation board is for
single-ended operation.
T3 and T4 are 3:1 impedance ratio transformers used to transform a 50 Ω,
single-ended output into a 150 Ω balanced differential load.
C40 to C43 are used for ac coupling. C44 and C45 are balun decoupling
capacitors.
R69 to R76 are provided for generic placement of matching components.
By removing R79 and R80 and installing 0 Ω at R81 and R82, the output is
converted to a differential output. L1 to L4 provide dc bias to the output
stages. R67 and R68 provide a connection to the 5 V power plane.
Optionally, R67 and R68 can be removed and the output stage biased
through the VXA and VXB terminals.
Power-up interface. The ADL5202 is powered up by applying a logic high
(1.4 V ≤ PWUPA/PWUPB ≤ 3.3 V) to PWUPA and PWUPB from an external
source or by installing a shunt between Pin1 and Pin 2 of P1 andP2.
Gain control interface. All of the gain control functions are fully controlled
via the USB microcontroller by using the supplied software. Three-pin
headers allow for manual operation of the gain control, if desired.
The R31 to R34, R45, R46, R53, R54, and R84 to R87 resistors and the C28 to
C35 and C47 to C50 capacitors allow for the generic placement of filter
components.
The R10 to R19, R31 to R62, and R84 to R87 resistors isolate the gain control
pins from the microcontroller and provide current limiting.
Rev. 0 | Page 27 of 32
Default Conditions
C24 to C27, C51 = 0.1 μF (Size 0603)
VPOS, 3V3 (test loop red) installed
GND (test loop black) installed
Installed
INA+ (SMA connector) installed
INA− (SMA connector) installed
INB+ (SMA connector) installed
INB− (SMA connector) installed
T1, T2 = TC3-1T+ (Mini-Circuits)
C18 to C23 = 0.1 μF (Size 0603)
R8, R9, R26 to R29 = 0 Ω (Size 0402)
R20 to R25, R88, R89 = open
OUTA+ (SMA connector) installed
OUTA− (SMA connector) installed
OUTB+ (SMA connector) installed
OUTB− (SMA connector) installed
T3, T4 = TC3-1T+ (mini-circuits)
C36 to C45 = 0.1 μF (Size 0603)
R63 to R72, R77 to R80 = 0 Ω
(Size 0402)
R73 to R76, R81, R82 = open
L1, L2, L3, L4 = 1 μH (Size 0805)
VXA, VXB (test loop) installed
P1 installed for enable
P2 installed for enable
PWUPA (SMA connector) installed
PWUPB (SMA connector) installed
R30 = open
A0 to A5 (3-pin header) installed
B0 to B5 (3-pin header) installed
LATCHA (3-pin header) installed
LATCHB (3-pin header) installed
MODE0 (3-pin header) installed
MODE1 (3-pin header) installed
PM (3-pin header) installed
R10 to R19 = 1 kΩ (Size 0603)
R35 to R44 = 1 kΩ (Size 0603)
R47 to R52 1 kΩ (Size 0603)
R55 to R62 1 kΩ (Size 0603)
R31 to R34 = open
R45, R46 = open
R53, R54 = open
R84 to R87 = open
C28 to C35 = open
C47 to C50 = open
ADL5202
Data Sheet
Configuration Options for the USB Section
Table 10. Bill of Materials for USB Section
Components
C7, C8
C13
C2, C3, C4, C6, C10, C11, C12, C14, C16, C46
C9, C15
C1, C5
CR1
P3
R1, R2, R5
R6,
R7
R3, R4
R83
U2
U1
U3
Y1
Default Conditions
22 pF (Size 0603)
1000 pF (Size 0603)
0.1 μF (Size 0402)
1 μF (Size 0402)
10 pF (Size 0402)
Green LED ( Panasonic LNJ308G8TRA)
USB SMT connector (Hirose Electric UX60A-MB-5ST 240-0003-4)
2 kΩ (Size 0603)
78.7 kΩ (Size 0603)
140 kΩ (Size 0603)
100 kΩ (Size 0603)
0 Ω (Size 0603)
USB microcontroller (Cypress CY7C68013A-56LFXC)
64 kB EEPROM (Microchip 24LC64-I/SN)
Low dropout regulator (Analog Devices ADP3334ACPZ)
24 MHz crystal oscillator (AEL Crystals X24M000000S244)
Rev. 0 | Page 28 of 32
Data Sheet
ADL5202
OUTLINE DIMENSIONS
0.30
0.23
0.18
31
40
30
0.50
BSC
1
TOP VIEW
0.80
0.75
0.70
10
11
20
0.05 MAX
0.02 NOM
COPLANARITY
0.08
0.20 REF
SEATING
PLANE
4.45
4.30 SQ
4.25
EXPOSED
PAD
21
0.45
0.40
0.35
PIN 1
INDICATOR
BOTTOM VIEW
0.25 MIN
FOR PROPER CONNECTION OF
THE EXPOSED PAD, REFER TO
THE PIN CONFIGURATION AND
FUNCTION DESCRIPTIONS
SECTION OF THIS DATA SHEET.
COMPLIANT TO JEDEC STANDARDS MO-220-WJJD.
05-06-2011-A
PIN 1
INDICATOR
6.10
6.00 SQ
5.90
Figure 66. 40-Lead Lead Frame Chip Scale Package [LFCSP_WQ]
6 mm × 6 mm Body, Very Very Thin Quad
(CP-40-10)
Dimensions shown in millimeters
ORDERING GUIDE
Model 1
ADL5202ACPZ-R7
ADL5202-EVALZ
1
Temperature Range
−40°C to +85°C
Package Description
40 Lead LFCSP_WQ, 7” Tape and Reel
Evaluation Board
Z = RoHS Compliant Part.
Rev. 0 | Page 29 of 32
Package Option
CP-40-10
ADL5202
Data Sheet
NOTES
Rev. 0 | Page 30 of 32
Data Sheet
ADL5202
NOTES
Rev. 0 | Page 31 of 32
ADL5202
Data Sheet
NOTES
©2011 Analog Devices, Inc. All rights reserved. Trademarks and
registered trademarks are the property of their respective owners.
D09387-0-10/11(0)
Rev. 0 | Page 32 of 32