MAXIM MAX2721EVKIT

19-1715; Rev 0; 4/00
MAX2720/MAX2721 Evaluation Kits
Features
♦ Easy MAX2720/MAX2721 Evaluation
♦ All Critical Peripheral Components Included
♦ SMA Input and Output Signal Connectors
♦ RF Ports Matched to 1900MHz (MAX2720)
♦ RF Ports Matched to 2315MHz (MAX2721)
♦ Fully Assembled and Tested
Ordering Information
TEMP. RANGE
IC PACKAGE
MAX2720EVKIT
PART
-40°C to +85°C
20 TSSOP-EP*
MAX2721EVKIT
-40°C to +85°C
20 TSSOP-EP*
*Exposed paddle
Components Common to MAX2720/MAX2721
DESIGNATION
QTY
470pF ±10% ceramic caps (0402)
Murata GRM36X7R471K050A
R4
1
20kΩ potentiometer
Bournes Digi-Key 3296W-203-ND
1
2pF ±0.25pF ceramic cap (0402)
Murata GRM36COG020C050A
R5, R7,
R9, R11
4
1.00kΩ ±1% resistors (0603)
C3, C10, C13
3
1000pF ±10% ceramic caps (0402)
Murata GRM36X7R102K050A
R6, R8,
R10, R45
4
49.9Ω ±1% resistors (0603)
C6, C7, C15,
C16, C22,
C23, C24
7
0.1µF ±10% ceramic caps (0603)
Murata GRM39X7R104K016A
J1, J3, J4, J5,
J7, J8
6
SMA edge-mount connectors
EFJohnson 142-0701-801
J2, J6
0
Not installed
1
3.0pF ±0.25pF ceramic cap (0402)
Murata GRM36COG030C050A
J10, J11, J12
3
Test points
C18
1
47pF ±5% ceramic cap (0402)
Murata GRM36COG470J050A
JU2
0
Not installed
2
1x3-pin headers (0.1in center)
1
10µF ±10% tantalum capacitor
AVX TAJC106K010
JU4, JU5
C19
JU6
1
1x2-pin header (0.1in center)
DESIGNATION
QTY
C1, C4, C8,
C9, C14, C17
6
C2
C11
DESCRIPTION
DESCRIPTION
C20, C21
0
Not installed
None
3
Shunts (JU4, JU5, JU6)
L1
0
Not installed
None
1
MAX2720/MAX2721 PC board
L2
1
3.9nH ±5% inductor
Toko LL1608-FS3N9J
None
1
MAX2720/MAX2721 EV kit data
sheet
R1, R3
2
100kΩ resistors (0402)
R2
1
10kΩ resistor (0402)
None
1
MAX2720/MAX2721 data sheet
________________________________________________________________ Maxim Integrated Products
1
For free samples and the latest literature, visit www.maxim-ic.com or phone 1-800-998-8800.
For small orders, phone 1-800-835-8769.
Evaluate: MAX2720/MAX2721
General Description
The MAX2720/MAX2721 evaluation kits (EV kits) simplify
evaluation of the MAX2720/MAX2721 direct I/Q modulator with variable gain amplifier (VGA) and power amplifier
(PA) driver. The MAX2720 is optimized for RF frequencies between 1700MHz and 2100MHz, while the
MAX2721 is optimized for RF frequencies between
2100MHz and 2500MHz. The EV kits are fully assembled
and tested, allowing simple evaluation of all device functions. All signal ports utilize SMA connectors, providing a
convenient interface to RF test equipment.
Evaluate: MAX2720/MAX2721
MAX2720/MAX2721 Evaluation Kits
MAX2720 EV Kit
Specific Components
DESIGNATION QTY
DESCRIPTION
DESIGNATION QTY
C5
1
8.0pF ±0.5pF ceramic cap (0402)
Murata GRM36COG080D050A
C12
1
0Ω resistor (0402)
L3
1
1.5nH ±5% inductor
Toko LL1608-FS1N5J
L4
U1
1
1
1pF ±0.25pF ceramic cap (0402)
Murata GRM36COG010C050A
PHONE
FAX
WEB
AVX
843-448-9411 843-448-1943
EFJohnson
402-474-4800 402-474-4858
Murata
800-831-9172 814-238-0490
Toko
800-pik-toko
708-699-1194
www.avxcorp.
com
www.efjohnson.
com
www.murata.
com
www.tokoam.
com
Quick Start
Test Equipment Required
• One low-noise RF-signal generator (50Ω source)
capable of delivering at least -10dBm of output power
over 1.7GHz to 2.5GHz (HP 8648C, for example)
• One I/Q generator capable of producing two 500kHz
sine waves, 90° out of phase with each other, with
an amplitude of 300mVp-p (HP 8904A with option 2,
for example)
• One dual-channel oscilloscope with a 100MHz minimum bandwidth
• Two low-capacitance (<3.0pF) oscilloscope probes
(Tektronix P6201, for example)
• One spectrum analyzer capable of covering the
MAX2720/MAX2721 RF frequency range of the HP
8561E, for example
• Two 50Ω BNC-to-SMA cables
• Two 50Ω SMA cables
• One power supply capable of providing a minimum
of 150mA of supply current at +3V
• (Optional) Digital multimeters (DMMs) to monitor DC
supply voltage and supply current
2
DESCRIPTION
C5
1
6.0pF ±0.5pF ceramic cap (0402)
Murata GRM36COG060D050A
C12
1
27pF ±5% ceramic cap (0402)
Murata GRM36COG270J050A
L3
1
1.2nH ±5% inductor
Toko LL 1608-FS1N2J
L4
1
3.3nH ±5% inductor
Toko LL1608-FS3N3J
U1
1
MAX2721EUP, 20-pin TSSOP-EP
MAX2720EUP, 20-pin TSSOP-EP
Component Suppliers
SUPPLIER
MAX2721 EV Kit
Specific Components
• (Optional) A second power supply for varying the
gain of the modulator
I/Q Modulator Connections and Setup
1) DC Power Supply: Set the power-supply voltage to
+3V, and connect it to VCC and GND on the EV kit.
If desired, place an ammeter in series with the power
supply to measure supply current and a voltmeter in
parallel with VCC and GND to measure the supply
voltage delivered to the EV kit. Short jumper JU4 to
VCC to enable the device. Short jumper JU6 to allow
the potentiometer to vary the modulator gain; turn the
potentiometer until V PC = 2.5V. If desired, open
jumper JU6 and connect to an additional voltage
supply to control the modulator gain.
2) LO Signal Source: The MAX2720/MAX2721 LO
port can be driven at full or half frequency. Connect
jumper JU5 (X2 ENB) to GND to enable the internal
LO frequency doubler, allowing the external LO signal source to operate at half frequency. Set the LO
signal source operating frequency to 950MHz
(MAX2720) or 1157.5MHz (MAX2721) at an output
power of -13dBm.
Connect jumper JU5 (X2 ENB) to VCC to disable the
internal LO frequency doubler, and run the external
LO source at the fundamental frequency. Set the LO
signal source frequency to 1900MHz (MAX2720) or
2315MHz (MAX2721) at an output power of -13dBm.
Connect the LO signal generator to the LO port SMA
connector using a 50Ω SMA cable.
3) I/Q Signal Source: Configure the dual-output function generator for a 500kHz IF frequency, with a
300mVp-p amplitude and a 90° phase difference
between channels. Connect a 50Ω cable from the
I/Q signal source to the EV kit’s I+ and Q+ inputs.
The EV kit inputs are terminated with a 50Ω resistor
shunted to ground and a 1kΩ resistor in series with
_______________________________________________________________________________________
SMA
SMA
J8
J3
SMA
J2
C4
470pF
R5
1k
C7
0.1µF
C20
OPEN
C5
8pF
(5pF*)
VCC
C6
0.1µF
C2
2.0pF
C1
470pF
C24
0.1µF
C8
470pF
VCC
L2
3.9nH
VCC
1
3
C18
47pF
10
9
8
7
6
5
4
3
2
1
2
GND
VCC
I+
I-
VCC
GND
VCC
SHDN
DROUT
GND
1
VCC
U1
1
PC
GND
DRIN
R4
20k
LO
VCC
Q+
Q-
VCC
ENX2
11
12
13
14
15
16
17
18
19
20
JU2
2 JU6
MODOUT
JU5
3
X2_ENB
MAX2720
MAX2721
2
VCC
JU4
3
SHDN
*COMPONENT VALUES ARE FOR MAX2721 ONLY.
R6
49.9Ω
R7
1k
C23
0.1µF
C3
1000pF
C19 C22
10µF 0.1µF
R45
49.9Ω
R1
VCC 100k
SHDN
J1
SMA
J12
J10
VCC
VCC
C11
3.0pF
J11
L1
OPEN
C14
470pF
C16
0.1µF
C15
0.1µF
PC
R11
1k
C21
OPEN
R3
100k
VCC
C13
C9
1000pF
470pF
X2_ENB
J4
R9
1k
L3
1.5nH
(1.2nH*)
C10
1000pF
SMA
VCC
C17
470pF
R10
49.9Ω
L4
C12
1pF
(3.3nH*) 0Ω
(27pF*)
R2
10k
R8
49.9Ω
PC
SMA
J7
SMA
J6
SMA
J5
Evaluate: MAX2720/MAX2721
VCC VCC
MAX2720/MAX2721 Evaluation Kits
Figure 1. MAX2720/MAX2721 EV Kits Schematic
_______________________________________________________________________________________
3
Evaluate: MAX2720/MAX2721
MAX2720/MAX2721 Evaluation Kits
the baseband input of the MAX2720/MAX2721,
which has a 2kΩ (typ) input impedance. This voltage divider results in a 200mVp-p signal applied to
the MAX2720/MAX2721s’ I+ and Q+ inputs. Use the
oscilloscope and its two probes to verify that the
amplitude difference between the two signals at the
I and Q inputs is at a minimum and the phase difference is 90°.
4) Spectrum Analyzer: Connect the spectrum analyzer to the MODOUT SMA connector using a 50Ω
SMA cable. Set the spectrum analyzer’s center frequency to 1900MHz (MAX2720) or 2315MHz
(MAX2721). Set the spectrum analyzer’s reference
level to 0dBm and the span to 1.2MHz.
I/Q Modulator Analysis
Turn on the power supply and the LO and I/Q signal
generators. The ammeter should read approximately
77mA (MAX2720) or 86mA (MAX2721) with the LO doubler enabled, or 72mA (MAX2720) or 81mA (MAX2721)
with the LO doubler disabled.
Using the spectrum analyzer, observe the modulator
output spectrum. Notice three tones: the carrier, and
the lower and upper sidebands 500kHz below and
above the carrier. In its peak power setting (V PC =
2.5V), the desired sideband will have an amplitude of
-8.5dBm (MAX2720) or -5.0dBm (MAX2721). The carrier suppression is typically 33dB (MAX2720) or 31dB
(MAX2721), while the sideband suppression is typically
40dB (MAX2720) or 35dB (MAX2721). Phase and
amplitude differences at the I and Q inputs result in
degradation of the carrier and sideband suppression.
Be sure to take into account board losses (0.3dB) when
calculating the output power of the device.
PA Driver Connections and Setup
1) DC Power Supply: Set the power-supply voltage to
+3V, and connect it to VCC and GND on the EV kit.
If desired, place an ammeter in series with the
4
power supply to measure supply current and a voltmeter in parallel with the VCC and GND connections to measure the supply voltage delivered to the
EV kit. Short jumper JU4 to VCC to enable the
device.
2) Spectrum Analyzer: Connect the spectrum analyzer to the DROUT SMA connector using a 50Ω SMA
cable. Set the spectrum analyzer’s center frequency
to 1900MHz (MAX2720) or 2315MHz (MAX2721).
Set the spectrum analyzer’s reference level to
10dBm and the span to 1MHz.
3) RF Signal Source: Set the signal generator to an
output power of -12dBm at a frequency of 1900MHz
(MAX2720) or 2315MHz (MAX2721). Connect the
signal generator to the DRIN SMA connector using
a 50Ω SMA cable.
PA Driver Analysis
Turn on the power supply and RF signal generator. The
spectrum analyzer should measure an output power of
+1.5dBm (13.5dB gain) for the MAX2720 or -0.5dBm
(11.5dB gain) for the MAX2721. Be sure to take into
account board losses (0.3dB at the input, 0.3dB at the
output) when calculating the output power of the
device.
Layout and Bypassing
Good PC board layout is an essential aspect of RF circuit design. The MAX2720/MAX2721 EV board can
serve as a guide for layout of your board. Make sure
the input traces to the I and Q input pins are of equal
length and in the same environment as much as possible to keep the I and Q signals in quadrature for maximum sideband rejection at the modulated output. Keep
PC board trace lengths as short as possible to minimize parasitics and losses. Keep bypass capacitors as
close to the device as possible with low-inductance
connections to the ground plane.
_______________________________________________________________________________________
MAX2720/MAX2721 Evaluation Kits
Evaluate: MAX2720/MAX2721
1.0"
1.0"
Figure 2. MAX2720/MAX2721 EV Kits PC Board Layout—
Component Placement Guide
Figure 3. MAX2720/MAX2721 EV Kits PC Board Layout—
Component Side (Layer 1, Top)
1.0"
Figure 4. MAX2720/MAX2721 EV Kits PC Board Layout—
Ground Plane (Layer 2)
_______________________________________________________________________________________
5
Evaluate: MAX2720/MAX2721
MAX2720/MAX2721 Evaluation Kits
1.0"
1.0"
Figure 5. MAX2720/MAX2721 EV Kits PC Board Layout—
Power Plane (Layer 3)
Figure 6. MAX2720/MAX2721 EV Kits PC Board Layout—
Power Plane (Layer 4, Bottom)
Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are
implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.
6 _____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600
© 2000 Maxim Integrated Products
Printed USA
is a registered trademark of Maxim Integrated Products.