19-2564; Rev 1; 10/02
MAX2648 Evaluation Kit
General Description
The MAX2648 evaluation kit (EV kit) simplifies the evalu-
ation of the MAX2648 5GHz low-noise amplifier. It
enables testing of the device’s performance and
requires no additional support circuitry. All inputs and
outputs use SMA connectors to facilitate easy connec-
tion of RF test equipment.
This EV kit is factory-tuned for operation in the
5150MHz to 5350MHz band but can be retuned for
operation in any band from 5000MHz to 6000MHz.
Table 1 provides component selection information to
retune the MAX2648 for operation in the 5725MHz to
5825MHz band. Consult the MAX2648 device S-para-
meter and noise parameter data (Tables 1 and 2 of the
MAX2648 data sheet) to design a matching network for
any other band.
o
Easy Evaluation of MAX2648
o
+2.7V to +3.6V Single-Supply Operation
o
All Peripheral Components Included
o
Fully Assembled and Tested
Features
Evaluates: MAX2648
Ordering Information
PART
MAX2648EVKIT
TEMP RANGE
-40°C to +85°C
IC PACKAGE
2
✕
3 UCSP
Component Suppliers
SUPPLIER
ATC
Coilcraft
EFJohnson
Kamaya
Murata
PHONE
631-622-4700
800-322-2645
402-474-4800
219-489-1533
770-436-1300
FAX
631-622-4748
847-639-1469
402-474-4858
219-489-2261
770-436-3030
WEBSITE
www.atceramics.com
www.coilcraft.com
www.efjohnson.com
www.kamaya.com
www.murata.com
Component List
DESIGNATION
C1, C2, C6
QTY
3
DESCRIPTION
100pF ±5% ceramic
capacitors (0402)
Murata GRM36COG101J050A
1000pF ±10% ceramic
capacitor (0402)
Murata GRM36X7R102K050A
0.01µF ±10% ceramic
capacitor (0402)
Murata GRM36X7R103K016A
0.01µF ±10% ceramic
capacitor (1206)
Murata GRM42-6X7R103K2000A
1.0pF ±0.05pF ATC 500-series
porcelain capacitor (0603)
ATC 5001R0AT100X
DESIGNATION
C8
QTY
1
DESCRIPTION
0.9pF ±0.05pF ATC 500-series
porcelain capacitor (0603)
ATC 500S0R9AT100X
SMA connectors, edge mount
EFJohnson 142-0701-851
22nH wirewound inductor (0805)
Coilcraft 0805CS-220XJBC
8.2Ω ±1% resistor (0402)
Kamaya RMC16S-08R2FTH
MAX2648EBT, 2
✕
3 UCSP
Test points
DigiKey 5000-ND
J1, J2
L1
2
1
1
1
2
C3
1
C4
1
R2
U1
VCC, GND
C5
1
C7
1
________________________________________________________________
Maxim Integrated Products
1
For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at
1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.
MAX2648 Evaluation Kit
Evaluates: MAX2648
Quick Start
The MAX2648 EV kit is fully assembled and factory test-
ed. Follow the instructions in the
Connections and
Setup
section for proper device evaluation.
Table 1. Replacement Matching Elements
for 5800MHz Band
DESIGNATION
QTY
DESCRIPTION
5725MHz to 5825MHz (HiperLAN/2, upper-UNII)
C7
1
0.7pF high-Q porcelain
capacitor (0603)
ATC500S0R7AT100X
0.8pF high-Q porcelain
capacitor (0603)
ATC500S0R8AT100X
Test Equipment Required
This section lists the recommended test equipment to
verify the operation of the MAX2648. It is intended as a
guide only, and some substitutions are possible.
•
•
One DC power supply, +2.7V to +3.6V output
One RF vector network analyzer capable of making
accurate measurements up to 6GHz (the HP/Agilent
8753D or 8753E with option 006 work nicely)
Calibration kit for vector network analyzer
Two high-quality 50Ω SMA cables
C8
1
•
•
Connections and Setup
1) Allow the vector network analyzer to warm up, and
configure it for the following:
• Stimulus power level = -30dBm
• Linear frequency sweep: 5000MHz to 6000MHz,
at least 201 points
• Turn on averaging, at least four sweeps
2) Connect SMA cables to VNA, and perform a
full 2-port calibration, omitting the isolation
calibration if desired. Save this setup for recall later,
makng sure that the calibration array is included in
this saved state.
3) Connect the EV kit to the VNA.
4) Verify the DC power supply is set no higher than
+3.6V and is off before connecting the supply to the
EV kit. A good starting voltage is +3.0V. Connect
the power supply between VCC and GND, and
power up the kit.
5) Restart averaging on the VNA, and verify that it
measures some forward gain. If the measurement
appears to be in error, verify the quality of the cali-
bration by replacing the EV kit with an SMA through.
Repeat the calibration procedure if necessary.
Analysis
Set the vector network analyzer to measure forward
gain (S21). Peak gain should be about 17dB at
5250MHz. Verify input return loss, output return loss,
and reverse isolation if so desired.
Detailed Description
This section describes the circuitry surrounding the IC
in the MAX2648 EV kits. For more detailed information
covering device operation, please consult the
MAX2648 data sheet.
VCC
J1
SMA
C1
100pF
WIDTH = 21 mils
LENGTH = 85 mils
C8
0.9pF
RFIN
GND
GND
U1
MAX2648
V
CC
GND
RFOUT
C2
100pF
C3
1000pF
L1
22nH
R2
8.2Ω
C4
0.01µF
C5
0.01µF
J3
J4
WIDTH = 21 mils
LENGTH = 65 mils
WIDTH = 21 mils
LENGTH = 150 mils
C6
100pF
C7
1.0pF
J2
SMA
ROGERS 4350, 10 mils FROM RF TRACE TO GROUND PLANE.
Figure 1. MAX2648 EV Kit Schematic
2
_______________________________________________________________________________________
MAX2648 Evaluation Kit
The schematic for the MAX2648 EV kit is shown in
Figure 1. Looking at the input and output transmission
lines, capacitors C1 and C6 are 100pF DC-blocking
capacitors. Capacitors C2 and C3 form the local V
CC
decoupling network. A larger 0.01µF decoupling capac-
itor sits further from the IC, and an RC filter formed by
C4 and R2 provides still more supply filtering.
Shunt-capacitor tuning elements C7 and C8 are ultra-
high-Q porcelain capacitors from ATC. Their value is
determined by the following factors: 1) the desired
band of operation; 2) the position on the transmission
line between the DC block and the IC; and 3) Z
0
of that
transmission line. The values provided in this EV kit will
most likely not provide optimal performance at 5.25GHz
if a different PC board material or layout is used.
Although the matching network component values pro-
vided here will offer a rough estimate of values for a
new design, refer to Tables 1 and 2 in the MAX2648
data sheet when designing matching networks for a
particular application.
The MAX2648’s output is an open-collector transistor,
and must be biased to V
CC
through an RF choke. RF
choke inductor L1 is placed as close to the output trans-
mission line as possible, so that its mounting pad nearest
the IC does not have the effect of a tuning stub. If PC
board space allows, the output stage can alternatively
be biased through a high-Z
0
quarter-wave transmission
line, which is AC-shorted to ground on the V
CC
side.
Good grounding is essential for optimum performance.
Note the numerous plated vias from the top ground
plane to the signal ground plane—ground discontinu-
ities can cause unpredictable parasitics and make pro-
duction-run tuning all but impossible. The high-frequen-
cy layer of the evaluation board is constructed from
Rogers RO4350 (10mil distance to ground plane)
microwave laminate, a cost-effective PC board material
that offers a low dielectric constant (to keep electrical
lengths manageable), a low loss tangent, and is com-
patible with conventional FR-4 fabrication methods.
Handling chip-scale packages requires special
care and considerations; refer to Maxim’s technical
article
Wafer-Level Ultra-Chip-Scale Package
(at
www.maxim-ic.com).
Evaluates: MAX2648
Prototype Chip Installation
Alignment keys on the PC board around the area where
the chip is located will be helpful in the prototype
assembly process. The MAX2648 EV kit PC board has
L-shaped alignment keys at the diagonal corners of the
chip. It is best to align the chip on the board before any
other components are placed, and then place the
board on a hotplate until the solder begins to flow. After
about 20 seconds, carefully remove the board from the
hotplate without disturbing the position of the IC, and
let it cool down to room temperature before stuffing any
more components. It is often difficult to know when the
solder balls on the UCSP are flowing. Watch for nearby
capacitors or inductors to start flowing—a good rule of
thumb is that if they are flowing, then so is the IC.
Rework for UCSP ICs can be tricky and requires
patience and experience. To remove an IC, place the
PC board on a hotplate preheated to about 300°C until
the IC begins to reflow. Again, use nearby components
as a cue. Remove the IC so as not to disturb other
components. Remove the PC board from the hotplate—
do not attempt to solder a new IC yet. Allow the PC
board to cool and, under a microscope, carefully clean
the residual solder and flux away from the mounting
pads. Now repeat the steps above to reinstall the IC.
In rework situations, it might be advantageous to perch
the PC board up on a small aluminum block, or even a
steel nut, so that heat is conducted to the PC board
directly under the IC. This allows the IC to be one of the
first components to flow, and this technique can often
keep the designer from having to remove edge connec-
tors or components on the bottom-side of the PC board.
_______________________________________________________________________________________
3
MAX2648 Evaluation Kit
Evaluates: MAX2648
832 mils
832 mils
925 mils
925 mils
1.0"
Figure 2. MAX2648 EV Kit PC Board Layout—Component Side
1.0"
Figure 3. MAX2648 EV Kit PC Board Layout—Ground Plane
832 mils
832 mils
925 mils
925 mils
1.0"
Figure 4. MAX2648 EV Kit PC Board Layout—Ground Plane
1.0"
Figure 5. MAX2648 EV Kit PC Board Layout—Solder Side
4
_______________________________________________________________________________________
MAX2648 Evaluation Kit
Evaluates: MAX2648
832 mils
832 mils
925 mils
925 mils
1.0"
Figure 6. MAX2648 EV Kit PC Board Layout—Top Side
Soldermask
1.0"
Figure 7. MAX2648 EV Kit PC Board Layout—Drill and
Mechanicals
832 mils
832 mils
925 mils
925 mils
1.0"
Figure 8. MAX2648 EV Kit PC Board Layout—Top Side
Silkscreen
1.0"
Figure 9. MAX2648 EV Kit PC Board Layout—Bottom Side
Soldermask
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.
Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 _____________________
5
© 2002 Maxim Integrated Products
Printed USA
is a registered trademark of Maxim Integrated Products.
京公网安备 11010802033920号
Copyright © 2005-2026 EEWORLD.com.cn, Inc. All rights reserved
电子工程世界
