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19-4786; Rev 1; 11/98
MAX2680/MAX2681/MAX2682 Evaluation Kits
General Description
The MAX2680/MAX2681/MAX2682 evaluation kits (EV
kits) simplify the evaluation of the MAX2680/
MAX2681/MAX2682 downconverter mixers. They
enable testing of all device functions and require no
additional support circuitry. Signal inputs and outputs
use SMA connectors to ease the connection of RF test
equipment.
All three EV kits share the same PC board but have RF
input matching components optimized for each device
at an RF frequency of 900MHz. Be sure to select the EV
kit for the device that meets your performance needs.
Consult the
Selector Guide
in the MAX2680/
MAX2681/MAX2682 data sheet for the various combi-
nations of power gain, input IP3, noise figure, and sup-
ply current offered by each device. The IF output
matching components are optimized for an IF frequen-
cy of 70MHz. All matching components may be
changed to match RF frequencies from 400MHz to
2.5GHz and IF frequencies from 10MHz to 500MHz.
Consult Tables 2 and 4 in the MAX2680/MAX2681/
MAX2682 data sheet for component values appropriate
for each device at other RF and IF operating frequen-
cies.
Features
o
Easy Evaluation of MAX2680/MAX2681/MAX2682
o
Easy Evaluation of All Device Functions
o
+2.7V to +5.5V Single-Supply Operation
o
RF Input Matched to 50Ω at 900MHz
o
IF Output Matched to 50Ω at 70MHz
o
SMA Input and Output Signal Connectors
o
All Critical Peripheral Components Included
Evaluate: MAX2680/MAX2681/MAX2682
Components Common
to All Three EV Kits
DESIGNATION QTY
C1
C2
C3, C4, C6
C5
C7, C8
L1
1
1
3
1
2
1
0
0
3
1
3
1
DESCRIPTION
270pF ceramic capacitor (0603)
15pF ceramic capacitor (0603)
1000pF ceramic capacitors (0603)
10µF, 10V tantalum capacitor (0805)
Open
330nH inductor
Coilcraft 1008HS-330TJBC
Open
Not installed, short
SMA connectors (edge mount)
3-pin header
Eyelets
MAX2680/MAX2681/MAX2682 PC board
Ordering Information
PART
TEMP.
RANGE
IC PACKAGE
6 SOT23-6
6 SOT23-6
6 SOT23-6
SOT
TOP MARK
AAAR
AAAS
AAAT
R1
R2
IF, LO, RF
JU1
GND, V
CC
,
SHDN
None
MAX2680EVKIT
-40°C to +85°C
MAX2681EVKIT
-40°C to +85°C
MAX2682EVKIT
-40°C to +85°C
Component Suppliers
SUPPLIER
AVX
Coilcraft
Toko America
PHONE
803-946-0690
847-639-6400
708-297-0070
FAX
803-626-3123
847-639-1469
708-699-1194
Z1
Z2
Z3
U1
1
1
0
1
MAX2680 EV Kit
Additional Components
DESIGNATION QTY
DESCRIPTION
270pF ceramic capacitor (0603)
22nH inductor
Toko LL1608-FH22NJ
Open
MAX2680EUT-T (6-pin SOT23)
________________________________________________________________
Maxim Integrated Products
1
For free samples & the latest literature: http://www.maxim-ic.com, or phone 1-800-998-8800.
For small orders, phone 1-800-835-8769.
MAX2680/MAX2681/MAX2682 Evaluation Kits
Evaluate: MAX2680/MAX2681/MAX2682
MAX2681 EV Kit
Additional Components
DESIGNATION QTY
Z1
Z2
Z3
U1
1
1
0
1
DESCRIPTION
270pF ceramic capacitor (0603)
18nH inductor
Toko LL1608-FHI8NJ
Open
MAX2681EUT-T (6-pin SOT23)
Z1
Z2
Z3
U1
1
1
1
1
MAX2682 EV Kit
Additional Components
DESIGNATION QTY
DESCRIPTION
1.5pF ceramic capacitor (0603)
270pF ceramic capacitor (0603)
10nH inductor
Toko LL1608-FH10NJ
MAX2682EUT-T (6-pin SOT23)
Quick Start
The MAX2680/MAX2681/MAX2682 EV kits are fully
assembled and factory tested. Follow the instructions in
the
Connections and Setup
section for proper device
evaluation.
quency to 970MHz and output power level to
-5dBm.
5) Use a third 50Ω SMA cable to connect the IF con-
nector of the EV kit to the spectrum analyzer. Take
care to use quality connector adapters for the
spectrum analyzer’s input. Avoid the use of BNC-
type connectors due to their high VSWR while oper-
ating in the GHz range.
Test Equipment Required
This section lists the recommended test equipment to
verify the operation of the MAX2680/MAX2681/
MAX2682. It is intended as a guide only, and some
substitutions are possible.
• DC power supply capable of supplying a minimum
of 50mA at +2.7V to +5.5V
• HP8561E spectrum analyzer or equivalent high-
sensitivity spectrum analyzer
• Digital multimeter (DMM) to monitor DC supply volt-
age and supply current (if desired)
• Two HP8648C RF signal generators or equivalent
(50Ω) sine-wave sources for the RF and LO inputs
• Three 50Ω SMA cables (RG-58A/U or equivalent)
Analysis
1) Set the spectrum analyzer’s center frequency to
70MHz, with a frequency span of 1MHz.
2) Set the spectrum analyzer’s marker to read the
peak power level of the center frequency. For the
MAX2680 the IF power level is nominally -13.4dBm.
The IF output power is equal to the RF input power
plus the conversion gain of the downconverter
mixer. The MAX2680 has a typical conversion gain
of 11.6dB. The MAX2681 has a typical conversion
gain of 14.2dB. The MAX2682 has a typical conver-
sion gain of 14.7dB.
Connections and Setup
1) Verify the DC power supply is set to less than +5.5V
and is off before connecting the supply to the EV
kit. A good starting point is +3.0V. Connect the
power supply between V
CC
and GND, and turn the
power supply on.
2) Verify the jumper JU1 is in the “on” position, pin 1
shorted to pin 2 (SHDN = V
CC
).
3) Use a 50Ω SMA cable to connect a signal genera-
tor to the SMA RF connector of the EV kit. Set the
signal generator’s output frequency to 900MHz and
output power level to -25dBm.
4) Use another 50Ω SMA cable to connect a second
signal generator to the SMA LO connector of the EV
kit. Set the second signal generator’s output fre-
2
Detailed Description
This section describes the circuitry surrounding the
MAX2680/MAX2681/MAX2682 EV kits. For more
detailed information covering device operation, please
consult the MAX2680/MAX2681/MAX2682 data sheet.
Figure 1 is the schematic for the MAX2680/MAX2681/
MAX2682 EV kits. The RF input matching components
Z1, Z2, and Z3 are optimized for each device and for
an RF frequency of 900MHz. A DC-blocking capacitor
is required on the RF port. The IF output matching com-
ponents, L1 and C2, are optimized for an IF frequency
of 70MHz and are independent of the device chosen.
Consult Tables 2 and 4 in the MAX2680/MAX2681/
MAX2682 data sheet for components appropriate for
each device at other RF and IF frequencies. Capacitor
_______________________________________________________________________________________
MAX2680/MAX2681/MAX2682 Evaluation Kits
C1 is a DC-blocking capacitor and is required for the
LO input port. Pads C7 and C8 are left open on the EV
kits, but are provided for experimentation. Pad R1 is left
open on the kits, but is provided as an option to resis-
tively terminate the IFOUT port.
Capacitors C4, C5, and C6 form the V
CC
decoupling
network. Note the location of each component. C5, a
10µF tantalum capacitor, is located near the V
CC
con-
nector. This serves as the central node for distribution
of V
CC
to the mixer’s supply pin and the IFOUT output
pull-up inductor L1. Capacitor C6, placed near the V
CC
connection, and capacitor C4, placed near the device,
help to reduce any high-frequency crosstalk. Capacitor
C3, placed near the
SHDN
pin on the device, helps to
filter out any noise. For additional filtering, add resistor
R2 to the EV kit after cutting the short across the pads
for R2.
Modifying the EV Kit
The MAX2680/MAX2681/MAX2682 EV kits are easily
used at RF frequencies from 400MHz to 2500MHz, and
at IF frequencies from 10MHz to 500MHz. To operate at
frequencies other than the factory configuration of
900MHz RF and 70MHz IF, refer to Tables 2 and 4 in
the MAX2680/MAX2681/MAX2682 data sheet for the
suggested component values. For operation at frequen-
cies other than those given here, consult the graphs RF
Port Impedance vs. RF Frequency and IF Port
Impedance vs. IF Frequency in the
Typical Operating
Characteristics
in the MAX2680/MAX2681/MAX2682
data sheet and follow typical impedance matching
methods.
Evaluate: MAX2680/MAX2681/MAX2682
C3
1000pF
C1
270pF
1
LO
SHDN
6
C4
1000pF
2
2
GND
3
JU1
1
V
CC
5
C6
1000pF
SMA
IF
C2
15pF
C7
OPEN
C5
10µF
10V
R2
SHORT
SHDN
SMA
LO
GND
U1
MAX2680
MAX2681
MAX2682
VCC
R1
OPEN
SMA
RF
C8
OPEN
Z3
Z1
Z2
3
RFIN
IFOUT
4
L1
330nH
Figure 1. MAX2680/MAX2681/MAX2682 EV Kits Schematic
_______________________________________________________________________________________
3
MAX2680/MAX2681/MAX2682 Evaluation Kits
Evaluate: MAX2680/MAX2681/MAX2682
1.0"
Figure 2. MAX2680/MAX2681/MAX2682 EV Kits PC Board
Layout —Component Silkscreen
1.0"
Figure 3. MAX2680/MAX2681/MAX2682 EV Kits PC Board
Layout —Component Side Metal
1.0"
Figure 4. MAX2680/MAX2681/MAX2682 EV Kits PC Board
Layout —Ground Plane
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.
4
_____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600
© 1998 Maxim Integrated Products
Printed USA
is a registered trademark of Maxim Integrated Products.

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