General Description
The MAX9982 evaluation kit (EV kit) simplifies the evaluation of the MAX9982 825MHz to 915MHz high-linearity
active down-converter mixer. It is fully assembled and
tested at the factory. Standard 50Ω SMA connectors
are included on the EV kit for the inputs and outputs to
allow quick and easy evaluation on the test bench.
This document provides a list of equipment required to
evaluate the device, a straightforward test procedure to
verify functionality, a description of the EV kit circuit, the
circuit schematic, a bill of materials (BOM) for the kit,
and artwork for each layer of the PC board.
Contact MaximDirect sales at 888-629-4642 to check
on pricing and availability for these kits.
Features
♦ Fully Assembled and Tested
♦ +26.8dBm Input IP3
♦ +13dBm Input 1dB Compression Point
♦ 825MHz to 915MHz RF Frequency
♦ 725MHz to 1085MHz LO Frequency
♦ 70MHz to 170MHz IF Frequency
♦ 2dB Conversion Gain
♦ 12dB Noise Figure
♦ -5dBm to +5dBm LO Drive
♦ Built-In LO Switch with 43dB LO1-to-LO2 Isolation
Evaluates: MAX9982
MAX9982 Evaluation Kit
________________________________________________________________ Maxim Integrated Products 1
19-2693; Rev 1; 1/04
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.
Ordering Information
Component Suppliers
*EP = Exposed paddle.
*The exposed paddle conductor on U1 must be solder
attached to a grounded pad on the circuit board to ensure a
proper electrical/thermal design.
PART TEMP RANGE IC PACKAGE
MAX9982EVKIT -40°C to +85°C
Thin QFN 20-EP*
(5mm
✕ 5mm)
Component List
DESIGNATION
DESCRIPTION
R1 1 249Ω ±1% resistor (0603)
R3, R4 1 137Ω ±1% resistors (0603)
R5 1 47kΩ ±5% resistor (0603)
J1–J4 4
PC board edge-mount SMA RF
connectors (flat tab launch)
Johnson 142-0741-856
T1 1
4:1 transformer (200:50)
Mini-Circuits TC4-1W-7A
TP1 1
Large test point for 0.062in PC board
(red) Mouser 151-107
TP2 1
Large test point for 0.062in PC board
(black) Mouser 151-103
TP3 1
Large test point for 0.062in PC board
(white) Mouser 151-101
U1 1 MAX9982ETP-T*
SUPPLIER PHONE WEBSITE
Coilcraft 800-322-2645 www.coilcraft.com
Digi-Key 800-344-4539 www.digikey.com
Johnson 507-833-8822 www.johnsoncomponents.com
Mini-Circuits 718-934-4500 www.minicircuits.com
Murata 770-436-1300 www.murata.com
DESIGNATION QTY DESCRIPTION
33pF ±5%, 50V C0G ceramic
C1, C2, C6, C7 4
C3 1
C4, C5 2
C8, C11 2
C9, C10 2
L1, L2 2
capacitors (0603)
Murata GRM1885C1H330J
0.033µF ±10%, 25V X7R ceramic
capacitor (0603)
Murata GRM188R71E333K
0.1µF ±10%, 16V X7R ceramic
capacitors (0603)
Murata GRM188R71C104K
220pF ±5%, 50V C0G ceramic
capacitors (0603)
Murata GRM1885C1H221J
330pF ±5%, 50V C0G ceramic
capacitors (0603)
Murata GRM1885C1H331J
560nH ±5% wire-wound inductors
(1008)
Coilcraft 1008CS-561XJBC
QTY
Evaluates: MAX9982
MAX9982 Evaluation Kit
2 _______________________________________________________________________________________
Quick Start
The MAX9982 EV kit is fully assembled and factory
tested. Follow the instructions in the Connections and
Setup section for proper device evaluation.
Test Equipment Required
Table 1 lists the equipment required to verify the opera-
tion of the MAX9982 EV kit. It is intended as a guide
only, and some substitutions can be made.
Connections and Setup
This section provides a step-by-step guide for testing
the basic functionality of the EV kit. As a general precaution to prevent damaging the outputs by driving
high-VSWR loads, do not turn on DC power or RF
signals until all connections are made.
This procedure is specific to operation with an RF
input-frequency range of 825MHz to 915MHz, low-side
injected LO for a 100MHz IF. Choose the test frequency based on the particular system’s frequency plan,
and adjust the following procedure accordingly. See
Figure 1 for the mixer test setup diagram.
1) Calibrate the power meter for 870MHz. For safety
margin, use a power sensor rated to at least
+20dBm, or use padding to protect the power
head as necessary.
2) Connect 3dB pads to DUT ends of each of the
three RF signal generators’ SMA cables. This
padding improves VSWR and reduces the errors
because of mismatch.
3) Use the power meter to set the RF signal generators according to the following:
• RF signal source: -5dBm into DUT at 870MHz
(approximately -2dBm before the 3dB pad)
• LO1 signal source: 0dBm into DUT at 770MHz
(approximately +3dBm before the 3dB pad)
• LO2 signal source: 0dBm into DUT at 771MHz
(approximately +3dBm before the 3dB pad)
4) Disable the signal generator outputs.
5) Connect the RF source (with pad) to RF IN.
6) Connect the LO1 and LO2 signal sources to the EV
kit LO inputs.
7) Measure loss in the 3dB pad and the cable that is
connected to IF OUT. Losses are frequency dependent, so test this at 100MHz (the IF frequency).
Use this loss as an offset in all output power/gain
calculations.
8) Connect this 3dB pad to the EV kit’s IF OUT connector, and connect a cable from the pad to the
spectrum analyzer.
9) Set the DC supply to +5.0V, and set a current limit
of approximately 250mA if possible. Disable the
output voltage and connect supply to the EV kit
through a low internal resistance ammeter. Enable
the supply. Re-adjust the supply to get +5.0V at the
EV kit because there will be a voltage drop across
the ammeter when the mixer is drawing current.
10) Select LO1 by leaving LO_SEL (TP3) unconnected
or connecting it to +5V. If left floating, LO_SEL pulls
high by an on-board pullup resistor.
11) Enable the LO and the RF sources.
Testing the Mixer
Adjust the center and span of the spectrum analyzer to
observe the IF output tone at 100MHz. The level should
be at approximately -5.4dBm (2.6dB conversion gain,
3dB pad loss). The spectrum analyzer’s absolute magnitude accuracy is typically no better than ±1dB; therefore, use the power meter to get an accurate output
power measurement. There will also be a tone at
99MHz, which is due to the LO signal applied to LO2.
The amount of suppression between the 100MHz and
99MHz signals is the switch isolation.
Connect LO_SEL to GND to select LO2. Observe that
the IF output level at 99MHz increases while the
100MHz level decreases.
Detailed Description
The MAX9982 is a highly integrated downconverter. RF
and LO baluns are integrated on-chip, as well as an LO
buffer and a SPDT LO input select switch. The EV kit circuit consists mostly of supply decoupling capacitors and
DC-blocking capacitors, allowing for a simple design-in.
Table 1. Test Equipment
EQUIPMENT
DESCRIPTION
HP E3631A 1 DC power supply
Fluke 75 series II
1 Digital multimeter (ammeter)
HP/Agilent 8648B
3 RF signal generators
HP 437B 1 RF power meter
HP 8561 1 Spectrum analyzer
HP 8482A 1
High-power sensor (power head)
3dB pad 4 3dB attenuators
QTY
Evaluates: MAX9982
MAX9982 Evaluation Kit
_______________________________________________________________________________________ 3
Supply Decoupling Capacitors
Ceramic capacitors C4 and C5 are 0.1µF used for filtering lower frequency noise on the supply. C8 is a 220pF
bypass capacitor for IF frequencies. C11 is used to
provide an IF ground for the center tap of T1. Although
called out, replacing C11 with a short circuit causes little to no change in performance.
DC-Blocking Capacitors
The MAX9982 has internal baluns on the RF, LO1, and
LO2 inputs. These inputs have almost 0Ω resistance at
DC; therefore, 33pF DC-blocking capacitors C1, C6,
and C7 are used to prevent any external bias from
being shunted directly to ground. C9 and C10 are used
to block DC current from flowing into the transformer
along with providing the flexibility for matching.
RFBIAS
Bias current for the mixer is set with resistor R1 (249Ω,
±1%). This value was carefully chosen for best linearity
and lowest supply current through testing at the factory. Changing this value, or using lower tolerance resistors, degrades performance.
IF±
The MAX9982 employs a differential IF output to offer
increased IP2 system performance. The IF outputs look
like an open collector with 1.8pF of differential capacitance. Inductors L1 and L2 are used to resonate out
the on-chip and evaluation board capacitance at the IF
frequency of interest along with providing a low resistance path for biasing of the IF amplifier. R3 and R4
provide a real impedance used to establish the 200Ω
differential impedance. C9 and C10 provide DC blocking along with adding in the flexibility for tuning. The
4:1 balun (T1) transforms the 200Ω differential impedance to 50Ω single ended for ease of measurement.
The EV kit IF is matched for operation over the 70MHz
to 100MHz frequency range.
Resistors R3 and R4 affect the gain of the mixer. For a
typical 2.0dB gain, 137Ω resistors are used for R3 and
R4. Higher mixer gain can be realized by increasing R3
and R4 and returning L1, L2, C9, and C10 for IF impedance matching. For example, R3 = R4 = 250Ω, L1 = L2
= 330nH, C9 = C10 = 56pF yields a mixer gain of
4.5dB at 70MHz IF with an IF return loss of 12dB.
As the differential IF outputs are relatively high imped-
ance (200Ω), they are more susceptible to component
parasitics. Relieve the ground plane directly underneath large components to reduce associated shunt-C
parasitics.
LO_SEL
The EV kit includes a 47kΩ pullup resistor for easy
selection of the LO port. Providing a ground at TP3
selects LO2, and leaving TP3 open selects LO1. To
drive TP3 from an external source, follow the limits
called out in the MAX9982 data sheet. Logic voltages
should not be applied to TP3 without the +5V applied.
Doing so can cause the on-chip ESD diodes to conduct and could damage the part.
Modifying the EV Kit
The RF and LO inputs are broadband matched, so
there is no need to modify the circuit for use anywhere
in the 825MHz to 915MHz RF range (725MHz to
1085MHz LO range).
Retuning for a different IF is as simple as scaling the
values of the IF pullup inductors up or down with frequency. The IF outputs look like an open collector with
3.6pF to ground (1.8pF differential) from the chip. This
capacitance, along with approximately 5.6pF from the
evaluation board can be resonated out at the frequency
of interest by proper selection of the bias inductor (L1,
L2). To determine the inductor value use the following
equation:
The IF output network is tuned for operation at approximately 70MHz, so a 560nH inductor is used. For lower
IF frequencies (i.e., larger component values), maintain
the component’s Q value at the cost of a larger case
size unless it is unavoidable.
Layout Considerations
The MAX9982 evaluation board can be a guide for your
board layout. Pay close attention to thermal design and
close placement of parts to the IC. The MAX9982 package exposed paddle (EP), conducts heat from the part
and provides a low-impedance electrical connection.
The EP must be attached to the PC board ground plane
with a low thermal and electrical impedance contact.
Ideally, this can be achieved by soldering the backside
package contact directly to a top metal ground plane
on the PC board. Alternatively, the EP can be connected to a ground plane using an array of plated vias
directly below the EP. The MAX9982 EV kit uses nine
equally spaced, 0.016in-diameter, plated through holes
to connect the EP to the lower ground planes.
Depending on the ground plane spacing, large surfacemount pads in the IF path may need to have the ground
plane relieved under them to reduce shunt capacitance.
fIF =
1
2π L x C
Evaluates: MAX9982
MAX9982 Evaluation Kit
4 _______________________________________________________________________________________
5.0V 250mA (MAX)
168 mA
870.000MHz
770.000MHz
771.000MHz
LO2
RFIN
LO1
3dB
3dB
3dB
OPEN = LO1
GND = LO2
3dB
+5V
GND
LO_SEL
IFOUT
MAX9982
RF SIGNAL GENERATOR
(HP 8648B)
RF SIGNAL GENERATOR
(HP 8648B)
RF SIGNAL GENERATOR
(HP 8648B)
BENCH MULTIMETER
(HP 34401A)
(AMMETER)
POWER SUPPLY
(AG E3631A)
RF SPECTRUM ANALYZER
(HP 8561x)
RF POWER METER
(GIGA 80701A, HP 437B)
RF HIGH
POWER SENSOR
U1
Figure 1. Test Setup Diagram
Evaluates: MAX9982
MAX9982 Evaluation Kit
_______________________________________________________________________________________ 5
1
2
3
4
5
678910
20 19 18 17 16
15
14
13
12
11
LOSEL
GND
V
CC
GND
IF-
IF+
GND
GND
V
CC
LO1
GND
GND
RF
TAP
C2
33pF
C3
0.033µF
GND
RFBIAS
GND
J4
SMA
LO1
J3
SMA
LO2
GND
LO2
C8
220pF
C11
220pF
C10
330pF
C7
33pF
C6
33pF
C9
330pF
T1
L1
560nH
L2
560nH
R3
137Ω
3
6
4
4:1 (200:50)
TRANSFORMER
2
1
R4
137Ω
5.0V
GND
MAX9982
U1
5.0V
TP1
+5V
TP2
GND
J2
SMA
IFOUT
C1
33pF
J1
SMA
RFIN
5.0V
R1
249Ω
5.0V
C5
0.1µF
R5
47kΩ
TP3
LO_SEL
C4
0.1µF
EXPOSED
PADDLE
Figure 2. MAX9982 EV Kit Schematic
Evaluates: MAX9982
MAX9982 Evaluation Kit
6 _______________________________________________________________________________________
Figure 3. MAX9982 EV Kit PC Board Layout—Top Silkscreen
Figure 4. MAX9982 EV Kit PC Board Layout—Top Soldermask
Figure 5. MAX9982 EV Kit PC Board Layout—Top Layer Metal
Figure 6. MAX9982 EV Kit PC Board Layout—Inner Layer 2
(GND)
1.0"
1.0"
1.0"
1.0"
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 _____________________ 7
© 2004 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.
Evaluates: MAX9982
MAX9982 Evaluation Kit
Figure 7. MAX9982 EV Kit PC Board Layout—Inner Layer 3
(Routes)
Figure 8. MAX9982 EV Kit PC Board Layout—Bottom Layer
Metal
Figure 9. MAX9982 EV Kit PC Board Layout—Bottom
Soldermask
Figure 10. MAX9982 EV Kit PC Board Layout—Bottom
Silkscreen
1.0"
1.0"
1.0"
1.0"
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