Maxim MAX9995 User Manual

General Description

The MAX9995 evaluation kit (EV kit) simplifies the evalu­ation of the MAX9995 dual high-linearity mixer. It is fully
assembled and tested at the factory. Standard 50Ω
SMA connectors are included on the EV kit for the input
and output 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 and availability of these kits.

Features

♦ Fully Assembled and Tested

♦ 1700MHz to 2200MHz RF Frequency Range

♦ 1400MHz to 2000MHz LO Frequency Range

(MAX9995)

♦ 1900MHz to 2400MHz LO Frequency Range

(Contact Factory)

♦ 40MHz to 350MHz IF Frequency Range

♦ 6.1dB Conversion Gain

♦ +25.6dBm Input IP3

♦ 9.8dB Noise Figure

♦ 66dBc 2RF to 2LO Spurious Rejection at

PRF= -10dBm

♦ Dual Channels Ideal for Diversity Receiver

Applications

♦ Integrated LO Buffer

♦ Integrated RF and LO Baluns for Single-Ended

Inputs

♦ Low -3dBm to +3dBm LO Drive

♦ Built-In SPDT LO Switch with 50dB LO1 to LO2

Isolation and 50ns Switching Time

♦ 44dB Channel-to-Channel Isolation

Evaluates: MAX9995

MAX9995 Evaluation Kit

________________________________________________________________ Maxim Integrated Products 1

19-3390; Rev 0; 8/04

Component List

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

PART TEMP RANGE IC PACKAGE

MAX9995EVKIT

36 Thin QFN-EP*

*EP = Exposed paddle.

**T

C

= Case temperature.

Note: When contacting these suppliers, indicate that you are
using the MAX9995.

Component Suppliers

SUPPLIER

PHONE WEBSITE

Coilcraft

www.coilcraft.com

Digi-Key

www.digikey.com

Johnson

www.johnsoncomponents.com

Mini-Circuits

www.minicircuits.com

Murata

www.murata.com

800-322-2645

800-344-4539

507-833-8822

718-934-4500

770-436-1300

DESIGNATION QTY DESCRIPTION

4pF ±0.25pF, 50V C0G ceramic

C1, C8 2

C2, C7 2

C3, C6 2

C4, C5, C14,

C16

capacitors (0402)
Murata GRP1555C1H4R0C

10pF ±5%, 50V C0G ceramic
capacitors (0402)
Murata GRP1555C1H100J

0.033µF ±10%, 25V X7R ceramic
capacitors (0603)
Murata GRM188R71E333K

22pF ±5%, 50V C0G ceramic

4

capacitors (0402)
Murata GRP1555C1H220J

TC = -40°C to +85°C**

DESIGNATION QTY DESCRIPTION

C9, C13, C15,

C17, C18

C10, C11, C12,

C19, C20, C21

J1–J6 6

L1, L2, L4, L5 4

5

6

0.01µF ±10%, 25V X7R ceramic
capacitors (0402)
Murata GRP155R71E103K

150pF ±5%, 50V C0G ceramic
capacitors (0603)
Murata GRM1885C1H151J

PC board edge-mount SMA RF
connectors (flat-tab launch)
Johnson 142-0741-856

330nH ±5% wire-wound inductors
(0805)
Coilcraft 0805CS-331XJBC

Evaluates: MAX9995

MAX9995 Evaluation Kit

2 _______________________________________________________________________________________

Quick Start

The MAX9995 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 opera­tion of the MAX9995 EV kit. It is intended as a guide
only, and some substitutions are possible.

Connections and Setup

This section provides a step-by-step guide to 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

signal generators until all connections are made:

1) Calibrate the power meter for 1900MHz. 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 the DUT ends of each of the
three RF signal generators’ SMA cables. This
padding improves VSWR, and reduces the errors
due to mismatch.

3) Use the power meter to set the RF signal generators
according to the following:

• RF signal source: -5dBm into DUT at 1900MHz

• LO1 signal source: 0dBm into DUT at 1700MHz

(fIF= 200MHz)

• LO2 signal source: 0dBm into DUT at 1701MHz
(f

IF

= 199MHz)

4) Disable all three signal sources. Connect the LO1
and LO2 signal sources to the EV kit LO inputs.

5) Connect the signal sources to the appropriate SMA
inputs. The RF input can be connected to either the
RFMAIN or RFDIV inputs, depending on test.

6) Measure loss in 3dB pad and cable that is connect­ed to IFMAIN/IFDIV. Losses are frequency depen­dent, so test this at 200MHz (the IF frequency). Use
this loss as an offset in all output power/gain
calculations.

7) Connect this 3dB pad to the EV kit’s appropriate
IFMAIN/IFDIV connector, and connect a cable from
the pad to the spectrum analyzer.

8) Set the DC supply to +5.0V and set a current limit
around 500mA, if possible. Connect supplies to the
EV kit through the ammeter. Turn on the supply.
Readjust the supply to get +5.0V at the EV kit.
There will be a voltage drop across the ammeter
when the mixer is drawing current.

9) Select LO2 by grounding LOSEL.

10) 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 199MHz. The level should
be about -2dBm (6dB conversion gain, 3dB pad loss).
The spectrum analyzer’s absolute magnitude accuracy
is typically no better than ±1dB. Use the power meter to

Component List (continued)

DESIGNATION

QTY

DESCRIPTION

L3, L6 2

10nH ±5% wire-wound inductors
(0603)
Coilcraft 0603CS-10NXJBC

R1, R4 2 1.21kΩ ±1% resistors (0402)

R2, R5 2 392Ω ±1% resistors (0402)

R3, R6 2 10Ω ±1% resistors (1206)

R7 1 47kΩ ±5% resistor (0603)

T1, T2 2

4:1 transformers ( 200:50 )
Mini Circuits TC4-1W-7A

TP1 1

Large test point for 0.062in PC board
(red)
Mouser 151-107 or equivalent

TP2 1

Large test point for 0.062in PC board
(black)
Mouser 151-103 or equivalent

DESIGNATION QTY DESCRIPTION

Large test point for 0.062in PC board

TP3 1

U1 1

(white)
Mouser 151-101 or equivalent

Active dual mixer IC (6mm x 6mm
thin QFN, exposed paddle) Maxim:
MAX9995ETX

NOTE: U1 HAS AN EXPOSED
PADDLE CONDUCTOR THAT
REQUIRES IT TO BE SOLDER
ATTACHED TO A GROUNDED PAD
ON THE CIRCUIT BOARD TO
ENSURE PROPER
ELECTRICAL/THERMAL DESIGN.

get an accurate output power measurement.

Disconnect the GND connection to LOSEL. It will be
pulled high by a pullup resistor on the board. This
selects LO1. Observe the new IF output at 200MHz.

Reconfigure the test setup using a combiner or hybrid
to sum the two RF inputs to do a two-tone IP3 measure­ment, if desired. Terminate the unused LO input in 50Ω.

Detailed Description

The MAX9995 is a highly integrated dual downconvert­er; RF and LO baluns are integrated on-chip, as well as
two double-balanced mixers, two IF amplifiers, an LO
buffer, and a single-pole/double throw (SPDT) LO input
select switch. The EV kit circuit consists mostly of sup­ply decoupling capacitors and DC-blocking capacitors,
making for a simple design-in.

DC-Blocking Capacitors

The MAX9995 has internal baluns on the RFMAIN,
RFDIV, LO1, and LO2 inputs. These inputs have almost
0Ω resistance at DC, so DC-blocking capacitors C1,
C8, C14, and C16 are used to prevent any external
bias from being shunted directly to ground. Capacitors
C10, C11, C19, and C20 are used to keep DC current
from flowing into the transformer, as well as providing
the flexibility for matching.

LO Buffer and IF Amplifier Bias

Bias currents for the integrated LO buffers and the IF
output amplifiers are set with resistors R2, R5, and R1,
R4, respectively. These values were carefully chosen
for best linearity and lowest supply current through test­ing at the factory. Changing these values, or using
lower tolerance resistors, degrades performance. If
lower currents are desired, consult the factory for opti­mum resistor settings.

Current-Limiting Resistors

Resistors R3 and R6 are used for current limiting at the
supply. These resistors typically dissipate 50mW each.

TAP Network

The network at TAP formed by C2, C3, C6, and C7
helps to terminate the second-order intermodulation
products at the RF inputs.

IND_EXT

The 10nH wire-wound inductors L3 and L6 improve LO­to-IF and RF-to-IF isolation. If isolation is not critical,
then the corresponding pins can be grounded.

IF Outputs

The MAX9995 employs a differential IF output to offer
increased IP2 system performance. For convenience,
the EV kit uses a 4:1 balun to transform the 200Ω differ­ential output impedance to a 50Ω single-ended output.
Inductive pullups provide DC bias to the IF output
amplifiers. Series capacitors C10, C11, C19, and C20
work in conjunction with the inductors and the 4:1 balun
transformers (T1 and T2) to match the IF outputs for
200MHz operation.

As the differential IF outputs are relatively high imped­ance (200Ω), they are more susceptible to component
parasitics. It is often good practice to relieve the
ground plane directly underneath large components to
reduce associated shunt-C parasitics (see Figure 6).

LOSEL

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 MAX9995 device data sheet. Do not
apply logic voltages to TP3 without the +5V supply
applied. Doing so can cause the on-chip ESD diodes to
conduct and could damage the part.

Evaluates: MAX9995

MAX9995 Evaluation Kit

_______________________________________________________________________________________ 3

EQUIPMENT

QTY

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

50Ω termination 1 50Ω (1W) termination

Table 1. Test Equipment

Evaluates: MAX9995

MAX9995 Evaluation Kit

4 _______________________________________________________________________________________

-+ -+

POWER SUPPLY

3-OUT, HPIB
(AG E3631A)

RF SIGNAL GENERATOR

(HP 8648B)

RF POWER METER

(GIGA 80701A,

HP 437B)

RF HIGH-

POWER SENSOR

(AMMETER)

3dB

3dB

3dB

3dB

LO2

RFMAIN/RFDIV

LO1

IFMAIN/IFDIV

+5V

GND

MAX9995EVKIT

RF SIGNAL GENERATOR

(HP 8648B)

RF SIGNAL GENERATOR

(HP 8648B)

1900.000MHz

1700.000MHz

1701.000MHz

5.0V (MAX)

RF SPECTRUM ANALYZER

(HP 8561x)

BENCH

MULTIMETER HPIB

(HP 34401A)

LOSEL

GND

OPEN

Figure 1. Test Setup Diagram

Evaluates: MAX9995

MAX9995 Evaluation Kit

_______________________________________________________________________________________ 5

Layout Considerations

The MAX9995 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 package’s
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 EV kit uses nine evenly
spaced, 0.016in-diameter, plated through holes to con­nect the EP to the lower ground planes.

Depending on the RF ground-plane spacing, large sur­face-mount pads in the RF path may need the ground
plane relieved under them to reduce shunt capacitance.

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 1700MHz to 2200MHz RF range (1400MHz to
2000MHz LO range).

Retuning for a different IF frequency is as simple as
scaling the values of the IF pullup inductors up or down
with frequency. The IF output looks like 200Ω differen-
tial in parallel with a capacitor. The capacitance is due
to the combination of the IC, PC board, and external IF
components. The capacitance from the IC is approxi­mately 2pF to ground (1pF differential), while that from
the PC board and external components is approxi­mately 3.5pF to ground. The total 5.5pF of capacitance
is resonated out at the frequency of interest by the bias
inductors. To determine the inductor value, use the fol­lowing equation:

The IF output is tuned for operation at approximately
200MHz, so a 330nH inductor is used. For lower IF fre­quencies (i.e., larger component values), maintain the
component’s Q value at the cost of larger case size,
unless it is unavoidable.

f

LxC

IF

=

1

2π

Evaluates: MAX9995

MAX9995 Evaluation Kit

6 _______________________________________________________________________________________

C2
10pF

C3

0.033µF

C1

4pF

C17

0.01µF

C18

0.01µF

R1

1.21kΩ

VCC

L2
330nH

L1
330nH

R3

10Ω

C20

150pF

C19

150pF

J2

SMA

IF MAIN OUTPUT

T1

R2

392Ω

L3

10nH

4:1

4:1

VCC

VCC

VCC

VCC

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

28

29

30

31

32

33

34

35

36

19

20

21

22

23

24

25

26

27

LO2

V

CC

GND

V

CC

GND

GND

TAPDIV

TAPMAIN

RFMAIN

RFDIV

EXPOSED

PADDLE

IFD_SET

GND

IND_EXTD

LO_ADJ_D

N.C.

V

CC

V

CC

N.C.

LO_ADJ_M

V

CC

IND_EXTM

GND

IFM_SET

IFD+

IFD-

V

CC

IFM+

IFM-

LO1

LOSEL

GND

GND

GND

GND

GND

V

CC

MAX9995

C4

22pF

C7
10pF

VCC

VCC

VCC

VCC

T2

VCC

TP1
+5V

TP2
GND

C21

150pF

J1

SMA

RF MAIN INPUT

C5

22pF

C6

0.033µF

J6

SMA

RF DIV INPUT

C8

4pF

C9

0.01µF

R4

1.21kΩ
L6

10nH

R5

392Ω

C13

0.01µF

R6

10Ω

C11

150pF

L5
330nH

C12

150pF

C10

150pF

L4
330nH

J5

SMA

IF DIV OUTPUT

C14

22pF

C15

0.01µF

J4
SMA
LO1

C16
22pF

J3

SMA

LO2

R7
47kΩ

TP3
LOSEL

VCC

U1

Figure 2. MAX9995 EV Kit Schematic

Evaluates: MAX9995

MAX9995 Evaluation Kit

_______________________________________________________________________________________ 7

Figure 3. MAX9995 EV Kit PC Board Layout—Top Silkscreen

1.0"

Figure 4. MAX9995 EV Kit PC Board Layout—Top Soldermask

1.0"

Figure 5. MAX9995 EV Kit PC Board Layout—Top Layer Metal

1.0"

Figure 6. MAX9995 EV Kit PC Board Layout—Inner Layer 2
(GND)

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.

8 _____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600

© 2004 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.

Evaluates: MAX9995

MAX9995 Evaluation Kit

Figure 7. MAX9995 EV Kit PC Board Layout—Inner Layer 3
(Routes)

1.0"

Figure 8. MAX9995 EV Kit PC Board Layout—Bottom Layer
Metal

1.0"

Figure 9. MAX9995 EV Kit PC Board Layout—Bottom
Soldermask

1.0"

Figure 10. MAX9995 EV Kit PC Board Layout—Bottom
Silkscreen

1.0"