General Description

The MAX2683/MAX2684 evaluation kits (EV kits) simplify
evaluation of the MAX2683/MAX2684 3.4GHz to 3.8GHz
downconverter mixers. The EV kits are fully assembled
and tested, allowing simple evaluation of all device func-
tions. All signal ports utilize SMA connectors, providing a
convenient interface to RF test equipment.

The MAX2683/MAX2684 are downconversion mixers
intended for operation in the 3.4GHz to 3.8GHz frequen-
cy range. The MAX2683 is optimized for downconversion
to IF frequencies between 100MHz and 400MHz, and
allows high-side or low-side LO injection. The MAX2684
is optimized for IF frequencies between 800MHz to
1000MHz and only allows low-side LO injection. A logic-
level enabled LO frequency doubler allows the external
LO source to run at half frequency, or at full frequency if
disabled. As assembled, the MAX2683/MAX2684 EV kits
are configured for operation of the LO at half frequency.
A few simple component changes configure the EV kit
for operation of the LO at full frequency. In addition, an
external resistor allows adjustment of device linearity and
supply current.

Features

o Easy Evaluation of MAX2683/MAX2684
o All Critical Peripheral Components Included
o SMA Input and Output Signal Connectors
o RF Input Matched to 50 at 3600MHz
o IF Output Matched to 50 at 300MHz (MAX2683)
o IF Output Matched to 50 at 900MHz (MAX2684)
o Fully Assembled and Tested

Evaluate: MAX2683/MAX2684

MAX2683/MAX2684 Evaluation Kits

________________________________________________________________ Maxim Integrated Products

19-1620; Rev 0; 1/00

MAX2683 Component List

PART

MAX2683EVKIT

MAX2684EVKIT

-40°C to +85°C

TEMP. RANGE

IC PACKAGE

16 TSSOP-EP*

Ordering Information

3-pin header

JU1

3.3pF ±0.1pF ceramic cap (0603)
Murata GRM39COG3R3B050

C10

8.2pF ±0.25pF ceramic caps (0603)
Murata GRM39COG8R2C050 or
Taiyo Yuden UMK107CH8R2CZ

C8, C9

1000pF ±10% ceramic capacitor
(0603) Murata GRM39X7R102K050

1.2nH ±0.2nH inductor (0402)
Murata LQP10A1N2C00

Not installed

10µF, 10V tantalum capacitor
AVX TAJB106M010

100pF ±5% ceramic capacitors (0603)
Murata GRM39COG101J050 or
Taiyo Yuden UMK107CH101JZ

C3, C6, C12

DESIGNATION

1pF ±0.1pF ceramic capacitor (0603)
Murata GRM39COG010B050

3300pF ±10% ceramic capacitor (0402)
Murata GRM36X7R332K050 or
Taiyo Yuden UMK105B332KW

DESCRIPTION

QTY

Test points

VCC, GND

MAX2683EUE (16-pin TSSOP)

Balun transformer, B4F type
Toko 617DB-1018

Not installed

1.50k

±1% resistor (0603)

1.21k

±1% resistors (0603)

R1, R2

3.9nH ±3nH inductor (0603)
Murata LQG11A3N9S00

39nH ±5% inductors (0603)
Murata LQG11A39NJ00

L3, L4

MAX2683/MAX2684 EV kit data sheet

None

MAX2683/MAX2684 data sheet

None

MAX2683/MAX2684 PC board

None

DESIGNATION

Shunt (JU1)

None

DESCRIPTION

QTY

*Exposed paddle

SMA connectors (PC edge mount)
EFJohnson 142-0701-801

RFIN, LOX, IF

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.

Test Equipment Required

This section lists the test equipment required for evalu-
ating the MAX2683/MAX2684:

One power supply capable of providing 100mA of
supply current over the supply voltage range of
+2.7V to +5.5V.

Two low-noise RF-signal generators or equivalent
(50

) sine-wave sources capable of delivering at

least 0dBm of output power up to 4GHz. One gen-
erator is required for the RF signal source, while the
second generator is required for the LO signal
source.

One HP 8561E RF-spectrum analyzer or equivalent
that covers the downconverter mixer's output fre-
quency range, as well as a few harmonics (6GHz).

Three 50

SMA cables (RG-58A/U or equivalent).

Optional: digital multimeters (DMMs) to monitor DC
supply voltage and supply current.

Connections and Setup

This section provides step-by-step instructions for get-
ting the EV kit up and running:

1) DC Power Supply: Set the power-supply voltage to

+5V. Turn the power supply off and connect it to the
VCC and GND connections 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 the VCC and GND connections to measure the
supply voltage delivered to the device.

Evaluate: MAX2683/MAX2684

MAX2683/MAX2684 Evaluation Kits

_______________________________________________________________________________________

MAX2684 Component List

MAX2684EUE (16-pin TSSOP)

Balun transformer, B4F type
Toko 617DB-1018

SMA connectors (PC edge mount)
EFJohnson 142-0701-801

RFIN, LOX, IF

Not installed

301

±1% resistor (0603)

1.21k

±1% resistors (0603)

R1, R2

3.9nH ±0.3nH inductor (0603)
Murata LQG11A3N9S00

6.8nH ±5% inductors (0603)
Murata LQG11A6N8J00

L3, L4

MAX2683/MAX2684 data sheet

None

MAX2683/MAX2684 PC board

None

DESIGNATION

Shunt (JU1)

None

Test points

VCC, GND

DESCRIPTION

QTY

3-pin header

JU1

Not installed

C10

8.2pF ±0.25pF ceramic caps (0603)
Murata GRM39COG8R2C050 or
Taiyo Yuden UMK107CH8R2CZ

C8, C9

1000pF ±10% ceramic cap (0603)
Murata GRM39X7R102K050

1.2nH ±0.2nH inductor (0402)
Murata LQP10A1N2C00

Not installed

10µF, 10V tantalum capacitor
AVX TAJB106M010

100 pF ±5% ceramic capacitors (0603)
Murata GRM39COG101J050 or
Taiyo Yuden UMK107CH101JZ

C3, C6, C12

DESIGNATION

1pF ±0.1pF ceramic capacitor (0603)
Murata GRM39COG010B050

3300pF ±10% ceramic cap (0402)
Murata GRM36X7R332K050 or
Taiyo Yuden UMK105B332KW

DESCRIPTION

QTY

SUPPLIER

PHONE

FAX

AVX

843-448-9411 843-448-1943

EFJohnson

402-474-4800 402-474-4858

Murata

800-831-9172 814-238-0490

Taiyo
Yuden

800-348-2496 847-925-0899

Toko

800-PIK-TOKO 708-699-1194

WEB

www.
avxcorp.com

www.
efjohnson.com

www.
murata.com

www.
T-Yuden.com

www.
tokoam.com

Component Suppliers

MAX2683/MAX2684 EV kit data sheet

None

2) RF Signal Source: Set one signal generator to an

RF frequency of 3.6GHz at an output power level of
-20dBm. Turn the output of the signal generator off.
Connect the signal generator to the RF port SMA
connector using a 50

SMA cable.

3) LO Signal Source: The MAX2683/MAX2684 can be

configured for full- or half-frequency operation of
the external LO signal source. As assembled, the
MAX2683/MAX2684 EV kits are configured for half-
frequency operation of the LO signal source. The
half-frequency LO port, LOX2, is coupled to the
MAX2683/MAX2684 EV kit LO port SMA connector,
while the LOX1 port is left unconnected.

To evaluate the devices with the LO doubler
enabled, be sure jumper JU1 is shorted to GND
(ENX2 = GND). Set the LO signal generator output
power to -5dBm at a frequency of 1650MHz
(MAX2683) or 1350MHz (MAX2684). Turn the out-
put of the signal generator off. Connect the signal
generator to the LO port SMA connector using a
50

SMA cable.

Evaluation of the devices with full-frequency opera-
tion of the LO signal source requires two compo-
nent changes. Remove inductor L5 and leave the
LOX2 port unconnected. Short the unpopulated
pads of resistor R4 with a 0

resistor. Disable the

LO frequency doubler by shunting jumper JU1 to
VCC (ENX2 = VCC). Set the LO signal generator
output power to -5dBm, at a frequency of 3300MHz
(MAX2683) or 2700MHz (MAX2684). Turn the out-
put of the signal generator off. Connect the signal
generator to the LO port SMA connector using a
50

SMA cable.

4) Spectrum Analyzer: Connect the spectrum analyz-

er to the IF port SMA connector using a 50

SMA

cable. Set the center frequency of the spectrum
analyzer to 300MHz (MAX2683) or 900MHz
(MAX2684). Set the reference level of the spectrum
analyzer to -10dBm and the span to 1MHz.

Analysis

Turn on the power supply and RF and LO signal gener-
ators. The ammeter should read approximately 55mA
with the LO doubler enabled (ENX2 = GND) or 40mA
with the LO doubler disabled (ENX2 = V

). If evaluat-

ing the MAX2683, the spectrum analyzer should show
an output power of approximately -14dBm at a center
frequency of 300MHz. If evaluating the MAX2684, the
output power should read approximately -20dBm at a
center frequency of 900MHz. Be sure to take into
account cable, board, and balun losses when calculat-
ing power gain. Typical balun losses are 0.3dB at

300MHz for the MAX2683 EV kit and 0.8dB at 900MHz
for the MAX2684 EV kit.

Detailed Description

This section describes the circuitry surrounding the
MAX2683/MAX2684 EV kits. Figure 1 is the schematic
for the MAX2683/MAX2684 EV kits as assembled. For
more detailed information covering device operation,
refer to the MAX2683/MAX2684 data sheet.

RF Input

The RFIN port of the MAX2683/MAX2684 is internally
biased and requires a DC-blocking capacitor, as well as
a matching network for optimum power transfer.
Capacitor C1 functions as a DC block, while inductor L1
and capacitor C2 function as a matching network, tuning
the RF input of the device for maximum gain at 3.6GHz.

LO Input and LO Frequency

Doubler Control

The MAX2683/MAX2684 include a logic-level-enabled
LO frequency doubler. Jumper JU1 controls the LO
doubler. A logic-level low on the ENX2 pin enables the
frequency doubler, and the external LO signal source
operates at half frequency. A logic-level high on the
ENX2 pin disables the frequency doubler, and the
external LO signal source operates at full frequency.
Half-frequency LO signals are applied to the LOX2
port, while full-frequency LO signals are applied to the
LOX1 port. Both ports are internally biased and require
a DC-blocking capacitor. The unused LO port should
be left unconnected.

The MAX2683/MAX2684 EV kits, as assembled, are con-
figured for operation of the LO signal source at half fre-
quency. Capacitor C6 functions as a DC block, while
inductor L5 improves the return loss of the port. The LOX1
port is left unconnected for half-frequency operation.

To evaluate the device with full-frequency operation of
the LO source, remove inductor L5 and leave the LOX2
port unconnected (Figure 2). Short resistor R4 with a
0

resistor. Capacitor C6 now functions as the DC

block for the LOX1 port.

IF Output

The MAX2683/MAX2684 incorporate differential, open-
collector IF output ports for use in either differential or
single-ended applications. To ease evaluation of the
devices, the MAX2683/MAX2684 EV kits utilize a balun
to convert the differential signal to a single-ended sig-
nal compatible with 50

test equipment. The IF output

of the MAX2683 is tuned for an IF frequency of
300MHz, while the IF output of the MAX2684 is tuned
for an IF frequency of 900MHz. Inductors L3 and L4
provide DC biasing and impedance matching of the

Evaluate: MAX2683/MAX2684

MAX2683/MAX2684 Evaluation Kits

_______________________________________________________________________________________

Evaluate: MAX2683/MAX2684

IFOUT+, and IFOUT- ports. Resistor R3 resistively ter-
minates the IF output. Capacitors C8 and C9 provide
impedance matching in addition to DC blocking. In the
MAX2683, C10 is also part of an impedance-matching
network. The balun provides differential to single-ended
conversion as well as 4:1 impedance transformation.
The IF output is then connected to the IF port SMA con-
nector.

Linearity and Supply Current Adjustment

The MAX2683/MAX2684 allow the linearity and supply
current of the device to be adjusted via an external
resistor, R1, to ground. Increased linearity also results
in increased supply current. The MAX2683/MAX2684
EV kits are assembled with a nominal R1 value of
1.21k

. Replace R1 with a resistor value in the range of

820

to 2k to experiment with the linearity of the

device.

Layout and Bypassing

Good PC board layout is an essential aspect of RF cir-
cuit design. The EV kits' PC board can serve as a guide
for laying out a board using the MAX2683/MAX2684.
Keep PC board trace lengths as short as possible to
minimize parasitics and losses. Keep bypass capaci-
tors as close to the device as possible with low-induc-
tance connections to the ground plane.

Capacitor C4, placed near the VCC connection, and
capacitors C3 and C7, placed near the device, help to
reduce any high-frequency crosstalk. Capacitor C12
and resistor R2, placed near the ENX2 pin on the
device, help to filter out any noise that may be coupled
into the ENX2 pin.

MAX2683/MAX2684 Evaluation Kits

_______________________________________________________________________________________

SMA

BALUN TOKOB4F

BIAS

GND

IFOUT+

GND

IFOUT-

GND

OPEN

C5
OPEN

VCC

GND

RFIN

GND

LOX2

LOX1

C7
1000pF

C10*

3.3pF

L4*

39nH

L3*

39nH

R3*
1.50k

ENX2

C4
10

µF

10V

C3
100pF

R1
1.21k

3300pF

SMA

LOX

100pF

3.9nH

1.2nH

C2
1pF

GND

SMA
RFIN

JU1

1.21k

LOX1

LO MODE

LOX2

C12
100pF

MAX2683
MAX2684

8.2pF

VCC

* VALUES ARE FOR MAX2683 EV KIT ONLY.
REFER TO COMPONENT LIST FOR
MAX2684 VALUES.

Figure 1. MAX2683/MAX2684 EV Kits Schematic

Figure 2. MAX2683/MAX2684 Full-Frequency LO Port
Configuration

INPUT

OPEN

SHORT

100pF

LOX2

LOX1

MAX2683
MAX2684

Part Number MAX2684EVKIT