19-1670; Rev 0; 7/00
MAX2740 Evaluation Kit
General Description
The MAX2740 evaluation kit (EV kit) simplifies testing of
the MAX2740 GPS receiver. This kit allows evaluation of
the device’s LNA, mixers, variable gain amplifier (VGA),
fixed gain amplifier, voltage-controlled oscillator (VCO),
and synthesizer.
The EV kit provides 50Ω SMA connectors for all signal
inputs and outputs. A varactor-based tank circuit is pro-
vided for the on-chip VCO and is phase locked with the
on-chip phase-locked loop (PLL).
o
Differential Baseband Outputs
o
+2.7V to +3.3V Single-Supply Operation
o
SMA Connectors on All Signal Ports
Features
Evaluates: MAX2740
Ordering Information
PART
MAX2740EVKIT
TEMP.RANGE
-40°C to +85°C
IC PACKAGE
48 TQFP-EP*
*Exposed Paddle
Component List
DESIGNATION
C1
C2, C10, C14,
C18, C20, C21,
C32, C33, C35,
C36, C37, C38,
C43
C3
QTY
1
DESCRIPTION
10µF
±10%
tantalum capacitor
AVX TAJC106K016R
1000pF
±
10% ceramic capacitors
(0402)
Murata GRM36X7R102K050A
12pF
±5%
ceramic capacitor
(0402)
Murata GRM36COG120J050A
0.015µF
±10%
ceramic capacitors
(0402)
Murata GRMX5R153K016A
100pF
±5%
ceramic capacitors
(0402)
Murata GRM36COG101J050A
7pF
±0.1pF
ceramic capacitor
(0402)
Murata GRM36COG070B050A
Leave sites open
DESIGNATION
C40
QTY
1
DESCRIPTION
2.7pF
±0.1pF
ceramic capacitor
(0402)
Murata GRM36COG2R7B050A
3pF
±0.1pF
ceramic capacitor
(0402)
Murata GRM36COG030B050A
2pF
±0.1pF
ceramic capacitor
(0402)
Murata GRM36COG020B050A
BBY 51-03W Siemens tuning
diode
100Ω variable resistor
Bourns 3796W Digi-Key
100Ω
±5%
resistors (0402)
12.1kΩ
±1%
resistors (0402)
2.74kΩ
±1%
resistors (0402)
1.21kΩ
±1%
resistors (0402)
2kΩ
±1%
resistors (0402)
453Ω
±1%
resistor (0402)
15kΩ
±1%
resistor (0402)
220nH inductors
Toko LL1608-FSR22J
8.2nH inductors
Toko LL1608-FH8N2K
Leave site open
1.8nH inductor
Murata LQP10A1N8B00
0Ω resistors (0603)
12
C42
1
1
C44
1
C4, C8, C16,
C22−C31,
C5, C7, C13,
C15, C17, C19,
C39
D1
R2
R3, R4
R5, R8
R6, R7, R9, R10
R11, R12
R13−R18
R19
R20
L1, L2, L5
L8, L9
L3
L10
L11, L12
1
1
2
2
4
2
6
1
1
3
2
1
1
2
13
7
C6
C9, C12, C41,
C45, C46, C47
1
6
________________________________________________________________
Maxim Integrated Products
1
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.
MAX2740 Evaluation Kit
Evaluates: MAX2740
Component List (continued)
DESIGNATION
U1
U2
J3−J22
JU1−JU4, JU7,
JU8, JU9
VCC, GND
—
—
QTY
1
1
20
DESCRIPTION
MAX2740ECM 48-pin TQFP-EP*
MAX4122EUK SOT23-5
SMA connectors (PC mount)
Johnson 142-0701-201 or
Digi-Key J500-ND
2-pin headers
Test points
Digi-Key 5000K-ND
MAX2740 EV kit circuit board,
Rev. B
MAX2740 data sheet
Power Supply
Spectrum Analyzer
Balun (2)
Extra Voltage Source
RF Signal
Generators (2)
Table 1. Recommended Test Equipment
EQUIPMENT
DESCRIPTION
One HP 8648C or equivalent
and one HP 83712A or equivalent.
These should be capable of
delivering -70dBm to 0dBm of
output power in the 10MHz to
2000MHz frequency range. The
HP 8648C is required to test the
receive signal path, and the HP
83712A is a low-phase noise
source for the reference frequency.
Capable of providing at least
100mA at +2.7V to +3.3V
HP 8561E
M/A Com Anzac 96341
For external control of VGA
functions
7
2
1
1
*Note: U1 has an exposed paddle that requires it to be solder
attached to the circuit board to ensure proper functionality of
the part.
Component Suppliers
SUPPLIER
AVX
Coilcraft
Digi-Key
Infineon
Murata
Toko
PHONE
803-946-0690
847-639-6400
218-681-6674
408-501-6000
949-852-2001
708-297-0070
FAX
803-626-3123
847-639-1469
218-681-3380
408-501-2424
949-852-2002
708-699-1194
2) Connect V
CC
and GND. Set the supply voltage to
+3.0V. When the power is turned on, the current
should be approximately 55mA.
3) For evaluation of the LNA gain, first calibrate the
setup for cable losses. Connect the signal genera-
tor with 1575.42MHz at -30dBm to LNA_IN.
Connect LNA_OUT to the spectrum analyzer. The
measured power gain will be approximately 16dB.
4) Repeat the calibration procedure (step 3) for use on
the RF mixer. Connect the 1575.42MHz (-30dBm)
signal source to the RFMIX_IN+. Connect
RFMIX_OUT+ and RFMIX_OUT- through the balun
to the spectrum analyzer. At 135MHz, losses due to
the Anzac balun are approximately 0.65dB. The
measured power gain should be approximately
22dB. If a balun is unavailable, a single-ended
measurement of the output can be taken. Terminate
the unused output in 50Ω, and add 3dB to the final
output power measurement.
5) Repeat the calibration procedure (step 3) for use
on the IF mixer. Use the baluns on the input and
output to allow a fully differential measurement.
Connect IFMIX_IN+ and IFMIX_IN- through one
balun to the 135.42MHz (-47dBm) signal source.
Connect IFMIX_OUT+ and IFMIX_OUT- through the
second balun to the spectrum analyzer. At 135MHz,
losses due to the Anzac balun are approximately
0.65dB, and at 15MHz, the losses are approximately
0.3dB. For gain calculation, the attenuation due to
Note:
Please indicate that you are using the MAX2740 when
contacting these component suppliers.
Quick Start
The MAX2740 EV kit is fully assembled and factory test-
ed. Follow the instructions in the
Connections and
Setup
section. Table 1 lists the test equipment recom-
mended to verify MAX2740 operation. This list is intend-
ed as a guide only; substitutions may be possible.
Figure 1 shows the MAX2740 EV kit schematic.
Connections and Setup
The customer has the option of closing the PLL loop or
externally driving the LO. The PLL loop is closed on the
assembled EV kit. To externally drive the LO, remove
L10 and place C9. A 1440MHz, -10dBm signal is
required at the TANK SMA connector. Perform the fol-
lowing steps to evaluate the MAX2740:
1) Verify that jumpers JU1, JU2, and JU7, JU8, JU9
are in place.
2
_______________________________________________________________________________________
MAX2740 Evaluation Kit
the 2kΩ load resistor on each output must be taken
into account. The total differential gain calculation,
assuming two baluns, is:
P
IN
=
P
IN(MEAS)
−
P
LOSS(BALUN AT 135MHz)
P
OUT
=
P
OUT(MEAS)
+
P
LOSS(BALUN AT 15MHz)
+
P
LOSS(LOAD)
where:
100
P
LOSS(LOAD)
=
20log
½ =
32.3dB
4100
Power_Gain = P
OUT
−
P
IN
The measured power gain should be approximately
36dB.
6) To control the VGA gain, connect the second power
supply to the nongrounded terminal of jumper JU3,
and open jumper JU4. The VGA gain will be evalu-
ated at V
GC
= 0.5V and 2.5V. It is important to note
that the VGA gain and subsequent FGA gain are
voltage-gain measurements. Repeat the calibration
procedure as before (step 3). Connect VGA_IN+
and VGA_IN- through one balun to the 15.42MHz
(-27dBm) signal source. Connect VGA_OUT+ and
VGA_OUT- through the second balun to the spec-
trum analyzer. At 15.42MHz, losses due to the
Anzac balun are approximately 0.3dB. For gain cal-
culation, the attenuation due to the 2kΩ load resis-
tor on each output must be taken into account. The
total differential gain calculation, assuming two
baluns, is:
P
IN
=
P
IN(MEAS)
−
P
LOSS(BALUN AT 15MHz)
P
OUT
=
P
OUT(MEAS)
+
P
LOSS(BALUN AT 15MHz)
+
P
LOSS(LOAD)
where:
100
P
LOSS(LOAD)
=
20log
½ =
32.3dB
4100
Voltage_Gain=P
OUT
−
P
IN
−
6dB
The measured voltage gain at V
GC
= 2.5V should
be approximately 15dB. The gain range should be
more than 50dB.
7) The FGA procedure will be similar to the VGA,
minus the need for the second voltage source.
Repeat the calibration procedure as before (step
3). Connect FGA_IN+ and FGA_IN- through one
balun to the 15.42MHz (-43dBm) signal source.
Connect FGA_OUT+ and FGA_OUT- through the
second balun to the spectrum analyzer. At
15.42MHz, losses due to the Anzac balun are
approximately 0.3dB. Calculations are identical to
that of the VGA. The measured voltage gain should
be approximately 40dB.
Evaluates: MAX2740
Adjustments and Control
The MAX2740 EV kit is configured with a 100kΩ trim pot
for setting and adjusting the VGA gain. To use an exter-
nal supply, remove the 2-pin series and shunt jumpers
(JU3 and JU4). Connect the supply directly to the
nongrounded terminal of JU3.
Detailed Description
The following sections cover the EV kit’s circuit blocks
in detail. (Refer to the MAX2740 data sheet for addition-
al information.)
LNA
The LNA is a two-stage amplifier using feedback to set
the gain. The circuit requires input and output match-
ing. It is externally biased through the output matching
network.
RF MIXER
The RF mixer is a double-balanced Gilbert cell with
local LO drive provided from a low-impedance differen-
tial pair. The second RF input is brought out to a sepa-
rate pin for external decoupling on pin 7. The IF output
is delivered through low-output-impedance emitter fol-
lowers. The input is matched to 50Ω, and the outputs
are individually matched to 50Ω (100Ω differential).
The mixer is intended to drive a 400Ω SAW filter.
IF MIXER
The IF mixer is very similar to the RF mixer, except the
IF mixer input is fully differential. The emitter follower
outputs are intended to drive directly into a high-imped-
ance, differential, 3-pole lowpass filter made up of dis-
crete components.
_______________________________________________________________________________________
3
MAX2740 Evaluation Kit
Evaluates: MAX2740
VGA and FGA
The inputs and outputs of both circuits are differential.
The VGA has a useful gain-control range of >50dB. The
FGA was designed to deliver 40dB of differential gain
at the second IF frequency of 15.42MHz. In the appli-
cation, the FGA differential inputs are received from the
VGA outputs through a balanced lowpass filter circuit.
The FGA’s differential output is designed to drive a dig-
itizer with a typical load impedance of 4kΩ differential.
PC Board Layout/Construction
The MAX2740 EV kit can serve as a board layout guide.
Keep PC board trace lengths as short as possible to
minimize parasitics. Keep decoupling capacitors close
to the device, with a low inductance via connection to
the ground plane. The GLSOUT signal must not be
routed parallel to the REF input to avoid loss of frequen-
cy lock due to coupling between the two signals.
The MAX2740 EV kit PC board uses 14mil-wide traces
for 50Ω traces. The PC board has an 8mil layer profile
to the ground plane on FR4, with a dielectric constant
of 4.5, and 75mil trace-to-ground-plane spacing.
4
_______________________________________________________________________________________
MAX2740 Evaluation Kit
Evaluates: MAX2740
+3VA
JU9
+3VA
J1
+
C1
10µF
JU1
L1
220nH
L2
220nH
+3VA_VCO
C10
1000pF
+3VA_AN
C2
1000pF
C4
0.015µF
C5
100pF
L8
8.2nH
C40
2.7pF
C41
OPEN
J22
SMA
L12
0Ω
C12
OPEN
L11
0Ω
C45
OPEN
J21
SMA
+3VA
JU8
RFMIX_OUT+
J20
J19
RFMIX_OUT-
SMA SMA
C35
1000pF
C46
OPEN
C47
OPEN
C33
1000pF
C32
1000pF
IFMIX_OUT+
J18
J17
IFMIX_OUT-
SMA
SMA
VCC
C39
100pF
J2
GND
JU2
C37
1000pF
R12
1.1k
C38
1000pF
R11
1.1k
43
IFRMIXN_OUT
R3
100Ω
C43
1000pF
38
IFMIXN_IN
39
IFMIX_IN
L9
8.2nH
44
FRMIX_OUT
LNA_OUT
+3VA
C42
3pF
48
47
46
45
42
41
40
VCCIF_MIX
GND
LNA_OUT
GND
GND
VCCRF_MIX
IFRMIX_OUT-
FRMIX_OUT+
GNDIF_MIX
FRMIX_IN+
IFMIX_IN+
IFMIX_IN-
37
1
GND_2LNA
IFMIX_OUT+
IFMIX_OUT-
VGA_IN+
VGA_IN-
GND
36
35
34
33
32
31
30
29
28
27
26
25
C31
0.015µF
C30
0.015µF
C29
0.015µF
R13
2k
J16
SMA
IFMIX_OUT+
J15
IFMIX_OUT-
SMA
J14
VGA_IN+
SMA
J13
VGA_IN-
SMA
2
GND_2LNA
LNA_IN
J3
SMA
L3
NO_LOAD
C6
7pF
3
4
5
6
+3VA
JU4
R2
100k
JU3
C8
0.015µF
C7
100pF
+3V_AN
9
10
11
+3V_VCO
VCC_ANA
GND_ANA
GND
7
8
LNA_IN
GND_1LNA
GND_1LNA
GND_AMIX
FRMIX_IN-
AGCON
R14
2k
C28
0.015µF
C27
0.015µF
R15
2k
U1
MAX2740
VGA_OUT+
VGA_OUT-
GND
FGA_IN+
FGA_IN-
GND
FGA_OUT+
REF_IN
J12
VGA_OUT+
SMA
J11
VGA_OUT-
SMA
C26
0.015µF
C25
0.015µF
R16
2k
J10
SMA
FGA_IN+
J9
FGA_IN-
SMA
C24
0.015µF
R17
2k
C23
0.015µF
12
VCC_VCO
GND_VCO
GND_VCO
GLS_OUT
GND_DIG
DOWN
GND_DIG
VCC_DIG
J8
SMA
FGA_OUT+
13
14
15
16
17
18
UP
19
20
21
22
23
R20
15k
C13
100pF
D1
SIEMENS
BBY 51-03W
C3
12pF
C44
2pF
J4
SMA
L10
1.8nH
C20
1000pF
R19
453Ω
J5
SMA
GLS_OUT
J6
SMA
REF_IN
C21
1000pF
FGAN_OUT
24
FGA_OUT-
C22
0.015µF
R18
2k
J7
SMA
FGA_OUT_
TANK
C9
OPEN
C16
0.015µF
C17
100pF
L5
220nH
JU7
TANK
+3VA
R9
2.74k
R4
100Ω
+3VA
5
MAX4122
R5
12.1k
U2
R8
12.1k
C18
1000pF
R6
2.74k
C15
100pF
R7
2.74k
C19
100pF
R10
2.74k
2
+
3
-
4
C14
1000pF
Figure 1. MAX2740 EV Kit Schematic
_______________________________________________________________________________________
GND
5
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