Maxim MAX2740 Evaluation kit Datasheet

19-1670; Rev 0; 7/00
MAX2740 Evaluation Kit
Features
♦ Differential Baseband Outputs
♦ +2.7V to +3.3V Single-Supply Operation
♦ SMA Connectors on All Signal Ports
Ordering Information
PART
MAX2740EVKIT
TEMP.RANGE
IC PACKAGE
-40°C to +85°C
48 TQFP-EP*
*Exposed Paddle
Component List
DESIGNATION
QTY
DESCRIPTION
C40
1
2.7pF ±0.1pF ceramic capacitor
(0402)
Murata GRM36COG2R7B050A
C42
1
3pF ±0.1pF ceramic capacitor
(0402)
Murata GRM36COG030B050A
C44
1
2pF ±0.1pF ceramic capacitor
(0402)
Murata GRM36COG020B050A
0.015µF ±10% ceramic capacitors
(0402)
Murata GRMX5R153K016A
D1
1
BBY 51-03W Siemens tuning
diode
R2
1
100Ω variable resistor
Bourns 3796W Digi-Key
100pF ±5% ceramic capacitors
(0402)
Murata GRM36COG101J050A
R3, R4
2
100Ω ±5% resistors (0402)
7
R5, R8
2
12.1kΩ ±1% resistors (0402)
1
7pF ±0.1pF ceramic capacitor
(0402)
Murata GRM36COG070B050A
DESIGNATION
QTY
C1
1
10µF ±10% tantalum capacitor
AVX TAJC106K016R
C2, C10, C14,
C18, C20, C21,
C32, C33, C35,
C36, C37, C38,
C43
12
1000pF ±10% ceramic capacitors
(0402)
Murata GRM36X7R102K050A
C3
1
12pF ±5% ceramic capacitor
(0402)
Murata GRM36COG120J050A
13
C4, C8, C16,
C22−C31,
C5, C7, C13,
C15, C17, C19,
C39
C6
C9, C12, C41,
C45, C46, C47
6
DESCRIPTION
Leave sites open
R6, R7, R9, R10
4
2.74kΩ ±1% resistors (0402)
R11, R12
2
1.21kΩ ±1% resistors (0402)
R13−R18
6
2kΩ ±1% resistors (0402)
R19
1
453Ω ±1% resistor (0402)
R20
1
15kΩ ±1% resistor (0402)
L1, L2, L5
3
220nH inductors
Toko LL1608-FSR22J
L8, L9
2
8.2nH inductors
Toko LL1608-FH8N2K
L3
1
Leave site open
L10
1
1.8nH inductor
Murata LQP10A1N8B00
L11, L12
2
0Ω resistors (0603)
________________________________________________________________ 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.
Evaluates: MAX2740
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 provided for the on-chip VCO and is phase locked with the
on-chip phase-locked loop (PLL).
Evaluates: MAX2740
MAX2740 Evaluation Kit
Component List (continued)
DESIGNATION
QTY
DESCRIPTION
U1
1
MAX2740ECM 48-pin TQFP-EP*
U2
1
MAX4122EUK SOT23-5
J3−J22
20
SMA connectors (PC mount)
Johnson 142-0701-201 or
Digi-Key J500-ND
JU1−JU4, JU7,
JU8, JU9
7
2-pin headers
VCC, GND
2
Test points
Digi-Key 5000K-ND
—
1
MAX2740 EV kit circuit board,
Rev. B
—
1
MAX2740 data sheet
*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
PHONE
FAX
AVX
803-946-0690
803-626-3123
Coilcraft
847-639-6400
847-639-1469
Digi-Key
218-681-6674
218-681-3380
Infineon
408-501-6000
408-501-2424
Murata
949-852-2001
949-852-2002
Toko
708-297-0070
708-699-1194
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 tested. Follow the instructions in the Connections and
Setup section. Table 1 lists the test equipment recommended to verify MAX2740 operation. This list is intended 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 following steps to evaluate the MAX2740:
1) Verify that jumpers JU1, JU2, and JU7, JU8, JU9
are in place.
2
Table 1. Recommended Test Equipment
EQUIPMENT
RF Signal
Generators (2)
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.
Power Supply
Capable of providing at least
100mA at +2.7V to +3.3V
Spectrum Analyzer
HP 8561E
Balun (2)
M/A Com Anzac 96341
Extra Voltage Source
For external control of VGA
functions
2) Connect VCC 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 generator 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
_______________________________________________________________________________________
MAX2740 Evaluation Kit
PIN = PIN(MEAS) − PLOSS(BALUN AT 135MHz)
POUT = POUT(MEAS) + PLOSS(BALUN AT 15MHz)
+ PLOSS(LOAD)
where:
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.
Adjustments and Control
 100 
PLOSS(LOAD) = 20log
 = 32.3dB
 4100 
Power_Gain = POUT − PIN
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 evaluated at VGC = 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 spectrum analyzer. At 15.42MHz, losses due to the
Anzac balun are approximately 0.3dB. For gain calculation, the attenuation due to the 2kΩ load resistor on each output must be taken into account. The
total differential gain calculation, assuming two
baluns, is:
PIN = PIN(MEAS) − PLOSS(BALUN AT 15MHz)
POUT = POUT(MEAS) + PLOSS(BALUN AT 15MHz)
+ PLOSS(LOAD)
where:
 100 
PLOSS(LOAD) = 20log
 = 32.3dB
 4100 
Voltage_Gain=POUT − PIN − 6dB
The MAX2740 EV kit is configured with a 100kΩ trim pot
for setting and adjusting the VGA gain. To use an external 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 additional information.)
LNA
The LNA is a two-stage amplifier using feedback to set
the gain. The circuit requires input and output matching. 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 differential pair. The second RF input is brought out to a separate pin for external decoupling on pin 7. The IF output
is delivered through low-output-impedance emitter followers. 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-impedance, differential, 3-pole lowpass filter made up of discrete components.
The measured voltage gain at VGC = 2.5V should
be approximately 15dB. The gain range should be
more than 50dB.
_______________________________________________________________________________________
3
Evaluates: MAX2740
the 2kΩ load resistor on each output must be taken
into account. The total differential gain calculation,
assuming two baluns, is:
Evaluates: MAX2740
MAX2740 Evaluation Kit
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 application, 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 digitizer 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 frequency 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
+3VA
JU8
RFMIX_OUT+
J20
J19 RFMIX_OUTSMA SMA
C35
1000pF
JU9
C46
OPEN
+3VA_AN
C47
OPEN
C2
1000pF
C33
1000pF
3
C6
7pF
L3
NO_LOAD
4
5
6
+3VA
7
C7
100pF
JU4
R2
100k
JU3
C8
0.015µF
8
IFMIX_OUT-
LNA_IN
VGA_IN+
GND_1LNA
VGA_IN-
GND_1LNA
GND
U1
GND_AMIX
VGA_OUT+
MAX2740
FRMIX_IN-
VGA_OUTGND
AGCON
9
11
+3V_VCO
VCC_ANA
FGA_IN+
GND_ANA
FGA_IN-
GND
GND
C3
12pF
C44
2pF
C9
OPEN
J4
SMA
+3VA
R10
2.74k
R9
2.74k
5
MAX4122
R5
12.1k
+3
-
U2
2 4
L5
220nH
JU7
C20
1000pF
C21
1000pF
R19
453Ω
J5
SMA
GLS_OUT
GND_DIG
23
GND_DIG
GND
22
21
20
REF_IN
GLS_OUT
19
UP
18
VCC_DIG
DOWN
17
16
C16
0.015µF
C17
100pF
TANK
+3VA
GND_VCO
L10
1.8nH
R20
15k
R4
100Ω
15
GND_VCO
FGA_OUT+
14
13
TANK
12 VCC_VCO
D1
SIEMENS
BBY 51-03W
36
35
34
C31
0.015µF
R13
2k
C30
0.015µF
C29
0.015µF
R14
2k
33
32
31
29
28
C27
0.015µF
R15
2k
C26
0.015µF
R16
2k
C25
0.015µF
R17
2k
C23
0.015µF
J14 VGA_IN+
SMA
J12 VGA_OUT+
SMA
J11 VGA_OUTSMA
J9
FGA_INSMA
C24
0.015µF
25
J15 IFMIX_OUTSMA
J10
SMA FGA_IN+
27
26
J16
SMA IFMIX_OUT+
J13 VGA_INSMA
C28
0.015µF
30
+3V_AN
10
C13
100pF
37
IFMIX_OUT+
2 GND_2LNA
LNA_IN
J3
SMA
GNDIF_MIX
39 IFMIX_IN
IFMIX_IN+
VCCRF_MIX
GND_2LNA
R3
100Ω
40
R11
1.1k
VCCIF_MIX
R12
1.1k
41
C38
1000pF
45
46
47
LNA_OUT
GND
48
C43
1000pF
1
C37
1000pF
C42
3pF
L9
8.2nH
FRMIX_IN+
LNA_OUT
+3VA
C45
OPEN
GND
J22
SMA
C12
OPEN
42
C41
OPEN
GND
C40
2.7pF
C32
1000pF
L11
0Ω
L12
0Ω
L8
8.2nH
43 IFRMIXN_OUT
C5
100pF
IFRMIX_OUT-
C4
0.015µF
44 FRMIX_OUT
GND
FGA_OUT-
L2
220nH
JU2
C39
100pF
C10
1000pF
FRMIX_OUT+
J2
JU1
+ C1
10µF
FGAN_OUT 24
J1
IFMIX_OUT+
J18
J17 IFMIX_OUTSMA
SMA
38 IFMIXN_IN
VCC
J21
SMA
+3VA_VCO
IFMIX_IN-
L1
220nH
+3VA
Evaluates: MAX2740
+3VA
J8
SMA FGA_OUT+
C22
0.015µF
R18
2k
J6
SMA
REF_IN
J7
SMA
FGA_OUT_
C19
100pF
R8
12.1k
C18
1000pF
R6
2.74k
C14
1000pF
R7
2.74k
C15
100pF
Figure 1. MAX2740 EV Kit Schematic
_______________________________________________________________________________________
5
Evaluates: MAX2740
MAX2740 Evaluation Kit
1.0"
1.0"
Figure 2. MAX2740 EV Kit PC Board Layout—Component Side
Figure 3. MAX2740 EV Kit PC Board Layout—Ground Plane
1.0"
Figure 4. MAX2740 EV Kit PC Board Layout—Power Plane
6
_______________________________________________________________________________________
MAX2740 Evaluation Kit
Evaluates: MAX2740
NOTES
_______________________________________________________________________________________
7
Evaluates: MAX2740
MAX2740 Evaluation Kit
NOTES
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
© 2000 Maxim Integrated Products
Printed USA
is a registered trademark of Maxim Integrated Products.
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