19-0409; Rev 1; 3/07
MAX3654 Evaluation Kit
________________General Description
The MAX3654 evaluation kit (EV kit) is a factory-
assembled printed circuit board (PCB) that provides two
circuit versions—optical input and electrical input.
The optical circuit includes the photodiode bias circuitry,
an op amp for feed-forward AGC operation, and a balun
for single-ended 75Ω output. Through-hole pads are
provided to attach a triplexer analog photodiode. It is
important to select a photodiode with capacitance and
inductance in the anode and cathode connections as
symmetric as possible for optimum linearity.
The electrical circuit is normally configured with a 50Ω
input for use with conventional test and measurement
equipment and a 75Ω output. The 75Ω output can be
connected to 50Ω test and measurement equipment using
a minimum loss pad. If desired, the MAX3654 input can
also provide a 75Ω input by replacing R12 and R13 with
25Ω resistors.
♦
♦
♦
_________________________
Features
Fully Assembled and Tested
Optical and Electrical Inputs
Automatic Gain Control
Evaluates: MAX3654
_______________Ordering Information
PART
MAX3654EVKIT
TEMP RANGE
-40°C to +85°C
IC-PACKAGE
16 QFN
__________________________________________________ Evaluation Component List
DESIGNATION
C1, C2, C4, C5,
C19–C22
C3, C7, C8, C9,
C12, C16, C17,
C23, C24, C27,
C29
C6, C10, C11,
C25, C26
C13, C14, C28
R6, R18
R2
R3, R4, R5,
R16, R17
R1, R21
R7, R19
R9, R15
R12, R13
R8, R20
R22
QTY
8
11
5
3
2
1
6
2
2
2
2
2
1
DESCRIPTION
0.001μF
±10%
ceramic
capacitors (0402)
0.1μF
±5%
ceramic
capacitors (0603)
1μF 10V,
±10%
min ceramic
capacitors
33μF 10V,
±20%
min
tantalum capacitors
1.62kΩ
±1%
resistors (0402)
10Ω
±1%
resistor (0402)
100kΩ
±1%
resistors (0402)
1kΩ
±1%
resistors (0402)
2.43kΩ
±1%
resistors (0402)
20kΩ
±1%
resistors (0402)
12.1Ω
±1%
resistors (0402)
6.04kΩ
±1%
resistors (0402)
open (0402)
DESIGNATION
J2, J4
J3
TP1–TP13
JU1–JU3, JU5,
JU6
L1, L5
L2, L6
U1, U3
U2, U4
U5
U6
U7, U8
QTY
2
1
13
5
2
2
2
2
0
1
2
DESCRIPTION
BNC 75Ω, Edge Mount
Trompeter UCBJE20-1
SMA connector, tab contact,
Johnson, 142-0701-851
Test Points
2-pin headers, 0.1in centers
Bead, Murata
BLM15HD182SN1 (0402)
10μH inductor, TDK
MLF1608E100K (0603)
MAX3654ETE+
MAX4240EUK
Photodiode not supplied
Balun Pulse Engineering
CX2039
Balun Pulse Engineering
CX2038
__________________________________________
Maxim Integrated Products
1
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.
MAX3654 Evaluation Kit
Evaluates: MAX3654
_____________Component Suppliers
SUPPLIER
AVX
Pulse
Engineering
Murata
PHONE
803-448-9411
858-674-8100
770-436-1300
WEBSITE
www.avxcorp.com
www.pulseeng.com
www.murata.com
5)
6)
Connect a +5V supply to the VCC terminal, TP7
and ground to the GND terminal, TP8.
Apply 1.4V to TP12 to set the MAX3654 gain to
minimum, 43.5dBΩ. A voltage from 0.175V to
1.4V at TP12 adjusts the gain from 62dBΩ to
43.5dBΩ
Input and Output Signal Levels
When used in the electrical input configuration shown
in Figure 2, the MAX3654 is intended to operate with
AC input signal current from 175μA
P-P
to 1.6mA
P-P
. The
corresponding electrical input is -37dBm (0 < VAGC <
0.175V) to -18dBm (VAGC = 1.4V), on 50Ω. The
MAX3654 EV Kit can also be configured to provide
75Ω input impedance by replacing R12 and R13 with
25Ω resistors.
When used in the optical input configuration shown in
Figure 2, JU2 may be connected to R3 to configure the
MAX3654 for AGC operation based on the average
optical power level. In this case, the MAX3654
transimpedance is controlled by the average optical
power level, as measured by the voltage across R21.
The values of R1, R21 and R22 shown in Figure 1 will
provide an output level of 15dBmV/ch (+1dB) for
optical input signals ranging from -6dBm to +2dBm,
(OMI = 3.5%, N = 129) using a typical triplexer
photodiode. The total output signal level in this case is
15dBmV/ch + 10 log(129 channels) = 36dBmV, which
is the maximum operating level at which the specified
linearity will be achieved. Operating at higher outputs
may reduce MAX3654 performance.
Operating conditions (OMI, number of channels,
responsivity, etc) change the VAGC setting required for
a given output voltage. EV Kit AGC circuit gain can be
increased by adding a voltage-divider, R22, to the
op amp. To reduce gain the values of R1 and R21
should both be increased. Remember to keep the total
output at 36dBmV or less to maintain the desired
MAX3654 performance.
Note:
Please indicate that you are using the MAX3654 when
contacting these component suppliers.
________________________Quick Start
Optical Evaluation
1)
Attach triplexer photodiode to IN+ and IN- of the
MAX3654. The cathode normally connects to IN+.
The photodiode case should be grounded to the
most convenient ground via. Make certain that the
anode and cathode leads are symmetric in length
and orientation, lead lengths should normally be
about 5mm.
Set JU2 to R4 to manually adjust the gain with an
input from 0 to 1.4V on TP3.
Leave JU3 open for minimum hysteresis.
Set JU1 to R8 to enable the output signal.
Connect the signal output at J2 to a 75Ω
spectrum-analyser input. A minimum loss pad may
also be used to connect J2 to 50Ω test equipment.
Connect a +5V supply to the VCC terminal, TP1
and ground to the GND terminal, TP2.
Connect the photodiode bias supply to TP13.
Typically use +12V bias supply, or as required by
the photodiode.
2)
3)
4)
5)
6)
7)
Electrical Evaluation
1)
Connect a 50Ω signal source to IN at J3. Set the
input signal level to P
IN
= -18dBm, so that the
voltage on 50Ω produces the maximum input
level of 1.6mA
P-P
.
Connect the RF output at J4 to a 75Ω spectrum
analyser input. A minimum loss pad may also be
used to connect J4 to 50Ω test equipment.
Leave JU6 open for minimum hysteresis.
Set JU5 to R20 to enable output.
Photodiode Lead Configuration
Photodiode lead parasitic impedances can significantly
effect performance of the MAX3654. It is especially
important that the anode and cathode connections are
electrically symmetric. Refer to Figure 1 in the
MAX3654 data sheet. Note that the EV Kit layout is
designed to minimize capacitance to ground in the
input signal path.
2)
3)
4)
2
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