19-2158; Rev 0; 9/01
MAX3271 Evaluation Kit
General Description
The MAX3271 evaluation kit (EV kit) allows complete
evaluation of the MAX3271 transimpedance amplifier.
The EV kit includes a circuit that emulates the high-
speed, zero-to-peak current input signal that would be
produced by a photodiode. The kit also includes a cali-
bration circuit that allows accurate bandwidth measure-
ment. The MAX3271 EV kit is fully assembled and tested.
o
Fully Assembled and Tested
o
Includes Photodiode Emulation Circuit
o
Calibration Circuit for Accurate Bandwidth
Measurement
Features
Evaluates: MAX3271
Component Suppliers
SUPPLIER
AVX
Coilcraft
Murata
PHONE
843-444-2863
847-639-6400
415-964-6321
FAX
843-626-3123
847-639-1469
415-964-8165
PART
MAX3271EVKIT
Ordering Information
TEMP. RANGE
-40°C to +85°C
IC PACKAGE
Chip-On-Board
Note:
Please indicate that you are using the MAX3271 when
contacting these component suppliers.
Component List
DESIGNATION
C1, C5, C6, C8
QTY
4
DESCRIPTION
0.01µF
±10%
ceramic
capacitors (0402)
Murata GRM36X7R103K016A
0.1µF
±10%
ceramic capacitors
(0402)
Murata GRM36X5R104K010AD
10µF
±10%
tantalum capacitor
AVX TAJC106K010R
100pF
±10%
ceramic capacitor
(0402)
Murata GRM36X7R102K050AD
SMA connectors (edge-mount,
round contact)
Note:
Cut center pin to
approximately 1/16in length.
1
×
2-pin header (0.1in centers)
56nH inductor
Coilcraft 0805HS-560XKBC
0Ω resistors
DESIGNATION
R1A, R1B, R5A,
R5B
R3, R7
R4, R8
TP1, J4, J5
U1
Outside Vendor
to Supply
Outside Vendor
to Supply
None
None
QTY
4
2
2
3
1
0
DESCRIPTION
499Ω
±1%
resistors (0402)
4.99kΩ
±1%
resistors (0402)
49.9Ω
±1%
resistors (0402)
Test points
Digi-Key 5000K-ND
MAX3271E/D die
1mil Au wire (8 bonds)
American Fine Wire EL4-7 TS8
AW8
Epoxy, Ablefilm 84-1 LMI
MAX3271 EV kit circuit board
MAX3271 data sheet
C2–C4, C9, C10
5
C7
1
C11
1
0
1
1
J1–J3, J6, J7
5
JU1
L1
L2, L3
1
1
2
________________________________________________________________
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.
MAX3271 Evaluation Kit
Evaluates: MAX3271
Quick Start
1) Connect a signal source to IN (J1). Set the signal
amplitude to 40mVp-p (this may require some atten-
uation between the source and the MAX3271 EV kit.)
The signal should have a data rate of 2.5Gbps.
2) Connect OUT+ and OUT- to the 50Ω inputs of a
high-speed oscilloscope at J2 and J3.
3) Remove the shunt from jumper JU1.
4) Connect a +3.3V supply to the VCC terminal and
ground to the GND terminal.
5) The differential signal at the oscilloscope should be
between 75mVp-p and 150mVp-p.
10
(P
AVE /
10)
I
AVE
=
×ρ
1000
(ρ
=
photodiode responsivity in A/W)
3) Calculate the AC signal current and adjust the signal
generator to obtain it.
r
−
1
I
AC
=
2
×
I
AVE
×
e
r
e
+
1
For example, to emulate a photodiode with an average
power of -16dBm and an extinction ratio of 10:
1) -16dBm optical power will produce 25µA of average
input current (assume photodiode responsivity of
1A/W). Set the DC current input to 25µA at TP1.
2) The signal amplitude is 2 I
AVE
(r
e
-1)/(r
e
+1) = 41µA.
To generate this current through the 1000Ω input
resistors, set the signal source to produce an output
level of 41µA
✕
1000Ω = 41mVp-p.
Photodiode Emulation
The following procedure can be used to emulate the
high-speed current signal generated by a photodiode:
1) Select the desired optical power (P
AVE
, dBm) and
extinction ratio (r
e
).
2) Calculate the average current (I
AVE
, A). Set the DC
current at TP1 to I
AVE
.
Detailed Description
The MAX3271 EV kit allows characterization without a
photodiode. The MAX3271 is designed to accept a DC-
coupled input from a high-speed photodiode. Diode
currents may have 20µAp-p to 2mAp-p AC current with
a DC component from 10µA to 1mA. The high-speed
current source of the photodiode is emulated on the EV
kit using separate AC and DC paths. The AC signal is
supplied from a standard 50Ω lab source that delivers
power to an onboard termination resistor. A current is
then generated from the voltage signal by a resistor
with low stray capacitance. The effect of the DC photo-
diode current may be emulated by a current source at
TP1. An isolation resistor prevents the DC source from
loading the AC path.
The values of the series resistive elements, R1A and
R1B, have been carefully selected so that the band-
width of the transimpedance amplifier is not altered.
Surface-mount resistors have parasitic capacitance that
reduces their impedance at frequencies above 1GHz.
Changes to R1A and R1B must be evaluated using the
calibration network.
Noise Measurement
Remove R1A and R1B before attempting noise measure-
ments to minimize input capacitance. With R1A and R1B
removed, the total capacitance at the IN pin is approxi-
mately 0.85pF. Refer to the
Layout Considerations
sec-
tion in the MAX3271 data sheet for more information.
Adjustment and Control Descriptions (see Quick Start)
COMPONENT
JU1
TP1
NAME
OFFSET CORRECTION
DC CURRENT INPUT
FUNCTION
Install a shunt on JU1 to disable offset correction.
Apply DC current for photodiode emulation.
2
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