General Description
The MAX3266 and MAX3267 evaluation kits (EV kits)
simplify evaluation of the MAX3266 and MAX3267
transimpedance preamplifiers.
The EV kits include 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-
ments.
The MAX3266 and MAX3267 EV kits are fully assem-
bled and tested.
Features
o Fully Assembled and Tested
o Includes Photodiode Emulation Circuit
o Calibration Circuit for Accurate Bandwidth
Measurements
Quick Start
1) Connect a signal source to INPUT. Set the signal
amplitude to 50mVp-p (this may require some attenu-
ation between the source and the MAX3266 EV kit.)
The signal should have data rate between 500Mbps
and 1250Mbps.
2) Connect OUT+ and OUT- to the 50
inputs of a
high-speed oscilloscope.
3) Remove shunts from jumpers JU1 and JU2.
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 50mVp-p and 100mVp-p.
Detailed Description
The MAX3266 is designed to accept a DC-coupled
input from a high-speed photodiode, with an amplitude
of 10A to 1mA zero-to-peak. Unfortunately, high-speed
current sources are not common laboratory equipment.
Also, because the MAX3266 provides a DC bias for the
photodiode, it cannot be DC coupled to signal sources.
Evaluate: MAX3266/MAX3267
MAX3266/MAX3267 Evaluation Kits
________________________________________________________________ Maxim Integrated Products
1
19-1447; Rev 2; 6/01
SUPPLIER
PHONE
FAX
AVX
843-444-2863
843-626-3123
Component List
Central
Semiconductor
516-435-1110
516-435-1824
Murata
415-964-6321
415-964-8165
Zetex
516-543-7100
516-864-7630
PART
MAX3266EVKIT-SO
MAX3267EVKIT-SO
0C to +70C
0C to +70C
TEMP. RANGE
IC PACKAGE
8 SO
8 SO
Ordering Information
Component Suppliers
SMA connectors (Edge Mount)
5
J1J5
33F 10%, 25V min tantalum
capacitors AVX TAJE336K025
2
C8, C9
0.1F, 25V min, 10% ceramic
capacitors
9
C3, C5, C6,
C12C17
1000pF, 10% ceramic capacitors
6
C1, C2, C4, C7,
C10, C11
DESCRIPTION
QTY
DESIGNATION
Ferrite beads Murata BLM11A601S
2
L1, L2
Shunts for JU1, JU2
2
None
2-pin headers (0.1" centers)
2
JU1, JU2
Open
4
J11J14
User-supplied optical module
0
U4
MAX400CSA (8-pin SO)
1
U3
CMPT3906 PNP transistor
1
U2
MAX3266CSA or MAX3267CSA
(8-pin SO)
1
U1
10k
potentiometer
1
R7
10k
, 5% resistors
2
R6, R8
1k
potentiometer
1
R5
1k
, 5% resistors
2
R4, R12
49.9
, 1% resistors
2
R3, R11
See Table 1
4
R1, R2, R9,
R10
U5
0
User-supplied optical module
VCC, +15V,
GND
3
Test points
None
1
MAX3266/MAX3267 evaluation kit
(rev. b) circuit board
None
1
MAX3266/MAX3267 data sheet
Note: Please indicate that you are using the MAX3266/MAX3267
when contacting these component suppliers.
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.
Evaluate: MAX3266/MAX3267
MAX3266/MAX3267 Evaluation Kits
2
_______________________________________________________________________________________
To allow characterization without a photodiode, the
MAX3266 EV kit provides a simple circuit that emulates
a photodiode using common voltage output signal
sources.
The connector at INPUT is terminated with 50
to
ground. This voltage is then AC coupled to a resistance
in series with the MAX3266's input, creating an input
current. U2 and U3 form a simple DC current source
that is used to apply a DC current to the input signal.
The values of the series resistive elements, R1 and R2,
have been carefully selected not to change the band-
width of the transimpedance amplifier. Surface-mount
resistors have parasitic capacitance that reduces their
impedance at frequencies above 1GHz. The user
should carefully evaluate any changes to R1 and R2
using the calibration network provided on the EV kit.
Table 1 shows the recommended resistor values.
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
AVG
in dBm)
and extinction ratio (r
e
).
2) Calculate the average current (I
AVG
), and adjust R7
and R5 to obtain it.
(
= photodiode responsivity in A/W)
3) Calculate the AC signal current, and adjust the sig-
nal generator to obtain it.
I
INPUT
= 2
I
AVG
(r
e
- 1) / (r
e
+ 1)
For example:
1) Emulate a signal with an average power of -20dBm
and an extinction ratio of 10.
2) -20dBm optical power will produce 10A of aver-
age input current (assume photodiode responsivity
of 1A/W). Install a current meter at JU1. Adjust R7
and R5 until the current is 10A.
3) The signal amplitude is 2P
AVG
(r
e
- 1) / (r
e
+ 1) =
16A. To generate this current through the 1500
input resistors, set the signal source to produce an
output level of 16A
1500
= 24mVp-p.
Noise Measurement
Remove R2 before attempting noise measurements to
minimize input capacitance. With R2 removed the total
capacitance at the IN pin is approximately 0.5pF. Refer
to the Layout Considerations section in the MAX3266/
MAX3267 data sheet for more information.
I
10
1000
AVG
P
/10
AVG
=
(
)
Table 1. Recommended Resistor Values
1020
(composed
of two 510
(0402)
resistors)
200
(0402)
MAX3267EVKIT-SO
510
(0603)
1000
(0603)
MAX3266EVKIT-SO
R2, R10
R1, R9
EVALUATION KIT
Input Connection for a Signal Generator
INPUT
Connections for the MAX3266/MAX3267 Output Signal
OUT+, OUT-
Potentiometer. Coarse adjustment of the DC current input.
R7
Potentiometer. Fine adjustment of the DC current input.
R5
Test Pin. Shunting JU2 disables the MAX3266/MAX3267 DC cancellation amplifier.
JU2
When shunted, the photodiode emulation circuit is active. This is a convenient location to measure
the emulated photodiode current.
JU1
Connection for Ground
GND
Supply Voltage Connection for Photodiode Emulator Circuit (+15V, 25mA)
+15V
Supply Voltage Connection (3.0 to 5.5V, 100mA current limit)
VCC
DESCRIPTION
CONTROL
Table 2. Connections, Adjustments, and Control
Evaluate: MAX3266/MAX3267
MAX3266/MAX3267 Evaluation Kits
_______________________________________________________________________________________
3
1
2
4
J12
J11
3
OUT+
OUT-
V
CC
VCC2
C14
0.1
F
C10
1000pF
C15
0.1
F
GND
U5
1
2
8
7
GND
OUT+
3
4
6
5
OUT-
GND
FILTER
N.C.
IN
C2
1000pF
C5
0.1
F
C6
0.1
F
C1
1000pF
C4
1000pF
C3
0.1
F
JU2
OUT+
OUT-
JU1
3
2
1
6
4
2
3
2
1
3
1
3
2
7
U2
500
R1
VCC1
+15V
+15V
1k
J1
J3
J2
INPUT
R3
49.9
R4
1k
R8
10k
R7
10k
R5
1k
R6
10k
R2
NO GND PLANE
J13
1
2
4
3
OUT+
OUT-
V
CC
GND
U4
VCC2
C11
1000pF
J14
C12
0.1
F
C13
0.1
F
V
CC
GND
VCC
C8
33
F
25V
C9
33
F
25V
+15V
+15V
VCC1
FERRITE
L1
FERRITE
L2
VCC2
J6
J7
J9
J10
J8
C7
1000
F
C17
0.1
F
C15
0.1
F
1k
J4
J5
INPUT
SEE TABLE 1 FOR
MAX3267 RESISTOR VALUES
SEE TABLE 1 FOR
MAX3267 RESISTOR
VALUES
R12
1k
R11
49.9
R9
500
R10
NO GND PLANE
MAX3266
MAX3267
U1
U3
MAX400
Figure 1. MAX3266/MAX3267 EV Kits Schematic
Evaluate: MAX3266/MAX3267
MAX3266/MAX3267 Evaluation Kits
4
_______________________________________________________________________________________
Figure 2. MAX3266 EV Kit Component Placement Guide
Figure 4. MAX3266 EV Kit PC Board Layout--Ground Plane
Figure 3. MAX3266 EV Kit PC Board Layout--Component Side
1.0"
1.0"
1.0"
Figure 5. MAX3266 EV Kit PC Board Layout--Power Plane
Figure 6. MAX3266 EV Kit PC Board Layout--Solder Side
1.0"
1.0"
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.
Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 _____________________ 5
2001 Maxim Integrated Products
Printed USA
is a registered trademark of Maxim Integrated Products.
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