19-1622; Rev 0; 1/00
MAX3665 Evaluation Kit
General Description
The MAX3665 evaluation kit (EV kit) simplifies evalua-
tion of the MAX3665 transimpedance preamplifier. The
EV kit includes a circuit that emulates the zero-to-peak
current input signal that would be produced by a pho-
todiode. It also includes a calibration circuit that allows
accurate bandwidth measurements.
The MAX3665 EV kit is fully assembled and tested.
PART
MAX3665EVKIT
Features
o
Fully Assembled and Tested
o
Includes Photodiode Emulation Circuit
o
Calibration Circuit for Accurate Bandwidth
Measurements
Evaluates: MAX3665
Ordering Information
TEMP. RANGE
-40°C to +85°C
IC PACKAGE
8 µMAX
Component List
DESIGNATION QTY
C1, C2, C4, C7,
C10, C11
C3, C5, C6,
C12–C16
C8, C9
C17, C20, C23
C18, C19, C21
J1–J5
J11–J14
JU1, JU2
L1, L2
L3–L8
R1, R9
R2, R4, R10,
R12
R3, R11
R5
R6, R8
R7
U1
U2
U3
U4, U5
VCC, +15V,
GND
None
None
None
6
8
2
3
3
5
4
2
2
6
2
4
2
1
2
1
1
1
1
0
3
2
1
1
DESCRIPTION
1000pF ±10%, 25V min ceramic
capacitors
0.1µF 10%, 10V min ceramic caps
33µF ±10%, 16V min tantalum caps
AVX TAJC336K016
5pF ±0.1pF, 50V capacitors
4pF ±0.1pF, 50V capacitors
SMA connectors (edge mount)
Open
2-pin headers (0.1in centers)
Ferrite beads
Murata BLM11HA601S
22nH ±5% inductors
2kΩ ±1% resistors
1kΩ ±1% resistors
49.9Ω ±5% resistors
1kΩ potentiometer
10kΩ ±5% resistors
10kΩ potentiometer
MAX3665EUA (8-pin µMAX)
CMPT3906 PNP transistor
MAX400CSA (8-pin SO)
User-supplied optical modules
Test points
Shunts for JU1, JU2
MAX3665 evaluation kit (rev B)
circuit board
MAX3665 data sheet
SUPPLIER
AVX
Central
Semiconductor
Murata
Zetex
Component Suppliers
PHONE
843-444-2863
516-435-1110
770-684-7821
516-543-7100
FAX
843-626-3123
516-435-1824
–
516-864-7630
Note:
Please indicate that you are using the MAX3665 when
contacting these component suppliers.
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 MAX3665 EV kit).
The signal should have a data rate up to 622Mbps.
2) Connect OUT+ and OUT- to the 50Ω inputs of a
high-speed oscilloscope.
3) Remove shunts from jumpers JU1 and JU2.
4) Connect a +3.3V or +5.0V supply to the VCC termi-
nal and ground to the GND terminal.
5) The differential signal at the oscilloscope should be
between 100mVp-p and 150mVp-p.
Detailed Description
The MAX3665 is designed to accept a DC-coupled
input from a photodiode with an amplitude up to 450µA
peak-to-peak. Because the MAX3665 provides a DC
bias for the photodiode, it cannot be DC-coupled to sig-
nal sources. To allow characterization without a photodi-
ode, the MAX3665 EV kit provides a simple circuit that
emulates a photodiode using common voltage output
signal sources.
________________________________________________________________
Maxim Integrated Products
1
For free samples & the latest literature: http://www.maxim-ic.com, or phone 1-800-998-8800.
For small orders, phone 1-800-835-8769.
MAX3665 Evaluation Kit
Evaluates: MAX3665
The connector at INPUT is terminated with 50Ω to
ground. This voltage is then AC-coupled to a resistance
in series with the MAX3665’s input, creating an input cur-
rent. U2 and U3 form a simple DC current source that is
used to apply a DC offset to the input signal.
The values of the series resistive elements, R1 and R2,
have been carefully selected so as not to change the
bandwidth 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.
3) Calculate the AC signal current (I
INPUT
in Amps) as
follows, and adjust the signal 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 10µA 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 10µA.
3) The signal amplitude is I
AVG
(r
e
- 1) / (r
e
+ 1) =
16µA. To generate this current through the 3000Ω
input resistors, set the signal source to produce an
output level of 16µA · 3000Ω = 48mVp-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
AVG
in dBm)
and extinction ratio (r
e
).
2) Calculate the average current (I
AVE
in Amps) as fol-
lows, and adjust R7 and R5 to obtain it:
I
AVG
=
10
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 MAX3665 data sheet for more information.
(
PAVG/10
)
ρ
1000
where
ρ
= photodiode responsivity in A/W.
Table 1. Connections, Adjustments, and Control
CONTROL
VCC
+15V
GND
JU1
JU2
R5
R7
OUT+, OUT-
INPUT
DESCRIPTION
Supply Voltage Connection (+3.3V or +5V, 100mA current limit)
Supply Voltage Connection for Photodiode Emulator Circuit (+15V, 25mA)
Connection for Ground
When shunted, the photodiode emulation circuit is active. This is a convenient location to measure
the emulated photodiode current.
Test Pin. Shunting JU2 disables the MAX3665 DC cancellation amplifier.
Potentiometer. Fine adjustment of the DC current input.
Potentiometer. Coarse adjustment of the DC current input.
Connections for the MAX3665 Output Signal
Input Connection for a Signal Generator
2
_______________________________________________________________________________________
C7
1000µF
R12
1k
C16
0.1µF
J5
NOTE: VCC1 AND VCC2 ARE INTERNAL
POWER CONNECTIONS.
NO GND PLANE
R10
R9
1k
2k
+15V
J4
INPUT
R11
49.9Ω
2
2
U3
6 1
U2
+15V
3
7
+15V
C4
1000pF
JU1
J7
VCC
FERRITE
L2
C9
33µF
25V
J8
GND
C8
33µF
25V
2
3
MAX400
R6
10k
2
4
J6
+15V
FERRITE
L1
Figure 1. MAX3665 EV Kit Schematic
J9
VCC1
J10
NO GND PLANE
J1
INPUT
3
R3
49.9Ω
4
JU2
FILT
2
IN
U1
C3
0.1µF
VCC1
V
CC
R1
2k
R2
1k
1
C2
1000pF
GND
OUT-
8
7
6
GND
5
C18
4pF
L4
22nH
L3
22nH
VCC2
C5
0.1µF
C17
5pF
C6
0.1µF
J3
OUT+
C1
1000pF
R4
1k
J2
OUT-
N.C.
MAX3665
OUT+
1
V
CC
U5
GND OUT+
3
L8
22nH
C15
0.1µF
C23
5pF
J11
OUT-
2
4
C21
4pF
L7
22nH
J12
VCC2
C11
1000pF
C14
0.1µF
1
2
V
CC
GND
OUT-
U4
OUT+
4
3
C19
4pF
L5
22nH
C20
5pF
L6
22nH
C13
0.1µF
C12
0.1µF
J14
J13
1
R5
1k
3
1
R7
10k
3
R8
10k
Evaluates: MAX3665
_______________________________________________________________________________________
VCC2
C10
1000pF
MAX3665 Evaluation Kit
3
MAX3665 Evaluation Kit
Evaluates: MAX3665
1.0"
Figure 2. MAX3665 EV Kit Component Placement Guide
1.0"
1.0"
Figure 3. MAX3665 EV Kit PC Board Layout—Component Side
Figure 4. MAX3665 EV Kit PC Board Layout—Ground Plane
4
_______________________________________________________________________________________
MAX3665 Evaluation Kit
Evaluates: MAX3665
1.0"
1.0"
Figure 5. MAX3665 EV Kit PC Board Layout—Power Plane
Figure 6. MAX3665 EV Kit PC Board Layout—Solder Side
_______________________________________________________________________________________
5
stm32/stm8
京公网安备 11010802033920号
Copyright © 2005-2026 EEWORLD.com.cn, Inc. All rights reserved
电子工程世界
