MAXIM MAX3970EVKIT

19-2059; Rev 1; 4/02
MAX3970 Evaluation Kit
Features
♦ Easy +3.3V Electrical Evaluation of the MAX3970
♦ Fully Assembled and Tested
♦ EV Kit Designed for 50Ω Interfaces
Ordering Information
PART
TEMP RANGE
MAX3970EVKIT
0°C to +85°C
Component Suppliers
SUPPLIER
PHONE
FAX
AVX
843-444-2863
803-626-3123
Murata
814-237-1431
814-238-0490
Note: Please indicate that you are using the MAX3970 when
ordering from these suppliers.
IC PACKAGE
Dice
Component List
DESIGNATION
QTY
DESCRIPTION
C2, C4, C13
3
1000pF ±10% ceramic
capacitors (0402)
C11, C12, C15,
C16
4
0.01µF ±10% ceramic
capacitors (0402)
C14
1
33µF ±10% tantalum capacitor
J1–J5
5
SMA connectors edge mount
JU1
1
2-pin header, 0.1in centers
1
Ferrite bead (0603)
Murata BLM11HA601SG (0603)
L1
R1, R2, R4, R5
4
243Ω 1% resistors (0402)
R3, R6
2
49.9Ω 1% resistors (0402)
R7
1
10kΩ 1% resistor (0402)
TP1, TP2, VCC,
GND
4
Test points
U1
1
MAX3970U/D
None
1
Shunt
________________________________________________________________ Maxim Integrated Products
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.
1
Evaluates: MAX3970
General Description
The MAX3970 evaluation kit (EV kit) is a fully assembled
chip-on-board electrical demonstration kit that provides
easy evaluation of the MAX3970 10.3Gbps, +3.3V transimpedance amplifier. Note that the MAX3970 EV kit
provides an electrical interface to the IC, which is similar to, but not exactly the same as, a photodiode. The
circuit used tends to increase bandwidth and jitter
beyond what is expected for typical photodiode inputs.
Evaluates: MAX3970
MAX3970 Evaluation Kit
Quick Start
1) Connect a signal source with 500mVP-P amplitude to
the INPUT. Set the data rate for the signal source to
10.3Gbps.
2) Connect OUT+ (J2) and OUT- (J3) to the 50Ω inputs
of a high-speed oscilloscope.
3) Remove the shunt from JU1.
4) Connect a +3.3V supply to the proper terminals and
power up the EV kit.
5) The differential signal at the oscilloscope should be
approximately 450mVP-P.
Detailed Description
The MAX3970 accepts a DC-coupled input from a highspeed photodiode, at optical modulation amplitudes
ranging from 40µAP-P to 2.0mAP-P. To facilitate characterization without a photodiode, the MAX3970 EV kit
provides a simple circuit that emulates the photodiode
using the signal voltage from a 50Ω source.
The connector at IN (J1) is terminated with 50Ω to
ground. Signal voltage applied to the EV kit's input is
AC-coupled to a resistance in series with the
MAX3970's input, creating an input signal current.
Photodiode DC current can be emulated by injecting
DC current into the TEST pin (TP1). The TEST pin is
connected to IN through an on-chip 1kΩ resistor.
3) Calculate the AC signal current (IINPUT in amps) as
follows, and adjust the signal generator to obtain it:
(r − 1)
I INPUT = 2IAVE e
(re + 1)
For example, to emulate a signal with an average
power of -10dBm and an extinction ratio of 8:
1) -10dBm optical power will produce 85µA of average
input current (assume a photodiode responsivity of
0.85A/W). Install a current meter between the TEST pin
and a DC source. Adjust the source to provide 85µA.
2) The signal amplitude is 2IAVE(re -1)/(re +1) = 132µA.
To generate this current through the two 243Ω series
input resistors, set the signal source to produce an
output level of 64mVP-P.
Noise Measurements
Remove R1 before attempting noise measurements.
With R1 removed, the total capacitance at the IN pin is
approximately 0.2pF.
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 (PAVE in dBm) and
extinction ratio (re).
2) Calculate the average current (IAVE in amps) as follows:
IAVG =
10(PAVE / 10)
ρ
1000
where ρ is photodiode responsivity in A/W
2
_______________________________________________________________________________________
MAX3970 Evaluation Kit
Evaluates: MAX3970
J8
GND
3.3V
C15
0.01µF
C14
33µF
J7
VCC
L1
BP17
TP2
R7
10kΩ
3.3V
3.3V
3.3V
3.3V
BP18
BP1
17 BP16 16
18
VCC1
RSSI
1
VCC2 15
VCC1
BP2
2
U1
VCC1
VCC2
BP3
JU1
J1
IN
R2
243Ω
MAX3970
FILTER
GND
C13
1000pF
BP14
14
13
BP13
BP4
C16 TP1
0.01µF
C2
1000pF
3
BP15
VCC2
4
R1
243Ω
TEST
OUT+
12
BP5
C11
0.01µF
BP12
C12
0.01µF
BP11
5
IN
OUT-
GND
GND
BP6
11
J3
OUT -
BP10
R3
49.9Ω
6
BP7
C4
1000pF
J5
CALIN
R6
49.9Ω
GND
GND
7
8
BP8
R5
243Ω
J2
OUT +
10
GND
9
BP9
R4
243Ω
J4
CALOUT
Figure 1. MAX3970 EV Kit Schematic
_______________________________________________________________________________________
3
Evaluates: MAX3970
MAX3970 Evaluation Kit
1.0"
Figure 2. MAX3970 EV Kit Component Placement Guide—
Component Side
1.0"
Figure 4. MAX3970 EV Kit PC Board Layout—Solder Side
4
1.0"
Figure 3. MAX3970 EV Kit PC Board Layout—Component Side
1.0"
Figure 5. MAX3970 EV Kit PC Board Layout—Ground Plane
_______________________________________________________________________________________
MAX3970 Evaluation Kit
Figure 6. MAX3970 EV Kit PC Board Layout—Power Plane
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
© 2002 Maxim Integrated Products
Printed USA
is a registered trademark of Maxim Integrated Products.
Evaluates: MAX3970
1.0"