Electronic Components Datasheet Search
  English  ▼

Delete All
ON OFF
ALLDATASHEET.COM

X  

Preview PDF Download HTML

ADN2531ACPZ-WP Datasheet(PDF) 12 Page - Analog Devices

Part No. ADN2531ACPZ-WP
Description  11.3 Gbps, Active Back-Termination, Differential Laser Diode Driver
Download  20 Pages
Scroll/Zoom Zoom In 100% Zoom Out
Maker  AD [Analog Devices]
Homepage  http://www.analog.com
Logo 

ADN2531ACPZ-WP Datasheet(HTML) 12 Page - Analog Devices

Zoom Inzoom in Zoom Outzoom out
 12 / 20 page
background image
ADN2531
Rev. 0 | Page 12 of 20
The equivalent circuits of the BSET, IBIAS, and IBMON pins
are shown in Figure 26 to Figure 28.
VCC
BSET
VCC
800
200
Figure 26. Equivalent Circuit of the BSET Pin
10
2k
100
IBIAS
VCC
VCC
Figure 27. Equivalent Circuit of the IBIAS Pin
IBMON
100
500
VCC
VCC
VCC
Figure 28. Equivalent Circuit of the IBMON Pin
The recommended configuration for the BSET, IBIAS, and
IBMON pins is shown in Figure 29.
ADN2531
BSET
VBSET
GND
IBMON
IBIAS
TO LASER CATHODE
L
RIBMON
750
IBIAS
Figure 29. Recommended Configuration for BSET, IBIAS, and IBMON Pins
The circuit used to drive the BSET voltage must be able to drive
the 1 kΩ input resistance of the BSET pin. For proper operation
of the bias current source, the voltage at the IBIAS pin must be
between the compliance voltage specifications for this pin over
supply, temperature, and bias current range (see Table 1). The
maximum compliance voltage is specified for only two bias
current levels (10 mA and 100 mA), but it can be calculated for
any bias current by
VCOMPLIANCE (V) = VCC (V) − 0.75 − 4.4 × IBIAS (A)
See the Headroom Calculations section for examples.
The function of Inductor L is to isolate the capacitance of the
IBIAS output from the high frequency signal path. For
recommended components, see Table 6.
AUTOMATIC LASER SHUTDOWN (ALS)
The ALS pin is a digital input that enables/disables both the bias
and modulation currents, depending on the logic state applied,
as shown in Table 5.
Table 5. ALS Logic States
ALS Logic State
IBIAS and IMOD
High
Disabled
Low
Enabled
Floating
Enabled
The ALS pin is compatible with 3.3 V CMOS and LVTTL logic
levels. Its equivalent circuit is shown in Figure 30.
VCC
VCC
ALS
100
42k
2k
Figure 30. Equivalent Circuit of the ALS Pin
MODULATION CURRENT
The modulation current can be controlled by applying a dc
voltage to the MSET pin. This voltage is converted into a dc
current via a voltage-to-current converter that uses an
operational amplifier and a bipolar transistor, as shown in
Figure 31.
100
200
400
MSET
GND
IMODP
IMODN
ADN2531
VCC
FROM CPA STAGE
IMOD
Figure 31. Generation of Modulation Current on the ADN2531
The dc current is switched by the data signal applied to the
input stage (DATAP and DATAN pins) and gained up by the
output stage to generate the differential modulation current at
the IMODP and IMODN pins. The output stage also generates
the active back-termination, which provides proper transmission
line termination. Active back-termination uses feedback around
an active circuit to synthesize a broadband termination resistance.
This provides excellent transmission line termination while
dissipating less power than a traditional resistor passive back-
termination. No portion of the modulation current flows in the
active back-termination resistance. All of the preset modulation
current (IMOD), the range of which is specified in Table 1, flows
into the external load.


Html Pages

1  2  3  4  5  6  7  8  9  10  11  12  13  14  15  16  17  18  19  20 


Datasheet Download




Link URL




Privacy Policy
ALLDATASHEET.COM
Does ALLDATASHEET help your business so far?  [ DONATE ]  

About Alldatasheet   |   Advertisement   |   Datasheet Upload   |   Contact us   |   Privacy Policy   |   Alldatasheet API   |   Link Exchange   |   Manufacturer List
All Rights Reserved© Alldatasheet.com


Mirror Sites
English : Alldatasheet.com  |   English : Alldatasheet.net  |   Chinese : Alldatasheetcn.com  |   German : Alldatasheetde.com  |   Japanese : Alldatasheet.jp
Russian : Alldatasheetru.com  |   Korean : Alldatasheet.co.kr  |   Spanish : Alldatasheet.es  |   French : Alldatasheet.fr  |   Italian : Alldatasheetit.com
Portuguese : Alldatasheetpt.com  |   Polish : Alldatasheet.pl  |   Vietnamese : Alldatasheet.vn