ONET9901TA
10.7 Gbps TRANSIMPEDANCE AMPLIFIER WITH RSSI
SLLS615 - APRIL 2004
1
POST OFFICE BOX 655303
DALLAS, TEXAS 75265
features
D
11.2-GHz Bandwidth
D
5.5-k
Differential Transimpedance
D
8.5-pA/
/
Hz Typical Input Referred Noise
D
2-mA Maximum Input Current
D
Received Signal Strength Indication
D
CML Data Outputs
D
Offset Cancellation
D
Single 3.3-V Supply
D
Bare-Die Option
applications
D
SONET OC-192
D
10-Gbps Ethernet Receivers
D
10-Gbps Fibre Channel Receivers
description
The ONET9901TA is a high-speed transimpedance amplifier used in SDH/SONET systems with data rates up
to 10.7 Gbps. It features a low input referred noise, 11.2-GHz bandwidth and a 5.5-k
transimpedance.
The ONET9901TA device is available in die form and requires a single 3.3-V supply. The ONET9901TA is power
efficient and dissipates less than 100 mW (typical). The ONET9901TA is characterized for operations from 0
_
C
to 85
_
C.
available options
TA
PACKAGED DEVICE
0
C to 85
C
ONET9901TAY
Copyright
2004, Texas Instruments Incorporated
Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of
Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of Texas Instruments
standard warranty. Production processing does not necessarily include
testing of all parameters.
ONET9901TA
10.7 Gbps TRANSIMPEDANCE AMPLIFIER WITH RSSI
SLLS615 - APRIL 2004
2
POST OFFICE BOX 655303
DALLAS, TEXAS 75265
block diagram
The ONET9901TA is a high performance 10.7-Gbps transimpedance amplifier that can be segmented into the
signal path, filter, and offset cancellation block. The signal path consists of a transimpedance amplifier stage,
a voltage amplifier, and an output buffer. The filter circuit provides a filtered VCC for the photodiode. The offset
correction circuit uses an internal low-pass filter to cancel the dc on the input and it provides a signal to monitor
the received signal strength. A simplified block diagram of the ONET9901TA is shown in Figure 1.
VCCI
FILTER
TEST
IN
GND
RSSI
VCCO
OUT+
OUT-
Offset
Cancellation
Disable
Transimpedance
Amplifier
Voltage
Amplifier
CML
Output
Buffer
410
W
1 k
W
RF
Bandgap
Voltage Reference
and Bias Current
Generation
+
-
+
-
Figure 1. Block Diagram
signal path
The first stage of the signal path is a transimpedance amplifier that takes the photodiode current and converts
it to a voltage signal. The second stage is a voltage amplifier that provides additional gain. The output of the
second stage feeds the output buffer and the offset cancellation circuitry. The third and final signal path stage
of the ONET9901TA is the output buffer. The output buffer provides CML outputs with an on-chip 50-
back-termination to VCCO.
filter circuitry
The filter pin provides a filtered VCC for the photodiode bias. The on-chip low-pass filter for the photodiode VCC
is implemented using a filter resistor of 410
and an internal capacitor. If additional filtering is required for the
application, an external capacitor should be connected to the FILTER pin.
offset cancellation and RSSI
The offset cancellation circuitry performs low pass filtering of the output of the voltage amplifier. This senses
the dc offset at the input of the ONET9901TA. The circuitry subtracts current from the input to effectively cancel
the dc. The sensed current is mirrored and is used to generate the RSSI output through an external 10-k
resistor. To disable the offset correction loop, the FILTER pin should be tied to GND.
ONET9901TA
10.7 Gbps TRANSIMPEDANCE AMPLIFIER WITH RSSI
SLLS615 - APRIL 2004
3
POST OFFICE BOX 655303
DALLAS, TEXAS 75265
bond pad assignment
The ONET9901TA is available as bare-die. The location of the bondpads is shown in Figure 2. The circuit is
characterized for ambient temperatures between 0
C and 85
C.
PAD#1
2
3
4
5
6
1
VCCI
VCCI
FILTER
TEST
IN
GND
15
14
13
12
11
10
VCCO
VCCO
GND
OUT+
OUT
GND
VCCO
VCCI
RSSI
16
17
18
9
8
7
GND
GND
GND
Figure 2. Bond Pad Assignment of the ONET9901TA
terminal functions
The following table shows a pad description for the ONET9901TA.
TERMINAL
TYPE
DESCRIPTION
NAME
NO.
TYPE
DESCRIPTION
VCCI
1, 2, 18
Supply
Input stage 3.3-V
10% supply voltage.
FILTER
3
Analog
Bias voltage for the photodiode (connects to an internal 410-
resistor to VCCI).
To disable the offset correction loop, connect the FILTER pin to GND.
TEST
4
Analog in
Test pad. Connects to IN via a 1-k
resistor.
IN
5
Analog in
Data input to TIA
GND
6-10,13
Supply
Circuit ground
OUT-
11
Analog out
Inverted data output. On-chip 50-
back-terminated to VCCO.
OUT+
12
Analog out
Non-inverted data output. On-chip 50-
back-terminated to VCCO.
VCCO
14-16
Supply
Output stage 3.3-V
10% supply voltage.
RSSI
17
Analog out
Analog output voltage proportional to the input data amplitude. Indicates the
strength of the received signal (RSSI).
ONET9901TA
10.7 Gbps TRANSIMPEDANCE AMPLIFIER WITH RSSI
SLLS615 - APRIL 2004
4
POST OFFICE BOX 655303
DALLAS, TEXAS 75265
absolute maximum ratings
over operating free-air temperature range unless otherwise noted
VALUE
UNIT
VCCI, VCCO
Supply voltage, See Note 1
0.3 to 4
V
V(FILTER), V(OUT+), V(OUT-), V(RSSI)
Voltage at FILTER, OUT+, OUT-, and RSSI, See Note 1
0.3 to 4
V
I(IN), I(TEST)
Supply current into IN and TEST
-5 to 5
mA
I(FILTER)
Supply current into FILTER
-8 to 8
mA
I(OUT+), I(OUT-)
Continuous current at outputs
-25 to 25
mA
ESD
ESD rating at all pins
2
kV (HBM)
TJ(max)
Maximum junction temperature
125
C
Tstg
Storage temperature range
-65 to 85
C
TA
Operating free-air temperature range
0 to 85
C
Stresses beyond those listed under "absolute maximum ratings" may cause permanent damage to the device. These are stress ratings only, and
functional operation of the device at these or any other conditions beyond those indicated under "recommended operating conditions" is not
implied. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.
NOTE 1: All voltage values are with respect to the network ground terminal.
recommended operating conditions
MIN
TYP
MAX
UNIT
Supply voltage, VCCI, VCCO
3
3.3
3.6
V
Operating free-air temperature, TA
0
85
C
dc electrical characteristics
over recommended operating conditions (unless otherwise noted), typical operating condition is at V
CCI
= V
CCO
=
3.3 V and T
A
= 25
C
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX
UNIT
VCC
Supply voltage
3
3.3
3.6
V
ICC
Supply current
30
41
mA
VIN
Input bias voltage
0.84
0.96
V
ro
Output resistance
Single-ended to VCC
50
r(FILTER)
Photodiode filter resistance
330
410
500
ONET9901TA
10.7 Gbps TRANSIMPEDANCE AMPLIFIER WITH RSSI
SLLS615 - APRIL 2004
5
POST OFFICE BOX 655303
DALLAS, TEXAS 75265
ac electrical characteristics
over recommended operating conditions (unless otherwise noted), typical operating condition is at V
CCI
= V
CCO
=
3.3 V and T
A
= 25
C
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX
UNIT
IIN,OVL
AC input overload current
2
mAp-p
Input linear range
0.95 < linearity < 1.05
50
60
Ap-p
ARSSI
RSSI gain
10-k
load, See Note 2
1500
2000
2500
V/A
Z(21)
Small signal transimpedance
Differential output, 10
Ap-p < IIN = < 50
Ap-p
4400
5500
6600
BW(H_3dB)
Small signal bandwidth
CPD = 0.2 pF
11.2
GHz
BW(L_3dB)
Low frequency -3 dB bandwidth
-3 dB, IIN = < 50
Ap-p dc
17
kHz
BW(H_3dB_RSSI) RSSI bandwidth
5
kHz
IN,IN
Input referred RMS noise
CPD = 0.2 pF
900
nA
Input referred noise density
CPD = 0.2 pF
8.5
pA/
Hz
DJ
Deterministic jitter
IIN < 1.3 mAp-p (K28.5 pattern)
7
psp-p
DJ
Deterministic jitter
IIN = 2 mAp-p (K28.5 pattern)
11
22
psp-p
VOD(max)
Maximum differential output
voltage
IIN = 1 mAp-p
500
700
mVp-p
NOTE 2: On the chip, a 6725-
resistor is used in parallel to the external 10-k
resistor, resulting in a total 4-k
resistor for a typical process.
By choosing an appropriate external resistor, the typical RSSI gain can be adjusted. Without an external resistor, the RSSI gain is
approximately 3360 V/A under typical conditions.
APPLICATION INFORMATION
Figure 3 shows the ONET9901TA being used as a receiver in a typical fiber optic application. The ONET9901TA
converts the electrical current generated by the PIN photodiode into a differential voltage output. The FILTER
input provides a dc bias voltage for the PIN that is low pass filtered by the combination of the internal 410-
resistor and internal capacitor. For additional power supply filtering, use an external capacitor (C
FILTER
). The
RSSI output is used to mirror the photodiode output current and must be connected via a 10-k
resistor to GND
or left open. Within the ONET9901TA, the OUT+ and OUT- pins are internally terminated by a 50-
pullup to
VCCO.
ONET9901TA
10.7 Gbps TRANSIMPEDANCE AMPLIFIER WITH RSSI
SLLS615 - APRIL 2004
6
POST OFFICE BOX 655303
DALLAS, TEXAS 75265
PAD#1
VCC
GND
OUT+
RSSI
2
1
3
4
5
6
14
15
13
12
11
10
18
17
16
7
8
9
ONET
9901TA
CFILTER
(Optional)
10 k
W
410
W
C1
C2
OUT-
Figure 3. Basic Application Circuit
board layout
Careful attention to board layout parasitics and external components is necessary to achieve optimal
performance with a high-performance transimpedance amplifier like the ONET9901TA.
Recommendations that optimize performance include:
1.
Minimize total capacitance on the IN pad by using a low-capacitance photodiode and paying attention to
stray capacitances. Place the photodiode close to the ONET9901TA die in order to minimize the bond wire
length and thus the parasitic inductance.
2.
The external filter capacitor (C
FILTER
) may have an impact on the transfer function of the TIA and must be
chosen with care based on the module implementation.
3.
Use identical termination and symmetrical transmission lines at the differential output pins OUT+ and
OUT.
4.
Use short bond wire connections for the supply terminals VCCI, VCCO, and GND. Provide sufficient supply
voltage filtering.
ONET9901TA
10.7 Gbps TRANSIMPEDANCE AMPLIFIER WITH RSSI
SLLS615 - APRIL 2004
7
POST OFFICE BOX 655303
DALLAS, TEXAS 75265
chip dimensions and pad locations
X
Y
PAD#1
1189
m
729
m
Origin
0,0
Figure 4.
Chip Dimensions and Pad Locations
Figure 5.
Chip Layout
ONET9901TA
10.7 Gbps TRANSIMPEDANCE AMPLIFIER WITH RSSI
SLLS615 - APRIL 2004
8
POST OFFICE BOX 655303
DALLAS, TEXAS 75265
PAD
LOWER LEFT
COORDINATE
UPPER RIGHT
COORDINATE
SYMBOL
TYPE
DESCRIPTION
x [
m
m]
y [
m
m]
x [
m
m]
y [
m
m]
1
57
887
162
972
VCCI
Supply
Input stage 3.3-V
10% supply voltage
2
57
767
162
852
VCCI
Supply
Input stage 3.3-V
10% supply voltage
3
67
637
152
722
FILTER
Analog
Bias voltage for photodiode
4
67
517
152
602
TEST
Analog in
Test pad. Connects to IN via a 1-k
resistor
5
67
397
152
482
IN
Analog in
Data input to TIA
6
57
267
162
352
GND
Supply
Circuit ground
7
162
57
247
162
GND
Supply
Circuit ground
8
327
57
412
162
GND
Supply
Circuit ground
9
492
57
577
162
GND
Supply
Circuit ground
10
567
237
672
322
GND
Supply
Circuit ground
11
577
367
662
452
OUT
Analog out
Inverted data output
12
577
487
662
572
OUT+
Analog out
Non-inverted data output
13
567
617
672
702
GND
Supply
Circuit ground
14
567
747
672
832
VCCO
Supply
Output stage 3.3-V
10% supply voltage
15
567
877
672
962
VCCO
Supply
Output stage 3.3-V
10% supply voltage
16
492
1027
577
1132
VCCO
Supply
Output stage 3.3-V
10% supply voltage
17
327
1027
412
1132
RSSI
Analog out
RSSI output voltage signal
18
162
1027
247
1132
VCCI
Supply
Input stage 3.3-V
10% supply voltage
Table 1. Pad Locations and Description of the ONET9901TA
ONET9901TA
10.7 Gbps TRANSIMPEDANCE AMPLIFIER WITH RSSI
SLLS615 - APRIL 2004
9
POST OFFICE BOX 655303
DALLAS, TEXAS 75265
TYPICAL CHARACTERISTICS
Figure 6
Average Input Current -
A
600
700
800
900
1000
1100
1200
1300
1400
1500
1600
0
200
400
600
800
1000
1200
Input Referred Noise Current - nA
RMS
INPUT REFERRED NOISE CURRENT
vs
AVERAGE INPUT CURRENT
Figure 7
Ambient Temperature -
C
600
700
800
900
1000
1100
1200
1300
1400
1500
1600
0
10
20
30
40
50
60
70
80
90
Input Referred Noise Current - nA
RMS
INPUT REFERRED NOISE CURRENT
vs
AMBIENT TEMPERATURE
Figure 8
Input Current -
A
-300
-200
-100
0
100
200
300
-1000 -750 -500 -250
0
250
500
750
1000
Differential Output V
oltage - mV
DIFFERENTIAL OUTPUT VOLTAGE
vs
INPUT CURRENT
Figure 9
Ambient Temperature -
C
72
73
74
75
76
77
78
0
10
20
30
40
50
60
70
80
90
T
ransimpedance - dB
TRANSIMPEDANCE
vs
AMBIENT TEMPERATURE
ONET9901TA
10.7 Gbps TRANSIMPEDANCE AMPLIFIER WITH RSSI
SLLS615 - APRIL 2004
10
POST OFFICE BOX 655303
DALLAS, TEXAS 75265
TYPICAL CHARACTERISTICS
Figure 10
Ambient Temperature -
C
9
10
11
12
13
0
10
20
30
40
50
60
70
80
90
Small Signal Bandwidth - GHz
SMALL SIGNAL BANDWIDTH
vs
AMBIENT TEMPERATURE
Figure 11
Average Input Current -
A
0.0
0.5
1.0
1.5
2.0
2.5
0
200
400
600
800
1000
1200
RSSI Output V
o
ltage - V
RSSI OUTPUT VOLTAGE
vs
AVERAGE INPUT CURRENT
Figure 12
Input Current -
AP-P
0
2
4
6
8
10
12
0
250
500
750
1000 1250 1500 1750 2000
Deterministic Jitter - ps
P-P
DETERMINISTIC JITTER
vs
INPUT CURRENT
ONET9901TA
10.7 Gbps TRANSIMPEDANCE AMPLIFIER WITH RSSI
SLLS615 - APRIL 2004
11
POST OFFICE BOX 655303
DALLAS, TEXAS 75265
TYPICAL CHARACTERISTICS
Figure 13
Time - 20 ps/Div
Differential Output V
oltage - 25 mV/Div
OUTPUT EYE DIAGRAM AT 10.7 GBPS
AND 20
m
A
P-P
INPUT CURRENT
Figure 14
Time - 20 ps/Div
Differential Output V
oltage - 100 mV/Div
OUTPUT EYE DIAGRAM AT 10.7 GBPS
AND 2 mA
P-P
INPUT CURRENT
PACKAGING INFORMATION
Orderable Device
Status
(1)
Package
Type
Package
Drawing
Pins Package
Qty
Eco Plan
(2)
Lead/Ball Finish
MSL Peak Temp
(3)
ONET9901TAY
ACTIVE
XCEPT
Y
0
360
TBD
Call TI
Call TI
(1)
The marketing status values are defined as follows:
ACTIVE: Product device recommended for new designs.
LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect.
NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in
a new design.
PREVIEW: Device has been announced but is not in production. Samples may or may not be available.
OBSOLETE: TI has discontinued the production of the device.
(2)
Eco
Plan
-
The
planned
eco-friendly
classification:
Pb-Free
(RoHS)
or
Green
(RoHS
&
no
Sb/Br)
-
please
check
http://www.ti.com/productcontent
for the latest availability information and additional product content details.
TBD: The Pb-Free/Green conversion plan has not been defined.
Pb-Free (RoHS): TI's terms "Lead-Free" or "Pb-Free" mean semiconductor products that are compatible with the current RoHS requirements
for all 6 substances, including the requirement that lead not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered
at high temperatures, TI Pb-Free products are suitable for use in specified lead-free processes.
Green (RoHS & no Sb/Br): TI defines "Green" to mean Pb-Free (RoHS compatible), and free of Bromine (Br) and Antimony (Sb) based flame
retardants (Br or Sb do not exceed 0.1% by weight in homogeneous material)
(3)
MSL, Peak Temp. -- The Moisture Sensitivity Level rating according to the JEDEC industry standard classifications, and peak solder
temperature.
Important Information and Disclaimer:The information provided on this page represents TI's knowledge and belief as of the date that it is
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incoming materials and chemicals. TI and TI suppliers consider certain information to be proprietary, and thus CAS numbers and other limited
information may not be available for release.
In no event shall TI's liability arising out of such information exceed the total purchase price of the TI part(s) at issue in this document sold by TI
to Customer on an annual basis.
PACKAGE OPTION ADDENDUM
www.ti.com
3-Aug-2005
Addendum-Page 1
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