08/2001
FEATURES
Single +5 Volt Supply
Automatic Gain Control
-32 dBm Sensitivity
0 dBm Optical Overload
550 MHz Bandwidth
APPLICATIONS
SONET OC-12 /SDH STM-4 (622Mb/s)
Receiver
FITL
BISDN
Workstation Interconnects
Low Noise RF Amplifier
PRODUCT DESCRIPTION
Figure 1: Equivalent Circuit
ATA06211
AGC Transimpedance Amplifier
SONET OC-12
PRELIMINARY DATA SHEET-Rev 4
D1
The ANADIGICS ATA06211 is a 5V low noise
transimpedance amplifier with AGC designed to be
used in OC-12/STM-4 fiber optic links. The device is
used in conjunction with a photodetector (PIN diode
or avalanche photodiode) to convert an optical signal
into an output voltage. The ATA06211 offers a
bandwidth of 550MHz and a dynamic range of 32dB.
It is manufactured in a GaAs MESFET process and
is available in bare die form.
V
DD2
V
OUT
C
AGC
GND
V
DD1
I
IN
C
BY
US PATENT
GND
or
neg.supply
VGA
- 35
70K
+
4pF
+ 0.8
AGC
19 K
Photodector cathode must be connected
to Iin for proper AGC operation
I
IN
PRELIMINARY DATA SHEET - Rev 4
08/2001
2
ATA06211
Table 1: ATA06211D1C Pad Description
Figure 2: Bonding Pad Layout
ELECTRICAL CHARACTERISTICS
Table 2: Absolute Maximum Ratings
D
A
P
N
O
I
T
P
I
R
C
S
E
D
T
N
E
M
M
O
C
V
1
D
D
V
1
D
D
e
g
a
t
s
n
i
a
g
t
u
p
n
i
r
o
f
y
l
p
p
u
s
e
v
it
i
s
o
P
V
2
D
D
V
2
D
D
e
g
a
t
s
n
i
a
g
d
n
o
c
e
s
r
o
f
y
l
p
p
u
s
e
v
it
i
s
o
P
I
N
I
t
n
e
r
r
u
C
t
u
p
n
I
A
I
T
n
o
it
a
r
e
p
o
r
e
p
o
r
p
r
o
f
e
d
o
h
t
a
c
r
o
t
c
e
t
e
d
t
c
e
n
n
o
C
V
T
U
O
e
g
a
tl
o
V
t
u
p
t
u
O
A
I
T
k
c
o
l
b
C
D
l
a
n
r
e
t
x
e
s
e
ri
u
q
e
R
C
C
G
A
r
o
ti
c
a
p
a
C
C
G
A
l
a
n
r
e
t
x
E
C
*
K
0
7
C
G
A
t
n
a
t
s
n
o
C
e
m
i
T
C
G
A
=
C
Y
B
s
s
a
p
y
B
e
g
a
t
S
n
i
a
G
t
u
p
n
I
r
o
ti
c
a
p
a
C
F
p
6
5
>
V
1
D
D
V
0
.
7
V
2
D
D
V
0
.
7
I
N
I
A
m
5
T
A
C
5
2
1
o
t
C
0
4
-
.
p
m
e
T
g
n
it
a
r
e
p
O
T
S
C
0
5
1
o
t
C
5
6
-
.
p
m
e
T
e
g
a
r
o
t
S
Stresses in excess of the absolute ratings may cause
permanent damage. Functional operation is not
implied under these conditions. Exposure to absolute
ratings for extended periods of time may adversely
affect reliability.
PRELIMINARY DATA SHEET - Rev 4
08/2001
3
ATA06211
Table 3: Electrical Specifications
(1)
(T
A
= 25
C, V
DD
=+5.0V + 10%, C
DIODE
+ C
STRAY
= 0.5 pF, Det. cathode to I
IN
)
Notes:
1. f = 50MHz
2. Measured with I
in
below AGC Threshold. During AGC, input impedance will decrease
proportionally to I
in.
3. Defined as the I
in
where Transresistance has decreased by 50%.
4. See note on Indirect Measurement of Optical Overload.
5. See note on Measurement of Input Referred Noise Current.
6. C
AGC
= 220 pF
7. Parameter is guaranteed (not tested) by design and characterization data @622 Mb/s,
assuming dectector responsivity of 0.9.
R
E
T
E
M
A
R
A
P
N
I
M
P
Y
T
X
A
M
T
I
N
U
R
(
e
c
n
a
t
s
i
s
e
r
s
n
a
r
T
L
I,
=
C
D
)
A
n
0
0
5
<
6
K
R
(
e
c
n
a
t
s
i
s
e
r
s
n
a
r
T
L
)
0
5
=
)
1
(
5
.
2
3
K
B
d
3
-
h
t
d
i
w
d
n
a
B
0
0
5
0
5
5
z
H
M
e
c
n
a
t
s
i
s
e
R
t
u
p
n
I
)
2
(
0
8
2
e
c
n
a
t
s
i
s
e
R
t
u
p
t
u
O
0
3
0
5
0
6
t
n
e
rr
u
C
y
l
p
p
u
S
5
1
0
3
5
4
A
m
e
g
a
tl
o
V
t
e
s
ff
O
t
u
p
n
I
4
.
1
6
.
1
9
.
1
s
tl
o
V
e
g
a
tl
o
V
t
e
s
ff
O
t
u
p
t
u
O
8
.
1
s
tl
o
V
I(
d
l
o
h
s
e
r
h
T
C
G
A
N
I
)
)
3
(
0
6
0
0
1
d
a
o
lr
e
v
O
l
a
c
it
p
O
)
4
(
3
-
0
m
B
d
t
n
e
rr
u
C
e
s
i
o
N
t
u
p
n
I
)
5
(
0
5
0
6
A
n
t
n
a
t
s
n
o
C
e
m
i
T
C
G
A
)
6
(
6
1
c
e
s
tf
ir
D
e
g
a
tl
o
V
t
e
s
ff
O
1
/
V
m
C
y
ti
v
it
i
s
n
e
S
l
a
c
it
p
O
)
7
(
1
3
-
2
3
-
m
B
d
e
g
n
a
R
e
g
a
tl
o
V
g
n
it
a
r
e
p
O
5
.
4
+
0
.
5
+
0
.
6
+
s
tl
o
V
e
g
n
a
R
e
r
u
t
a
r
e
p
m
e
T
g
n
it
a
r
e
p
O
0
4
-
5
8
C
W
m
mA
W
W
W
W
PRELIMINARY DATA SHEET - Rev 4
08/2001
4
ATA06211
Figure 3: Typical Bonding Diagram
APPLICATION INFORMATION
Power Supplies and General Layout Considerations
The ATA06211D1C may be operated from a positive
supply as low as + 4.5 V and as high as + 6.0 V.
Below + 4.5 V, bandwidth, overload and sensitivity
will degrade, while at + 6.0 V, bandwidth, overload
and sensitivity improve (see Bandwidth vs.
Temperature curves). Use of surface mount
(preferably MIM type capacitors), low inductance
power supply bypass capacitors (>=56pF) are
essential for good high frequency and low noise
performance. The power supply bypass capacitors
should be mounted on or connected to a good low
inductance ground plane.
General Layout Considerations
Since the gain stages of the transimpedance
amplifier have an open loop bandwidth in excess of
1.0 GHz, it is essential to maintain good high
frequency layout practices. To prevent oscillations, a
low inductance RF ground plane should be made
the utmost care should available for power supply
bypassing. Traces that can be made short should
be made short, and be taken to maintain very low
capacitance at the photodiode-TIA interface (I
IN
), as
excess capacitance at this node will cause a
degradation in bandwidth and sensitivity (see
Bandwidth vs. C
T
curves).
Note: All performance curves are typical @ TA =25 C
unless otherwise noted.
925 um
V
DD1
I
IN
GND
GND
GND GND
GND
GND
GND
GND
C
BY
C
BY
C
AGC
V
OUT
1992
1250 um
V
DD2
ATA06211D1C Bonding Pads
7I
VDD
56pF
56pF
PIN
56pF
56pF
OUT
GND
0.90
0.80
0.70
0.60
0.50
0.40
-40
10
60
85
V
DD
=
4.5 V
V
DD
=
5.0 V
V
DD
=
5.5 V
B
a
n
d
w
i
d
t
h
(
M
H
z
)
Temperature (
O
C)
C
T
= 0.5 pF
Figure 4: Bandwidth vs. Temperature
PRELIMINARY DATA SHEET - Rev 4
08/2001
5
ATA06211
V
OUT
Connection
The output pad should be connected via a coupling
capacitor to the next stage of the receiver channel
(filter or decision circuits), as the output buffers are
not designed to drive a DC coupled 50 ohm load
(this would require an output bias current of
approximately 36 mA to maintain a quiescent 1.8
Volts across the output load). If V
OUT
is connected to a
high input impedance decision circuit (>500 ohms),
then a coupling capacitor may not be required,
although caution should be exercised since DC
offsets of the photo detector/TIA combination may
cause clipping of subsequent gain or decision
circuits.
I
IN
Connection
(Refer to the equivalent circuit diagram.) Bonding the
detector cathode to I
IN
(and thus drawing current from
the ATA06211) improves the dynamic range. Although
the detector may be used in the reverse direction for
input currents not exceeding 25 mA, the specifications
for optical overload will not be met.
V
DD
= 4.5 V
V
DD
= 5.0 V
V
DD
= 5.5 V
900
800
700
600
500
400
300
0 0 .2 0 .4 0 .6 0 .8 1 .0 1 .2 1 .4 1 .6
B(3dB) A / 2
Rf (C
in
+C
t
)
C
T
(pF)
B
a
n
d
wit
h
(
M
Hz)
I
V
DD
= 5.5 V
V
DD
= 4.5 V
I
IN
(mA DC)
5
4
3
2
1
T
r
an
si
m
p
eda
nce (
K
Ohm
)
I
IN
50
-2.1 - 1.6 -1.1 - 0.6 - 0.1
R
f
50
I
IN
(mA DC)
I
IN
BANDW
IDTH
(
M
Hz
)
2.1 - 1.6 - 1.1 - 0.6 - 0.1
1.2
1.1
1.0
0.9
0.8
0.7
0.6
0.5
V
DD
= 5.5 V
V
DD
= 4.5 V
V
DD
=4.5 V
V
DD
=5.5 V
Output Collapse
I
IN
V
OUT
I
IN
(mA DC)
heavy AGC
Linear Region
V
OU
T
(V
o
l
ts
)
R
f
3.4
3.2
3.0
2.9
2.7
2.5
2.4
2.2
2.0
1.9
1.7
1.5
1.4
1.2
1.0
0.8
0.7
0.5
0.3
0.2
0.0
- 4
- 3
- 2
- 1
Figure 5: Bandwidth vs. CT
Figure 6: Transimpedance vs. I
IN
Figure 7: Bandwidth vs. I
IN
Figure 8: V
OUT
vs. I
IN
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