a
FEATURES
Low Cost, Wide Bandwidth, Low Noise
Bandwidth: 240 MHz
Pulse Width Modulation: 500 ps
Rise Time/Fall Time: 1.5 ns
Input Current Noise: 3.0 pA/√Hz @ 100 MHz
Total Input RMS Noise: 26.5 nA to 100 MHz
Wide Dynamic Range
Optical Sensitivity: –36 dBm @ 155.52 Mbps
Peak Input Current: 350 A
Differential Outputs
Low Power: 5 V @ 25 mA
Wide Operating Temperature Range: –40 C to +85 C
APPLICATIONS
Fiber Optic Receivers: SONET/SDH, FDDI, Fibre Channel
Stable Operation with High Capacitance Detectors
Low Noise Preamplifiers
Single-Ended to Differential Conversion
I-to-V Converters
Wideband/Differential Output
Transimpedance Amplifier
AD8015
FUNCTIONAL BLOCK DIAGRAM
AD8015
NC 1
I
IN
2
G = 30
G=3
NC 3
+1
V
BYP
4
– +
1.7V
NC = NO CONNECT
+V
S
5 –V
S
50Ω
6 –OUTPUT
8 +V
S
10kΩ
50Ω
+1
7 +OUTPUT
25.0E+3
DIFFERENTIAL
20.0E+3
X-RESISTANCE –
Ω
15.0E+3
SINGLE-ENDED
10.0E+3
PRODUCT DESCRIPTION
5.0E+3
The AD8015 is a wide bandwidth, single supply transimpedance
amplifier optimized for use in a fiber optic receiver circuit. It is a
complete, single chip solution for converting photodiode current
into a differential voltage output. The 240 MHz bandwidth enables
AD8015 application in FDDI receivers and SONET/SDH
receivers with data rates up to 155 Mbps. This high bandwidth
supports data rates beyond 300 Mbps. The differential outputs
drive ECL directly, or can drive a comparator/ fiber optic post
amplifier.
In addition to fiber optic applications, this low cost, silicon al-
ternative to GaAs-based transimpedance amplifiers is ideal for
systems requiring a wide dynamic range preamplifier or single-
ended to differential conversion. The IC can be used with a
standard ECL power supply (–5.2 V) or a PECL (+5 V) power
supply; the common mode at the output is ECL compatible.
The AD8015 is available in die form, or in an 8-pin SOIC
package.
000.E+0
10.0E+6
100.0E+6
FREQUENCY – Hz
1.0E+9
Figure 1. Differential/Single-Ended Transimpedance vs.
Frequency
5.0
EQUIVALENT INPUT CURRENT NOISE – pA
√
Hz
4.5
2.0pF
4.0
1.5pF
3.5
3.0pF
3.0
2.5
0.5pF
2.0
000.0E+0
20.0E+6
40.0E+6
60.0E+6
1.0pF
80.0E+6
100.0E+6
FREQUENCY – Hz
REV. A
Information furnished by Analog Devices is believed to be accurate and
reliable. However, no responsibility is assumed by Analog Devices for its
use, nor for any infringements of patents or other rights of third parties
which may result from its use. No license is granted by implication or
otherwise under any patent or patent rights of Analog Devices.
Figure 2. Noise vs. Frequency (SO-8 Package with
Added Capacitance)
© Analog Devices, Inc., 1996
One Technology Way, P.O. Box 9106, Norwood, 02062-9106, U.S.A.
Tel: 617/329-4700
Fax: 617/326-8703
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