Sa5211, Philips semiconductors – Philips SA5211 User Manual
Page 16
Philips Semiconductors
SA5211
Transimpedance amplifier (180 MHz)
Product specification
Rev. 03 — 07 October 1998
16 of 28
9397 750 07427
© Philips Electronics N.V. 2001. All rights reserved.
where e = electron charge = 1.6
×
10
-19
Coulombs
Responsivity R =
Amp/watt
Assuming a data rate of 400 Mbaud (Bandwidth, B = 200 MHz), the noise parameter
Z
n
may be calculated as:
1
(8)
where Z is the ratio of
RMS
noise output to the peak response to a single hole-electron
pair. Assuming 100% photodetector quantum efficiency, half mark/half space digital
transmission, 850nm lightwave and using Gaussian approximation, the minimum
required optical power to achieve 10
-9
BER is:
(9)
where h is Planck’s Constant, c is the speed of light,
λ
is the wavelength. The
minimum input current to the SA5211, at this input power is:
(10)
Choosing the maximum peak overload current of I
avMAX
= 60
µ
A, the maximum mean
optical power is:
(11)
Thus the optical dynamic range, D
O
is:
(12)
1.
S.D. Personick,
Optical Fiber Transmission Systems,
Plenum Press, NY, 1981, Chapter 3.
I
∴
η
P
hc
-----
λ
-----
×
e Amps (Coulombs/sec.)
×
=
η
e
×
hc
-------------
λ
-------------
I
P
R
×
=
Z
I
EQ
qB
--------
41
10
9
–
Ч
1.6
10
19
–
Ч
(
)
200
10
6
Ч
(
)
------------------------------------------------------------
1281
=
=
=
P
avMIN
12
hc
λ
-----
BZ
12
2.3
Ч
10
19
–
Ч
=
=
200
10
6
Ч
1281
(
)
719 nW
31.5 dBm
–
1139 nW
29.4 dBm
–
=
=
=
=
I
avMIN
qP
avMIN
λ
hc
-----
1
Joule
------------
Joule
sec
------------
×
q
×
= l =
707
10
9
–
Ч
1.6
Ч
10
19
–
Ч
2.3
10
19
–
Ч
-----------------------------------------------------------
500 nA
=
=
P
avMAX
hcl
avMAX
λ
q
----------------------
2.3
10
19
–
Ч
1.6
10
19
–
Ч
--------------------------
60
10
µ
A
×
86
µ
W or
10.6 dBm (optical)
–
=
=
=
D
O
P
avMAX
P
avMIN
–
4.6
–
29.4
–
(
)
24.8 dB
=
–
=
=
D
O
P
avMAX
P
avMIN
–
31.5
–
10.6
–
(
)
–
=
=