22 Lucent Technologies Inc.
Data Sheet
November 2000
131-Type Long-Wavelength PIN Photodetector
Description
The 131-Type photodetectors represent a family of low-
profile, high-reliability pigtailed devices specially
engineered for the rigorous demands of either analog
applications or digital fiber-optic applications. These
photodetectors are based upon Lucent Technologies’
patented Advanced Lightwave Platform technology,
permitting high optical coupling stability and
unparalleled performance.
The low-profile package is an 8-lead DIP that allows
pinout-equivalent replacements for lower-performance
coaxial-type packages. The low profile makes it ideal
for close board-to-board spacing situations.
The 131-Type PIN Photodetectors contain a rear-
illuminated planar diode structure. Lucent Technologies
employs unique diode processing steps to achieve a
low capacitance and highly linear active area that
ensures a wide dynamic operating range . Responsivity
is typically >0.85 A/W with rise and fall times of <0.5 ns
at the 1.3
µ
m wavelength.
Figure 1. Typical Bias Connection
This PIN’s construction involves a patented silicon
optical bench that supplies mechanical stability to the
fiber and directive channeling of input light. The
structure also allows it to handle strong levels of input
power. All fiber types are specially terminated inside
the package to minimize back reflections.
These PIN photodetectors perform effectively and
efficiently over the entire 1.1
µ
m to 1.6
µ
m long
wavelength range. They have been employed in a
number of div erse applications including digital cellular ,
remote monitoring, high-speed datacom, fiber-to-the-
curb, and CATV signaling.
Notes:
This equivalent circuit is intended as an aid for modeling the device/
package parasitics in order for the circuit designer to better match
impedance and optimize bandwidth performance.
Minimum parasitic effects can be achieved by connecting the PIN
cathode (N-side) to circuit ground, applying a negative voltage to the
PIN anode (P-side), and allowing the package voltage to float by
not
connecting the package ground to circuit ground.
Typical values are as follows:
C
O
= Bulk capacitance of the diode = 0.3 pF to 0.5 pF.
R
NSS
, R
PSS
= Bulk resistance of the contacts = 5
Ω
.
L
SBW
= Series inductance of P-side bond wire = 0.25 nH.
C
NSS
, C
PSS
= Substrate capacitance = 0.975 pF/0.28 pF, respectively.
L
NBW
, L
PBW
= Series inductance of the substrate to package lead
bond wire = 2.0 nH.
C
NPL
, C
PPL
= Package lead capacitance = 0.40 pF/0.46 pF,
respectively.
Figure 2. Equivalent ac Circuit for Analog
Applications
Figure 3. 8-Lead DIP Electrical Connections
1-928
RBIAS
VBIAS
+
(N-SIDE)
PIN CATHODE
RLOAD
PIN ANODE
(P-SIDE)
CAPACITOR
dc DECOUPLING
1-929
RNSS
RPSS (P-SIDE)
PIN ANODE
LNBW
LPBW
CNSS
CPSS
CNPL
CPPL
PACKAGE
GROUND
(N-SIDE)
PIN CATHODE
LSBW
CO
PIN
CURRENT
SOURCE
1-698
4 3 2 1
5 6 7 8
GROUND (OPTIONAL)
TERMINAL N
TERMINAL P