Bandwidth And Response; Terminating Resistance - THORLABS PDA10D2 User Manual

Extended InGaAs Amplified Fixed Gain Detector
Material
Silicon (Si)
Germanium (Ge)
Gallium Phosphide (GaP)
Indium Gallium Arsenide
(InGaAs)
Extended Range: Indium
Gallium Arsenide (InGaAs)

4.4. Bandwidth and Response

For the PDA detectors, the gain of the detector is dependent on the feedback
element (R ). The bandwidth of the detector can be calculated using the
f
following:
Where GBP is the amplifier gain bandwidth product and C
photodiode junction capacitance and the amplifier capacitance.

4.5. Terminating Resistance

The maximum output of the PDA10A2 is 10 V for high impedance loads (i.e.
> 5 kΩ) and 5 V for 50 Ω loads. Adjust the gain so that the measured signal
R
Load
level out of the PDA10A2 is below 10 V (5 V with a 50 Ω load) to avoid
saturation.
For low terminating resistors, <5 kΩ or 1% error, an additional factor needs to be
considered. The output of the PDA includes a 50 Ω series resistor (R
output load creates a voltage divider with the 50 Ω series resistor as follows:

( �� ) ∗ ���������������������������� �������� ∗ ���������� ������������ ∗ ���������� ���������� (��)
�� =
������
Note that we already include the scale factor in our specification for the gain at
50 Ω. Refer to the table in Chapter 6 for additional performance specifications.
1
Approximate values; actual wavelength values will vary.
Rev B, January 3, 2019
Dark
Current
Low
High
Low
Low
High
�� ( −3���� ) = √
4����
���������� ������������ =
Sensitivity
Speed
400 – 1000
High
900 – 1600
Low
150 – 550
High
800 – 1800
High
1200 – 2600
High
������
× ��
�� ��
��
��������
�� + ��
�������� ��
Chapter 4: Operation
1
Cost
(nm)
Low
Low
Med
Med
High
is the sum of the
D
). The
s
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