PR EVB User’s Manual
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Optilab, LLC
600 E. Camelback Road, Phoenix, AZ 85012
Phone: (602) 343-1496, Fax: (602) 343-1489, Email: [email protected]
1.2 Bandwidth Adjustment
PR-30 offers a bandwidth adjustment feature that allows users to optimize
optical receiver performance for different applications. PR-30 bandwidth can
be adjusted as needed. The table below gives the bandwidth based on BWH
and BWL settings when photo diode is reversed biased at 3.3V.
Table 2. Bandwidth Setting Lookup Table
BWH
BWL
Min. Bandwidth
(GHz)
GND
VCC
13
GND
FLT
15
GND
GND
16
FLT
FLT
18
VCC
GND
20
VCC
FLT
20.5
VCC
VCC
21
In default setting on the evaluation board, both BWH and BWL are preset to
VCC to achieve the largest bandwidth. If a bandwidth smaller than 13 GHz is
desired, the user can lower VPD to further reduce the overall bandwidth of PR-
30.
1.3 Operation Mode
PR-30 integrates a single, differential linear trans-impedance / variable-gain
amplifier (TIA/VGA). The TIA offers two gain control modes: manual gain
control and automatic gain control. In manual mode, MC pin should be
connected to GND. The gain is adjustable from 50 Ω to 5000 Ω differential by
adjusting the GC level. When MC and GC pins are floating, device is operating
in automatic gain control (AGC) mode. In AGC mode, the gain is
automatically adjusted to deliver a constant output voltage. The output
amplitude is adjustable over 20 dB dynamic range by adjusting the level of OA.
Table 3. Operation Mode Selection
Operation Mode
MC Setting (Pin 6)
Amplitude / Gain Adjustment
Manual Gain Control
GND
GC (Pin 3), 0 ~ 3.3V
Auto Gain Control
FLT
OA (Pin 4), 0 ~ 3.3 V
Shut Down
VCC
N.A.
The default setting on the evaluation board is MGC. GC is preset to Vcc to
maximize the TIA gain.