SBOS492F June 2009 – May 2018 OPA2354A-Q1 , OPA354A-Q1 , OPA4354-Q1
PRODUCTION DATA.
Wide gain bandwidth, low input bias current, low input voltage, and current noise make the OPAx354-Q1 family of devices a preferred wideband photodiode transimpedance amplifier. Low-voltage noise is important because photodiode capacitance causes the effective noise gain of the circuit to increase at high frequency.
The key elements to a transimpedance design, as shown in Figure 37, are the expected diode capacitance (C(D)), which must include the parasitic input common-mode and differential-mode input capacitance (4 pF + 5 pF); the desired transimpedance gain (R(FB)); and the gain-bandwidth (GBW) for the OPAx354-Q1 family of devices (20 MHz). With these three variables set, the feedback capacitor value (C(FB)) is set to control the frequency response. C(FB) includes the stray capacitance of R(FB), which is 0.2 pF for a typical surface-mount resistor.
NOINDENT:
C(FB) is optional to prevent gain peaking. C(FB) includes the stray capacitance of R(FB).