Datasheet TSV7721, TSV7722, TSV7723 (STMicroelectronics) - 22
| Manufacturer | STMicroelectronics |
| Description | High bandwidth (22 MHz) low offset (200 μV) 5 V op amp |
| Pages / Page | 33 / 22 — TSV7721, TSV7722, TSV7723. Photodiode transimpedance amplification. 6.2 |
| File Format / Size | PDF / 4.5 Mb |
| Document Language | English |
TSV7721, TSV7722, TSV7723. Photodiode transimpedance amplification. 6.2
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TSV7721, TSV7722, TSV7723 Photodiode transimpedance amplification 6.2 Photodiode transimpedance amplification
The TSV7722, with high bandwidth and slew rate, is well suited for photodiode signal conditioning in a transimpedance amplifier circuit. This application is useful in high performance UV sensors, smoke detectors or particle sensors.
Figure 48. Photodiode transimpedance amplifier circuit
The transimpedance amplifier circuit converts the small photodiode output current in the nA range, into a voltage signal readable by an ADC following Equation 12: VOut = Rf . Ipℎotodiode (6) The feedback resistance is usually in the MΩ range, in order to get a large enough voltage output range. However, together with the diode parasitic capacitance, the op amp input capacitances and the PCB stray capacitance, this feedback network creates a pole that makes the circuit oscillate. Using a small (few pF) capacitor in parallel with the feedback resistor is mandatory to stabilize the circuit. The value of this capacitor can be tuned to optimize the application settling time with a SPICE simulation using the op amp macromodel, or by prototyping. For more details on tuning this circuit, please read the application note AN4451.
DS13614
-
Rev 1 page 22/33
Document Outline Features Applications Description 1 Pin connections 2 Absolute maximum ratings and operating conditions 3 Electrical characteristics 4 Typical performance characteristics 5 Application information 5.1 Operating voltages 5.2 Input offset voltage drift over the temperature 5.3 Unused channel 5.4 EMI rejection 5.5 Maximum power dissipation 5.6 Capacitive load and stability 5.7 Resistor values for high speed op amp design 5.8 Settling time 5.9 PCB layout recommendations 5.10 Decoupling capacitor 5.11 Macro model 6 Typical applications 6.1 Low-side current sensing 6.2 Photodiode transimpedance amplification 7 Package information 7.1 SOT23-5 package information 7.2 DFN8 2x2 package information 7.3 MiniSO8 package information 7.4 SO-8 package information 7.5 MiniSO10 package information 8 Ordering information Revision history
The TSV7722, with high bandwidth and slew rate, is well suited for photodiode signal conditioning in a transimpedance amplifier circuit. This application is useful in high performance UV sensors, smoke detectors or particle sensors.
Figure 48. Photodiode transimpedance amplifier circuit
The transimpedance amplifier circuit converts the small photodiode output current in the nA range, into a voltage signal readable by an ADC following Equation 12: VOut = Rf . Ipℎotodiode (6) The feedback resistance is usually in the MΩ range, in order to get a large enough voltage output range. However, together with the diode parasitic capacitance, the op amp input capacitances and the PCB stray capacitance, this feedback network creates a pole that makes the circuit oscillate. Using a small (few pF) capacitor in parallel with the feedback resistor is mandatory to stabilize the circuit. The value of this capacitor can be tuned to optimize the application settling time with a SPICE simulation using the op amp macromodel, or by prototyping. For more details on tuning this circuit, please read the application note AN4451.
DS13614
-
Rev 1 page 22/33
Document Outline Features Applications Description 1 Pin connections 2 Absolute maximum ratings and operating conditions 3 Electrical characteristics 4 Typical performance characteristics 5 Application information 5.1 Operating voltages 5.2 Input offset voltage drift over the temperature 5.3 Unused channel 5.4 EMI rejection 5.5 Maximum power dissipation 5.6 Capacitive load and stability 5.7 Resistor values for high speed op amp design 5.8 Settling time 5.9 PCB layout recommendations 5.10 Decoupling capacitor 5.11 Macro model 6 Typical applications 6.1 Low-side current sensing 6.2 Photodiode transimpedance amplification 7 Package information 7.1 SOT23-5 package information 7.2 DFN8 2x2 package information 7.3 MiniSO8 package information 7.4 SO-8 package information 7.5 MiniSO10 package information 8 Ordering information Revision history
