The SPD6528Q is a Geiger-mode InGaAs avalanche photodiode (APD) module with single-photon sensitivity and integrated negative feedback resistance. It utilizes Geiger-mode high gain to amplify detected photons into macroscopic current, while the feedback resistor dynamically quenches and restores the avalanche field.
The module integrates an NFAD chip, capacitor, thermistor, ceramic carrier, and TEC in a butterfly hermetic package with metalized fiber coupling. Optical input: 62.5 μm multimode fiber (0.9 mm tight buffer) with FC/UPC connector.
Main Optoelectronic Indicators
1. Linear mode parameters
Parameters1. Linear mode parameters | Test conditions（unless otherwise specified，TC =25±5℃) | Min | Max | Unit |
Spectral response range | — | 950 | 1650 | nm |
Reverse breakdown voltage VBR | IR=10 μA ，Φe=0 | 60 | 85 | V |
Responsivity Re | Φe=1μW，VR=(VBR-1)V, λ=1550 nm±50 nm | 8 |
| A/W |
Dark current ID | VDC =(VBR-1) V，Φe=0 |
| 1 | nA |
Capacitance Ctot | VDC =(VBR-1) V，f=1MHz | — | 0.6 | pF |
Integrated resistance (Re) | I=200μA,Φe=0 | 200±50 | KΩ |
Breakdown voltage temperature coefficient η | TC =-45～+30℃ , IR =10μA，φe=0 | 0.10 | 0.15 | V/℃ |
2. Geiger Mode Parameters
Parameters | Test Conditions TC =-40±3℃ , fp=50KHz | Min | Max | Unit |
Single photon detection efficiency PDE | λ=1550nm | 15 |
| % |
Dark count rate DCR | PDE=15% |
| 10 | kcps |
After pulse probability APP | PDE=15% ，λ=1550nm ， Δt=1us |
| 15 | % |
Pulse output amplitude Vout | PDE=15% ，R=50 Ω | 0.5 |
| mV |
Note: λ is the wavelength of incident light, fp is the frequency of the optical pulse signal, and R is the sampling resistor.
Absolute Maximum Ratings and Recommended Operating Conditions
Item | Parameter | Rating |
Absolute Maximum Ratings | 1 | Storage temperatureTSTG | -50℃~+85℃ |
| 2 | Operating environment temperatureTC | -50℃~60℃ |
| 3 | Soldering temperatureTsld（time） | 260℃（10s） |
| 4 | Reverse DC bias voltage VDC | VBR+5 V |
| 5 | Input optical powerφe（continuous） | 1 mW |
| 6 | Forward currentIF（continuous） | 200 μA |
| 7 | Electrostatic discharge sensitivityESD | ≥300 V |
| 8 | Pigtail pulling force | 3.0 N |
Item | Parameter | Rating |
|
Recommended Operating Conditions | 1 | APD chip operating temperatureTth | -50℃~-30℃ |
|
| 2 | Reverse DC bias voltageVDC | VBR+1V～VBR+5V |
|
Typical characteristic curve
Figure 1 Photocurrent and dark current curves
Figure 2 Breakdown voltage temperature coefficient
SPD6528Q InGaAs Negative-Feedback Avalanche Photodiode Module .pdf
