C30645 and C30662 Series

Large area InGaAs Avalanche Photodiodes

Table 1: Electrical Characteristics at TA = 22°C

Parameter

Active Diameter

Breakdown voltage (Vbr)

Operation Point from Breakdown (Vbr-Vop)

Temperature Coefficient of Vbr for Constant Gain

Responsivity (@ 1550 nm)

Dark Current (@ M=10) (id)

Spectral Noise Current (@ M=10) (in)

Capacitance

Bandwidth (@ M=10)

Quantum Efficiency (1300-1550 nm)

Maximum Useable Gain (M)

C30645

Min Typ Max

80

45 50 70

0.14 0.20

9.3

3 50

0.2 1.0

1.25

1000

75

10 20

C30662

Min Typ Max

200

45 50 70

0.14 0.20

9.3

45 150

0.7 1.5

2.5

600 850

75

10 20

C30662-1

Min Typ Max

200

45 50 70

4.0

Units

µm

V

V

V / deg C

A/W

nA

pA/rt(Hz)

pF

MHz

%

No units

Conditions

(@ M=10) (Note 6)

Notes for Table 1

1. A specific voltage, , is supplied with each device. When the photodiode is operated at this voltage (at 22 °C), the device will meet the

electrical characteristic limits shown above. The voltage value will be within the range of 45 to 70 volts.

2. The voltage dependence of the gain, , for gains above 4, is given approximately by the following empirical formula yielding a rough

approximation of the sensitivity:

where:

will vary from APD to APD, but should be within 40-50 for most InGaAs APDs

3. Gain, and quantum efficiency, , are not directly measurable quantities. The numbers quoted are estimated typical values. Gain,

quantum efficiency and responsivity are related by the following:

expressed in A/W

where:

is the quantum efficiency, expressed in %

is the wavelength in units of mm, and

is the APD gain

4. The detector noise current expressed in √ , is given by the following expression:

√(

)

where:

is the electron charge,

( ) ( ), is the excess noise factor, around 5.5 for InGaAs,

is ionization coefficient, typically around 0.45 for InGaAs, and

and are the un-multiplied and multiplied portions of the dark current, respectively.

The total dark current is given by:

However, since both and are somewhat voltage dependent, and is not directly measurable (see Note 3), it is not usually possible

to determine both and unambiguously. Since system performance depends on noise current and responsivity, these measurable

quantities are the ones that have been specified.

5. Most devices can be operated at gains up to about 30 or more, but with values of noise current correspondingly higher, as indicated by the

discussion in Note 4 above.

6. The product C30662EH can be ordered with a guaranteed minimal delta of the operation voltage bias from the voltage breakdown ( - ),

also known as deltaV or dV. Using the “-1” suffix specifies a dV larger than 4.0 V. Please contact us for more information.

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C30645 C30662 Series-Rev.1.2-2013.02