Si photodioe with preamp

S8745-01, S8746-01

Output noise voltage and NEP (noise equivalent power) characteristics allow you to check whether the device can detect the low-

level light you want to measure. Since NEP is given by the equation (1) as shown at the right, NEP at wavelengths other than

λp can

be easily calculated from Figure 1 and Figures 4.

Note) When S8745-01 and S8746-01 are used only with the internal current-to-voltage gain, it is recommended that the "-IN" lead (pin 6 for S8745-

01; pin 9 for S8746-01) be cut off to a short length in order to reduce the influence of external noise as much as possible.

Figure 4 NEP vs. frequency

KSPDB0237EA

KSPDB0238EA

Figure 3 Output noise voltage vs. frequency

KSPDB0235EA

NEP (f,

λ) : NEP at frequency and wavelength to be detected

NEP (f,

λp): NEP at peak wavelength (See Figures 4)

: Current-to-voltage conversion gain (See Figure 2)

Ssi (

λ)

: Sensitivity of Si photodiode

S (

λ)

: Sensitivity of S8745-01 and S8746-01 (See Figure 1.)

S (

λp)

: Sensitivity of S8745-01 and S8746-01 at peak wavelength, 0.5 V/nW

Vn (f)

: Output noise voltage (See Figure 3)

KSPDB0236EA

FREQUENCY (kHz)

Ω, dark state]

0.1

0.001

0.01

0.01

0.1

1

10

100

1

1000

100

10

S8745-01

+111 M

Ω

(EXTERNAL

CONNECTED)

+11 M

Ω

(EXTERNAL

CONNECTED)

+1 M

Ω

(EXTERNAL

CONNECTED)

FREQUENCY (kHz)

Ω, dark state]

0.1

0.001

0.01

0.01

0.1

1

10

100

1

1000

100

10

S8746-01

+111 M

Ω

(EXTERNAL

CONNECTED)

+1 M

Ω

(EXTERNAL

CONNECTED)

+11 M

Ω

(EXTERNAL

CONNECTED)

FREQUENCY (kHz)

Ω, dark state, l=lp]

0.1

0.001

0.01

1

1000

100

10

S8745-01

+111 M

Ω

(EXTERNAL

CONNECTED)

+1 M

Ω

(EXTERNAL

CONNECTED)

+11 M

Ω

(EXTERNAL

CONNECTED)

FREQUENCY (kHz)

Ω, dark state, l=lp]

0.1

0.001

0.01

1

1000

100

10

S8746-01

+111 M

Ω

(EXTERNAL

CONNECTED)

+1 M

Ω

(EXTERNAL

CONNECTED)

+11 M

Ω

(EXTERNAL

CONNECTED)

S8745-01

S8746-01

S8745-01

S8746-01

NEP (f,

λ) =

=

··· (1)

Vn (f)

λ)

NEP (f,

λp) · S (λp)

S (

λ)

3