
Si photodioe with preamp
S8745-01, S8746-01
2
Figure 2 Gain-frequency characteristics
Figure 1 Spectral response
KSPDB0232EA
KSPDB0233EA
The built-in feedback resistance and capacitance of S8745-
01 and S8746-01 are 1 G
and 5 pF, respectively. This
combination provides a sensitivity of about 0.1 to 0.5 V/nW in
the wavelength range of 190 to 1100 nm.
The current-to-voltage conversion gain can be varied by connecting an external feedback resistor between pins 4 and 6
for S8745-01, and between pins 9 and 12 for S8746-01 (see figure 5). Figure 2 shows the frequency response
characteristics of S8745-01 and S8746-01 with or without an externally connected feedback resistor. Because S8745-01
and S8746-01 have a built-in resistor of 1 G
, for example the total feedback resistance will be converted to 100 M by
externally connecting a resistor of 111 M
. Choose the desired constant according to the incident light level to be
detected.
Note) If the external feedback resistor is 1 M
or less, gain peaking may occur in the frequency response. Therefore, be sure to
connect a matched feedback capacitor for phase compensation.
190
400
600
800
1000
1200
0.6
0.5
0.3
0.1
0.4
0.2
0
[Typ.Ta=25 C, Rf=1 G
(built-in), Cf=5 pF (built-in)]
WAVELENGTH (nm)
PHOTO
SENSITIVITY
(V
nW)
FREQUENCY (kHz)
[Typ. Ta=25 C, Vcc=±15 V, Cf=5 pF (built-in), RL=1 M
]
CURRENT-TO-VOLTAGE
CONVERSION
GAIN
(M
)
1
0.01
0.1
10-2
10-1
100
101
104
102
103
10
100
S8745-01
+111 M
(EXTERNAL CONNECTED)
+11 M
(EXTERNAL
CONNECTED)
+1 M
(EXTERNAL
CONNECTED)
FREQUENCY (kHz)
[Typ. Ta=25 C, Vcc=±15 V, Cf=5 pF (built-in), RL=1 M
]
CURRENT-TO-VOLTAGE
CONVERSION
GAIN
(M
)
1
0.01
0.1
10-2
10-1
100
101
104
102
103
10
100
S8746-01
+111 M
(EXTERNAL CONNECTED)
+11 M
(EXTERNAL
CONNECTED)
+1 M
(EXTERNAL
CONNECTED)
KSPDB0234EA
S8745-01
S8746-01
S8745-01,S8746-01