AD8067(Rev0) Ver la hoja de datos (PDF) - Analog Devices
Número de pieza
componentes Descripción
Fabricante
AD8067 Datasheet PDF : 24 Pages
| |||
0.33pF
49.9kΩ
+5V
10µF
–5V
EPM 605 LL
0.1µF
AD8067
50Ω
VOUT
10µF
NOTES
0.33pF
ID @ –5V = 0.074nA
CD @ –5V = 0.690pF
RB @ 1550nm = –49dB
49.9kΩ
–5V
0.1µF
Figure 51. Photodiode Preamplifier
Test data for the preamp is shown in Figure 52 and Figure 53.
100
95
90
85
80
75
70
65
60
0.01
0.1
1
10
100
FREQUENCY – MHz
Figure 52. Photodiode Preamplifier Frequency Response
C1 RISE
31.2ns
T
C1 FALL
31.6ns
AD8067
Using the AD8067 at Gains of Less Than 8
A common technique used to stabilize decompensated amplifiers is
to increase the noise gain, independent of the signal gain. The
AD8067 can be used for signal gains of less than 8, provided that
proper care is taken to ensure that the noise gain of the amplifier
is set to at least the recommended minimum signal gain of 8
(See Figure 54).
The signal and noise gain equations for a noninverting amplifier
are shown below.
Signal Gain = 1 + R3
R1
Noise Gain = 1 + R3
R1
The addition of resistor R2 modifies the noise gain equation, as
shown below. Note the signal gain equation has not changed.
Noise Gain = 1 + R3
R1|| R2
R3
600Ω
+5V C1
10µF
R1
301Ω
R2
50Ω
VIN
C2
4
5 0.1µF
AD8067 1
3
2 C3
10µF
R4
51Ω
VOUT
RL
C4
–5V 0.1µF
Figure 54. Gain of Less than 2 Schematic
This technique allows the designer to use the AD8067 in gain
configurations of less than 8. The drawback to this type of
compensation is that the input noise and offset voltages are also
amplified by the value of the noise gain. In addition, the distortion
performance will be degraded. To avoid excessive overshoot and
ringing when driving a capacitive load, the AD8067 should be
buffered by a small series resistor; in this case, a 51 Ω resistor
was used.
CH1 500mV
M 50ns CH1 830mV
Figure 53. Photodiode Preamplifier Pulse Response
Rev. 0 | Page 21 of 24
Share Link: 