ADA4817-2ACPZ-RL Analog Devices Inc, ADA4817-2ACPZ-RL Datasheet - Page 19

• Manufacturer Part Number: ADA4817-2ACPZ-RL
• Description: Hi Speed FET Input Amp Dual
• Manufacturer: Analog Devices Inc
• Series: FastFET™r

Specifications of ADA4817-2ACPZ-RL

• Amplifier Type: Voltage Feedback
• Number Of Circuits: 2
• Slew Rate: 870 V/µs
• Gain Bandwidth Product: 410MHz
• -3db Bandwidth: 1.05GHz
• Current - Input Bias: 2pA
• Voltage - Input Offset: 400µV
• Current - Supply: 19mA
• Current - Output / Channel: 40mA
• Voltage - Supply, Single/dual (±): 5 V ~ 10 V, ±2.5 V ~ 5 V
• Operating Temperature: -40°C ~ 105°C
• Mounting Type: Surface Mount
• Package / Case: 16-LFCSP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Output Type: -
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

The pole in the loop transmission translates to a zero in the
amplifier’s noise gain, leading to an amplification of the
input voltage noise over frequency. The loop transmission
zero introduced by C
Table 8. RMS Noise Contributions of Photodiode Preamp
Contributor
R
VEN Amp
IEN Amp
F
45
40
35
30
25
20
15
10
–5
5
0
0.1
Figure 46. Photodiode Preamp Frequency Response
G = 63V/V
R
V
V
S
OUT
L
= 100Ω
= 10V
= 6V p-p
Expression
VEN
F
IEN
1
limits the amplification. The noise gain
4
kT
×
×
R
FREQUENCY (MHz)
×
C
F
R
S
×
F
+
×
C
f
10
2
f
M
2
×
C
×
+
. 1
F
. 1
C
57
57
D
+
C
100
F
×
f
3
×
. 1
1000
57
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bandwidth extends past the preamp signal bandwidth and
is eventually rolled off by the decreasing loop gain of the
amplifier. The current equivalent noise from the inverting
terminal is typically negligible for most applications. The
innovative architecture used in the ADA4817-1/ADA4817-2
makes balancing both inputs unnecessary, as opposed to
traditional FET input amplifiers. Therefore, minimizing the
impedance seen from the noninverting terminal to ground at
all frequencies is critical for optimal noise performance.
Integrating the square of the output voltage noise spectral
density over frequency and then taking the square root allows
users to obtain the total rms output noise of the preamp. Table 8
summarizes approximations for the amplifier and feedback and
source resistances. Noise components for an example preamp
with R
about 6.4 MHz) are also listed.
RMS Noise with R
94 μV
777.5 μV
0.4 μV
783 μV (total)
F
= 50 kΩ, C
S
= 30 pF, and C
F
= 50 kΩ, C
ADA4817-1/ADA4817-2
F
S
= 0.5 pF (bandwidth of
= 30 pF, C
F
= 0.5 pF