RHF310 STMICROELECTRONICS [STMicroelectronics], RHF310 Datasheet - Page 11

• Manufacturer Part Number: RHF310
• Description: Rad-hard 400 ?A high-speed operational amplifier
• Manufacturer: STMICROELECTRONICS [STMicroelectronics]

RHF310
3
3.1
Power supply considerations
Correct power supply bypassing is very important for optimizing the performance of the
device in high-frequency ranges. The bypass capacitors should be placed as close as
possible to the IC pins to improve high-frequency bypassing. A capacitor greater than 1 µF
is necessary to minimize the distortion. For better quality bypassing, a capacitor of 10 nF
can be added, which should also be placed as close as possible to the IC pins. The bypass
capacitors must be incorporated for both the negative and positive supply.
Figure 22. Circuit for power supply bypassing
Single power supply
If you use a single-supply system, biasing is necessary to obtain a positive output dynamic
range between the 0 V and +V
amplifier provides an output swing from +0.9 V to +4.1 V on 1 kΩ loads.
The amplifier must be biased with a mid-supply (nominally +V
DC component of the signal at this value. Several options are possible to provide this bias
supply, such as a virtual ground using an operational amplifier or a two-resistance divider
(which is the cheapest solution). A high resistance value is required to limit the current
consumption. On the other hand, the current must be high enough to bias the non-inverting
input of the amplifier. If we consider this bias current (55 µA maximum) as 1% of the current
through the resistance divider, two resistances of 470 Ω can be used to maintain a mid
supply.
The input provides a high-pass filter with a break frequency below 10 Hz, which is
necessary to remove the original 0 V DC component of the input signal and to set it at
+V
Figure 23 on page 12
A capacitor C
keep the right DC component at the output. C
and its value is calculated with a consideration of the cut-off frequency of this low-pass filter.
CC
/2.
G
is added in the gain network to ensure a unity gain at low frequencies to
illustrates a 5 V single power supply configuration.
Doc ID 15577 Rev 3
CC
supply rails. Considering the values of V
+
-
+V
-V
G
CC
CC
contributes to a high-pass filter with R
+
AM00835
10 µF
+
10 nF
10 nF
10 µF
Power supply considerations
CC
/2) in order to maintain the
OH
and V
OL
fb
, the
11/22
//R
G