OPA2810 Datasheet, PDF (20/26 Pages) Texas Instruments – OPA2810 Dual High-Performance, Low-Power, Wide Supply Range, Rail-to-Rail Input/Output FET-Input Operational Amplifier

OPA2810
SBOS789 – AUGUST 2017
www.ti.com
If the total output noise of the TIA is band-limited to a frequency less than the feedback pole frequency, a very
simple expression for the equivalent output noise voltage can be derived as shown in Equation 5. The low-
frequency output noise of 45 nV/√Hz is dominated by the 100-kΩ feedback resistor and can be input-referred to
0.45 pA/√Hz. The transimpedance gain resistor is the dominant noise source at low frequencies. A JFET input
amplifier's current noise is negligible and can therefore be ignored. At the mid and high frequencies the
operational amplifiers voltage noise gets peaked up by the noise gain zero formed by R_F and C_D. The output
noise contribution at the mid and high frequencies is represented by the fourth term in Equation 5.
where
• V_OUTN = Equivalent output noise when band limited to F < 1 / (2 ΩRfCf)
• I_N = Input current noise for the operational amplifier inverting input
• E_N = Input voltage noise for the operational amplifier
• C_D = Diode capacitance including operational amplifier and PCB parasitic capacitance
• F = Band-limiting frequency in Hz (usually a postfilter before further signal processing)
• 4 kT = 1.6 e – 20 J at T = 290°K
(5)
9 Power Supply Recommendations
The OPA2810 is intended for operation on supplies ranging from 4.75-V to 27-V. The OPA2810 may be operated
on single-sided supplies, split and balanced bipolar supplies or unbalanced bipolar supplies. Operating from a
single supply can have numerous advantages. With the negative supply at ground, the DC errors due to the
–PSRR term can be minimized. Typically, AC performance improves slightly at 12-V operation with minimal
increase in supply current.
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