OPA2836-Q1 Datasheet, PDF (21/44 Pages) Texas Instruments – Very-Low Power, Rail-to-Rail Out, Negative-Rail In, Voltage-Feedback Operational Amplifier

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8 Detailed Description
OPA2836-Q1
SBOS794 – DECEMBER 2016
8.1 Overview
The OPA2836-Q1 bipolar input operational amplifier offers an excellent bandwidth of 205 MHz with ultra-low
THD of 0.00003% at 1 kHz. The OPA2836-Q1 can swing to within 200 mV of the supply rails when driving a
1-kΩ load. The input common-mode of the amplifier can swing to 200 mV below the negative supply rail. This
level of performance is achieved at 1 mA of quiescent current per amplifier channel.
8.2 Functional Block Diagrams
V_SIG
V_REF
V_S+
V_IN
R_G
V_REF
OPA2836-Q1
V_S-
V_OUT
V_REF
GV_SIG
R_F
Copyright © 2016, Texas Instruments Incorporated
Figure 51. Noninverting Amplifier
V_REF
V_SIG
V_REF
V_S+
RG
VIN
OPA2836-Q1
V_S-
V_OUT
GV_SIG
V_REF
R_F
Copyright © 2016, Texas Instruments Incorporated
Figure 52. Inverting Amplifier
8.3 Feature Description
8.3.1 Input Common-Mode Voltage Range
When the primary design goal is a linear amplifier with high CMRR, the input common-mode voltage range (V_ICR)
of the amplifier must not be violated.
The common-mode input range low and high specifications are based on CMRR. The specification limits are
chosen to ensure CMRR does not degrade more than 3 dB below the mid-supply limit if the input voltage is kept
within the specified range. The limits cover all process variations and most parts are better than specified. The
typical specifications are from 0.2 V below the negative rail to 1.1 V below the positive rail.
Given that the operational amplifier is in linear operation, the voltage difference between the input pins is very
small (ideally 0 V), and input common-mode voltage can be analyzed at either input pin with the other input pin
assumed to be at the same potential. The voltage at V_IN+ is easy to evaluate. In the noninverting configuration,
Figure 51, the input signal V_IN must not violate V_ICR. In the inverting configuration, Figure 52, the reference
voltage V_REF must be within V_ICR.
Copyright © 2016, Texas Instruments Incorporated
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