| # Copyright 2025 NXP |
| # SPDX-License-Identifier: Apache-2.0 |
| |
| include: |
| - name: base.yaml |
| - name: pinctrl-device.yaml |
| |
| properties: |
| functional-mode: |
| required: true |
| type: string |
| enum: |
| - "differential" |
| - "inverting" |
| - "non_inverting" |
| - "follower" |
| - "standalone" |
| description: | |
| Selects opamp functional mode. |
| |
| a) differential mode |
| |
| - Signals applied to both inputs |
| - Amplifies the difference between two input signals |
| - Common-mode signals are rejected |
| - Used in instrumentation and noise rejection |
| - Vout = (Rf/Rin) * (Vin2 - Vin1), where Rf is the feedback resistor |
| and Rin is the input resistor, with gain (Rf/Rin) |
| |
| Rin Rf |
| Vin1 --/\/\/\--*--/\/\/\----- |
| | | |
| | |\ | |
| ------|- \ | |
| | >--*-- Vout |
| ------|+ / |
| | |/ |
| | |
| Vin2 --/\/\/\--*--/\/\/\----- |
| Rin Rf | |
| GND |
| |
| b) inverting mode |
| |
| - Input signal applied to inverting (-) terminal |
| - Non-inverting (+) terminal connected to ground |
| - Feedback resistor connects output to inverting input |
| - Output is 180° out of phase with input |
| - Vout = (-Rf/Rin) * Vin, where Rf is the feedback resistor |
| and Rin is the input resistor, s.t. gain is (-Rf/Rin) |
| |
| Rin Rf |
| Vin --/\/\/\--*--/\/\/\----- |
| | | |
| | |\ | |
| ------|- \ | |
| | >--*-- Vout |
| ------|+ / |
| | |/ |
| GND |
| |
| c) non_inverting mode |
| |
| - Input signal applied to non-inverting (+) terminal |
| - Inverting (-) terminal connected to feedback network |
| - Output is in phase with input |
| - Vout = (1 + (Rf/Rin)) * Vin, where Rf is the feedback resistor |
| and Rin is the input resistor, s.t. gain is (1 + (Rf/Rin)) |
| |
| Rin Rf |
| |--/\/\/\--*--/\/\/\----- |
| | | | |
| GND | |\ | |
| ------|- \ | |
| | >--*-- Vout |
| Vin ------|+ / |
| |/ |
| |
| d) follower mode (voltage follower or buffer) |
| |
| - Special case of non-inverting amplifier |
| - Vout = 1 * Vin, s.t. gain is 1 |
| - Direct feedback from output to inverting input |
| - Very high input impedance, very low output impedance |
| - Used for impedance matching |
| |
| -------------- |
| | | |
| | |\ | |
| ------|- \ | |
| | >--*-- Vout |
| Vin ------|+ / |
| |/ |
| |
| e) standalone mode |
| |
| - The opamp mode is defined by external circuitry |
| |
| |\ |
| Vin- -----|- \ |
| | >---- Vout |
| Vin+ -----|+ / |
| |/ |
| |
| References: |
| - https://www.electronics-tutorials.ws/category/opamp |
| |
| programmable-gain: |
| type: string-array |
| enum: |
| - "OPAMP_GAIN_1_7" |
| - "OPAMP_GAIN_1_3" |
| - "OPAMP_GAIN_1" |
| - "OPAMP_GAIN_5_3" |
| - "OPAMP_GAIN_2" |
| - "OPAMP_GAIN_11_5" |
| - "OPAMP_GAIN_3" |
| - "OPAMP_GAIN_4" |
| - "OPAMP_GAIN_13_3" |
| - "OPAMP_GAIN_7" |
| - "OPAMP_GAIN_8" |
| - "OPAMP_GAIN_15" |
| - "OPAMP_GAIN_16" |
| - "OPAMP_GAIN_31" |
| - "OPAMP_GAIN_32" |
| - "OPAMP_GAIN_33" |
| - "OPAMP_GAIN_63" |
| - "OPAMP_GAIN_64" |
| description: | |
| If the OPAMP supports programmable gain, then the gain of |
| the opamp can be changed dynamically at runtime. The gain |
| value needs to be one of the enumerations above. |
| Gain selection: |
| - OPAMP_GAIN_1_7 : x 1/7 |
| - OPAMP_GAIN_1_3 : x 1/3 |
| - OPAMP_GAIN_1 : x 1 |
| - OPAMP_GAIN_5_3 : x 5/3 |
| - OPAMP_GAIN_2 : x 2 |
| - OPAMP_GAIN_11_5 : x 11/5 |
| - OPAMP_GAIN_3 : x 3 |
| - OPAMP_GAIN_4 : x 4 |
| - OPAMP_GAIN_13_3 : x 13/3 |
| - OPAMP_GAIN_7 : x 7 |
| - OPAMP_GAIN_8 : x 8 |
| - OPAMP_GAIN_15 : x 15 |
| - OPAMP_GAIN_16 : x 16 |
| - OPAMP_GAIN_31 : x 31 |
| - OPAMP_GAIN_32 : x 32 |
| - OPAMP_GAIN_33 : x 33 |
| - OPAMP_GAIN_63 : x 63 |
| - OPAMP_GAIN_64 : x 64 |
