nxp,opamp

Description

NXP Operational Amplifier (opamp)

Properties

Properties not inherited from the base binding file.

Name

Type

Details

non-inverting-reference

string

 
Selects non-inverting path reference voltage source.
The actual meaning of each option:
"Input0": MCU internal DAC out
"Input1": VDD / 2
"Input2": MCU internal VREF out
"Input3": Fixed 520mv

Legal values: 'Input0', 'Input1', 'Input2', 'Input3'

operation-mode

string

 
Selects opamp operation mode.
Reasons why set default value to low_noise:
1. Matches the value after register reset.
2. If there is no special high slew rate requirement,
there is no need to change the mode to high speed mode.
The actual meaning of each option:
"low_noise": OPAMP in low noise mode
"high_speed": OPAMP in high slew rate mode

Default value: low_noise

Legal values: 'low_noise', 'high_speed'

enable-measure-reference

boolean

 
Specifies whether the measure positive gain resistor ladder
reference voltage switch is on or off for ADC channel.

enable-measure-output

boolean

 
Specifies whether the measure negative gain resistor ladder
voltage switch is on or off for ADC channel.

#nxp,opamp-cells

int

 
Number of items to expect in a opamp specifier.

Constant value: 1

functional-mode

string

 
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

This property is required.

Legal values: 'differential', 'inverting', 'non_inverting', 'follower', 'standalone'

programmable-gain

string-array

 
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

Legal values: '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'

pinctrl-0

phandles

 
Pin configuration/s for the first state. Content is specific to the
selected pin controller driver implementation.

pinctrl-1

phandles

 
Pin configuration/s for the second state. See pinctrl-0.

pinctrl-2

phandles

 
Pin configuration/s for the third state. See pinctrl-0.

pinctrl-3

phandles

 
Pin configuration/s for the fourth state. See pinctrl-0.

pinctrl-4

phandles

 
Pin configuration/s for the fifth state. See pinctrl-0.

pinctrl-names

string-array

 
Names for the provided states. The number of names needs to match the
number of states.

resets

phandle-array

 
Reset information

reset-names

string-array

 
Name of each reset

Specifier cell names

  • nxp,opamp cells: channel_id