RAIL 3 Power Amplifier (PA) PowerSetting tables Utility#

Overview#

The sl_rail_util_pa_tables component provides Power Amplifier (PA) powersetting mapping tables for RAIL (Radio Abstraction Interface Layer). This utility enables accurate conversion between dBm powers and hardware-specific PA power settings which is performed by RAIL 3 Power Amplifier (PA) Utility component.

Purpose#

This component provides:

• Pre-characterized PA Tables: Device-specific powersetting tables mapping dBm values to PA power settings

• Multi-Mode PA Support: Tables are available for multiple PA modes when supported.(2.4GHz, subGHz, Linear OFDM etc)

• Multiple Powersetting table options: Different options of tables are provided to choose from when supported on a board (High Power(HP), Medium Power(MP), Low Power(LP), Low Low Power(LLP), automode)

• Automatic PA Selection: Configuration support for automatic PA sub-mode selection based on power requirements

• Hardware Abstraction: Unified interface across EFR32 Series 2 and Series 3 SoCs.

Supported Devices#

The component provides PA tables for the following device families:

• means 4dBm variant is a power restricted 8dBm variant.

Configuration#

Universal Configurator (UC) Integration#

The component automatically selects the appropriate PA table based on:

1. Device Series

2. Device SDID

3. PA Capability

4. Package Type

5. Frequency Band

Configuration File#

Each device variant includes a configuration file:

plugin/sl_rail_util_pa_tables/{device}/config/{variant}/sl_rail_util_pa_tables_config.h

Example configuration (EFR32xG24 20dBm):

#define SL_RAIL_UTIL_PA_TABLE_HEADER    "sl_rail_util_pa_dbm_powersetting_mapping_table_20dbm.h"

This header is included in the build via the SL_RAIL_UTIL_PA_TABLES_CONFIG_HEADER define.

PA Power Sub-Modes#

The component supports multiple PA sub-modes for power-optimized operation:

Sub-Mode Types#

Sub-Mode Availability#

Refer to the Supported Devices section above for sub-mode availability by device.

PA Table Format#

Table Structure#

PA tables map dBm power levels to hardware power settings. Here is an example of EFR32xG28 20dBm power setting table:

#define SL_RAIL_PA_TABLE_0_NUM_VALUES  (55U)
#define SL_RAIL_PA_TABLE_0_STEP_DDBM   (10U)         // Step size in deci-dBm (1.0 dBm)
#define SL_RAIL_PA_TABLE_0_MAX_POWER_DDBM     (200U) // Max: 20.0 dBm
#define SL_RAIL_PA_TABLE_0_MIN_POWER_DDBM     (-338) // Min: -33.8 dBm

#define SL_RAIL_PA_TABLE_0                        \
  {                                               \
    0x0 /* est_deci-dBm:-338 act_deci-dBm:-338*/, \
    0x0 /* est_deci-dBm:-328 act_deci-dBm:-338*/, \
    0x0 /* est_deci-dBm:-318 act_deci-dBm:-338*/, \
    ...                                           \
    0x1 /* est_deci-dBm:-188 act_deci-dBm:-192*/, \
    ...                                           \
    0x6d /* est_deci-dBm:182 act_deci-dBm:182*/,  \
    0x86 /* est_deci-dBm:192 act_deci-dBm:192*/,  \
    0xa5 /* est_deci-dBm:200 act_deci-dBm:200*/,  \
  }

For custom table, make sure these parameters exist.

Power Units#

• deci-dBm: Power values in tenths of dBm (e.g., 200 deci-dBm = 20.0 dBm)

• Step Size: Typically 1.0 dBm (10 deci-dBm) between entries

• Power Setting: Hardware-specific raw value for PA registers

Usage#

Including the Component#

In your Universal Configurator project:

1. Add the sl_rail_util_pa_tables component

2. The appropriate PA table is automatically selected based on device configuration

3. The component provides the sl_rail_util_pa_tables.h header

API Usage#

The component provides enumeration types used by RAIL power conversion APIs:

#include "sl_rail_util_pa_tables.h"

// PA sub-modes are defined for use with power APIs
sl_rail_pa_power_setting_submode_t submode = SL_RAIL_PA_POWER_SETTING_SUBMODE_HP;

Integration with PA Conversion Plugin#

This component works in conjunction with sl_rail_util_pa_conversions:

// PA conversions plugin uses these tables internally
sl_rail_status_t status = sl_rail_set_tx_power_ddbm(rail_handle, 
                                                     power_ddbm);

// The conversion is handled automatically:
// 1. Current PA mode is determined
// 2. Appropriate PA table is selected
// 3. dBm value is converted to PA power setting
// 4. PA hardware is configured

Automode PA Tables#

Some devices support automatic PA mode switching:

Automode Configurations#

• EFR32xG21: Automode tables for 0/10 dBm, 0/10/20 dBm, 10/20 dBm

• EFR32xG22: Automode tables for 0/6 dBm

• EFR32xG24: Automode tables for 0/10 dBm

• EFR32xG26: Automode tables for 0/10 dBm (QFN and BGA)

• EFR32xG27: Automode tables for 0/4 dBm (CSP), 0/8 dBm (QFN)

• EFR32xG29: Automode tables for 0/8 dBm (CSP and QFN)

• SixG301: Automode tables for 0/10 dBm

Benefits of Automode#

• Automatic switching between low-power and high-power PAs

• Optimized current consumption at lower power levels

• Seamless power ramping across PA mode boundaries

Device-Specific Notes#

EFR32xG23/xG28 Sub-Modes#

These devices support four PA sub-modes (HP, MP, LP, LLP) for fine-grained power/efficiency tuning:

• HP (High Power): Best linearity, highest current

• MP (Medium Power): Balanced performance

• LP (Low Power): Good efficiency, lower harmonic distortion

• LLP (Low-Low Power): Maximum efficiency for low-power applications

EFR32xG25 Board-Specific Tables#

The xG25 includes a board-specific table for BRD4276A:

// Board-specific PA table selection
condition:
  - device_series_2
  - device_sdid_220
  - brd4276a

EFR32xG28 Frequency Bands#

The xG28 provides separate PA tables for different frequency bands:

• 868 MHz: European ISM band optimization

• 915 MHz: North American ISM band optimization

The correct table is selected based on hardware_board_supports_rf_band_868.

EFR32xG26 Package Variants#

The xG26 supports different PA tables for package types in addition to PA sub-modes:

• QFN Package: Standard power tables

• BGA Package (EFR32MG26B510F3200IL136): Optimized for BGA thermal characteristics

Series 3 (SIXG301)#

Series 3 devices use simplified PA table structure:

• 0 dBm Table: Low-power mode

• 10 dBm Table: High-power mode

• Automode Table: Automatic switching between 0/10 dBm

Requirements#

Component Dependencies#

• rail_lib: Core RAIL library (required)

• sl_rail_util_pa: PA plugin(required)

Build System Integration#

The build system automatically:

1. Detects device family and capabilities

2. Selects appropriate config file based on conditions

3. Includes device-specific PA table headers

4. Defines SL_RAIL_UTIL_PA_TABLES_CONFIG_HEADER macro

Troubleshooting#

Common Issues#

Issue: PA table not found at build time

• Solution: Verify device conditions match (SDID, PA capability, package type)

• Check: Component configuration in .slcp file

Issue: Incorrect power output

• Solution: Ensure correct PA mode is selected for channel configuration

• Check: Board files and hardware_board_supports_* conditions