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The AM64x and AM243x Sitara processor lines provide highly flexible, real-time, and low latency processing for a broad range of industrial applications. These processors come in an array of variants with up to two Arm® Cortex® -A53 cores and up to four Arm® Cortex® -R5F cores each. TI has multiple power management IC (PMIC) options to meet the complex power needs of each processor variant.
This application note reviews two variants of the LP8733xx and two variants of the TPS65218xx PMICs that power these Sitara processor lines. A selection guide outlines both a single-PMIC and dual-PMIC solution for the AM64x, and a single-PMIC solution for the AM243x. The application note also highlights the value each PMIC solution brings to the overall system and provides example power maps for each variant.
The LP8733xx and TPS65218xx are optimized and highly integrated power management solutions for the AM64x and AM243x processors. Table 2-1 provides an overview of the technical features for each PMIC family.
Features | LP8733xx | TPS65218xx |
---|---|---|
Input range | 2.8 V to 5.5 V | 2.7 V to
5.5 V (Converters) 1.8 V to 5.5 V (LDO) |
Number of regulators | 4 | 7 |
Number of DC-DC step-down converters | 2 | 3
(Adjustable output voltage) 2 (Backup battery domain) |
Number of Buck-boost converters | 0 | 1 |
Number of LDOs | 2 | 1 |
Additional Features |
|
|
Ability to reprogram using EEPROM | No | Yes |
The LP8733xx is a one-time programmable (OTP) device that comes pre-programmed to simplify the design process and allows direct implementation of the given power configuration with no modifications needed.
The TPS65218xx is a non-volatile memory (NVM) device that comes both pre-programmed and user-programmable. For example, the TPS6521855 is pre-programmed to meet the AM64x power sequence and configuration needs when paired with the LP873364. The TPS6521815 is a user programmable DIY device that comes with a blank EEPROM and disabled regulators to provide freedom to customize the desired output voltages, sequencing and more from start up as further explained in Section 6. All devices in the TPS65218xx family have a reprogrammable EEPROM, allowing flexibility to change configuration settings according to system needs.
Table 3-1 shows a comparison of the regulator output settings for each LP8733xx variant. The two LP8733xx variants are OTP devices that are pre-programmed with set output voltages and sequencing to match the different AM64x or AM243x specifications. For more information on this device, please see the LP8733xx data sheet. For more details on each variant, please refer to the LP873364 Technical Reference Manual and the LP87334D Technical Reference Manual.
PMIC | LP873364 | LP87334D | ||
---|---|---|---|---|
Regulator Settings | Output Voltage | Startup / Shutdown Delay | Output Voltage | Startup / Shutdown Delay |
Buck0 | 0.75 V | 2 ms / 2 ms | 0.85 V | 2 ms / 2 ms |
Buck1 | 3.3 V | 0 ms / 2 ms | 3.3 V | 0 ms / 2 ms |
LDO0 | 1.8 V | 1 ms / 2 ms | 1.8 V | 1 ms / 2 ms |
LDO1 | 1.8 V | 1 ms / 2 ms | 1.8 V | 1 ms / 2 ms |
GPO0 | X[1] | 15 ms / 0 ms | X[1] | 15 ms / 0 ms |
GPO2 | X[1] | 3 ms / 0 ms | X[1] | 3 ms / 0 ms |
[1] A set output voltage is not pre-programmed; GPO0 and GPO2 can be pulled up and used to sequence discrete components to the system.
Table 3-2 shows a comparison of the pre-programmed TPS6521855 versus the DIY TPS6521815 settings. The TPS6521855 is a pre-programmed NVM device that can be used with the LP873364 as a dual-PMIC solution for the AM64x processors. The TPS6521815 is the user-programmable DIY version, and will be discussed in greater detail in Section 6. For more information on each variant, please see the TPS6521855 and TPS6521815 data sheets.
PMIC | TPS6521855 | TPS6521815 | ||||
---|---|---|---|---|---|---|
Regulator Settings | Output Voltage | Enabled | Startup / Shutdown delay | Output Voltage | Enabled | Startup / Shutdown delay |
DCDC1 | 1.1 V | Yes | 10 ms / 8 ms | 0.85 V to 1.675 V | No | X[2] |
DCDC2 | 1.0 V | Yes | 8 ms / 10 ms | |||
DCDC3 | 1.8 V | Yes | 8 ms / 10 ms | 0.9 V to 3.4 V | No | X[2] |
DCDC4 | 2.5 V | Yes | 6 ms / 12 ms | 1.175 V to 3.4 V | No | X[2] |
DCDC5 | 1.0 V | No | X[2] | 1.0 V | No | X[2] |
DCDC6 | 1.8 V | No | X[2] | 1.8 V | No | X[2] |
LDO1 | 3.3 V | Yes | 4 ms / 14 ms | 0.9 - 3.4 V | No | X[2] |
[2] Register is not enabled, so regulator is not controlled by the sequencer. Regulator can be programmed with register enabled and desired startup/shutdown delay.
The AM64x and AM243x PMIC solution options using each LP8733xx and TPS65218xx PMIC variant are outlined in the next section in a PMIC Selection Guide.