The PCN is located here: http://support.logicpd.com/DesktopM...ntryId=751
SOMOMAPL138-10-1602AHCR-C is covered under PCN 595 in Section 8.
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The PCB layout was updated to accommodate two active component changes.
1. The Low-Dropout (LDO) regulator U10 was changed to a new component selection.
2. An external oscillator circuit (Y7) was added to drive the processor system clock (OSCIN).
Real-time Clock LDO Change
The U10 power regulation IC was changed from a 200 mA-rated LDO (TPS79912YZU) with a quiescent current up to 40 uA to a 150 mA-rated LDO (TPS78101DRVR) with a quiescent current up to 1 uA to address an issue with high quiescent current on the real-time clock (RTC) circuit.
This LDO change results in lower quiescent current drain on the RTC battery, creating an approximately 3x increase in the RTC battery life when the system is in an off state.
This change has no impact on software.
Processor System Clock Change
An external clock oscillator Y7 was added to drive the OSCIN system clock input on the processor. This external clock implementation replaces the use of the oscillator internal to the processor, which used crystal Y2.
This clock source change addresses the erratum related to system-level ESD immunity in "Section 2.1.4" of the Texas Instruments (TI) OMAP-L138 C6000 DSP+ARM Processor Silicon Errata13 (literature number SPRZ301M).
This change has no impact on software. However, software can optionally change the CLKMODE bit in the PLLCTL register to equal 1; this software change may save a small amount of additional power draw by turning off the internal processor oscillator, which is no longer used in this configuration.
Processor Silicon Revision Change
Texas Instruments (TI) has released new silicon revision 2.3 for the OMAPL138 processor. This silicon update fixes a USB0 PLL errata that appeared in silicon revision 2.1 parts as documented in “Section 3.2” of the Texas Instruments (TI) OMAP-L138 C6000 DSP+ARM Processor Silicon Errata14 (literature number SPRZ301M).
The former silicon revision 2.1 processor parts OMAPL138BZCE3 (commercial temp) and OMAPL138BZCEA3 (industrial temp) have now been replaced by the revision 2.3 parts OMAPL138EZCE3 and OMAPL138EZCEA3, respectively.
Logic PD has re-qualified the OMAPL138 SOM with the new processor revision and found no impact to the SOM functionality.