Here is more non-positive stuff on the Lory Semi LR8323 LDO. I'm just adding it here for info since it is somewhat relevant to folks who have boards that use LR8323 and is TL;DR on datasheets.
From their LR8323_Datasheet_EN_Rev.A (24V).pdf datasheet, page 9. The part has short-circuit protection, but NOT over current protection (more below). The DS does not have specifics on thermal shutdown protection, but instead pages 8-9 generally pushes thermal limit responsibility to the user. Compare that to Microchip's LDOs, which often have diagrams showing the behaviour of such protective features. On page 11, Layout Guidelines item 3, Lory advises the user to maximize thermal performance. But realistically, there's not much that one can do with a sot-23 power device -- they are tiny plastic parts with no thermal pads.
So on page 7, Figure 9.4 is misleading, since with VOUT above 0.7V, short circuit protection is turned OFF (as stated on page 9). The chart should not be labeled as over current protection. And then the trigger point is highly temperature dependent, going from 400mA (25C) to 150mA (105C). The performance of LR8323 at 105C is wildly different versus at 25C.
The next chart, Figure 9.5 is also not good. The dropout voltage is also highly temperature dependent. Dropout for a 50mA load go from 100mV (25C) to 900mV (105C). I guess the 150mA load chart will look much worse. Which, coupled with the BAT54 Schottky -- which is in the same current class as 1N4148 or SMD MMBD4148 -- totals at least 2V dropout with loads north of 100mA. This can be compared to a Microchip LDO DS which has a similar chart, e.g. MCP1824 has much less dropout voltage temperature dependence.
The temperature dependence characteristics of LR8323 looks to me like it can act as a thermal relaxation oscillator, or maybe it will do a chaotic dance with the BAT54.
From their LR8323_Datasheet_EN_Rev.A (24V).pdf datasheet, page 9. The part has short-circuit protection, but NOT over current protection (more below). The DS does not have specifics on thermal shutdown protection, but instead pages 8-9 generally pushes thermal limit responsibility to the user. Compare that to Microchip's LDOs, which often have diagrams showing the behaviour of such protective features. On page 11, Layout Guidelines item 3, Lory advises the user to maximize thermal performance. But realistically, there's not much that one can do with a sot-23 power device -- they are tiny plastic parts with no thermal pads.
So on page 7, Figure 9.4 is misleading, since with VOUT above 0.7V, short circuit protection is turned OFF (as stated on page 9). The chart should not be labeled as over current protection. And then the trigger point is highly temperature dependent, going from 400mA (25C) to 150mA (105C). The performance of LR8323 at 105C is wildly different versus at 25C.
The next chart, Figure 9.5 is also not good. The dropout voltage is also highly temperature dependent. Dropout for a 50mA load go from 100mV (25C) to 900mV (105C). I guess the 150mA load chart will look much worse. Which, coupled with the BAT54 Schottky -- which is in the same current class as 1N4148 or SMD MMBD4148 -- totals at least 2V dropout with loads north of 100mA. This can be compared to a Microchip LDO DS which has a similar chart, e.g. MCP1824 has much less dropout voltage temperature dependence.
The temperature dependence characteristics of LR8323 looks to me like it can act as a thermal relaxation oscillator, or maybe it will do a chaotic dance with the BAT54.
Statistics: Posted by katak255 — Wed Aug 21, 2024 2:35 am