Lac503p | Schematic
LDO_IN(Pin9)---------+----> From VOUT (3.3V) | LDO1_OUT(Pin10)------+---- C5 ---> 1.8V out LDO2_OUT(Pin11)------+---- C6 ---> 1.2V out
Download a generic buck converter calculator to fine-tune your feedback resistors, or use an oscilloscope to verify the SW node waveform (should be a clean 1.5MHz square wave). Have a correction or an original Lac503P datasheet? Share it in the comments below. Our community of hardware engineers is actively working to document this obscure but essential PMIC. lac503p schematic
| Pin # | Name | Function | Connection in Schematic | | :--- | :--- | :--- | :--- | | 1 | VIN | Main power input (3.3V-5V) | Connect to 5V USB or battery (+) via 10µF ceramic cap. | | 2 | EN | Global enable (active high) | Pull to VIN for always-on; or connect to MCU GPIO. | | 3 | SW | Switching node (Buck converter) | Connect to power inductor (2.2µH to 4.7µH). | | 4 | BST | Bootstrap capacitor pin | Connect 100nF cap between BST and SW. | | 5 | FB | Feedback for buck output | Connect voltage divider to set Vout (e.g., 3.3V). | | 6 | COMP | Compensation pin | RC network to ground (stability). | | 7 | AGND | Analog ground | Connect to main ground plane (star point). | | 8 | PGND | Power ground | Wide trace to input capacitor ground. | | 9 | LDO_IN | Input for LDOs | Usually tied to buck output (3.3V) or separate VIN. | | 10 | LDO1_OUT | Output LDO1 (e.g., 1.8V) | 2.2µF ceramic cap to ground. | | 11 | LDO2_OUT | Output LDO2 (e.g., 1.2V) | 1µF ceramic cap to ground. | | 12 | LDO_EN | LDO enable | If separate from main EN, tie to VIN. | | 13-16 | NC | No connect | Leave floating. | LDO_IN(Pin9)---------+----> From VOUT (3
Meta Description: Need the lac503p schematic ? This article provides a detailed breakdown of the Lac503P power management IC, including pin configuration, internal block diagram, typical application circuit, and troubleshooting tips for engineers and hobbyists. Introduction: What is the Lac503P? The Lac503P is a widely used, highly integrated Power Management Integrated Circuit (PMIC), commonly found in portable consumer electronics, single-board computers, and battery-operated devices. While the exact manufacturer specifications can vary (with "Lac" often being a shorthand or rebranding for specific OEM batches), the core topology of the IC revolves around a high-efficiency step-down (buck) converter combined with low-dropout (LDO) regulators. Our community of hardware engineers is actively working
For repair technicians and hardware designers, finding a clear is critical. Without it, diagnosing a dead device, reverse-engineering a board, or building a custom power supply becomes a guessing game. This article reconstructs the standard application circuit based on common PMIC architectures and available datasheet fragments.
