Calculadora de Regulador LDO
Disipación de potencia y análisis térmico
Required Parameters
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Quick Answer
LDO power dissipation: P = (Vin - Vout) × Iload. Junction temp: Tj = Ta + P × θJA. Ensure Tj < 125°C.
Design Notes
LDOs are simple but waste power as heat. Efficiency = Vout/Vin. For a 5V→3.3V conversion at 500mA, you dissipate 0.85W. Always check the dropout voltage spec at your load current — it increases with current. Use input and output capacitors (typically 1µF-10µF ceramic) for stability.
Common Mistakes
- 1
Forgetting that dropout voltage increases with load current — check the datasheet curves.
- 2
Ignoring thermal limits — a SOT-23 package can only dissipate ~0.4W without a heatsink.
- 3
Using an LDO where a switching regulator would be far more efficient (large Vin-Vout differential).
Knowledge Base
¿Qué es un regulador LDO?
Regulador lineal con diferencial mínimo de entrada-salida (100-500mV). Produce salida limpia con ruido mínimo, ideal para circuitos analógicos, ADC y etapas RF.
¿Cuándo usar LDO vs convertidor conmutado?
LDO: bajo ruido, Vin-Vout < 2V, corriente < 500mA. Conmutado: eficiencia, gran diferencial, alta corriente. Eficiencia LDO = Vout/Vin (3.3V desde 5V = 66%).
¿Cómo calculo la disipación del LDO?
P = (Vin - Vout) × Icarga. 5V a 3.3V a 500mA: P = 0.85W. Verificar Tj = Tamb + P×θJA < 125°C.
¿Qué LDOs son populares?
3.3V: AMS1117-3.3 (1A, barato), AP2112K (600mA, bajo ruido). Ajustable: LM317, TLV757P. Para batería: ME6211 (500mA, 100mV dropout, 40µA Iq).
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