LDO Regulator Dropout, Power Dissipation & Thermal Calculator
Calculate low-dropout (LDO) linear regulator minimum input voltage headroom, continuous power dissipation (Pd), silicon junction temperature rise (Tj), maximum allowable load current, and electrical efficiency.
Operating Voltages & Load Current
V
V
mA
mV
From datasheet at full rated load current.
mA
°C
°C/W
Regulator Thermal & Headroom
THERMAL OK
Power Dissipation (Pd)
0.875 W
Continuous heat generated
Junction Temp (Tj)
81.9 °C
Margin: +43.1 °C to 125°C
Min Input Voltage
3.650 V
Headroom: +1.350 V OK
Electrical Efficiency (η)
65.3 %
Vout / Vin power ratio
Maximum Continuous Current Rating
Safe Continuous Limit:
905 mA
Maximum load current before junction exceeds safe 125°C threshold under current ambient conditions.
LDO Governing Thermal Equations:
• Power Dissipation: (P_d = (V_{ ext{in}} - V_{ ext{out}}) cdot I_{ ext{load}} + V_{ ext{in}} cdot I_q)
• Junction Temperature: (T_j = T_a + P_d cdot heta_{ja})
• Safe Max Current: (I_{ ext{max}} = rac{T_{j, ext{max}} - T_a}{ heta_{ja} cdot (V_{ ext{in}} - V_{ ext{out}})})