Mxtronics Power Management

Mxtronics offers three main types of power management ICs: DC-DC converters (buck, boost, buck-boost) with radiation tolerance for efficient power conversion, Low-dropout regulators (LDOs) for low-noise analog supplies, and Voltage references for precision analog circuits. The MXP series DC-DC converters offer synchronous rectification for high efficiency. MXL series LDOs provide ultra-low noise for sensitive applications. MXR series references offer excellent temperature stability for precision measurement.

Choose DC-DC converters for efficiency-critical applications. Choose LDOs for low-noise analog supplies. Choose references for precision measurement circuits.

Mxtronics power management ICs are available in multiple radiation tolerance levels: Standard grade (-55°C to +125°C) without radiation testing, 10krad(Si) for low-earth orbit satellites, 50krad(Si) for medium orbit missions, and 100krad(Si) for geostationary and deep space applications. All radiation-tolerant devices undergo total ionizing dose (TID) testing per MIL-STD-883 Method 1019. Single event effects (SEE) characterization is also available. Custom radiation tolerance levels can be accommodated for specific mission requirements.

Select radiation tolerance based on mission orbit and duration. LEO missions typically need 10-50krad, GEO missions need 100krad.

Choose switching regulators (DC-DC) when: input-output voltage difference is large (efficiency advantage), battery life is critical, or heat dissipation is a concern. Choose LDO when: input-output voltage difference is small (<1V dropout), low output noise is required (RF, analog circuits), or simple, low-cost solution is preferred. Mxtronics offers both options with the MXP series for DC-DC and MXL series for LDOs. Some applications use both: switching regulator for efficient voltage step-down, followed by LDO for clean analog supply.

Use DC-DC for large voltage drops and efficiency. Use LDO for small drops and low noise. Consider cascaded approach for best of both.

Synchronous rectification replaces the Schottky diode in buck converters with a low-RDS(on) MOSFET, significantly reducing conduction losses. Efficiency improvement: 5-15% at heavy loads, especially at low output voltages. For example, a 3.3V output from 12V input: Schottky diode drop (0.4V) is 12% loss, while synchronous MOSFET (50mΩ at 3A = 0.15V drop) is only 4.5% loss. Mxtronics MXP series buck converters use synchronous rectification to achieve efficiencies up to 95%. The trade-off is slightly higher cost and more complex control, but the efficiency gain is usually worth it for aerospace applications where power is limited.

Use synchronous rectification for applications >1W or when efficiency is critical. Use non-synchronous for lowest cost applications <1W.

LDO power dissipation is calculated as: P_diss = (V_in - V_out) × I_out + V_in × I_quiescent. The first term dominates at moderate to high loads. For example: V_in = 5V, V_out = 3.3V, I_out = 200mA, I_q = 50μA. P_diss = (5 - 3.3) × 0.2 + 5 × 0.00005 = 0.34W + 0.00025W ≈ 0.34W. Junction temperature: T_j = T_a + P_diss × θ_ja. With T_a = 50°C and θ_ja = 50°C/W: T_j = 50 + 0.34 × 50 = 67°C. For reliable operation, keep T_j below 125°C. High input-output differential with high current can cause excessive heating - consider switching regulators for these cases.

Calculate dissipation before selecting LDO. Ensure T_j stays below 125°C. Use switching regulator for large voltage drops with high current.