LM5101CMA National Semiconductor, LM5101CMA Datasheet - Page 13

• Manufacturer Part Number: LM5101CMA
• Description: DRIVER, HALF BRIDGE, 100V 1A, SMD
• Manufacturer: National Semiconductor

Specifications of LM5101CMA

• Device Type: MOSFET
• Module Configuration: High Side / Low Side
• Peak Output Current: 1A
• Input Delay: 26ns
• Output Delay: 22ns
• Supply Voltage Range: 9V To 14V
• Driver Case Style: SOIC
• No. Of Pins: 8
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Diode Power Dissipation V
= 50V
Power Dissipation Considerations
IN
The total IC power dissipation is the sum of the gate driver
losses and the bootstrap diode losses. The gate driver losses
are related to the switching frequency (f), output load capac-
itance on LO and HO (C
), and supply voltage (VDD) and can
L
be roughly calculated as:
P
= 2 • f • C
• V
2
DGATES
L
DD
There are some additional losses in the gate drivers due to
the internal CMOS stages used to buffer the LO and HO out-
puts. The following plot shows the measured gate driver
power dissipation versus frequency and load capacitance. At
higher frequencies and load capacitance values, the power
dissipation is dominated by the power losses driving the out-
put loads and agrees well with the above equation. This plot
can be used to approximate the power losses due to the gate
drivers.
20203106
Gate Driver Power Dissipation (LO + HO)
V
= 12V, Neglecting Diode Losses
DD
20203105
The bootstrap diode power loss is the sum of the forward bias
power loss that occurs while charging the bootstrap capacitor
and the reverse bias power loss that occurs during reverse
recovery. Since each of these events happens once per cycle,
the diode power loss is proportional to frequency. Larger ca-
pacitive loads require more energy to recharge the bootstrap
capacitor resulting in more losses. Higher input voltages
(V
) to the half bridge result in higher reverse recovery loss-
IN
es. The following plot was generated based on calculations
and lab measurements of the diode recovery time and current
under several operating conditions. This can be useful for ap-
proximating the diode power dissipation.
The total IC power dissipation can be estimated from the pre-
vious plots by summing the gate drive losses with the boot-
strap diode losses for the intended application.
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