6
IR2086S(PbF)
www.irf.com
Detailed Pin Description continued
COM1, COM2: Signal ground and power ground for all functions. Due to high current and high frequency
operation, a low impedance circuit board ground plane is highly recommended.
HO1, HO2, LO1, LO2: High side and low side gate drive pins. The high and low side drivers can directly drive
the gate of a power MOSFET. The drivers are capable of 1A peak source and sink currents. It is recommended
that the high and low drive pins be very close to the gates of the high side and low side MOSFETs to prevent
any delay and distortion of the drive signals.
Vb1, Vb2: High side power input connection. The high side supplies are derived from bootstrap circuits using
low-leakage Schottky diodes and ceramic capacitors. To prevent noise, the Schottky diodes and bypass
capacitors should be very close to the IR2086S.
Vs1, Vs2: The high side power return connection. Vs should be connected directly to the source terminal of
high side MOSFET with a trace as short as possible.
Vcc: The IC bias input connection for the device. Although the quiescent Vcc current is very low, total supply
current will be higher, depending on the gate charge of the MOSFETs connected to the HO and LO pins, and
the programmed oscillator frequency, Total Vcc current is the sum of quiescent Vcc current and the average
current at HO and LO. Knowing the operating frequency and the MOSFET gate charge (Qg) at selected Vcc
voltage, the average current to drive four power MOSFETs in full-bridge configuration can be calculated from:
Iave = 4 x Qg X fosc
(Note that fosc is equal to the frequency per channel.)
To prevent noise problem, a bypass ceramic capacitor connected to Vcc and COM1 / COM2 should be placed
as close as possible to the IR2086S.
IR2086S has an under voltage lookout feature for the IC bias supply, Vcc. The minimum voltage required on
Vcc to make sure that IC will work within specifications must be higher than 8.5V (9.5V minimum Vcc is
recommended to prevent asymmetrical gates signals on HO and LO pins that are expected when Vcc is
between 7.5V and 8.5V).
