FAN7392N

The FAN7392N from onsemi (formerly Fairchild Semiconductor) is a monolithic high- and low-side gate drive IC in a 14-pin PDIP through-hole package. It can drive MOSFETs and IGBTs that operate up to +600V, making it suitable for half-bridge and full-bridge inverter applications. Note: This product is in Last Shipments status at onsemi, meaning it is approaching end-of-life and should not be designed into new products.

The FAN7392 provides independent high-side and low-side gate drive outputs (HO and LO), each capable of 3A source and 3A sink current. The buffered output stage uses all-NMOS transistors for high pulse current driving capability and minimum cross-conduction during switching transitions.

The high-side driver uses a bootstrap floating supply (VB-VS) that allows operation up to +600V. onsemi’s high-voltage process and common-mode noise canceling techniques provide stable operation under high dv/dt noise circumstances. The advanced level-shift circuit offers high-side gate driver operation down to VS = -9.8V (typical) for VBS = 15V, critical for motor drive applications where negative VS transients occur.

Logic inputs (HIN, LIN, SD) are compatible with standard CMOS or LSTTL output, down to 3.3V logic. A separate VDD logic supply pin (3.3V to 20V) allows direct interfacing with 3.3V microcontrollers without level translation. The SD (shutdown) pin provides cycle-by-cycle edge-triggered shutdown for both channels, useful for overcurrent protection.

The under-voltage lockout (UVLO) circuit prevents malfunction when VCC (low-side supply) and VBS (high-side supply) are below the specified threshold voltage, ensuring the MOSFETs/IGBTs are not driven into linear operation during power-up.

The propagation delay is matched for both channels (130 ns turn-on, 150 ns turn-off typical), enabling precise complementary switching in bridge configurations. The outputs are in-phase with the input signals (HIN=HIGH produces HO=HIGH).

The PDIP-14 package provides 1.6W power dissipation at 25C ambient with 75C/W thermal resistance. For surface-mount applications, the FAN7392MX (SOIC-16W) variant is also available but also in Last Shipments status.

For new designs, onsemi recommends the FAN7390 or NCP51530 as replacement devices.

**Bootstrap High-Side Drive:** The high-side driver is powered by a bootstrap capacitor connected between VB and VS. When the low-side MOSFET is on, VS is near ground, and the bootstrap capacitor charges through the bootstrap diode from VCC. When the high-side MOSFET turns on, VS rises to the bus voltage, and the bootstrap capacitor provides the floating supply for the high-side driver. This eliminates the need for an isolated power supply.

**Level Shifting:** The high-side driver is referenced to VS (the switch node), which swings between ground and the bus voltage at high dv/dt. The level-shift circuit translates the ground-referenced logic signals to the floating high-side domain. The common-mode dv/dt noise cancellation circuit prevents false triggering during these fast transitions.

**Cycle-by-Cycle Shutdown:** The SD (shutdown) pin provides an edge-triggered shutdown function. When a rising edge is detected on SD, both HO and LO are forced LOW for the remainder of the switching cycle. The outputs resume normal operation on the next HIN/LIN transition. This provides fast overcurrent protection without latching off the driver.

**UVLO Protection:** Both VCC and VBS are monitored by under-voltage lockout circuits. If VCC drops below the UVLO threshold (approximately 9.2V typical), the low-side output is disabled. If VBS drops below its UVLO threshold (approximately 8.6V typical), the high-side output is disabled. This prevents the MOSFETs from being driven with insufficient gate voltage, which would cause excessive conduction losses and potential device failure.