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LM5134

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SNVS808C – MAY 2012 – REVISED FEBRURARY 2016

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8.2.2.6 Propagation Delay

The acceptable propagation delay from the gate driver is dependent on the switching frequency at which it is

used, and the acceptable level of pulse distortion to the system. The LM5134 device features industry best-in-

class 17-ns (typical) propagation delays, which ensure very little pulse distortion and allow operation at very high

frequencies. See Electrical Characteristics for the propagation and switching characteristics of the LM5134

device.

8.2.2.7 PILOT MOSFET Selection

In general, a small-sized 20-V MOSFET with logic level gates can be used as the external turnoff switch. To

achieve a fast switching speed and avoid the potential shoot-through, select a MOSFET with the total gate

charge less than 3 nC. Verify that no shoot-through occurs for the entire operating temperature range. In

addition, a small Rds(on) is preferred to obtain the strong sink current capability. The power losses of the PILOT

MOSFET can be estimated in Equation 1.

where

•

(1)

8.2.3 Application Curves

Figure 25. OUT Turnoff to PILOT Turnon Propagation

Delay vs VDD

Figure 26. PILOT Turnoff to OUT Turnon Propagation

Delay vs VDD

9 Power Supply Recommendations

A low ESR/ESL ceramic capacitor must be connected close to the IC, between VDD and VSS pins to support the

high peak current being drawn from VDD during turnon of the FETs. Place the VDD decoupling capacitor on the

same side of the PC board as the driver. The inductance of via holes can impose excessive ringing on the IC

pins.