MCP1415RT datasheet(11/20 Pages) MICROCHIP

11 / 20 page

DS22092C-page 11

MCP1415/16

4.0

APPLICATION INFORMATION

4.1

General Information

MOSFET drivers are high-speed, high current devices

which are intended to source/sink high peak currents to

charge/discharge the gate capacitance of external

MOSFETs or IGBTs. In high frequency switching power

supplies, the PWM controller may not have the drive

capability to directly drive the power MOSFET. A

MOSFET driver like the MCP1415/16 family can be

used

provide

additional

source/sink

current

capability.

4.2

MOSFET Driver Timing

The ability of a MOSFET driver to transition from a fully

off state to a fully on state are characterized by the

drivers rise time (tR), fall time (tF), and propagation

delays (tD1 and tD2). The MCP1415/16 family of drivers

can typically charge and discharge a 1000 pF load

capacitance in 20 ns along with a typical turn on (tD1)

propagation delay of 41 ns. Figure 4-1 and Figure 4-2

show the test circuit and timing waveform used to verify

the MCP1415/16 timing.

FIGURE 4-1:

Inverting Driver Timing

Waveform.

FIGURE 4-2:

Non-Inverting Driver Timing

Waveform.

4.3

Decoupling Capacitors

Careful layout and decoupling capacitors are required

when using power MOSFET drivers. Large current are

required to charge and discharge capacitive loads

quickly. For example, approximately 720 mA are

needed to charge a 1000 pF load with 18V in 25 ns.

To operate the MOSFET driver over a wide frequency

range with low supply impedance, a ceramic and low

ESR film capacitor is recommended to be placed in

parallel between the driver VDD and GND. A 1.0 µF low

ESR film capacitor and a 0.1 µF ceramic capacitor

placed between pins 2 and 4 is required for reliable

operation. These capacitors should be placed close to

the driver to minimize circuit board parasitics and

provide a local source for the required current.

0.1 µF

+5V

10%

90%

10%

90%

10%

90%

18V

1µF

MCP1415

CL = 1000 pF

Input

Output

tD1

tD2

Output

DD = 18V

Ceramic

90%

Input

tD1

tD2

Output

10%

+5V

18V

90%

0.1 µF

1µF

MCP1416

CL = 1000 pF

Input

Output

DD = 18V

Ceramic

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