Detailed Description

The MAX17491 single-phase gate driver, along with the

MAX8736, MAX8786, or MAX17030 multiphase con-

trollers, provide flexible multiphase CPU core-voltage

supplies. The low driver resistance allows up to 7A out-

put peak current. Each MOSFET driver in the

MAX17491 can drive 3nF capacitive loads with only 9ns

propagation delay and 4ns/8ns (typ) fall/rise times,

allowing operation up to 3MHz per phase. Larger

capacitive loads are allowable but result in longer prop-

agation and transition times. Adaptive dead-time con-

trol prevents shoot-through currents and maximizes

converter efficiency while allowing operation with a vari-

ety of MOSFETs and PWM controllers. An input under-

voltage-lockout (UVLO) circuit allows proper power-on

sequencing.

PWM Input

The drivers for the MAX17491 are disabled—DH and

DL pulled low—if the PWM input remains in the midlevel

window for at least 300ns (typ). Once the PWM signal is

driven high or low, the MAX17491 immediately exits the

low-current shutdown state and resumes active opera-

tion. Outside the shutdown state, the drivers are

enabled based on the rising and falling thresholds

specified in the

Electrical Characteristics.

MOSFET Gate Drivers (DH, DL)

The high-side driver (DH) has a 0.9

Ω sourcing resis-

tance and 0.7

Ω sinking resistance, resulting in 2.2A

peak sourcing current and 2.7A peak sinking current

with a 5V supply voltage. The low-side driver (DL) has a

typical 0.7

Ω sourcing resistance and 0.3Ω sinking

resistance, yielding 2.7A peak sourcing current and 8A

peak sinking current. This reduces switching losses,

making the MAX17491 ideal for both high-frequency

and high-output-current applications.

Single-Phase Synchronous MOSFET Driver

_______________________________________________________________________________________

7

L1

0.36

μH

MAX17491

PWM

DH

BST

LX

DL

GND

PAD

PWM

+5V BIAS

SUPPLY

SKIP

SKIP

0.22

μF

2x 330

μF

6m

Ω

2x 10

μF

1.0

μF

Figure 3. Typical MOSFET-Driver Application Circuit

Table 1. Typical Components

DESIGNATION

QTY

COMPONENT SUPPLIERS

1 per phase

Siliconix Si4860DY

1–2 per phase

Siliconix Si4336DY

1 per phase

0.1µF or 0.22µF ceramic capacitor

Schottky Diode

Optional

3A, 40V Schottky diode

Inductor (L1)

1 per phase

0.36µH, 26A, 0.9m

Ω power inductor

1–2 per phase

330µF, 6m

Ω per phase

1–2 per phase

10µF, 25V X5R ceramic capacitors