MAX8791 데이터 시트보기 (PDF) - Maxim Integrated
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MAX8791 Datasheet PDF : 12 Pages
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Single-Phase, Synchronous MOSFET Drivers
PWM SKIP
+5V BIAS
SUPPLY
CVDD
1.0µF
PWM
DH
SKIP
BST
MAX8791
LX
VDD MAX8791B
DL
GND
PAD
NH
CBST
0.22µF
CIN
2x 10µF
L1
0.36µH
NL
DL
INPUT (VIN)
OUTPUT (VOUT)
COUT
2x 330µF
6mΩ
Figure 3. Typical MOSFET-Driver Application Circuit
Table 1. Typical Components
DESIGNATION
NH
NL
BST Capacitor (CBST)
Schottky Diode
Inductor (L1)
Output Capacitors (COUT)
Input Capacitors (CIN)
QTY
1 per phase
1–2 per phase
1 per phase
Optional
1 per phase
1–2 per phase
1–2 per phase
COMPONENT SUPPLIERS
Siliconix Si4860DY
Siliconix Si4336DY
0.1µF or 0.22µF ceramic capacitor
3A, 40V Schottky diode
0.36µH, 26A, 0.9mΩ power inductor
330µF, 6mΩ per phase
10µF, 25V X5R ceramic capacitors
Detail Description
The MAX8791/MAX8791B single-phase gate drivers,
along with the MAX8736 or MAX8786 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
MAX8791/MAX8791B is capable of driving 3nF capaci-
tive 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 propagation and transition times. Adaptive
dead-time control prevents shoot-through currents and
maximizes converter efficiency while allowing operation
with a variety of MOSFETs and PWM controllers. An
input undervoltage lockout (UVLO) circuit allows proper
power-on sequencing.
PWM Input
The drivers for the MAX8791/MAX8791B 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 MAX8791/
MAX8791B immediately exit the low-current shutdown
state and resume active operation. Outside the shut-
down 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 0.9Ω sourcing resis-
tance and 0.7Ω 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 0.7Ω sourcing resistance and 0.3Ω sinking
resistance, yielding 2.7A peak sourcing current and 8A
peak sinking current. This reduces switching losses,
making the MAX8791/MAX8791B ideal for both high-
frequency and high output-current applications.
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