Datasheet

MAX5054–MAX5057
The logic inputs are high impedance and must not be left
floating. If the inputs are left open, OUT_ can go to an
undefined state as soon as V
DD
rises above the UVLO
threshold. Therefore, the PWM output from the controller
must assume proper state when powering up the device.
The MAX5054 has two logic inputs per driver providing
greater flexibility in controlling the MOSFET. Use IN_+ for
noninverting logic and IN_- for inverting logic operation.
Connect IN_+ to V
DD
and IN_- to GND if not used.
Alternatively, the unused input can be used as an
ON/OFF function. Use IN_+ for active-low shutdown logic
and IN_- for active-high shutdown logic (see Figure 4).
See Table 1 for all possible input combinations.
Driver Output
The MAX5054–MAX5057 have low R
DS(ON)
p-channel
and n-channel devices (totem pole) in the output stage
for the fast turn-on and turn-off high gate-charge switch-
ing MOSFETs. The peak source or sink current is typically
4A. The OUT_ voltage is approximately equal to V
DD
when in high state and is ground when in low state. The
driver R
DS(ON)
is lower at higher V
DD
, thus higher
source-/sink-current capability and faster switching
speeds. The propagation delays from the noninverting
and inverting logic inputs to outputs are matched to 2ns.
The break-before-make logic avoids any cross-conduc-
tion between the internal p- and n-channel devices, and
eliminates shoot-through currents reducing the quiescent
supply current.
Applications Information
RLC Series Circuit
The driver’s R
DS(ON)
(R
ON
), internal bond and lead
inductance (L
P
), trace inductance (L
S
), gate inductance
(L
G
), and gate capacitance (C
G
) form a series RLC
circuit with a second-order characteristic equation. The
series RLC circuit has an undamped natural frequency
(ϖ
0
) and a damping ratio (ζ) where:
The damping ratio needs to be greater than 0.5 (ideally 1)
to avoid ringing. Add a small resistor (R
GATE
) in series
with the gate when driving a very low gate-charge
MOSFET, or when the driver is placed away from the
MOSFET. Use the following equation to calculate the
series resistor:
L
P
can be approximated as 3nH and 2nH for SO and
TDFN packages, respectively. L
S
is on the order of
20nH/in. Verify L
G
with the MOSFET vendor.
R
LLL
C
R
GATE
PSG
G
ON
≥
++
−
()
ϖ
ξ
0
1
2
=
++ ×
=
×
++
()
()
LLL C
R
LLL
C
PSG G
ON
PSG
G
4A, 20ns, Dual MOSFET Drivers
10 ______________________________________________________________________________________
MAX5054A
V
DD
GND
INA-
INA+ OUTA
PWM
INPUT
ON
OFF
Figure 4. Unused Input as an ON/OFF Function (1/2 MAX5054A)
Table 1. MAX5054 Truth Table
INA+/INB+ INA-/INB- OUTA/OUTB
Low Low Low
Low High Low
High Low High
High High Low
Table 2. MAX5055/MAX5056/MAX5057
Truth Table
NONINVERTING
IN_+ OUT_
Low Low
High High
INVERTING
IN_- OUT_
Low High
High Low