MAX4426EJA View Datasheet(PDF) - Maxim Integrated

Part Name

Description

Manufacturer

MAX4426EJA

Dual High-Speed 1.5A MOSFET Drivers

Maxim Integrated 

Dual High-Speed 1.5A MOSFET Drivers

Applications Information

The MAX4426/4427/4428 have easy-to-drive inputs.

However, these inputs must never be allowed to stay

between VIH and VIL for more than 50ns. Unused inputs

should always be connected to ground to minimize sup-

ply current. Drivers can be paralleled on the MAX4426 or

MAX4427 by tying both Inputs together and both outputs

together.

Supply bypassing and grounding are extremely impor-

tant with the MAX4426/4427/4428, as the peak supply

current can be as high as 3A, which is twice the peak

output current. Ground drops are a form of negative

feedback with inverters, and hence will degrade the

delay and transition time of the MAX4426/MAX4428.

Suggested bypass capacitors are a 4.7µF (low ESR)

capacitor in parallel with a 0.1µF ceramic capacitor,

mounted as close as possible to the MAX4426/4427/4428.

Use a ground plane if possible or separate ground

returns for inputs and outputs. Output voltage ringing

can be minimized with a 5Ω to 20Ω resistor in series with

the output, but this will degrade output transition time.

Ringing may be undesirable due to the large current that

flows through capacitive loads when the voltage across

these loads transitions quickly.

Operation at the upper end of the supply voltage range

(> 15V) requires that a capacitance of at least 50pF be

present at the outputs. This prevents the supply voltage

provided to the die (which can be different from that

seen at the Ie supply pin) from exceeding the 20V abso-

lute maximum rating, due to overshoot. Since at least

50pF of gate capacitance is present in all higher power

FETs, this requirement is easily met.

Power Dissipation

The MAX4426/4427/4428 power dissipation consists of

input inverter losses, crowbar current through the output

devices, and output current (either capacitive or resis-

tive). The sum of these must be kept below the maximum

power dissipation limit.

The DC input inverter supply current is 0.2mA when both

inputs are low and 2mA when both inputs are high. The

crowbar current through an output device making a tran-

sition is approximately 100mA for a few nanoseconds.

This is a small portion of the total supply current, except

for high switching frequencies or a small load capaci-

tance (100pF).

The MAX4426/4427/4428 power dissipation when driv-

ing a ground-referenced resistive load is:

P = (D) (rON(MAX)) (ILOAD2)

where D is the percentage of time the MAX4426/4427/4428

output pulls high, rON(MAX) is the MAX4426/4427/4428

maximum on resistance, and ILOAD is the MAX4426/4427/

4428 load current.

For capacitive loads. the power dissipation is:

P = (CLOAD) (VDD2) (FREQ)

where CLOAD is the capacItive load. VDD is the

MAX4426/4427/4428 supply voltage, and FREO is the

toggle frequency.

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