MP5090 Rev. 1.0

www.MonolithicPower.com

10

5/18/2017

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OPERATION

The MP5090 is designed to limit the inrush

current to the load when a circuit card is

inserted into a live backplane power source,

thereby limiting the backplane’s voltage drop

and the slew rate of the voltage to the load. The

MP5090 integrates dual load switches. Each

channel can provide 3A of current (for the

MP5090GQHT. The CSP package (MP5090GC)

can provide 2A of load capability. The MP5090

can

also

easily

parallel

both

channels

connected together to achieve a maximum 6A

load for the MP5090GQHT. The CSP package,

MP5090GC, can achieve 4A if the parallel is

used.

Enable (EN1, EN2)

When the input voltage is greater than the

under-voltage

lockout

threshold

(UVLO)

(typically 0.5V), and VCC is higher than 1.85V,

the MP5090 can be enabled by pulling EN

above 1.2V. Pull EN to ground to disable the

MP5090. The recommended start-up sequence

ready, pull the EN voltage high.

Short-Circuit Protection (SCP)

If the load current increases rapidly due to a

short circuit, the current may exceed the current

limit threshold greatly before the control loop

can respond. If the current reaches an internal

secondary current limit level (about 5A), a fast

turn-off circuit activates to turn off the power

MOSFET. This limits the peak current through

the switch to limit the input voltage drop. The

total short-circuit response time is about 200ns.

Fast off keeps the power MOSFET off for about

80µs before turning it back on.

If the current limit block starts to regulate the

output current, the power loss on the power

MOSFET causes the IC temperature to rise.

Hiccup protection limits the current for 2ms and

turns it off for another 90ms for the thermal sink.

If the junction temperature rises high enough

during the hiccup on time, thermal shutdown is

triggered. After thermal shutdown, the output is

disabled until the over temperature fault is

removed. The over-temperature threshold is

155°C, and the hysteresis is 30°C.

Output Discharge

The MP5090 has an output discharge function.

The output discharge resistor is active when EN

or VCC is low. This function can discharge Vo

by pulling down the resistance internally when

the IC is disabled and the load is very light.