Part Number: LM5050MKX-1/NOPB

Manufacturer: Texas Instruments

Description: 400-uA IQ ideal diode controller -40 to 125

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Technical Specifications of LM5050MKX-1/NOPB

Datasheet  LM5050MKX-1/NOPB datasheet
Category Integrated Circuits (ICs)
Family PMIC – OR Controllers, Ideal Diodes
Manufacturer Texas Instruments
Packaging Tape & Reel (TR)
Part Status Active
Type N+1 ORing Controller
FET Type N-Channel
Ratio – Input:Output N:1
Internal Switch(s) No
Delay Time – ON
Delay Time – OFF 486ns
Current – Output (Max)
Current – Supply 130μA
Voltage – Supply 5 V ~ 75 V
Applications Redundant Power Supplies
Operating Temperature -40°C ~ 125°C
Mounting Type Surface Mount
Package / Case SOT-23-6 Thin, TSOT-23-6
Supplier Device Package 6-SOT

LM5050MKX-1/NOPB Description

Connecting an LM5050MKX-1/NOPB High Side OR-ing FET Controller in series with a power supply allows the LM5050-1/-Q1 to act as a diode rectifier when combined with an external MOSFET. With this ORing controller, power distribution networks can employ MOSFETs instead of diode rectifiers, minimizing power loss and voltage drops. An external N-channel MOSFET can be driven by a charge pump thanks to the LM5050MKX-1/NOPB controller. A fast-response comparator is also employed to disable the FET in the event of reverse current flow. The LM5050-1/- Q1 may be powered by 5 V and 75 V sources and can withstand transients of up to 100 V.

LM5050MKX-1/NOPB Features

  • Standard and AEC-Q100 Qualified versions are available.
  • There are two variants available: LM5050Q0MK-1 (up to 150°C TJ) and LM5050Q1MK-1 (up to 125°C TJ).
  • Multiple Input Voltage Operating Range, VIN: 1 V to 75 V (VBIAS required for VIN 5 V).
  • Rapid 50-ns Current Reversal Gate with a 2 A peak turn-off current.
  • Package Including SOT-6 Minimum VDS Clamp for Rapid Shutoff (Thin SOT-23-6).

LM5050MKX-1/NOPB Overview

Blocking diodes are typically wired in series with power inputs. As a result, it is possible to OR together many power sources and safeguard against a potential inversion of power. Using the LM5050, an NMOSFET is utilized in place of diodes, avoiding the voltage drop and power loss that come with diodes. Especially in tight spots where headroom is at a premium, the reduction in forward voltage loss becomes immediately apparent at low input voltages.

There are several other external components besides the MOSFET, which is component Q1. Similarly, to how it is possible to witness reverse recovery in non-perfect diodes, it is also possible to observe it in ideal diodes. When employed with parasitic or consciously created inductances, an ideal diode may generate reverse recovery spikes during a reverse current cutoff. Protected by D1, D2, and R1, the LM5050 can withstand spikes that would otherwise exceed its 100 V survival rating. COUT also absorbs energy gained through reverse recovery.

Feature Description

IN, GATE, and OUT Pins

Load current flows from the source to drain through the MOSFET’s body diode when power is applied. Because of this, the MOSFET will start conducting. The LM5050-1 has a charge pump current source that generally delivers 32 microamperes to charge the MOSFET gate whenever the voltage measured across the body diode exceeds the VSD(REG) threshold. When the LM5050-1 is in forward mode, the gate of the MOSFET is allowed to charge until it reaches the clamping voltage of the 12-V GATE to IN pin Zener diode.

The LM5050-1 is a specialized voltage regulator made to control MOSFET gate-to-source levels. Let’s say the MOSFET’s current drops to where the voltage does not regulate it at VSD(REG), which is 22 mV. (typical). In that situation, the VSD(REG) voltage regulator will reduce the voltage at the GATE pin until the voltage across the MOSFET hits the setpoint. This cycle will repeat itself until the current through the MOSFET is restored to its initial value. The gate-to-source voltage will rise until it hits the 12-volt GATE to IN pin Zener clamp level if the source-to-drain voltage is greater than VSD(REG). This will occur if the voltage from the source to the drain exceeds the VSD(REG) voltage.

If the input supply fails and the MOSFET current inverts to the point where the voltage across the LM5050-1 IN and OUT pins is greater than the VSD(REV) voltage of -28 mV (typical), then the LM5050-1 will rapidly discharge the MOSFET gate through a strong GATE to IN pin discharge transistor. That way, the MOSFET gate can be cleared. The MOSFET will experience a brief flow of reverse current if the input supply abruptly fails, as it would if the supply were shorted straight to the ground, but only for as long as the gate cannot be entirely discharged.

The load capacitance and the paralleled supply are powering this reversing current. The LM5050-1 has a typical response time of 25 ns when faced with a voltage reversal scenario. The actual time needed to turn off the MOSFET will be determined by the amount of charge carried by the gate capacitance of the MOSFET being used. A MOSFET with an effective gate capacitance of 47 nF typically shuts down in 180 ns. The current transients and voltage spikes caused by the backup power sources are mitigated by switching off so quickly.

VS Pin

The LM5050-VS 1’s pin powers both internal biasing and the charge pump for the internal gate. The VS pin can be directly linked to the OUT pin for most LM5050-1 applications with more than 5 V input voltage. The impact of spurious voltage spikes that may appear on the OUT and IN pins when the input voltage is close to but not lower than the 5 V minimum can be reduced by connecting the VS pin to the OUT pin via an RC Low-Pass filter.

A crucial factor is minimizing the voltage drop across the series resistor. A resistor in series usually has a value of 100. The optimum capacitor value is the minimum value at which the voltage noise is adequately filtered. Roughly 0.5 mA will leak into the IC through the Vs pin, and about 3 mA will leak out the OUT pin when Vs is activated and IN is not attached to anything. The IN pin will leak about 50 uA, with the remaining going to the ground.

Device Functional Modes

ON/OFF Control Mode

A high assertion on the OFF pin will disable the MOSFET. Only the MOSFET is disabled in this mode; however, VOUT is still accessible via the MOSFET’s body diode.

External Power Supply Mode

The LM5050’s bias input supply can be powered by a voltage between 5 V and 75 V, which can be connected to its Vs. Pin. Using this setting, the VIN voltage can be as low as 1 V.


Suggestions for a Sufficient Electrical Supply Due to reverse recovery, transient voltages will emerge on the input and output when the LM5050-1/-Q1 turns off the external MOSFET. Clamping the negative Transient at the IN and OUT pins with TVS is essential to protect the LM5050-1 and its surrounding components in the case of a direct input short circuit.

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