Part Number: MP1591DN-LF-Z

Manufacturer: Monolithic Power Systems, Inc.


Shipped from: Shenzhen/HK Warehouse

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Technical Specifications of MP1591DN-LF-Z

Datasheet  MP1591DN-LF-Z datasheet
Category Integrated Circuits (ICs)
Family PMIC – Voltage Regulators – DC DC Switching Regulators
Manufacturer Monolithic Power Systems Inc.
Packaging Tape & Reel (TR)
Part Status Active
Function Step-Down
Output Configuration Positive
Topology Buck
Output Type Adjustable
Number of Outputs 1
Voltage – Input (Min) 6.5V
Voltage – Input (Max) 32V
Voltage – Output (Min/Fixed) 1.23V
Voltage – Output (Max) 21V
Current – Output 2A
Frequency – Switching 330kHz
Synchronous Rectifier Yes
Operating Temperature -40°C ~ 85°C (TA)
Mounting Type Surface Mount
Package / Case 8-SOIC (0.154″, 3.90mm Width) Exposed Pad
Supplier Device Package 8-SOIC-EP

MP1591DN-LF-Z Description

The MP1591 is a high-voltage step-down converter that is perfect for car battery charging that uses a power adapter. Its wide input voltage range of 6.5 V to 32 V meets the needs of car batteries, and its 2 A continuous output lets it charge quickly. Current-mode operation gives a quick reaction to changes in load and makes loop stabilisation easier. Fault prevention includes limiting the current cycle by cycle and shutting down when it gets too hot. When the adapter is turned off, it only uses 20 A of power. To make a 2A step-down DC-to-DC converter solution with the MP1591, you only need a small amount of external components that are easy to find.

MP1591DN-LF-Z Features

  • 120-m power MOSFET switch inside.
  • 20A Power Off Mode
  • The frequency is always 330 kHz.
  • Automatic Power Off.
  • Overcurrent protection for each cycle.
  • Under Voltage Lockout.
  • Reference Voltage Output
  • 8-Pin SOIC packages are available.

MP1591DN-LF-Z Applications

  • Power adapters for cars
  • Chargers for PDA and cell phone batteries
  • Power systems that are spread out.
  • Automotive Electronics for the Aftermarket

MP1591DN-LF-Z Operation

The MP1591 is a step-down regulator that works in current mode. It can take input voltages between 6.5 volts0 vol32 volts6.5V and 32V and turn them into output voltages as low as 1.230V. It can give up to 2 A of load current. The output voltage is controlled by the MP1591 through current-mode control. At FB, a resistance voltage divider is used to measure the output voltage, and an internal error amplifier is used to boost it. At COMP, where a network adjusts the regulation control system, the output current of the transconductance error amplifier is shown. To control the output voltage, the voltage at COMP is compared to the switch current, which is recorded on the inside.

The N-channel MOSFET switch inside the converter steps down the voltage from the input to the controlled output voltage. Since the MOSFET’s gate voltage needs to be higher than the input voltage, the gate is driven by a boost capacitor connected between SW and BS. When SW is low, the capacitor charges itself. An internal 10 switch connects SW to GND to make sure that SW is pulled to GND when the switch is off so that the BS capacitor can be fully charged.

MP1591DN-LF-Z Electrical Characteristics

The MP1591DN-LF-Z is a 2A adjustable buck regulator integrated circuit (IC) that is made for power conversion uses that need to be as efficient as possible. It comes in an 8SOIC package, which is small and doesn’t take up much room. This IC has a variety of electrical properties that make it useful for many different types of power supply designs. The output voltage of the MP1591DN-LF-Z can be changed, so users can make the output voltage fit their needs. It can send out 2 A of current, which is enough power for many low- to medium-power uses. The design of a buck regulator makes it possible for the conversion to be very efficient, with as little power loss as possible and as much energy use as possible.

This IC can work with a wide range of input voltages, usually from 4.5 volts to 24 volts.This gives it a lot of flexibility in different power-source situations. It has a synchronous rectification plan, which makes it more efficient and reduces the need for diodes on the outside. The MP1591DN-LF-Z also has safety features like over-temperature protection, over-current protection, and under-voltage shutdown, which make sure it works well and safely. The MP1591DN-LF-Z is a great choice for applications that need efficient power conversion in a small package. It has a small footprint, an adjustable output voltage, high efficiency, and a lot of safety features.

Pin Functions

● VIN (Pin 1)

This is the input voltage pin, which is where the power source goes. Most of the time, it can work with voltages from 4.5 volts to 24 volts.

● GND (Pin 2)

This pin is the IC’s ground reference, and it needs to be connected to the system’s shared ground.

● FB (Pin 3)

The regulator’s output voltage can be changed by moving the input pin. The ideal output voltage can be set by connecting external resistors or a voltage divider network.

● COMP (Pin 4)

The compensation pin is used to connect an external compensation network, which helps stabilise the regulation loop and improve the regulator’s transient reaction.

● SS (Pin 5)

The soft-start pin is used to control how the regulator starts up. This lets the output voltage rise slowly so that there isn’t too much inrush current.

● EN (Pin 6)

This pin tells the regulator to turn on. The regulator is turned on by giving it a high logic level (usually above 2.5 volts) or by connecting it to the VIN. If you give this bit a low logic level or connect it to ground, the regulator will be turned off and put into a low-power shutdown mode.

● SW (Pin 7)

The switch pin is linked to the buck regulator’s high-side switch. It switches the voltage coming in to the controlled voltage coming out.

● VOUT (Pin 8)

This is the buck regulator’s controlled output voltage pin, which gives the load the right amount of power.

Application Information

Component Selection

● Inductor (L1)

The split input voltage drives the inductor, and the output load needs a steady flow of current from it. When the value of an inductor goes up, the ripple current goes down, which makes the output ripple voltage go down. But the larger value inductor is bigger, has more resistance in series, and/or has a smaller saturation current. Choose an inductor that won’t get overloaded, even in the worst case. For figuring out the inductance, a good rule of thumb is to let the peak-to-peak ripple current in the inductor be about 30% of the highest load current that the IC can supply. Also, make sure that the peak inductor current (the load current plus half of the peak-to-peak inductor ripple current) is less than 2.3 A.

● Input Capacitor (C1)

The current going into the step-down converter isn’t steady, so a capacitor is needed to give the step-down converter AC current while keeping the DC voltage going into it. To keep noise from getting into the IC, you need a capacitor with a low ESR. Ceramic capacitors are best, but low-ESR electrolytic capacitors or tantalum capacitors may also work.

The amount of the input capacitor should be more than 10 f.Electrolytic, tantalum, or ceramic materials can be used to make the capacitor. But because it uses the switching current from the input, it needs a good ripple current value. Its value for RMS current should be more than about half of the DC load current. For stable function, C1 should be placed as close as possible to the IC. You could also put a smaller, high-quality ceramic 0.1-F capacitor closer to the IC and a larger one farther away. If you use this method, the bigger capacitor should be either a tantalum or an electrolytic type. All capacitors made of ceramic should be close to the MP1591.

● Output Rectifier Diode (D1)

When the high-side switch is off, the inductor gets power from the output rectifier diode. Use a Schottky rectifier to cut down on losses caused by the forward voltage and the time it takes for the diode to recover.


Finally, Monolithic Power Systems Inc.’s MP1591DN-LF-Z high-voltage step-down converter is adaptable and efficient for automobile power adapters, battery chargers, and other applications. It has a 6.5V–32V input voltage range and a 2A continuous output for fast charging. In current mode, it provides fast transient response, simple loop stabilisation, fault protection, and low shutdown current. It is suitable for automobile power adapters, PDA and cell phone chargers, distributed power systems, and aftermarket electronics due to its tiny size and minimum external components.

Adjustable output voltage, complete protection, and integrated synchronous rectification make the MP1591DN-LF-Z efficient and reliable. Selecting components carefully optimises performance. Its high conversion efficiency, stable performance, and small design make it a great power converter. ICRFQ, a leading Chinese electronic component supplier, sells the MP1591DN-LF-Z.

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