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Home > Products > Integrated Circuits (ICs) > Power Management (PMIC) > Voltage Regulators - DC DC Switching Regulators

Monolithic Power Systems Inc. MP1591DN-LF-Z

Name: MP1591DN-LF-Z
Brand: Monolithic Power Systems Inc.
SKU: MP1591DN-LF-Z
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: MP1591DN-LF-Z

Manufacturer:: Monolithic Power Systems Inc.

Category:: Voltage Regulators - DC DC Switching Regulators

Package:: 8-SOIC (0.154", 3.90mm Width) Exposed Pad

Datasheet:: MP1591DN-LF-Z.pdf

Description:: IC REG BUCK ADJ 2A 8SOICE

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Product details

Overview

MP1591DN-LF-Z from Monolithic Power Systems is a high-voltage current-mode step-down DC/DC converter designed for automotive power adapters and battery chargers. It operates from 6.5V to 32V input, delivers 2A continuous output, integrates a 120mΩ high-side MOSFET, features fixed 330kHz switching frequency, and provides adjustable output from 1.23V to 21V - enabling fast-charge capability in 12V/24V vehicle systems.

For engineers reviewing the MP1591DN-LF-Z datasheet, MP1591DN-LF-Z pinout, MP1591DN-LF-Z application, or MP1591DN-LF-Z equivalent, key selection criteria include its 34V absolute maximum input rating, cycle-by-cycle overcurrent protection, thermal shutdown at 160°C, 20μA shutdown quiescent current, and compatibility with low-ESR ceramic output capacitors.

Technical Context

The MP1591DN-LF-Z employs peak current-mode control with internal slope compensation to ensure stable regulation across wide input and load variations. Its transconductance error amplifier (700μA/V typ) drives the COMP node, where external RC networks set loop poles and zeros - targeting ~33kHz crossover frequency (1/10 of 330kHz switching frequency) for optimal transient response.

It integrates a bootstrap-capacitor-driven high-side N-MOSFET switch and uses an internal 10Ω low-side switch to fully discharge the SW node during off-time, ensuring reliable BS capacitor charging. The REF pin provides a regulated 5.0V ±100mV reference output capable of sourcing up to 1mA for external biasing.

Key Specifications

Parameter	Value and Actual Design Meaning
Input Voltage Range	6.5V to 32V - supports full automotive battery range including cold-crank (6.5V) and load-dump (32V) conditions.
Output Current	2A continuous - sufficient for USB-C PD-compliant automotive chargers and PDA battery charging circuits.
Switching Frequency	330kHz (±50kHz) - enables compact magnetics while avoiding AM radio band interference.
Feedback Reference	1.230V ±28mV - sets output voltage via external resistor divider; enables precise 3.3V/5V/12V rail generation.
Shutdown Current	20μA max - minimizes battery drain in always-on automotive modules during ignition-off state.
Thermal Shutdown	160°C - protects against sustained overload or poor PCB thermal design without latch-up.
EN Threshold	0.8–1.6V logic-low disable; 2.4–2.8V UVLO hysteresis - ensures clean start-up and brown-out immunity.

Pinout & Package

The MP1591DN-LF-Z is housed in an 8-pin SOIC package with exposed thermal pad (SOIC8E), rated for –40°C to +85°C operation. The exposed pad must be connected to Pin 4 (GND) for optimal thermal performance (θ_JA = 50°C/W).

Pin/Terminal	Circuit Role	Design Meaning
1 BS	Bootstrap Supply Input	Drives high-side MOSFET gate; requires ≥10nF capacitor from SW to BS for self-powered gate drive.
2 IN	Main Power Input	Accepts 6.5–32V supply; must be bypassed with low-ESR capacitor near IC for noise suppression.
3 SW	Switch Node Output	Connects to inductor and BS capacitor; carries high di/dt switching current - layout critical.
4 GND	Power & Signal Ground	Reference for all internal circuitry; exposed pad must be soldered to PCB ground plane.
5 FB	Voltage Feedback Input	Senses output via resistive divider; 1.230V threshold enables adjustable output from 1.23V to 21V.
6 COMP	Loop Compensation Node	Transconductance error amplifier output; external RC network sets stability and transient response.
7 EN	Enable / UVLO Input	Logic-controlled on/off; internal pull-up allows simple microcontroller interface or manual switch control.
8 REF	5V Reference Output	Stable 5.0V ±100mV source for external circuitry; requires ≥10nF bypass capacitor if used.

Key Features

Feature	Design Value
Integrated 120mΩ High-Side MOSFET	Eliminates need for external high-side switch, reducing BOM count and board area in 2A buck designs.
Stable with Ceramic Output Capacitors	Supports low-ESR MLCCs (e.g., 22μF X5R) without requiring ESR-based zero compensation.
Cycle-by-Cycle Overcurrent Protection	Detects and limits peak inductor current per switching cycle - prevents MOSFET failure during short-circuit events.
Internal 5V Reference (REF)	Provides precision bias for external comparators, ADC references, or auxiliary LDOs - no extra regulator needed.
Under-Voltage Lockout (UVLO)	Ensures controlled startup only when input exceeds 2.6V (typ), preventing erratic operation during battery sag.

Applications

Automotive Power Adapters

PDA & Cellular Phone Chargers

Use Scenario: 12V/24V vehicle socket powering dual-port USB-A/USB-C charger modules.

IC Role / Device Role / Timing Role: Primary step-down regulator delivering 5V/3A or 9V/2A output with fast load-step response.

Use Value: Wide 6.5–32V input handles engine cranking and alternator transients; 2A output supports simultaneous multi-device charging.

Use Scenario: Portable medical PDA with Li-ion battery pack requiring regulated 3.3V system rail from variable-input adapter.

IC Role / Device Role / Timing Role: Main DC/DC converter generating stable 3.3V from unregulated 7–28V wall adapter or car charger.

Use Value: 20μA shutdown current preserves battery life during standby; 330kHz switching enables small 2.2μH inductor footprint.

Distributed Power Systems

Automotive Aftermarket Electronics

Use Scenario: Centralized 24V bus powering multiple subsystems (camera, display, CAN gateway) in commercial vehicle telematics unit.

IC Role / Device Role / Timing Role: Point-of-load regulator converting 24V bus to isolated 5V/2A rails for digital logic and interface ICs.

Use Value: Thermal shutdown and current limiting protect against wiring faults; SOIC8E package enables efficient heat dissipation on dense PCBs.

Use Scenario: Rear-seat entertainment system with HDMI display, Bluetooth audio, and USB peripherals powered from vehicle battery.

IC Role / Device Role / Timing Role: Core power supply regulating 12V battery input to 5V/2A for SoC, memory, and peripheral ICs.

Use Value: 34V absolute max input withstands load-dump spikes; adjustable output supports future firmware-defined rail voltages.

Equivalent & Alternatives

The following parts are listed as comparable options for similar step-down converter applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
MP2451DT-LF-Z	36V max input, 0.8A output, 2MHz switching, no REF pin	Better for space-constrained, lower-current apps; lacks integrated reference and higher current capability	Select when board area is critical and output current ≤0.8A; not suitable for 2A automotive charging.
LM2678SX-5.0/NOPB	40V max input, 5A output, 260kHz, external MOSFET required	Higher current but needs external high-side FET and more external components	Choose for >2A loads or where thermal budget allows discrete FET; increases design complexity and BOM cost.

Compared with MP2451DT-LF-Z, the MP1591DN-LF-Z delivers double the output current and includes a 5V reference - making it superior for automotive chargers. Versus LM2678SX-5.0/NOPB, it reduces component count and layout sensitivity by integrating the power switch, though at lower peak current capacity.

Availability

MP1591DN-LF-Z is available at Aetrix Electronics and suitable for automotive power adapters, PDA battery chargers, and distributed power systems requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for MP1591DN-LF-Z includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Monolithic Power Systems (MPS) is a fabless semiconductor company specializing in high-performance analog and power ICs, with core expertise in DC/DC conversion, motor drivers, and LED lighting controllers.

The MP1591 belongs to MPS's high-voltage buck converter product line, engineered specifically for automotive-grade reliability, wide-input operation, and minimal external component count in battery-powered and vehicle-mounted electronics.

FAQ

What is the minimum recommended input voltage for reliable startup?

The MP1591DN-LF-Z has an under-voltage lockout (UVLO) with a rising threshold of 2.4–2.8V and hysteresis of 250mV. However, functional operation requires ≥6.5V input per datasheet specifications. Below this, regulation cannot be maintained due to insufficient headroom for the internal regulator and gate drive - so 6.5V is the practical minimum for continuous operation, not just startup.

Can the MP1591DN-LF-Z operate with a 5V input?

No - the MP1591DN-LF-Z requires a minimum input voltage of 6.5V to maintain regulation and proper gate drive for its internal high-side MOSFET. At 5V, the bootstrap circuit cannot generate sufficient gate voltage above the input rail, causing dropout and potential instability. For 5V-input applications, consider the MP2451 or MP1584 instead.

How is thermal performance affected by the exposed pad connection?

The exposed pad on the SOIC8E package must be soldered to a PCB ground plane to achieve the specified θ_JA = 50°C/W. Without this connection, thermal resistance rises to ~90°C/W (SOIC8), increasing junction temperature by ~40°C at full 2A load - risking premature thermal shutdown. A minimum 4-layer board with inner ground planes and ≥4 thermal vias is recommended.

Does the REF pin require external loading to function correctly?

No - the REF pin delivers a stable 5.0V output regardless of loading, and is specified to regulate within ±100mV from 0 to 1mA load. If unused, it should be left floating (not tied to GND or VOUT); adding a 10nF bypass capacitor is optional but improves noise immunity when driving sensitive external circuitry.

What causes the 35kHz oscillation observed during short-circuit conditions?

During output short-circuit, the MP1591DN-LF-Z enters hiccup-mode protection: the oscillator frequency drops from 330kHz to ~35kHz to limit average power dissipation and prevent thermal runaway. This is a deliberate fault-recovery behavior - not a malfunction - and resumes normal operation once the short is removed and FB voltage recovers above 1.23V.

Is an external bootstrap diode mandatory for all designs?

An external bootstrap diode (e.g., BAT54) is recommended - but not mandatory - when operating at high duty cycles (>65%), high output voltages (>12V), or with fixed 5V inputs. It improves BS capacitor charging efficiency and reduces switching losses, especially in high-V_IN/low-V_OUT configurations like 24V-to-3.3V conversion.

How does the COMP pin compensation affect transient response?

The COMP pin network directly sets loop bandwidth and phase margin. A properly designed RC network targeting ~33kHz crossover yields <100μs recovery time for 50% load steps. Oversizing C4 slows response; undersizing risks ringing. Table 4 in the datasheet provides validated values for common V_OUT/C_OUT combinations to avoid instability.

MP1591DN-LF-Z Specifications

Product attributes: Attribute value

Manufacturer:: Monolithic Power Systems Inc.

Series:: -

Package/Case:: 8-SOIC (0.154", 3.90mm Width) Exposed Pad

Packaging:: Tape & Reel (TR)

Product 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)

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: 8-SOICE

MP1591DN-LF-Z FAQ

1.How can I place an order for MP1591DN-LF-Z through Aetrix?

Please submit a Request for Quotation (RFQ) for MP1591DN-LF-Z on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.

2.Are the price and stock information for MP1591DN-LF-Z reliable?

The price and inventory of MP1591DN-LF-Z are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MP1591DN-LF-Z is usually 5 days.

3.What payment methods are accepted for MP1591DN-LF-Z?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MP1591DN-LF-Z transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for MP1591DN-LF-Z?

MP1591DN-LF-Z orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your MP1591DN-LF-Z order is processed, you will receive an email with the shipment details and tracking number.

Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.

5.How can I obtain technical support or documentation for MP1591DN-LF-Z?

For technical support, including MP1591DN-LF-Z datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MP1591DN-LF-Z requirements.

6.How does Aetrix verify that MP1591DN-LF-Z is sourced from the original manufacturer or authorized distributors?

All MP1591DN-LF-Z products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that MP1591DN-LF-Z meets industry standards.

7.What is the process for return or replacement of MP1591DN-LF-Z?

All MP1591DN-LF-Z units undergo pre-shipment inspection (PSI). If there is an issue with MP1591DN-LF-Z, returns or replacements are accepted under the following conditions:

1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.

2.The issue is reported within 90 days of delivery.

3.The MP1591DN-LF-Z part is unused and in its original packaging.

Return procedure for MP1591DN-LF-Z:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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