My Inquiry
My Account
Monolithic Power Systems Inc. MP4559DQ-LF-Z
- Part No.:
- MP4559DQ-LF-Z
- Manufacturer:
- Monolithic Power Systems Inc.
- Package:
- 10-VFDFN Exposed Pad
- Datasheet:
-
MP4559DQ-LF-Z.pdf
- Description:
- IC REG BUCK ADJ 1.5A 10QFN
- Quantity:
- Payment:
- Shipping:
Inventory:5,000
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
MP4559DQ-LF-Z from Monolithic Power Systems is a non-synchronous step-down DC/DC converter with integrated 250mΩ high-side 55V MOSFET, 2MHz programmable switching frequency, 3.8–55V input range, and 1.5A output current. It delivers up to 95% efficiency, features internal soft-start, current-mode control, and operates in pulse-skipping mode at light load for ultra-low quiescent current (140μA), enabling use in automotive battery systems and industrial power rails.
For engineers reviewing the MP4559DQ-LF-Z datasheet, MP4559DQ-LF-Z pinout, MP4559DQ-LF-Z application, or MP4559DQ-LF-Z equivalent, key selection criteria include its 2MHz operation for EMI-sensitive AM radio/ADSL systems, bootstrap capacitor charging constraints at high duty cycle, thermal shutdown threshold (150°C), and mandatory replacement guidance per MPS (not recommended for new designs; refer to MP4572).
Technical Context
The MP4559DQ-LF-Z implements peak-current-mode PWM control with a 100ns minimum on-time and frequency foldback during startup to prevent inductor current runaway. Its error amplifier provides 400V/V gain and 120μA/V transconductance, with COMP pin clamped between 0.9V and 2.0V for loop stability.
It integrates a 2.6V internal regulator powered from VIN across the full 3.8–55V range, a dedicated EN pin with 1.4–1.7V rising threshold and 320mV hysteresis, and a bootstrap driver regulated to ~5V with UVLO at 2.2V (150mV hysteresis) to sustain high-side gate drive.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 3.8V to 55V - supports direct connection to automotive battery (cold-crank down to 3.8V) and industrial 48V rails without pre-regulation. |
| Switching Frequency | Programmable up to 2MHz via external resistor - enables compact magnetics and avoids AM band EMI (530–1710kHz). |
| Output Current | 1.5A continuous - limited by internal MOSFET RDS(ON) (250mΩ typ) and thermal resistance (θJA = 50°C/W in QFN10). |
| Feedback Reference | 0.800V ±20mV - sets output voltage accuracy; used with external resistor divider to configure VOUT from 0.8V to 52V. |
| Quiescent Current | 140μA - enables >1-year standby in battery-powered systems with low-power shutdown (12μA). |
| Shutdown Supply Current | 12μA - ensures minimal battery drain when EN pin is pulled below 1.2V threshold. |
| Thermal Shutdown | 150°C with 20°C hysteresis - protects die during overload or poor PCB thermal layout; resumes operation at 130°C. |
Pinout & Package
MP4559DQ-LF-Z is housed in a RoHS-compliant 3mm × 3mm QFN-10 package with exposed thermal pad. The package supports high-power dissipation (2.5W at TA = 25°C) and requires soldering the exposed pad directly to a solid GND plane for optimal thermal performance.
| Pin | Circuit Role | Design Meaning |
|---|---|---|
| 1, 2 (SW) | Switch Node | Drain of internal high-side MOSFET; connects to cathode of external Schottky diode and inductor; high dv/dt node requiring tight layout and local decoupling. |
| 3 (EN) | Enable Input | Positive-logic control pin; chip enabled when voltage ≥1.55V (typ); floating state pulls up internally to ~3.0V via 1μA current source. |
| 4 (COMP) | Error Amplifier Output | Current-source output for external RC compensation network; clamped 0.9–2.0V; determines loop stability and transient response. |
| 5 (FB) | Feedback Input | Compares resistive divider output against 0.8V reference; sets regulated output voltage; leakage <1.0μA minimizes divider error. |
| 6 (GND) | Power & Signal Ground | Common return for IC core, power switch, and exposed thermal pad; must be connected to low-impedance GND plane near output capacitor. |
| 7 (FREQ) | Frequency Programming | Connects external resistor to GND to set fSW; 95kΩ yields ~1MHz; 47kΩ yields ~2MHz; tolerance affects regulation accuracy under line/load transients. |
| 8, 9 (VIN) | Input Supply | Primary power rail for control circuitry and high-side driver; requires local 4.7μF ceramic capacitor to suppress switching noise and supply current spikes. |
| 10 (BST) | Bootstrap Supply | Charged to ~5V relative to SW via internal PMOS; powers high-side gate driver; requires 0.1μF ceramic capacitor between BST and SW pins. |
Key Features
| Feature | Design Value |
|---|---|
| Ceramic capacitor stable | Supports low-ESR ceramic output capacitors without oscillation risk due to current-mode control and optimized compensation architecture. |
| Internal soft-start | 0.5ms internal ramp prevents output overshoot and inrush current during startup and short-circuit recovery. |
| Frequency foldback | Reduces switching frequency under overload or short-circuit conditions to limit peak inductor current and thermal stress. |
| Pulse-skipping light-load mode | Stretches switching period to zero at light loads, reducing gate drive and switching losses to maintain >85% efficiency at 1mA output. |
| Bootstrap UVLO protection | Disables high-side switch if BST-SW voltage drops below 2.2V, preventing shoot-through and ensuring safe gate drive during startup or high-duty-cycle operation. |
Applications
| Automotive Infotainment Power | Industrial PLC I/O Module |
|---|---|
|
Use Scenario: Powering 3.3V microcontroller, CAN transceiver, and display interface in head-unit design with 9–16V battery input and cold-crank down to 6V. IC Role / Device Role / Timing Role: Primary step-down regulator converting raw battery to stable 3.3V rail; handles wide input transients and meets automotive EMI requirements via 2MHz operation. Use Value: Eliminates need for external pre-regulator; 140μA quiescent current extends battery life during vehicle sleep mode; thermal shutdown prevents failure during engine-off hot-soak conditions. |
Use Scenario: Generating 5V/1.5A supply for isolated digital I/O channels in DIN-rail mounted programmable logic controller with 24V nominal input. IC Role / Device Role / Timing Role: Non-isolated buck converter providing main logic rail; withstands 40V surges per IEC 61000-4-5; supports fast load steps from sensor polling cycles. Use Value: 250mΩ internal MOSFET reduces conduction loss at full load; frequency foldback prevents thermal runaway during sustained overcurrent events; QFN10 footprint saves board space in dense I/O modules. |
| AM Radio EMI-Sensitive Power | Portable Test Equipment Battery Rail |
|
Use Scenario: Supplying 1.8V/1.2A to RF front-end and ADC in handheld spectrum analyzer operating near AM broadcast band (530–1710kHz). IC Role / Device Role / Timing Role: High-frequency buck converter placed away from RF section; 2MHz switching moves fundamental and harmonics above AM band to avoid heterodyne interference. Use Value: Enables clean analog measurements without filtering overhead; ceramic-capacitor stability simplifies layout; internal soft-start prevents RF stage disruption during power-on. |
Use Scenario: Providing adjustable 3.3V–12V output from two-cell Li-ion (6–8.4V) in portable oscilloscope with 12-hour runtime requirement. IC Role / Device Role / Timing Role: Programmable-output buck converter supporting multiple subsystem voltages; operates in pulse-skipping mode during idle to minimize battery drain. Use Value: 12μA shutdown current preserves charge during transport; 0.8V feedback reference enables precise output setting; SOIC8E and QFN10 options allow trade-off between thermal performance and assembly cost. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar step-down converter applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MP4572 | Successor device with improved efficiency (up to 96%), lower IQ (90μA), and enhanced thermal performance; same pinout and footprint as MP4559DQ. | Recommended for all new designs; supports identical input/output ranges but adds spread-spectrum frequency modulation for further EMI reduction. | Select MP4572 for new designs requiring longer battery life, lower thermal footprint, or stricter CISPR-25 compliance. |
| MPQ4572-AEC1 | Automotive-grade variant of MP4572 with AEC-Q100 Grade 1 qualification (–40°C to +125°C), enhanced ESD robustness (±8kV HBM), and extended lifetime reliability testing. | Required for under-hood or safety-critical automotive applications where qualification and traceability are mandatory. | Choose MPQ4572-AEC1 only when AEC-Q100 compliance is contractually required; not drop-in for industrial use due to higher cost and qualification overhead. |
Compared with MP4559DQ-LF-Z, MP4572 offers measurable improvements in light-load efficiency and thermal margin while maintaining pin compatibility-making it a true functional upgrade-not just a replacement. MPQ4572-AEC1 adds automotive qualification layers but introduces no electrical benefit for non-automotive use cases.
Availability
MP4559DQ-LF-Z is available at Aetrix Electronics and suitable for automotive infotainment power, industrial PLC I/O modules, AM radio EMI-sensitive power supplies, and portable test equipment battery rails requiring stable component supply and legacy design support.
Supply support for MP4559DQ-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 MP4559 belongs to MPS's high-voltage buck converter product line, designed specifically for rugged industrial and automotive environments where wide input range, thermal resilience, and EMI control are critical system requirements.
FAQ
Is MP4559DQ-LF-Z still recommended for new designs?
No. Monolithic Power Systems explicitly states "NOT RECOMMENDED FOR NEW DESIGNS, REFER TO MP4572" in the official datasheet revision 1.01. MP4572 is the designated successor with improved efficiency, lower quiescent current, and identical pinout-ensuring seamless migration without layout changes.
What is the maximum achievable switching frequency and how is it set?
The MP4559DQ-LF-Z supports up to 2MHz switching frequency, set by an external resistor (RFREQ) from the FREQ pin to GND. For 2MHz, RFREQ ≈ 47kΩ (calculated using fSW(kHz) = 100000 / RFREQ(kΩ) – 5). Operation near 2MHz requires an external bootstrap diode to ensure reliable BST capacitor charging.
Why does the MP4559 require an external Schottky diode?
As a non-synchronous buck converter, the MP4559 lacks an integrated low-side switch and relies on an external Schottky diode to provide the freewheeling path during high-side MOSFET off-time. Diode selection must meet ≥55V reverse voltage rating and ≥1.5A average current handling, with low forward voltage to preserve efficiency.
How does the bootstrap circuit function and what happens if BST voltage collapses?
The BST pin is charged to ~5V relative to SW via an internal PMOS when SW is low; this voltage powers the high-side gate driver. If BST-SW drops below 2.2V (UVLO threshold), the high-side switch disables to prevent shoot-through. A 0.1μF ceramic capacitor between BST and SW is mandatory; insufficient capacitance or poor layout causes erratic switching or dropout.
Can MP4559DQ-LF-Z operate with input voltage below 3.8V?
No. The absolute minimum operating input voltage is 3.8V per the Recommended Operating Conditions table. Below this, the internal 2.6V regulator cannot sustain full functionality, and UVLO (rising threshold 3.0V) will disable operation. Cold-crank scenarios must maintain ≥3.8V at VIN to guarantee regulation.
What thermal derating applies to the QFN10 package at 85°C ambient?
With θJA = 50°C/W and TJ(MAX) = 150°C, maximum allowable power dissipation at TA = 85°C is (150 – 85) / 50 = 1.3W. At 1.5A output and 12V input, typical losses exceed this-requiring careful PCB copper area, thermal vias under the exposed pad, and airflow to maintain safe junction temperature.
Does MP4559DQ-LF-Z support output voltages below 0.8V?
No. The internal feedback reference is fixed at 0.800V ±20mV, and the FB pin is designed to compare against this voltage. Output voltages below 0.8V cannot be regulated; attempting to do so results in uncontrolled high-duty-cycle operation and potential thermal failure due to insufficient feedback headroom.
MP4559DQ-LF-Z Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Monolithic Power Systems Inc.
- Series:
- MP
- Package/Case:
- 10-VFDFN 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):
- 3.8V
- Voltage - Input (Max):
- 55V
- Voltage - Output (Min/Fixed):
- 0.8V
- Voltage - Output (Max):
- 52V
- Current - Output:
- 1.5A
- Frequency - Switching:
- Up to 2MHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 10-QFN (3x3)
MP4559DQ-LF-Z FAQ
1.How can I place an order for MP4559DQ-LF-Z through Aetrix?
Please submit a Request for Quotation (RFQ) for MP4559DQ-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 MP4559DQ-LF-Z reliable?
The price and inventory of MP4559DQ-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 MP4559DQ-LF-Z is usually 5 days.
3.What payment methods are accepted for MP4559DQ-LF-Z?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MP4559DQ-LF-Z transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MP4559DQ-LF-Z?
MP4559DQ-LF-Z orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MP4559DQ-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 MP4559DQ-LF-Z?
For technical support, including MP4559DQ-LF-Z datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MP4559DQ-LF-Z requirements.
6.How does Aetrix verify that MP4559DQ-LF-Z is sourced from the original manufacturer or authorized distributors?
All MP4559DQ-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 MP4559DQ-LF-Z meets industry standards.
7.What is the process for return or replacement of MP4559DQ-LF-Z?
All MP4559DQ-LF-Z units undergo pre-shipment inspection (PSI). If there is an issue with MP4559DQ-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 MP4559DQ-LF-Z part is unused and in its original packaging.
Return procedure for MP4559DQ-LF-Z:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
MP4559DQ-LF-Z Tags
-
TPS562201DDCR
Texas Instruments
-
MC34063ABD-TR
STMicroelectronics
-
TPS561201DDCR
Texas Instruments
-
MC33063ADR
Texas Instruments
-
MC34063ADR
Texas Instruments
-
TPS560200DBVR
Texas Instruments
-
AP3012KTR-G1
Diodes Incorporated
-
TLV61048DBVR
Texas Instruments
-
AZ34063UMTR-G1
Diodes Incorporated
-
TPS562200DDCR
Texas Instruments
-
AP62300TWU-7
Diodes Incorporated
-
MC34063EBD-TR
STMicroelectronics
Tech Hub
A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.
The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…
The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…
A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…
A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …
An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…
Latch circuits retain one bit through feedback. This technical reference covers SR and D latches, truth tables, transparency, timing limits, latch-versus-flip-flop behavior, applications and common log…
An engineering guide to LED driver operation, constant-current and constant-voltage outputs, linear and switching topologies, dimming, IC selection, calculations, replacement compatibility, and fault c…
Operational amplifier guide covering op amp basics, feedback, ideal vs real op amps, common configurations, buffer circuits, offset, bias current, gain-bandwidth, slew rate, rail-to-rail limits and sel…
Jumper cables guide covering safe connection order, red and black clamp placement, final ground connection, cable gauge, length, clamp quality, copper vs CCA cables, jump starter comparison and battery…
