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Monolithic Power Systems Inc. MP3391EF-LF
- Part No.:
- MP3391EF-LF
- Manufacturer:
- Monolithic Power Systems Inc.
- Category:
- LED Drivers
- Package:
- 28-TSSOP (0.173", 4.40mm Width) Exposed Pad
- Datasheet:
-
MP3391EF-LF.pdf
- Description:
- IC LED DRVR CTRLR PWM 28TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:1,928
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Product details
Overview
MP3391EF-LF from Monolithic Power Systems is an 8-channel, 120mA/channel step-up WLED driver controller for large LCD panel backlighting. It uses fixed-frequency current-mode control, drives an external N-MOSFET to boost 9–35V input to up to 55V output, regulates LED string current via ISET resistor (±2.5% matching), and supports programmable PWM dimming frequency (via BOSC capacitor) and switching frequency (via OSC resistor). It operates in desktop LCD monitors and LCD TVs.
For engineers reviewing the MP3391EF-LF datasheet, MP3391EF-LF pinout, MP3391EF-LF application, or MP3391EF-LF equivalent, key selection considerations include its 8-string current balancing architecture, 450mV LED regulation voltage headroom, dual dimming mode (external PWM or DC-input burst PWM), open/short LED fault detection with VFAULT disconnection control, and TSSOP28 thermal performance (θJA = 32°C/W).
Technical Context
The MP3391EF-LF implements a peak-current-mode step-up converter with internal 10V VDD regulator for gate drive and 5V VCC regulator for logic. Its oscillator sets switching frequency (60–900 kHz) via ROSC, while BOSC defines internal dimming frequency (1.2–1.6 kHz) when used with DC dimming.
It integrates eight matched open-drain current sinks (LED1–LED8), each regulated to identical current via ISET reference (1.23V ±2%), achieving 2.5% inter-string matching. Protection includes programmable short-LED threshold (via SSET divider), timer-based fault latching (TSET capacitor), OVP (1.24V threshold), and thermal shutdown at 150°C.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 9V to 35V - supports wide industrial and display power rails without pre-regulation |
| Max LED Current per String | 120mA - sufficient for high-brightness white LED strings in 24–48 LED configurations |
| Current Matching Accuracy | ±2.5% - ensures uniform luminance across all 8 backlight zones without manual calibration |
| LED Regulation Voltage | 450mV - low dropout enables high efficiency and minimal power loss in current sources |
| Switching Frequency Range | 60kHz to 900kHz - adjustable via OSC resistor to optimize inductor size and EMI performance |
| Dimming Frequency Range | 1.2kHz to 1.6kHz - set by BOSC capacitor for flicker-free DC-input burst PWM dimming |
| OVP Threshold | 1.24V on OVP pin - corresponds to ~1.2× nominal output voltage when configured with R-divider |
| Thermal Shutdown | 150°C - protects IC during sustained overloads or poor PCB heatsinking |
Pinout & Package
TSSOP28 package with exposed thermal pad (RoHS-compliant, LF suffix); 0.65mm pitch, 9.7mm × 4.4mm body; θJA = 32°C/W on 4-layer PCB.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 VDD | 10V gate driver supply | Powers external N-MOSFET gate; requires local 1µF ceramic bypass to PGND |
| 2 VIN | Main power input | Accepts 9–35V; must be decoupled with ≥4.7µF X5R/X7R ceramic + bulk electrolytic |
| 5 EN | Enable control input | Active-high logic; 1.6V threshold; must not float - tie to VCC or microcontroller GPIO |
| 6 DBRT | Brightness control input | Accepts external PWM (0–5V) or DC analog (0.2–1.2V) for linear dimming duty cycle |
| 11 ISET | LED current programming | 1.23V reference; sets string current as ILED = 1230mV / RSET (e.g., 60.4kΩ → 20.4mA) |
| 21 NUMSEL | String count selection | Floating = 8 strings; high = 6 strings (LED1–LED6); low = 4 strings (LED1–LED4) |
| 25 GATE | External MOSFET gate driver | 10V push-pull output; 4.5Ω source / 1.5Ω sink impedance; drives N-ch FET directly |
| 26 FF | Fault flag output | Open-drain N-MOS; pulled low during open/short LED fault; requires external pull-up |
| 27 VFAULT | Fault disconnection driver | Drives external PMOS to isolate input from output during fault conditions |
Key Features
| Feature | Design Value |
|---|---|
| Programmable string count (4/6/8) | Reduces BOM cost and layout complexity when fewer LED strings are needed |
| 2.5% current matching between strings | Eliminates visible brightness gradients in multi-zone LCD backlights without trimming |
| 450mV LED regulation voltage | Lowers conduction loss in current sinks, improving system efficiency by ~3–5% vs. 800mV+ competitors |
| Integrated open/short LED protection | Automatically disables faulty strings and maintains operation of remaining strings with fault flag signaling |
| VFAULT-controlled PMOS disconnect | Prevents input-to-output short-circuit propagation during LED string faults, enhancing system safety |
Applications
| Desktop LCD Monitors | LCD TVs |
|---|---|
Use Scenario: 27-inch to 32-inch IPS panel with 8-zone edge-lit WLED array requiring uniform brightness and 10,000-hour lifetime. IC Role / Device Role / Timing Role: WLED driver controller managing 8 independent current-regulated strings, synchronizing dimming across zones via shared DBRT/BOSC signals. Use Value: Delivers consistent luminance (±2.5% current matching) and eliminates zone bleeding through fast open-string detection and dynamic bus voltage adjustment. |
Use Scenario: 43-inch 4K UHD TV backlight using 6 parallel WLED strings per side, driven from 24V rail with PWM dimming at 200Hz. IC Role / Device Role / Timing Role: Primary step-up WLED controller enabling high-efficiency boost conversion and synchronized burst-PWM dimming across all strings. Use Value: Achieves >90% efficiency at full load and flicker-free dimming via internally generated DPWM (1.2–1.6kHz) with no external timing IC required. |
| Flat Panel Video Displays | Industrial Control Panels |
Use Scenario: 15-inch medical-grade display with redundant LED strings and strict thermal limits in enclosed chassis. IC Role / Device Role / Timing Role: Fault-tolerant WLED driver with thermal shutdown, OVP, and VFAULT-controlled isolation for safe fail-operational behavior. Use Value: Maintains partial backlight operation during single-string failure and prevents thermal runaway via 150°C shutdown and 32°C/W θJA design. |
Use Scenario: Ruggedized HMI panel operating in -20°C to +70°C ambient with variable input (12–30V) and EMC-sensitive environment. IC Role / Device Role / Timing Role: Robust WLED controller supporting wide VIN, programmable fSW (to avoid noise bands), and low-noise current regulation. Use Value: Enables stable backlighting across temperature and input variation while meeting CISPR-22 Class B conducted emissions via optimized switching frequency selection. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar WLED driver controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MPQ3326-AEC1 | Automotive-grade AEC-Q100 qualified; 6-channel; integrated MOSFET; max 100mA/string | Designed for automotive infotainment displays; lacks VFAULT isolation and NUMSEL flexibility | Select for automotive designs requiring qualification; not drop-in due to lower channel count and integrated FET architecture |
| LM3409QMY/NOPB | Single-channel buck-boost WLED controller; no integrated current sinks; requires external sense resistors per string | Suitable for custom multi-string designs with discrete current regulation; higher BOM count and layout complexity | Choose when channel count exceeds 8 or when discrete current control per string is preferred for tuning |
Compared with MP3391EF-LF, MPQ3326-AEC1 offers automotive qualification but sacrifices channel count and VFAULT safety isolation, while LM3409QMY requires external current regulation circuitry and increases design effort-MP3391EF-LF remains optimal for cost-sensitive, high-channel-count industrial LCD backlighting.
Availability
MP3391EF-LF is available at Aetrix Electronics and suitable for desktop LCD monitors, LCD TVs, flat panel video displays, and industrial control panels requiring stable component supply, long-lifecycle support, and RoHS-compliant packaging.
Supply support for MP3391EF-LF 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, LED drivers, and motor control.
The MP3391 belongs to MPS's WLED backlight controller product line, designed specifically for large-format LCD panel applications demanding high channel count, tight current matching, and robust fault protection.
FAQ
What is the maximum number of LED strings supported by MP3391EF-LF?
The MP3391EF-LF supports up to 8 LED strings simultaneously. The actual count (4, 6, or 8) is selected dynamically via the NUMSEL pin: floating enables all 8 strings (LED1–LED8), high logic enables 6 strings (LED1–LED6), and low logic enables 4 strings (LED1–LED4). This configuration is hardware-selectable and does not require firmware or register writes.
How is LED current accuracy achieved across all channels?
MP3391EF-LF achieves ±2.5% current matching between strings using eight precision-matched internal current sinks referenced to a 1.23V bandgap voltage at the ISET pin. Each LEDX pin (LED1–LED8) acts as an open-drain current output with identical regulation characteristics, eliminating need for external current-setting components per string.
Does MP3391EF-LF integrate the power MOSFET?
No, MP3391EF-LF does not integrate the power MOSFET. It provides a dedicated GATE pin (Pin 25) that drives an external N-channel MOSFET in the step-up converter stage. This architecture allows designers to select MOSFETs optimized for voltage rating (≥1.5× output), RDS(on), and switching loss - critical for efficiency and thermal management in high-power backlight systems.
What protection features are implemented for LED string faults?
The MP3391EF-LF implements open-string detection (via OVP and LEDX voltage monitoring), short-string detection (via SSET-programmed threshold and TSET timer), overvoltage protection (OVP pin), thermal shutdown (150°C), and fault flag signaling (FF pin). When triggered, it disables affected strings and asserts VFAULT to disconnect input from output using an external PMOS.
Can MP3391EF-LF operate with a 5V input supply?
No, MP3391EF-LF requires a minimum 9V input supply as specified in Absolute Maximum Ratings and Recommended Operating Conditions. Attempting operation below 9V will prevent proper startup due to VCC UVLO (3.4V threshold) and insufficient headroom for the internal 10V VDD regulator and gate drive requirements.
What is the purpose of the VFAULT pin?
VFAULT is a driver output that controls an external PMOS transistor placed between VIN and the boost converter input. During normal operation, VFAULT turns on the PMOS to enable power flow. During open/short LED faults or shutdown, VFAULT turns off the PMOS to physically isolate the input supply from the faulty output stage - a critical safety feature for system-level fault containment.
Is MP3391EF-LF compatible with both PWM and analog dimming inputs?
Yes - MP3391EF-LF supports two dimming modes: (1) External PWM applied to DBRT pin (0–5V, 100Hz–20kHz), and (2) DC analog voltage (0.2–1.2V) applied to DBRT with BOSC capacitor, which converts it into internally generated burst-PWM at 1.2–1.6kHz. Both modes modulate all 8 strings simultaneously with identical duty cycle.
MP3391EF-LF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Monolithic Power Systems Inc.
- Series:
- -
- Package/Case:
- 28-TSSOP (0.173", 4.40mm Width) Exposed Pad
- Packaging:
- Tube
- Product Status:
- Active
- Type:
- DC DC Controller
- Topology:
- Step-Up (Boost)
- Internal Switch(s):
- No
- Number of Outputs:
- 8
- Voltage - Supply (Min):
- 9V
- Voltage - Supply (Max):
- 35V
- Voltage - Output:
- -
- Current - Output / Channel:
- 120mA
- Frequency:
- 280kHz
- Dimming:
- PWM
- Applications:
- Backlight
- Operating Temperature:
- -20°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 28-TSSOP-EP
MP3391EF-LF FAQ
1.How can I place an order for MP3391EF-LF through Aetrix?
Please submit a Request for Quotation (RFQ) for MP3391EF-LF 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 MP3391EF-LF reliable?
The price and inventory of MP3391EF-LF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MP3391EF-LF is usually 5 days.
3.What payment methods are accepted for MP3391EF-LF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MP3391EF-LF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MP3391EF-LF?
MP3391EF-LF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MP3391EF-LF 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 MP3391EF-LF?
For technical support, including MP3391EF-LF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MP3391EF-LF requirements.
6.How does Aetrix verify that MP3391EF-LF is sourced from the original manufacturer or authorized distributors?
All MP3391EF-LF 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 MP3391EF-LF meets industry standards.
7.What is the process for return or replacement of MP3391EF-LF?
All MP3391EF-LF units undergo pre-shipment inspection (PSI). If there is an issue with MP3391EF-LF, 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 MP3391EF-LF part is unused and in its original packaging.
Return procedure for MP3391EF-LF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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