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Analog Devices Inc. LT3579EUFD-1#TRPBF
- Part No.:
- LT3579EUFD-1#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 20-WFQFN Exposed Pad
- Datasheet:
-
LT3579EUFD-1#TRPBF.pdf
- Description:
- IC REG BST CHARGE PUMP ADJ 20QFN
- Quantity:
- Payment:
- Shipping:
Inventory:2,735
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Product details
Overview
LT3579EUFD-1#TRPBF from Analog Devices is a dual-phase capable 6A, 42V PWM DC/DC converter with integrated master/slave NPN switches (3.4A/2.6A), fault protection (output short, input overvoltage, overtemperature), and configurable undervoltage lockout. It supports Boost, SEPIC, Inverting, and Flyback topologies - delivering 12V at 1.7A or –12V at 1.2A from 5V input - and is used in automotive ECU power supplies and TFT-LCD bias generation.
For engineers reviewing the LT3579EUFD-1#TRPBF datasheet, LT3579EUFD-1#TRPBF pinout, LT3579EUFD-1#TRPBF application, or LT3579EUFD-1#TRPBF equivalent, key selection considerations include its 20-pin 4mm × 5mm QFN package, 200kHz–2.5MHz programmable switching frequency, dual-phase synchronization capability via CLKOUT/SYNC, and integrated fault-handling logic with soft-start and frequency foldback.
Technical Context
The LT3579EUFD-1#TRPBF implements constant-frequency current-mode control with independent master (SW1) and slave (SW2) NPN switches, enabling dual-phase operation where CLKOUT is 180° out-of-phase and duty cycle is fixed at ~50%. Its fault detection includes SW overcurrent (>3.4A on SW1 or >6A combined), VIN overvoltage (>16.2V), SW overvoltage (>42V), and die temperature (>165°C).
It features a high-gain SHDN pin accepting slowly varying signals, user-configurable UVLO via external resistor divider, and soft-start with linear GATE pull-down current ramp (0–933µA) tied to SS voltage. The VC pin provides error amplifier output for external compensation, while FB accepts both positive (1.215V reference) and negative (9mV reference) feedback configurations.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Switch Configuration | Dual-phase capable master/slave NPN switches: SW1 rated 3.4A min, SW2 rated 2.6A min; combined 6A peak current limit |
| Input Voltage Range | 2.5V to 16V operating range; 40V absolute max transient - supports wide automotive and industrial supply rails |
| Switching Frequency | 200kHz to 2.5MHz, set by RT-to-ground resistor or external SYNC clock - enables EMI optimization and compact magnetics |
| Fault Protection | Detects output short circuit, VIN overvoltage (>16.2V), SW overvoltage (>42V), and overtemperature (>165°C) - triggers automatic shutdown and timeout recovery |
| Package & Thermal | 20-pin 4mm × 5mm plastic QFN with exposed GND pad; θJA = 34°C/W, θJC = 2.7°C/W - optimized for high-power density PCB layouts |
| Soft-Start Control | SS pin charges to ~2.1V via internal 250kΩ resistor; GATE pull-down current ramps linearly to 933µA above 500mV - enables controlled PMOS turn-on and inrush limiting |
| CLKOUT Function | Buffered oscillator output with fixed ~50% duty cycle and 180° phase shift vs internal clock - synchronizes secondary regulators in multiphase designs |
Pinout & Package
LT3579EUFD-1#TRPBF is housed in a 20-lead (4mm × 5mm) plastic QFN package with exposed thermal pad (Pin 21 = GND). The package requires soldering of the exposed pad to the PCB ground plane for thermal and electrical integrity.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| FB (Pin 1) | Positive/Negative Feedback Input | Accepts 1.215V reference for boost/SEPIC or 9mV reference for inverting topologies; bias current 83.3µA typical |
| VC (Pin 2) | Error Amplifier Output | Drives external compensation network (R-C-RC); sets peak switch current for regulation |
| GATE (Pin 3) | PMOS Gate Drive Output | Pull-down current source (0–933µA) controlled by SS voltage; enables external PMOS for output disconnect during fault |
| FAULT (Pin 4) | Bidirectional Fault Indicator | Active-low open-collector; pulled low internally on fault or externally to trigger shutdown; threshold 750mV/1000mV |
| VIN (Pin 5) | Main Input Supply | 2.5V–16V operating input; bypass locally; 40V absolute max rating |
| SW1 (Pins 6–10) | Master Switch Collector | NPN collector terminal rated for ≥3.4A peak; minimize trace area to reduce EMI |
| GND (Pin 21, Exposed Pad) | Power & Signal Ground | Thermal and electrical ground; must be soldered to PCB ground plane |
| SW2 (Pins 11–15) | Slave Switch Collector | NPN collector terminal rated for ≥2.6A peak; used with SW1 for dual-phase or high-current single-phase operation |
| CLKOUT (Pin 16) | Synchronization Clock Output | 180° out-of-phase buffered oscillator signal; fixed ~50% duty cycle; usable as junction temperature monitor |
| SHDN (Pin 17) | Shutdown & UVLO Control | High-gain input; 1.33V typical turn-on threshold; supports external resistor divider for programmable UVLO |
| RT (Pin 18) | Frequency Setting Input | Connect resistor to GND to set free-running frequency (200kHz–2.5MHz); no floating allowed |
| SYNC (Pin 20) | External Clock Input | Accepts 0.4V–1.3V logic levels; overrides RT setting to synchronize switching frequency |
| SS (Pin 19) | Soft-Start Timing Node | Charges to ~2.1V via internal current source; controls GATE ramp and fault timeout timing |
Key Features
| Feature | Design Value |
|---|---|
| Dual-phase synchronization | CLKOUT provides 180° phase-shifted, fixed-50% duty clock - enables interleaved operation with matched LT3579-1 devices for reduced input/output ripple |
| Integrated fault protection | Detects and responds to five independent fault conditions (SW overcurrent, VIN OV, SW OV, overtemperature, external FAULT assertion) with automatic shutdown and timed recovery |
| Configurable UVLO | SHDN pin supports external resistor divider to set precise VIN turn-on threshold - eliminates need for external supervisor IC in battery-powered systems |
| Output short-circuit robustness | Sample Mode forces Q1/Q2 on every cycle when FB is out-of-regulation; detects short within one switching cycle and initiates fault sequence |
| Low-loss switching | Combined SW1+SW2 VCE(SAT) = 250mV typ at 5.5A - minimizes conduction loss in high-current boost/inverting applications |
Applications
| Automotive Engine Control Unit (ECU) Power | TFT-LCD Bias Supplies |
|---|---|
Use Scenario: Generating isolated ±12V rails from a 12V vehicle battery for microcontroller, sensor, and CAN transceiver power domains under cold-crank (5.5V) and load-dump (36V) conditions. IC Role / Device Role / Timing Role: Primary DC/DC controller implementing inverting topology with fault-triggered PMOS disconnect to protect downstream analog circuitry during battery short events. Use Value: Integrated 42V switches and 16.2V VIN OVLO eliminate external TVS/clamping; dual-phase capability reduces input capacitor RMS current by ~30% versus single-phase. | Use Scenario: Providing stable +15V and –10V bias voltages for TFT gate drivers and source drivers in industrial panel displays operating across –40°C to 85°C ambient. IC Role / Device Role / Timing Role: Dual-rail inverting/boost converter with soft-start-controlled GATE drive enabling hot-plug-safe power sequencing and inrush limiting during panel initialization. Use Value: 200kHz–2.5MHz frequency range allows optimal inductor sizing for size/cost trade-off; 125°C junction rating ensures reliability in sealed display enclosures. |
| Vacuum Fluorescent Display (VFD) Bias Supplies | Local Power Supply for Industrial PLC Modules |
Use Scenario: Delivering 30V–60V anode supply and –15V grid bias from 5V or 24V system rail in point-of-sale terminals and instrumentation front panels. IC Role / Device Role / Timing Role: High-voltage charge-pump-aided boost converter leveraging SW1/SW2 combination to achieve >40V output with minimal external components. Use Value: 42V switch rating and frequency foldback enable stable startup into high-capacitance VFD loads; integrated fault handling prevents latch-up during filament burn-in. | Use Scenario: Local 5V-to-12V boost supply for isolated I/O driver stages in programmable logic controllers subjected to 4kV EFT and 2kV surge per IEC 61000-4-4/5. IC Role / Device Role / Timing Role: Fault-protected primary regulator with GATE-driven PMOS isolation, enabling safe power cycling of field-side circuits without resetting the main controller. Use Value: Output short protection and automatic recovery prevent system downtime during field wiring faults; exposed QFN pad ensures thermal stability during continuous 1.7A load operation. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar DC/DC controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC3891EUF#PBF | Single-channel synchronous buck controller; no integrated switches; supports up to 60V VIN; requires external MOSFETs | Used in high-efficiency step-down applications only; lacks inverting/SEPIC capability and integrated fault protection | Select when higher efficiency (>95%) and lower quiescent current (<50µA) are required, and external FETs are acceptable |
| LT8330EDDB#TRPBF | Single-switch 60V boost/SEPIC/inverting controller; no slave switch; no dual-phase sync; 5A switch current limit | Supports same topologies but lacks SW2 for dual-phase or 6A combined current; no CLKOUT phase control | Select for cost-sensitive designs needing 60V capability and simpler layout, where dual-phase interleaving is unnecessary |
Compared with LTC3891EUF#PBF and LT8330EDDB#TRPBF, the LT3579EUFD-1#TRPBF uniquely integrates dual NPN switches with synchronized 180° CLKOUT, enabling true dual-phase operation without external timing coordination - critical for reducing EMI and input capacitor stress in space-constrained automotive and display power supplies.
Availability
LT3579EUFD-1#TRPBF is available at Aetrix Electronics and suitable for automotive ECU power, TFT-LCD bias supplies, VFD driver circuits, and industrial PLC local power requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for LT3579EUFD-1#TRPBF 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
Analog Devices, Inc. is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, serving industrial, automotive, communications, and healthcare markets.
The LT3579EUFD-1#TRPBF belongs to Analog Devices' Power by Linear™ family of robust DC/DC converters designed specifically for fault-tolerant local power generation in harsh environments - emphasizing integrated protection, wide input range, and multiphase scalability.
FAQ
What is the difference between LT3579EUFD-1#TRPBF and LT3579EUFD#TRPBF?
The LT3579EUFD-1#TRPBF includes dual-phase synchronization capability: its CLKOUT signal is 180° out-of-phase with the internal oscillator and has a fixed ~50% duty cycle, enabling interleaved operation with other LT3579-1 devices. The standard LT3579EUFD#TRPBF has a variable CLKOUT duty cycle (~42%) and no guaranteed phase relationship - making the -1 variant essential for multiphase current sharing. Both share identical pinout, package, and fault protection features.
Can LT3579EUFD-1#TRPBF be used in inverting configuration with negative feedback?
Yes, the LT3579EUFD-1#TRPBF supports inverting topology using its dual feedback reference: the FB pin accepts a negative feedback voltage of 9mV (typical) for inverting converters, with bias current of 83.3µA flowing out of the pin. This allows direct connection to the inverting output node through a single resistor (RFB = |VOUT| + 9mV / 83.3µA), eliminating need for level-shifting networks. The LT3579EUFD-1#TRPBF maintains full fault protection and soft-start functionality in this mode.
How does the fault recovery timeout work on LT3579EUFD-1#TRPBF?
Upon fault detection (e.g., output short), the LT3579EUFD-1#TRPBF pulls FAULT low, disables switches and CLKOUT, and initiates a timeout sequence where the SS pin is charged to ~1.8V then discharged to 50mV. This cycle - governed by internal current sources and external SS capacitor - enforces minimum off-time (typically 10–100ms depending on CSS) before automatic retry. If the fault persists, the cycle repeats; if cleared, normal operation resumes once SS exceeds 1.8V.
What is the maximum achievable output voltage using LT3579EUFD-1#TRPBF in boost mode?
The LT3579EUFD-1#TRPBF's internal switches are rated for 42V breakdown, limiting practical boost output to ≤40V with margin. However, the datasheet confirms use in "high voltage, high power charge pump topologies" - where SW1 and SW2 are configured in Dickson or voltage-doubling arrangements - enabling outputs exceeding 60V with appropriate external diodes and capacitors. For standard boost, 36V is recommended maximum for reliability across temperature and process variation.
Is the exposed pad (Pin 21) on LT3579EUFD-1#TRPBF electrically connected to GND?
Yes, the exposed thermal pad (Pin 21) on the LT3579EUFD-1#TRPBF is internally connected to GND and must be soldered directly to the PCB ground plane. This connection is mandatory for both thermal performance (θJC = 2.7°C/W) and electrical integrity - failure to solder the pad degrades thermal dissipation, increases junction temperature, and may cause premature thermal shutdown or reliability issues under 6A peak load conditions.
LT3579EUFD-1#TRPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 20-WFQFN Exposed Pad
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Function:
- Step-Up, Step-Up/Step-Down
- Output Configuration:
- Positive or Negative
- Topology:
- Boost, Charge Pump, Cuk, Flyback, SEPIC
- Output Type:
- Adjustable
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 2.5V
- Voltage - Input (Max):
- 16V
- Voltage - Output (Min/Fixed):
- 1.215V
- Voltage - Output (Max):
- 42V (Switch)
- Current - Output:
- 6A (Switch)
- Frequency - Switching:
- 200kHz ~ 2.5MHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 20-QFN (4x5)
LT3579EUFD-1#TRPBF FAQ
1.How can I place an order for LT3579EUFD-1#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3579EUFD-1#TRPBF 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 LT3579EUFD-1#TRPBF reliable?
The price and inventory of LT3579EUFD-1#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT3579EUFD-1#TRPBF is usually 5 days.
3.What payment methods are accepted for LT3579EUFD-1#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3579EUFD-1#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3579EUFD-1#TRPBF?
LT3579EUFD-1#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3579EUFD-1#TRPBF 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 LT3579EUFD-1#TRPBF?
For technical support, including LT3579EUFD-1#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3579EUFD-1#TRPBF requirements.
6.How does Aetrix verify that LT3579EUFD-1#TRPBF is sourced from the original manufacturer or authorized distributors?
All LT3579EUFD-1#TRPBF 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 LT3579EUFD-1#TRPBF meets industry standards.
7.What is the process for return or replacement of LT3579EUFD-1#TRPBF?
All LT3579EUFD-1#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3579EUFD-1#TRPBF, 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 LT3579EUFD-1#TRPBF part is unused and in its original packaging.
Return procedure for LT3579EUFD-1#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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