My Inquiry
My Account
Analog Devices Inc. LT3479EDE#TRPBF
- Part No.:
- LT3479EDE#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 14-WFDFN Exposed Pad
- Datasheet:
-
LT3479EDE#TRPBF.pdf
- Description:
- IC REG BOOST ADJ 3A 14DFN
- Quantity:
- Payment:
- Shipping:
Inventory:2,972
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
LT3479EDE#TRPBF from Analog Devices (formerly Linear Technology) is a current-mode, fixed-frequency step-up DC/DC converter with an integrated 3A, 42V NPN switch. It delivers up to 89% efficiency across 2.5V–24V input and supports programmable switching frequency (200kHz–3.5MHz), soft-start, and inrush current protection. It enables both positive and negative output configurations and is used in high-power LED drivers and distributed power systems.
For engineers reviewing the LT3479EDE#TRPBF datasheet, LT3479EDE#TRPBF pinout, LT3479EDE#TRPBF application, or LT3479EDE#TRPBF equivalent, key selection criteria include its 3A internal switch rating, 42V breakdown voltage, 1.235V reference accuracy, thermal performance in the 4mm × 3mm DFN package, and dual-polarity feedback architecture enabling ±VOUT designs.
Technical Context
The LT3479EDE#TRPBF employs fixed-frequency current-mode control with slope compensation, using an internal oscillator synchronized to an external RT resistor. Its dual-input error amplifier (FBP/FBN) allows flexible feedback topology-FBN for positive outputs, FBP for negative outputs-enabling buck-boost and inverting topologies without external op-amps.
It integrates inrush current protection via an 8.5mΩ sense resistor in series with the inductor, triggering soft-start when inductor current exceeds 5A. The low VCE(SAT) of 0.2V at 1A and 0.3V at 2.5A minimizes conduction loss, while the exposed PGND pad (Pin 15) ensures robust thermal dissipation (θJA = 43°C/W).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 2.5V to 24V - supports wide-range industrial and battery-powered inputs including 3.3V, 5V, and 12V rails. |
| Switch Rating | 3A continuous, 42V breakdown - handles peak inductor currents up to 6.5A (guaranteed limit), suitable for 0.8A–1A output designs with margin. |
| Reference Voltage | 1.235V ±1.2% (TYP) - sets precise output regulation; line regulation <0.03%/V ensures stability across input transients. |
| Switching Frequency | 200kHz to 3.5MHz (RT-programmable) - higher frequencies reduce inductor size but trade off ~4% efficiency per doubling (e.g., 1MHz → 2MHz). |
| Soft-Start Control | 10μA constant-current SS pin - enables controlled ramp-up of VC voltage to limit startup inrush and prevent output overshoot. |
| Thermal Package | 14-pin DFN (4mm × 3mm × 0.75mm) with exposed PGND pad - achieves θJA = 43°C/W; requires soldering exposed pad to PCB ground plane. |
| Operating Temp | –40°C to +85°C - qualified for industrial ambient conditions; junction limit is 125°C. |
Pinout & Package
LT3479EDE#TRPBF uses the DE14 (14-lead, 4mm × 3mm) plastic DFN package with an exposed power ground pad (Pin 15). The package height is 0.75mm, optimized for space-constrained applications. Thermal performance relies on proper soldering of the exposed pad to a PCB thermal plane.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| SW (Pins 1, 2) | Switch Collector | Connects to inductor and flyback diode; high dv/dt node requiring minimal trace area to reduce EMI. |
| L (Pin 3) | Inductor Supply Return | Return path for inductor current; must be locally bypassed to VS and tied to PGND via short low-inductance route. |
| VS (Pin 4) | Inductor Supply Input | Powers internal switch driver; tie to VIN if single supply is used, otherwise decouple separately near L pin. |
| VIN (Pin 5) | Control Circuit Input | Powers bias circuitry and references; requires local ceramic bypass (≥2.2μF) close to pin. |
| RT (Pin 6) | Oscillator Timing Input | Resistor-to-ground sets switching frequency; open-circuit causes undefined operation - must be terminated. |
| SHDN (Pin 7) | Enable/Shutdown Control | Active-high logic: >1.5V enables, <0.3V disables; draws ≤1μA in shutdown mode. |
| VREF (Pin 8) | Bandgap Reference Output | 1.235V source capable of sourcing 100μA; bypass with 100pF for noise immunity. |
| FBP (Pin 9) | Error Amp Non-Inverting Input | Used for negative-output feedback; connects to resistive divider tap referenced to –VOUT. |
| FBN (Pin 10) | Error Amp Inverting Input | Used for positive-output feedback; connects to resistive divider tap referenced to +VOUT. |
| VC (Pin 11) | Error Amp Compensation | Output of internal transconductance amplifier; connect RC network (e.g., 10kΩ + 2.2nF) to GND for loop stability. |
| SS (Pin 12) | Soft-Start Control | Charged by 10μA current; capacitor value (e.g., 10nF = 1.65ms ramp) controls startup slew rate. |
| GND (Pins 13, 14) | Analog Ground | Reference for control circuitry; separate from PGND but tied together at single point near exposed pad. |
| Exposed Pad (Pin 15) | Power Ground (PGND) | Mandatory connection to PCB ground plane; primary thermal and current return path for switch and inductor. |
Key Features
| Feature | Design Value |
|---|---|
| Dual-polarity feedback architecture | Enables both positive and negative output voltages using same IC - eliminates need for external op-amp in inverting configurations. |
| Inrush current protection | Detects >5A inductor current via internal 8.5mΩ sense resistor and initiates automatic soft-start recovery - protects switch during shorts/hot-plug events. |
| Programmable switching frequency | 200kHz–3.5MHz via single RT resistor - allows optimization of size (higher fSW) vs. efficiency (lower fSW) without changing layout. |
| Low VCE(SAT) switch | 0.2V at 1A and 0.3V at 2.5A - reduces conduction loss and thermal stress, enabling compact thermal design in 0.75mm-profile DFN. |
| Internal 3A/42V NPN switch | Integrates power switch, eliminating external transistor and associated gate-drive complexity - simplifies BOM and layout for boost/inverting converters. |
Applications
| High-Power LED Driver | DSL Modem Power Supply |
|---|---|
|
Use Scenario: Driving 12 white LEDs (3.2V each) from a 3.3V–4.2V Li-ion battery with constant current regulation. IC Role / Device Role / Timing Role: Acts as constant-current boost controller with adjustable output voltage (up to 40V) and inrush limiting during flash mode transitions. Use Value: Enables efficient 500mA LED drive with <85% efficiency at 8V input, leveraging soft-start to avoid current spikes during torch-to-flash switching. |
Use Scenario: Generating isolated ±5V and +12V rails from a single 5V input in DSL line card power management. IC Role / Device Role / Timing Role: Functions as triple-output inverting/boost regulator with independent feedback paths for each rail. Use Value: Delivers stable ±8V and +16V outputs simultaneously using one LT3479EDE#TRPBF and shared inductor, reducing component count vs. discrete solutions. |
| Distributed Power System | TFT-LCD Panel Supply |
|
Use Scenario: Local 12V boost generation from 5V backplane in telecom equipment with transient-heavy load profiles. IC Role / Device Role / Timing Role: Provides regulated 12V/0.8A output with hot-plug protection and fast transient response via current-mode control. Use Value: Maintains regulation during 24V line transients and recovers from short-circuit faults within milliseconds using inrush protection and soft-start restart. |
Use Scenario: Powering gate drivers and source drivers in TFT-LCD panels requiring tightly regulated +8V, –8V, and +16V supplies. IC Role / Device Role / Timing Role: Configured as triple-output inverting/boost converter with shared switching node and independent feedback networks. Use Value: Achieves <70% efficiency across all three outputs while meeting ripple requirements (<20mV p-p) using X5R/X7R ceramic capacitors and low-ESR inductors. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar boost converter applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC3436EFE#TRPBF | 3A/34V synchronous boost; TSSOP-16; IQ = 0.9mA; no inrush protection | Higher integration (integrated Schottky); lower quiescent current; lacks inrush current protection and dual-polarity feedback | Preferred for battery-life-critical apps where efficiency at light load matters more than fault robustness. |
| LT3466EUD#TRPBF | 2MHz dual-channel LED boost; 40V switch; integrated Schottky; DFN-16 | Optimized for LED current regulation; includes torch/flash mode control; no negative output capability | Best suited for portable LED flash applications requiring dual brightness modes, not general-purpose DC/DC conversion. |
Compared with LTC3436EFE#TRPBF and LT3466EUD#TRPBF, the LT3479EDE#TRPBF uniquely combines inrush current protection, dual-polarity feedback, and a 42V switch in a thermally enhanced DFN-making it optimal for industrial and telecom power where fault resilience and flexible topology matter more than ultra-low IQ or LED-specific features.
Availability
LT3479EDE#TRPBF is available at Aetrix Electronics and suitable for high-power LED drivers, DSL modem power supplies, and distributed power systems requiring stable component supply, long-term lifecycle support, and guaranteed industrial temperature operation.
Supply support for LT3479EDE#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 acquired Linear Technology in 2017 and maintains full product continuity, technical support, and manufacturing for legacy Linear parts including the LT3479 family.
The LT3479EDE#TRPBF belongs to Linear's high-voltage, high-current DC/DC converter product line, designed specifically for space-constrained industrial and telecom applications demanding robust fault protection and flexible output polarity.
FAQ
What is the maximum output voltage achievable with the LT3479EDE#TRPBF?
The LT3479EDE#TRPBF does not impose a hard upper limit on output voltage beyond its 42V switch breakdown rating and practical layout constraints. In typical applications, outputs up to 40V are reliably achieved - for example, driving 12-series white LEDs (3.2V × 12 = 38.4V) with margin. The actual maximum depends on external components (diode reverse voltage, capacitor rating) and PCB parasitics.
Can the LT3479EDE#TRPBF generate negative output voltages?
Yes, the LT3479EDE#TRPBF supports negative output configurations using its dual-input error amplifier. Connect VREF to FBP and use a resistive divider from –VOUT to FBN to set the output magnitude via VOUT = –1.235 × (R3/R4). This eliminates the need for external op-amps or charge pumps in inverting applications like TFT-LCD bias supplies.
How does the inrush current protection work in the LT3479EDE#TRPBF?
The LT3479EDE#TRPBF monitors inductor current through an internal 8.5mΩ sense resistor. When current exceeds 5A, it forces a soft-start cycle - resetting the VC voltage ramp and limiting peak switch current. This protects the internal NPN switch and external components during output shorts or hot-plug events, and recovery occurs automatically once the fault clears.
What is the recommended minimum soft-start capacitor value for the LT3479EDE#TRPBF?
A 10nF capacitor on the SS pin yields ~1.65ms soft-start time (10μA × 10nF = 100mV/ms ramp). For slower ramp rates, increase capacitance linearly - e.g., 22nF gives ~3.6ms. Avoid values below 1nF, which may not sufficiently suppress inrush; values above 100nF unnecessarily extend startup without added benefit in most applications.
Is the exposed pad on the LT3479EDE#TRPBF electrically connected, and how should it be handled?
Yes, the exposed pad (Pin 15) is electrically connected to PGND and is mandatory for both thermal performance and electrical functionality. It must be soldered to a dedicated PCB copper pour tied to system ground. Use ≥4 thermal vias (0.3mm diameter) under the pad, filled or capped, to ensure low-impedance thermal transfer and mechanical reliability.
LT3479EDE#TRPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 14-WFDFN Exposed Pad
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Function:
- Step-Up
- Output Configuration:
- Positive or Negative
- Topology:
- Boost
- Output Type:
- Adjustable
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 2.3V
- Voltage - Input (Max):
- 24V
- Voltage - Output (Min/Fixed):
- 1.235V
- Voltage - Output (Max):
- 42V (Switch)
- Current - Output:
- 3A (Switch)
- Frequency - Switching:
- 200kHz ~ 3.5MHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- -40°C ~ 85°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 14-DFN (4x3)
LT3479EDE#TRPBF FAQ
1.How can I place an order for LT3479EDE#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3479EDE#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 LT3479EDE#TRPBF reliable?
The price and inventory of LT3479EDE#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT3479EDE#TRPBF is usually 5 days.
3.What payment methods are accepted for LT3479EDE#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3479EDE#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3479EDE#TRPBF?
LT3479EDE#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3479EDE#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 LT3479EDE#TRPBF?
For technical support, including LT3479EDE#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3479EDE#TRPBF requirements.
6.How does Aetrix verify that LT3479EDE#TRPBF is sourced from the original manufacturer or authorized distributors?
All LT3479EDE#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 LT3479EDE#TRPBF meets industry standards.
7.What is the process for return or replacement of LT3479EDE#TRPBF?
All LT3479EDE#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3479EDE#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 LT3479EDE#TRPBF part is unused and in its original packaging.
Return procedure for LT3479EDE#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LT3479EDE#TRPBF 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…
