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Analog Devices Inc. LT3509EDE#TRPBF
- Part No.:
- LT3509EDE#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 14-WFDFN Exposed Pad
- Datasheet:
-
LT3509EDE#TRPBF.pdf
- Description:
- IC REG BUCK ADJ 700MA DL 14DFN
- Quantity:
- Payment:
- Shipping:
Inventory:1,608
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Product details
Overview
LT3509EDE#TRPBF from Analog Devices (formerly Linear Technology) is a dual-channel, current-mode, synchronous step-down DC/DC regulator IC with integrated 700mA power switches per channel, 3.6V–36V input range, and independent RUN/SS control for automotive and industrial power rails. It delivers regulated 3.3V and 5V outputs in compact multi-rail systems under harsh transients up to 60V.
For engineers reviewing the LT3509EDE#TRPBF datasheet, LT3509EDE#TRPBF pinout, LT3509EDE#TRPBF application, or LT3509EDE#TRPBF equivalent, key selection considerations include its 14-lead DFN (4mm × 3mm) thermal performance, adjustable 300kHz–2.2MHz switching frequency via RT resistor, cycle-by-cycle current limiting, overvoltage lockout at 38.5V, and integrated boost diodes enabling low dropout operation.
Technical Context
The LT3509EDE#TRPBF implements two independent current-mode buck regulators sharing a common 0.8V reference and oscillator, operating in-phase with fixed-frequency PWM control. Each channel uses internal NPN power switches with integrated boost diodes and on-chip slope compensation to suppress subharmonic oscillation above 50% duty cycle.
Its protection architecture includes cycle-by-cycle current limit (1.4A typ), DA-pin-based short-circuit detection (0.95A valley limit), thermal shutdown, undervoltage lockout (~3.6V), and overvoltage lockout (~38.5V). The BD pin supplies charge to both BOOST1/BOOST2 pins through internal Schottky diodes, enabling base-boosted switch drive for <0.32V saturation voltage and >95% maximum duty cycle.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 3.6V to 36V continuous; withstands 60V non-repetitive transients - supports automotive battery rail and industrial 24V systems. |
| Output Current per Channel | 700mA - sufficient for powering microcontrollers, FPGAs, and interface ICs without external pass devices. |
| Switching Frequency | Adjustable 300kHz to 2.2MHz via RT resistor; synchronizable externally - enables EMI optimization and small magnetics. |
| Feedback Reference Voltage | 0.8V ±2% over –40°C to 125°C - ensures stable output regulation across temperature with standard resistor dividers. |
| Max Duty Cycle | 95% - allows operation down to VIN ≈ VOUT + VF, supporting low-dropout behavior in wide-input applications. |
| Overvoltage Lockout Threshold | 38.5V typical - protects internal switches and downstream loads during load-dump events in automotive environments. |
| Thermal Shutdown Temp | 150°C junction - provides fail-safe protection during sustained overload or poor PCB thermal design. |
Pinout & Package
LT3509EDE#TRPBF is housed in a thermally enhanced 14-lead (4mm × 3mm) plastic DFN package with exposed GND pad (Pin 15) requiring soldering to PCB for thermal and electrical integrity. θJA = 43°C/W, θJC = 4.3°C/W.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| FB1, FB2 (Pins 14, 8) | Feedback input | Connects to resistor divider to regulate output voltage at 0.8V reference; bias current <500nA minimizes divider error. |
| RUN/SS1, RUN/SS2 (Pins 13, 9) | Enable & soft-start control | Pull <0.4V to shut down channel; 0.8–2.0V enables current-limited soft-start; internal 1µA pull-up allows floating enable. |
| BOOST1, BOOST2 (Pins 2, 6) | Bootstrap supply node | Tied to SW pins via external capacitors; receives charge from BD pin to drive switch base above VIN for low VCE(SAT). |
| SW1, SW2 (Pins 3, 5) | Switch node | Drives external inductor; connects to cathode of catch diode and BOOST capacitor; peak current limited to 1.4A. |
| VIN (Pin 4) | Main power input | Supplies control circuitry and power switches; accepts 3.6–36V; clamped to 60V max transient. |
| BD (Pin 12) | Boost diode anode | Common anode of internal Schottky diodes charging BOOST1/BOOST2; must be bypassed locally for stability. |
| DA1, DA2 (Pins 1, 7) | Catch diode anode | Internally connected to GND pad via current-sense resistors; used for valley-current monitoring and short-circuit protection. |
| RT (Pin 10) | Oscillator timing | Resistor-to-ground sets switching frequency (e.g., 40.2kΩ → 1MHz); supports external sync via SYNC pin. |
| SYNC (Pin 11) | External clock input | Accepts logic-level clock ≥1.0V threshold; requires free-run frequency ≥12% below sync source for reliable locking. |
Key Features
| Feature | Design Value |
|---|---|
| Dual independent buck regulators | Enables compact dual-rail power supply (e.g., 3.3V + 5V) with separate enable/soft-start, eliminating discrete controllers. |
| Integrated boost diodes and compensation | Reduces BOM count by 4 diodes and 2 compensation networks; simplifies layout and improves reliability vs. discrete boost solutions. |
| Short-circuit robust DA comparator | Monitors catch diode current to limit valley inductor current to 0.95A during output shorts - sustains operation without latch-off. |
| AM-band avoidance | Configurable >300kHz operation avoids interference with AM radio reception - critical for automotive infotainment compliance. |
| Thermally enhanced DFN | Exposed pad (Pin 15) tied to GND enables 4.3°C/W junction-to-case thermal resistance - supports 700mA/channel at 125°C ambient with proper PCB copper. |
Applications
| Automotive Infotainment Power | Industrial PLC I/O Module |
|---|---|
Use Scenario: Powering DSP, audio codec, and display controller in head-unit with 12V battery input subject to load-dump transients. IC Role / Device Role / Timing Role: Dual-output buck regulator providing isolated 3.3V (DSP core) and 5V (interface logic) rails with independent sequencing and fault recovery. Use Value: Overvoltage lockout at 38.5V and 60V transient tolerance prevent damage during ISO 7637-2 pulse 5a; soft-start prevents inrush into large display capacitors. | Use Scenario: Generating 5V and 3.3V from 24V industrial bus for microcontroller, analog front-end, and CAN transceiver. IC Role / Device Role / Timing Role: Compact dual-buck IC delivering stable, low-noise rails in space-constrained DIN-rail mounted PLC modules. Use Value: Adjustable switching frequency avoids noise coupling into sensitive analog inputs; thermal DFN package sustains full load at 85°C ambient. |
| Networking Equipment PoE PD | FPGA Core & I/O Supply |
Use Scenario: Secondary regulation stage after PoE interface IC (e.g., LT4275), converting 48V PoE-derived 12V to 5V/3.3V system rails. IC Role / Device Role / Timing Role: High-efficiency dual buck converter handling variable load from Ethernet PHY, MAC, and memory interfaces. Use Value: 95% max duty cycle supports operation during brownouts; cycle-by-cycle current limit protects against PHY short-circuits. | Use Scenario: Powering Xilinx Artix-7 FPGA requiring tightly regulated 1.0V core and 3.3V I/O rails from shared 12V input. IC Role / Device Role / Timing Role: Dual-channel buck supplying FPGA I/O bank (3.3V) and auxiliary logic (5V), with independent RUN/SS for power sequencing. Use Value: Independent soft-start prevents ground bounce during FPGA configuration; internal compensation eliminates external loop components. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar dual-output buck regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM5160QPWPRQ1 | Single-channel 65V buck with external FETs; no integrated switches or dual outputs. | Requires two ICs + MOSFETs for dual-rail; higher BOM cost but supports >700mA per rail. | Select when >700mA/channel or >36V input is required; not drop-in for LT3509EDE#TRPBF footprint or function. |
| TPS54290PWPR | Dual 600mA buck with 3.5–60V input; no integrated boost diodes; requires external bootstrap diodes. | Needs 4 external Schottky diodes and additional compensation components; lower thermal efficiency in DFN. | Choose when wider input range (up to 60V) is mandatory and board area allows added discretes. |
Compared with LM5160QPWPRQ1 and TPS54290PWPR, the LT3509EDE#TRPBF offers integrated dual 700mA switches, on-chip boost diodes, and single-resistor frequency setting - reducing component count and layout complexity for 3.6–36V dual-rail designs where 700mA/channel suffices.
Availability
LT3509EDE#TRPBF is available at Aetrix Electronics and suitable for automotive infotainment, industrial PLCs, networking equipment, FPGA power, and wall transformer regulation requiring stable component supply across extended temperature and transient conditions.
Supply support for LT3509EDE#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. (acquired Linear Technology in 2017) is a global leader in high-performance analog, mixed-signal, and power management semiconductors.
The LT3509EDE#TRPBF belongs to Linear's legacy high-voltage buck regulator product line, designed specifically for robust, compact dual-rail power conversion in automotive, industrial, and telecom applications with stringent transient and thermal requirements.
FAQ
What is the maximum input voltage rating for LT3509EDE#TRPBF?
The LT3509EDE#TRPBF has an absolute maximum VIN rating of 60V for non-repetitive 1-second transients, with guaranteed continuous operation from 3.6V to 36V. Its overvoltage lockout activates at ~38.5V typical, protecting internal circuitry during automotive load-dump events per ISO 7637-2.
Does LT3509EDE#TRPBF require external boost diodes?
No. The LT3509EDE#TRPBF integrates Schottky boost diodes connected to the BD pin, eliminating the need for external diodes in standard configurations. External diodes may only be considered for extreme duty cycles (>95%) or when BD is sourced from a low-voltage rail like 3.3V.
How is switching frequency set on LT3509EDE#TRPBF?
Switching frequency on the LT3509EDE#TRPBF is set by a single resistor (RT) from Pin 10 to GND. For example, a 40.2kΩ resistor yields ~1MHz. The device also supports external synchronization via the SYNC pin (Pin 11), provided the free-run frequency is set at least 12% lower than the sync source.
What thermal performance can be expected from LT3509EDE#TRPBF in its DFN package?
The LT3509EDE#TRPBF in the 14-lead DFN package achieves θJA = 43°C/W and θJC = 4.3°C/W when the exposed pad (Pin 15) is properly soldered to a thermal plane with ≥4 vias. This enables full 700mA/channel operation at up to 125°C junction temperature with adequate PCB copper area.
Can LT3509EDE#TRPBF operate with only one channel enabled?
Yes. The LT3509EDE#TRPBF supports independent channel control: pulling RUN/SS1 low disables Channel 1 while Channel 2 remains active if RUN/SS2 is high. When both RUN/SS pins are low, the common circuitry enters ultra-low-current shutdown (~9µA), minimizing quiescent draw in standby mode.
LT3509EDE#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-Down
- Output Configuration:
- Positive
- Topology:
- Buck
- Output Type:
- Adjustable
- Number of Outputs:
- 2
- Voltage - Input (Min):
- 3.6V
- Voltage - Input (Max):
- 36V
- Voltage - Output (Min/Fixed):
- 0.8V
- Voltage - Output (Max):
- 34.2V
- Current - Output:
- 700mA
- Frequency - Switching:
- 260kHz ~ 2.15MHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 14-DFN (4x3)
LT3509EDE#TRPBF FAQ
1.How can I place an order for LT3509EDE#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3509EDE#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 LT3509EDE#TRPBF reliable?
The price and inventory of LT3509EDE#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT3509EDE#TRPBF is usually 5 days.
3.What payment methods are accepted for LT3509EDE#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3509EDE#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3509EDE#TRPBF?
LT3509EDE#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3509EDE#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 LT3509EDE#TRPBF?
For technical support, including LT3509EDE#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3509EDE#TRPBF requirements.
6.How does Aetrix verify that LT3509EDE#TRPBF is sourced from the original manufacturer or authorized distributors?
All LT3509EDE#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 LT3509EDE#TRPBF meets industry standards.
7.What is the process for return or replacement of LT3509EDE#TRPBF?
All LT3509EDE#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3509EDE#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 LT3509EDE#TRPBF part is unused and in its original packaging.
Return procedure for LT3509EDE#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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