My Inquiry
My Account
Analog Devices Inc. LT3509EDE#PBF
- Part No.:
- LT3509EDE#PBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 14-WFDFN Exposed Pad
- Datasheet:
-
LT3509EDE#PBF.pdf
- Description:
- IC REG BUCK ADJ 700MA DL 14DFN
- Quantity:
- Payment:
- Shipping:
Inventory:2,547
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
LT3509EDE#PBF from Analog Devices (formerly Linear Technology) is a dual-channel, current-mode, 36V-input synchronous step-down DC/DC regulator with integrated 700mA power switches per channel, internal boost diodes and compensation, operating from 3.6V to 36V input and delivering independently regulated 3.3V and 5V outputs - widely used in automotive infotainment power rails and industrial control subsystems.
For engineers reviewing the LT3509EDE#PBF datasheet, LT3509EDE#PBF pinout, LT3509EDE#PBF application, or LT3509EDE#PBF equivalent, key selection considerations include its 300kHz–2.2MHz adjustable switching frequency, overvoltage lockout up to 60V transients, thermally enhanced 14-lead DFN package, independent RUN/SS control per channel, and integrated boost circuitry enabling >95% duty cycle operation.
Technical Context
The LT3509EDE#PBF implements a dual-channel, constant-frequency, current-mode control architecture with shared oscillator and reference but independent error amplifiers, soft-start, and cycle-by-cycle current limiting. Each channel features dedicated FB, RUN/SS, BOOST, SW, and DA pins, enabling precise output voltage regulation and fault management.
Its internal boost diode (BD pin) supplies charge to external BOOST capacitors, allowing gate drive above VIN for low dropout operation; minimum on-time is 80ns and maximum duty cycle reaches 95%, supporting high step-down ratios without pulse-skipping under full load at moderate frequencies.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 3.6V to 36V continuous; withstands 60V non-repetitive transients - enables direct connection to 24V/36V automotive or industrial bus rails. |
| Output Current per Channel | 700mA continuous - sufficient for powering microcontrollers, sensors, and interface ICs in multi-rail embedded systems. |
| Switching Frequency | Adjustable 300kHz to 2.2MHz via RT resistor; synchronizable externally - allows EMI optimization and ceramic capacitor use. |
| Feedback Reference Voltage | 0.800V ±2% over temperature - sets output voltage accuracy via resistor divider; supports 1.8V–12V outputs. |
| Overvoltage Lockout Threshold | 38.5V typical - protects internal switches and downstream loads during load-dump events in automotive applications. |
| Thermal Shutdown Junction Temp | 125°C (E-grade) - activates to prevent permanent damage; device resumes operation after cooldown with soft-start. |
| Package | 14-lead (4mm × 3mm) plastic DFN with exposed GND pad - provides θJA = 43°C/W for reliable operation in compact, convection-cooled layouts. |
Pinout & Package
LT3509EDE#PBF uses the DE14 (14-lead, 4mm × 3mm) plastic DFN package with exposed thermal pad (Pin 15) soldered to PCB ground. The package supports high-power density and efficient heat dissipation in space-constrained designs.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| FB1, FB2 | Output voltage feedback input | Connects to resistor divider to regulate each output at 0.8V reference; determines VOUT = 0.8V × (1 + R1/R2). |
| RUN/SS1, RUN/SS2 | Channel enable & soft-start control | Pull <0.4V to disable; 0.8–2.0V enables with current-limited soft-start; >2.0V enables full 700mA output. |
| SW1, SW2 | Power switch output | Drives external inductor; connects to cathode of catch diode and BOOST capacitor; carries peak switch current up to 1.4A. |
| BOOST1, BOOST2 | Boost capacitor node | Tied to SW pin through 0.1µF ceramic capacitor; enables gate drive above VIN for low RDS(on) and high efficiency. |
| DA1, DA2 | Catch diode anode sense | Internally connected to GND via current-sense resistor; monitors valley inductor current for short-circuit protection. |
| BD | Common boost diode anode | Supplies charge current to both BOOST capacitors; must be bypassed locally with 1µF ceramic capacitor. |
| VIN | Main power input | Supplies control circuitry and power switches; accepts 3.6–36V; requires low-ESR input capacitor near pins 4 and 12. |
| RT | Oscillator timing input | Resistor to GND sets switching frequency: 40.2kΩ → 1MHz; 15.8kΩ → 2MHz; supports synchronization via SYNC pin. |
| SYNC | External clock input | Accepts logic-level clock ≥1.0V threshold; free-run frequency must be ≥12% below sync source for stable locking. |
| GND (Exposed Pad) | Power and signal reference | Pin 15 is exposed thermal pad; must be soldered to large PCB ground plane with ≥4 thermal vias for thermal performance. |
Key Features
| Feature | Design Value |
|---|---|
| Dual independent regulators | Two fully functional 700mA buck channels sharing reference and oscillator - eliminates need for two discrete converters in dual-rail systems. |
| Integrated boost diodes and compensation | Reduces BOM count by 4 diodes and 2 compensation networks - simplifies layout and improves reliability in harsh environments. |
| Overvoltage lockout to 60V | Survives automotive load-dump transients without external TVS - reduces system-level protection component count. |
| 95% maximum duty cycle | Enables operation down to VIN ≈ VOUT + 0.5V - supports low-dropout behavior critical for battery-powered or brownout-prone systems. |
| Independent shutdown and soft-start | Per-channel RUN/SS pins allow staggered power-up, sequencing, and fault isolation - essential for FPGA/CPU core-and-I/O rail coordination. |
Applications
| Automotive Infotainment Power | Industrial PLC I/O Module |
|---|---|
Use Scenario: Powering 3.3V MCU, 5V CAN transceiver, and display backlight in vehicle head unit exposed to 12V/24V battery variations and load-dump transients. IC Role / Device Role: Dual-output primary DC/DC regulator providing isolated, sequenced, and transient-hardened rails. Use Value: Eliminates need for external TVS and discrete boost diodes while maintaining regulation during 60V transients and cold-crank down to 3.6V. | Use Scenario: Generating 3.3V logic and 5V sensor interface power in DIN-rail mounted programmable logic controller with wide input range and EMI constraints. IC Role / Device Role: Compact, high-efficiency dual buck converter with adjustable frequency to avoid AM-band interference. Use Value: Enables use of small 2.2µH inductors and ceramic output caps, reducing board area by >40% vs. legacy controllers. |
| Networking Edge Router Board | FPGA Core & Auxiliary Power |
Use Scenario: Supplying 3.3V PHY and 5V USB port power in fanless enterprise switch operating from 48V PoE-derived supply. IC Role / Device Role: Secondary regulation stage converting intermediate 12V rail to clean, low-noise point-of-load voltages. Use Value: Synchronization capability allows alignment with system clock to suppress beat frequencies and simplify EMI filtering. | Use Scenario: Delivering 1.8V core and 3.3V I/O power to Xilinx Artix-7 FPGA in test equipment requiring precise power sequencing and fault reporting. IC Role / Device Role: Dual-channel regulator with independent RUN/SS pins enabling controlled ramp-up of core before I/O. Use Value: Built-in cycle-by-cycle current limit and DA-based short-circuit detection prevent FPGA latch-up during hot-plug events. |
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 |
|---|---|---|---|
| LTC3631EMSE#PBF | Single-channel, 36V, 1A buck with integrated MOSFETs; no dual output or BD pin; requires external diodes. | Suitable only when one regulated rail is needed; lacks independent soft-start and overvoltage lockout to 60V. | Select if single-rail simplicity outweighs need for dual outputs and transient robustness. |
| TPS65270PWP | Dual 3A/2A buck with PMBus interface, 4.5–18V input, no 36V rating or 60V transient tolerance. | Targets data center and telecom; lacks automotive-grade OVP and wide VIN range required for industrial/automotive use. | Choose only for lower-voltage, digitally controlled systems where telemetry and higher current are priorities. |
Compared with LTC3631EMSE#PBF and TPS65270PWP, the LT3509EDE#PBF uniquely combines dual 700mA outputs, 36V input with 60V transient survival, integrated boost diodes, and independent RUN/SS control - making it the only option among the three qualified for unregulated 24V automotive or 36V industrial bus applications requiring dual-rail sequencing and ruggedness.
Availability
LT3509EDE#PBF is available at Aetrix Electronics and suitable for automotive electronics, industrial controls, and networking devices requiring stable component supply across extended temperature and voltage ranges.
Supply support for LT3509EDE#PBF 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 its high-performance analog and power management portfolio with rigorous automotive and industrial qualification standards.
The LT3509EDE#PBF belongs to Linear's high-voltage monolithic buck regulator product line, designed specifically for robust, compact DC/DC conversion in electrically noisy, wide-input-voltage environments such as automotive, transportation, and factory automation.
FAQ
What is the maximum input voltage transient the LT3509EDE#PBF can survive?
The LT3509EDE#PBF is rated for non-repetitive 60V transients on the VIN pin for up to 1 second, with continuous operation supported from 3.6V to 36V. This 60V transient rating meets ISO 7637-2 Pulse 5a requirements for 24V automotive systems, enabling direct connection to battery rails without external TVS diodes in many implementations.
Does the LT3509EDE#PBF require external catch diodes?
No, the LT3509EDE#PBF does not require external catch diodes. It integrates Schottky boost diodes connected to the BD pin and uses internal current-sense resistors on the DA pins to monitor catch diode conduction - eliminating four external diodes and simplifying layout while maintaining short-circuit robustness.
How is output voltage set on the LT3509EDE#PBF?
Each output voltage is set independently using a resistor divider from VOUT to FBx (x = 1 or 2), configured so the FB pin voltage equals the internal 0.800V reference. For example, a 3.3V output uses R1 = 31.6kΩ and R2 = 10.2kΩ; the datasheet specifies R2 ≤ 20kΩ to minimize bias current error.
Can the LT3509EDE#PBF operate with input voltage close to the output voltage?
Yes, the LT3509EDE#PBF supports >95% duty cycle operation due to its integrated boost architecture, enabling regulation with VIN as low as ~3.8V for a 3.3V output and ~5.5V for a 5V output under full load - making it suitable for battery-powered systems experiencing deep discharge or brownout conditions.
What thermal management is required for the LT3509EDE#PBF in continuous 700mA operation?
The LT3509EDE#PBF requires the exposed thermal pad (Pin 15) to be soldered to a minimum 100mm² PCB copper area with ≥4 thermal vias to internal ground planes. At 700mA per channel and 12V input, junction temperature rise is ~43°C/W; derating is recommended above 85°C ambient to maintain 125°C max junction temperature.
LT3509EDE#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 14-WFDFN Exposed Pad
- Packaging:
- Tube
- 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#PBF FAQ
1.How can I place an order for LT3509EDE#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3509EDE#PBF 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#PBF reliable?
The price and inventory of LT3509EDE#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT3509EDE#PBF is usually 5 days.
3.What payment methods are accepted for LT3509EDE#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3509EDE#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3509EDE#PBF?
LT3509EDE#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3509EDE#PBF 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#PBF?
For technical support, including LT3509EDE#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3509EDE#PBF requirements.
6.How does Aetrix verify that LT3509EDE#PBF is sourced from the original manufacturer or authorized distributors?
All LT3509EDE#PBF 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#PBF meets industry standards.
7.What is the process for return or replacement of LT3509EDE#PBF?
All LT3509EDE#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3509EDE#PBF, 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#PBF part is unused and in its original packaging.
Return procedure for LT3509EDE#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LT3509EDE#PBF 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…
