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Analog Devices Inc. LT3509EMSE#TRPBF
- Part No.:
- LT3509EMSE#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 16-TFSOP (0.118", 3.00mm Width) Exposed Pad
- Datasheet:
-
LT3509EMSE#TRPBF.pdf
- Description:
- IC REG BUCK ADJ 700MA DL 16MSOP
- Quantity:
- Payment:
- Shipping:
Inventory:8,220
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Product details
Overview
LT3509EMSE#TRPBF 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 on-chip compensation. It delivers independent 3.3V and 5V outputs in automotive and industrial power systems requiring robust transient immunity up to 60V and operation from –40°C to 125°C.
For engineers reviewing the LT3509EMSE#TRPBF datasheet, LT3509EMSE#TRPBF pinout, LT3509EMSE#TRPBF application, or LT3509EMSE#TRPBF equivalent, key selection criteria include its adjustable 300kHz–2.2MHz switching frequency, independent RUN/SS control per channel, overvoltage lockout at 38.5V (typ), and thermally enhanced 16-lead MSOP package with exposed pad.
Technical Context
The LT3509EMSE#TRPBF implements constant-frequency current-mode control with shared oscillator and reference across two independent channels operating in-phase. Each channel features cycle-by-cycle current limiting via internal main comparator and DA-pin valley-current monitoring, plus thermal shutdown and overvoltage/undervoltage protection.
Its boost architecture uses internal Schottky diodes (BD pin) and external capacitors to drive switch bases above VIN, enabling >95% duty cycle and low dropout operation. Frequency is set by RT resistor or synchronized externally via SYNC pin with ≥12% margin below target clock.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 3.6V to 36V continuous; withstands 60V transients - enables direct battery connection in 12V/24V automotive systems. |
| Output Current per Channel | 700mA - supports powering microcontrollers, sensors, and interface ICs without external pass devices. |
| Switching Frequency | 300kHz to 2.2MHz (adjustable via RT); synchronizable - avoids AM band interference and allows small 1–10µH inductors. |
| Feedback Reference Voltage | 0.800V ±2% (–40°C to 125°C) - enables precise output regulation with standard resistor dividers. |
| Overvoltage Lockout Threshold | 38.5V (typ) - protects internal switches and downstream circuitry during load-dump events. |
| Thermal Shutdown Temp | 150°C junction - safeguards against sustained overload or poor PCB thermal design. |
| Quiescent Current (Active) | 2.2mA (typ) - minimizes standby power loss in always-on subsystems. |
| Shutdown Current | 15µA (max) - enables ultra-low-power sleep modes in battery-backed applications. |
Pinout & Package
LT3509EMSE#TRPBF is housed in a 16-lead plastic MSOP package (4.0mm × 3.0mm) with exposed thermal pad (Pin 17 = GND). The package provides θJA = 43°C/W and requires soldering of the exposed pad to a PCB ground plane with thermal vias for reliable 700mA/channel operation at full temperature range.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| DA1, DA2 (Pins 1, 8) | Catch diode anode sense | Internally connected to GND via current-sense resistors; monitors valley inductor current for short-circuit protection. |
| BOOST1, BOOST2 (Pins 2, 7) | Bootstrap capacitor node | Tied to SW pins via external capacitors; supplies boosted gate drive to minimize switch VCE(SAT) and dropout. |
| SW1, SW2 (Pins 3, 6) | Power switch output | Drives external inductors; voltage swings from VIN to ~–0.7V during conduction; requires low-ESR ceramic input/output caps. |
| VIN (Pins 4, 5) | Main power input | Dual pins must be tied together; accepts 3.6–36V; bypassed with ≥10µF ceramic cap placed adjacent to pins. |
| FB1, FB2 (Pins 16, 9) | Output voltage feedback | Compares divider output to 0.8V reference; sets regulated VOUT; R2 ≤20kΩ recommended to limit bias error. |
| RUN/SS1, RUN/SS2 (Pins 15, 10) | Enable & soft-start control | 0.4–0.8V = shutdown; 0.8–2.0V = current-limited soft-start; >2.0V = full 700mA; 1µA internal pull-up enables float-to-run. |
| RT (Pin 11) | Oscillator timing | Resistor to GND sets fSW; 40.2kΩ = 1MHz; formula: RT(kΩ) = (1.215/fSW(MHz) − 0.215) × 40.2. |
| SYNC (Pin 12) | External clock input | 1.0V threshold; accepts CMOS/TTL; requires RT set ≥12% below sync frequency; tie to GND via ≤10kΩ if unused. |
| BD (Pin 13) | Boost diode common anode | Supplies charge current to BOOST caps; must be locally bypassed with 1µF ceramic; max 20V rating. |
| AGND (Pin 14) | Analog ground reference | Separate low-noise return for FB/RUN/SS/RT/SYNC; must connect to main GND plane but not carry high-current return paths. |
Key Features
| Feature | Design Value |
|---|---|
| Dual independent regulators | Enables simultaneous 3.3V/5V rails with separate enable, soft-start, and fault response - eliminates need for discrete sequencing logic. |
| Integrated boost diodes and compensation | Reduces BOM count by 4 diodes and 4–6 external compensation components - simplifies layout and improves reliability. |
| 95% maximum duty cycle | Supports <1V input-to-output differential (e.g., 5.5V → 5V) with minimal dropout - critical for post-regulation in low-headroom systems. |
| Short-circuit robustness | DA-pin current comparator limits valley inductor current to 0.95A (typ) during output shorts - prevents thermal runaway without external current sense. |
| Automotive-grade temp range | Specified from –40°C to 125°C junction - qualified for under-hood and infotainment applications without derating. |
| AM-band quiet operation | Configurable fSW >300kHz avoids 530–1710kHz broadcast band - eliminates radio interference in vehicle audio systems. |
Applications
| Automotive Infotainment Power | Industrial PLC I/O Module |
|---|---|
Use Scenario: Supplying 3.3V for MCU, CAN transceiver, and display controller alongside 5V for USB hub and audio codec in a vehicle head unit. IC Role / Device Role / Timing Role: Dual-output primary DC/DC regulator providing isolated, sequenced, and transient-hardened rails directly from 12V battery. Use Value: Withstands 60V load-dump transients and operates continuously at 105°C ambient - eliminates need for upstream TVS or derating. | Use Scenario: Generating 5V for fieldbus communication ICs and 3.3V for FPGA configuration and sensor ADCs in a DIN-rail mounted programmable logic controller. IC Role / Device Role / Timing Role: Compact, rugged point-of-load regulator replacing discrete buck controllers and external MOSFETs. Use Value: Integrated current limiting and thermal shutdown prevent field failures during wiring faults or ambient temperature excursions. |
| Networking Equipment Midspan PSE | FPGA Core & Auxiliary Power |
Use Scenario: Providing 5V auxiliary power and 3.3V logic rail for PoE midspan power sourcing equipment with wide 36–57V input range. IC Role / Device Role / Timing Role: Secondary regulator stepping down from intermediate 12V bus derived from active rectification. Use Value: Adjustable switching frequency allows optimization for EMI filtering while maintaining >90% efficiency at full load. | Use Scenario: Delivering 3.3V I/O bank power and 5V transceiver power for Xilinx Artix-7 FPGA in test instrumentation with strict ripple requirements. IC Role / Device Role / Timing Role: High-PID-stability current-mode regulator with internal compensation and low-noise AGND pin. Use Value: 10mV p-p output ripple (typ) at 700mA/1MHz enables clean FPGA operation without additional LDO post-regulation. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar dual-output step-down regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC3631EMSE#PBF | Single-channel, 36V, 1A; no integrated boost diodes; requires external bootstrap diodes; 200kHz–2MHz range. | Lacks dual independent outputs and DA-pin short-circuit protection; better suited for single-rail high-current designs. | Select when only one regulated rail is needed and board space permits external diodes. |
| TPS54240DGQR | Single-channel, 40V, 2.5A; external compensation; no integrated boost diodes; 100kHz–2.5MHz sync capable. | Higher current, wider VIN, but no dual output or valley-current fault detection; requires more external components. | Choose for cost-sensitive, high-current single-rail applications where sequencing is handled externally. |
Compared with LTC3631EMSE#PBF and TPS54240DGQR, the LT3509EMSE#TRPBF uniquely integrates dual 700mA regulators with on-chip boost diodes, DA-based short-circuit protection, and independent RUN/SS control - reducing component count and improving fault resilience in multi-rail embedded systems.
Availability
LT3509EMSE#TRPBF is available at Aetrix Electronics and suitable for automotive infotainment, industrial PLCs, and networking equipment requiring stable component supply across extended temperature and high-transient environments.
Supply support for LT3509EMSE#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. (ADI) is a global semiconductor leader specializing in high-performance analog, mixed-signal, and power management ICs for precision, reliability, and ruggedness-critical applications.
The LT3509EMSE#TRPBF belongs to ADI's legacy Linear Technology power management portfolio, designed specifically for harsh-environment DC/DC conversion in automotive, industrial, and telecom infrastructure where input transients, wide temperature range, and multi-rail integration are essential.
FAQ
What is the maximum input voltage transient the LT3509EMSE#TRPBF can survive?
The LT3509EMSE#TRPBF features overvoltage lockout that disables switching when VIN exceeds 38.5V (typical), and its absolute maximum VIN rating is 60V for non-repetitive 1-second transients. This allows direct connection to 12V or 24V automotive batteries while surviving ISO 7637-2 load-dump pulses. Continuous operation is rated up to 36V.
Can the LT3509EMSE#TRPBF generate both 3.3V and 5V outputs simultaneously?
Yes, the LT3509EMSE#TRPBF is explicitly designed for dual-output operation. Each channel has independent FB, RUN/SS, and BOOST pins, enabling simultaneous 3.3V and 5V regulation using standard resistor dividers (e.g., R1=30.1kΩ/R2=10kΩ for 3.3V; R1=51.1kΩ/R2=10kΩ for 5V), as confirmed in the Typical Application schematic (TA01a).
Does the LT3509EMSE#TRPBF require external boost diodes?
No, the LT3509EMSE#TRPBF integrates Schottky boost diodes connected to the BD pin - eliminating the need for external diodes. The BD pin supplies charge current to the BOOST1/BOOST2 capacitors, and the internal diodes are rated for 20V reverse voltage and 36mA forward current at 0.9A switch current, as specified in the Electrical Characteristics table.
What is the purpose of the AGND pin on the LT3509EMSE#TRPBF?
The AGND pin (Pin 14) on the LT3509EMSE#TRPBF provides a dedicated low-noise analog ground return for sensitive control circuitry - including FB, RUN/SS, RT, SYNC, and BD pins. It must be connected to the main system GND plane but should not carry high-current return paths (e.g., from SW or DA pins) to avoid noise coupling into regulation loops.
How does the LT3509EMSE#TRPBF handle short-circuit conditions on either output?
The LT3509EMSE#TRPBF uses DA-pin sensing to monitor valley inductor current. During a short, the DA comparator triggers at 0.95A (typical), forcing pulse skipping until the current falls below threshold. This limits power dissipation and prevents thermal runaway without external current-sense resistors or shutdown propagation between channels.
LT3509EMSE#TRPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 16-TFSOP (0.118", 3.00mm Width) 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:
- 16-MSOP-EP
LT3509EMSE#TRPBF FAQ
1.How can I place an order for LT3509EMSE#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3509EMSE#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 LT3509EMSE#TRPBF reliable?
The price and inventory of LT3509EMSE#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT3509EMSE#TRPBF is usually 5 days.
3.What payment methods are accepted for LT3509EMSE#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3509EMSE#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3509EMSE#TRPBF?
LT3509EMSE#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3509EMSE#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 LT3509EMSE#TRPBF?
For technical support, including LT3509EMSE#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3509EMSE#TRPBF requirements.
6.How does Aetrix verify that LT3509EMSE#TRPBF is sourced from the original manufacturer or authorized distributors?
All LT3509EMSE#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 LT3509EMSE#TRPBF meets industry standards.
7.What is the process for return or replacement of LT3509EMSE#TRPBF?
All LT3509EMSE#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3509EMSE#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 LT3509EMSE#TRPBF part is unused and in its original packaging.
Return procedure for LT3509EMSE#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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