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Analog Devices Inc. LT3437IDD#TRPBF
- Part No.:
- LT3437IDD#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 10-WFDFN Exposed Pad
- Datasheet:
-
LT3437IDD#TRPBF.pdf
- Description:
- IC REG BUCK ADJ 500MA 10DFN
- Quantity:
- Payment:
- Shipping:
Inventory:4,758
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Product details
Overview
LT3437IDD#TRPBF from Analog Devices (formerly Linear Technology) is a high-voltage, current-mode monolithic buck switching regulator optimized for automotive and industrial power systems. It delivers 500mA peak switch current, operates from 3.3V to 60V input, maintains 100µA quiescent current in Burst Mode, features 200kHz fixed-frequency operation, and integrates a 0.8Ω on-resistance NPN switch - enabling robust 14V/42V automotive load-dump protection and efficient battery-powered system conversion.
For engineers reviewing the LT3437IDD#TRPBF datasheet, LT3437IDD#TRPBF pinout, LT3437IDD#TRPBF application, or LT3437IDD#TRPBF equivalent, key selection criteria include its 80V transient-rated VIN, defeatable Burst Mode for ripple-sensitive light-load operation, soft-start via CSS pin, SYNC capability up to 700kHz, and thermal performance in the 3mm × 3mm 10-pin DFN package with exposed GND pad.
Technical Context
The LT3437IDD#TRPBF employs current-mode control with cycle-by-cycle peak current limiting and an internal 200kHz oscillator, delivering fast transient response and stable loop behavior across wide input/output conditions. Its architecture uses a BOOST capacitor to saturate the integrated NPN switch, reducing VCE(SAT) to 400mV at 500mA while maintaining peak switch current over full duty cycle range.
Burst Mode operation reduces quiescent current to 100µA by disabling non-essential circuitry during light loads; this mode is defeatable via logic-high signal on SYNC, trading efficiency for lower output ripple. Shutdown draws <1µA, and FB voltage regulation is referenced to a precise 1.25V bandgap with ±2.5% tolerance over –40°C to 125°C.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 3.3V to 60V continuous; withstands 80V/100ms transients - supports 12V/24V/42V automotive and industrial rails with load-dump immunity. |
| Output Current | 500mA peak switch current - enables compact 3.3V/5V/12V step-down designs without external MOSFETs. |
| Quiescent Current | 100µA in Burst Mode - extends battery life in always-on vehicle modules and IoT edge nodes. |
| Switch On-Resistance | 0.8Ω typical - minimizes conduction loss and thermal rise in high-input-voltage buck stages. |
| Feedback Reference | 1.25V ±2.5% - ensures accurate output regulation across temperature and line/load variations. |
| Switching Frequency | 200kHz nominal (140–240kHz range) - balances EMI, inductor size, and efficiency for cost-sensitive industrial converters. |
| Package | 10-pin 3mm × 3mm DFN with exposed GND pad - achieves θJA = 45°C/W for reliable operation at 125°C junction temperature. |
Pinout & Package
The LT3437IDD#TRPBF is housed in a thermally enhanced 10-pin (3mm × 3mm) DFN package with exposed GND pad (Pin 11), requiring soldering to PCB ground plane for thermal and electrical integrity. Pin 4 is also GND; both pins must be connected to system ground.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Pin 1 (SW) | Switch emitter | Connects to inductor and catch diode cathode; carries full switched current; requires low-inductance layout. |
| Pin 2 (VIN) | Input supply collector | Primary power input for internal circuitry and switch; rated to 80V transient; bypass with 2.2µF ceramic. |
| Pin 3 (BOOST) | Switch drive boost | Accepts external boost capacitor/diode to raise gate drive above VIN - enables saturation of internal NPN switch. |
| Pin 4 (GND) | Power/Signal ground | Reference for FB, VC, and output regulation; must tie directly to exposed pad and load return path. |
| Pin 5 (CSS) | Soft-start control | Sinks current proportional to FB voltage; capacitor to VOUT sets controlled dV/dt ramp rate during startup. |
| Pin 6 (BIAS) | Efficiency bias supply | Accepts regulated output voltage ≥2.7V to source internal bias current - improves light-load efficiency at high VIN/VOUT ratios. |
| Pin 7 (VC) | Error amplifier output | Drives switch current limit threshold; used for compensation, current clamping, or forced shutdown when pulled to GND. |
| Pin 8 (FB) | Feedback input | Monitors resistive divider output; 1.25V reference sets VOUT = 1.25V × (1 + R1/R2); enables frequency foldback below 0.9V. |
| Pin 9 (SYNC) | External sync input | Logic-compatible input (1.5–6V) accepting 240–700kHz external clock; disables Burst Mode when high. |
| Pin 10 (SHDN) | Shutdown control | Active-high enable; >1.3V required to exit shutdown; draws <1µA in shutdown state. |
Key Features
| Feature | Design Value |
|---|---|
| Load-dump protected input | Withstands 80V/100ms transients per ISO 7637-2 - eliminates need for external TVS in 14V/42V automotive designs. |
| Defeatable Burst Mode | SYNC pin logic-high disables Burst Mode, reducing light-load output ripple at cost of higher IQ - critical for noise-sensitive analog supplies. |
| Thermally optimized DFN | Exposed GND pad and θJC(PAD) = 10°C/W enable 125°C continuous operation without heatsink in space-constrained modules. |
| Integrated soft-start | CSS pin current threshold scales with FB voltage - provides automatic, load-independent dV/dt control without external timers. |
| Current-mode stability | Single-pole compensation via VC pin - simplifies loop design and ensures stability across wide input/output/inductor ranges. |
Applications
| Automotive Body Control Module | Industrial PLC I/O Power |
|---|---|
Use Scenario: Powering microcontrollers, CAN transceivers, and sensor interfaces in door modules and lighting controllers under cold-crank (4.5V) and load-dump (80V) conditions. IC Role / Device Role / Timing Role: Primary 5V/3.3V buck regulator with integrated transient protection and ultra-low-IQ sleep mode. Use Value: Eliminates discrete TVS and external soft-start circuitry while maintaining 100µA quiescent current for battery drain compliance. | Use Scenario: Generating isolated 5V rails for digital I/O conditioning circuits in programmable logic controllers operating from 24V DC field buses. IC Role / Device Role / Timing Role: High-reliability step-down converter with 125°C rated operation and robust EMI performance. Use Value: Enables compact, fanless enclosure designs with no derating required up to ambient 85°C. |
| Distributed Telecom Power | Battery-Powered Test Equipment |
Use Scenario: Local 3.3V conversion for FPGA configuration and Ethernet PHYs in remote radio units powered from 48V PoE or -48V telecom supplies. IC Role / Device Role / Timing Role: Wide-input buck regulator supporting both positive and negative input configurations via external diode routing. Use Value: Delivers 500mA output with 200kHz switching - avoids audible noise and simplifies filtering vs. lower-frequency alternatives. | Use Scenario: Supplying precision ADCs and op-amps in handheld multimeters and portable oscilloscopes powered by Li-ion batteries (3.0–4.2V) or 9V alkaline packs. IC Role / Device Role / Timing Role: Efficient step-down regulator with Burst Mode disabled via SYNC to minimize measurement noise floor. Use Value: Achieves <10mVPP output ripple at 100mA load - preserves 16-bit ADC accuracy without post-regulation LDOs. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar high-voltage buck regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC3642EMSE#PBF | 40V max input, 1.2A output, 3MHz switching, integrated MOSFETs - higher frequency, lower current, no BOOST pin. | Better suited for compact, high-density 5V/3.3V point-of-load where input ≤40V and efficiency at 1A matters more than 80V transients. | Select LTC3642EMSE#PBF when board space is constrained and input voltage never exceeds 40V; avoid for automotive load-dump environments. |
| MAX5033BASA+T | 76V max input, 500mA, 125kHz, no Burst Mode, no SYNC, larger SO-8 package - simpler control but higher IQ (250µA). | Ideal for cost-sensitive industrial AC/DC auxiliary supplies where synchronization and ultra-low IQ are not required. | Select MAX5033BASA+T for legacy designs needing drop-in replacement with minimal layout change and no soft-start tuning. |
Compared with LTC3642EMSE#PBF and MAX5033BASA+T, the LT3437IDD#TRPBF uniquely combines 80V transient tolerance, defeatable Burst Mode, and BOOST-assisted saturation in a 3mm × 3mm DFN - making it the only choice for space-limited automotive modules requiring both robustness and low-noise light-load operation.
Availability
LT3437IDD#TRPBF is available at Aetrix Electronics and suitable for automotive body electronics, industrial PLC power supplies, and distributed telecom systems requiring stable component supply across extended temperature and high-reliability qualification cycles.
Supply support for LT3437IDD#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 technical and manufacturing continuity for the LT® product family, known for high-performance analog and power management ICs.
The LT3437IDD#TRPBF belongs to Linear's high-voltage monolithic buck regulator product line, designed specifically for automotive, industrial, and battery-powered systems demanding wide input range, transient resilience, and ultra-low quiescent current.
FAQ
What is the maximum input voltage rating for LT3437IDD#TRPBF during transient conditions?
The LT3437IDD#TRPBF supports 80V for 100ms transients with <15% duty cycle, meeting ISO 7637-2 Pulse 5a requirements for 12V automotive systems. Continuous operation is rated to 60V. This transient rating allows direct connection to vehicle batteries without external TVS diodes in most body electronics applications. The LT3437IDD#TRPBF achieves this via proprietary high-voltage process and internal clamp structures.
How does Burst Mode operation work in LT3437IDD#TRPBF, and how can it be disabled?
Burst Mode in LT3437IDD#TRPBF reduces quiescent current to 100µA by cycling the controller on/off at light loads, minimizing switching losses. It is automatically active below ~10mA load and can be disabled by applying a logic-high signal (>2V) to the SYNC pin - forcing continuous 200kHz operation and lowering output ripple at the expense of higher IQ. The LT3437IDD#TRPBF datasheet specifies this behavior in the Burst Mode Operation section.
What is the purpose of the BOOST pin on LT3437IDD#TRPBF, and what external components are required?
The BOOST pin on LT3437IDD#TRPBF supplies elevated drive voltage to fully saturate the internal NPN power switch, reducing VCE(SAT) from ~1.5V to 400mV at 500mA. It requires an external flying capacitor (typically 100nF ceramic) and Schottky diode (e.g., BAS21) connected between SW and BOOST. The LT3437IDD#TRPBF datasheet Figure 1 shows the standard BOOST network and specifies minimum boost voltage (1.8V) for full saturation.
Can LT3437IDD#TRPBF be synchronized to an external clock, and what is the valid frequency range?
Yes, the LT3437IDD#TRPBF supports external synchronization via its SYNC pin, accepting logic-level inputs (1.5–6V) with 25–75% duty cycle across 240kHz to 700kHz. Synchronization disables Burst Mode and forces continuous operation. The LT3437IDD#TRPBF maintains stable regulation across this range, with typical max sync frequency of 500kHz at 125°C per electrical characteristics table.
What thermal considerations apply to the LT3437IDD#TRPBF's exposed pad in the DFN package?
LT3437IDD#TRPBF's exposed pad (Pin 11) is electrically GND and must be soldered to a PCB copper ground plane to achieve θJA = 45°C/W and θJC(PAD) = 10°C/W. Insufficient solder coverage or missing thermal vias will cause junction temperature to exceed 125°C under 500mA load. The LT3437IDD#TRPBF datasheet Application Information section mandates soldering both Pin 4 and the exposed pad to GND for thermal and electrical integrity.
LT3437IDD#TRPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 10-WFDFN Exposed Pad
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Function:
- Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck
- Output Type:
- Adjustable
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 3V
- Voltage - Input (Max):
- 60V
- Voltage - Output (Min/Fixed):
- 1.25V
- Voltage - Output (Max):
- 57V
- Current - Output:
- 500mA (Switch)
- Frequency - Switching:
- 200kHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 10-DFN (3x3)
LT3437IDD#TRPBF FAQ
1.How can I place an order for LT3437IDD#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3437IDD#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 LT3437IDD#TRPBF reliable?
The price and inventory of LT3437IDD#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT3437IDD#TRPBF is usually 5 days.
3.What payment methods are accepted for LT3437IDD#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3437IDD#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3437IDD#TRPBF?
LT3437IDD#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3437IDD#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 LT3437IDD#TRPBF?
For technical support, including LT3437IDD#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3437IDD#TRPBF requirements.
6.How does Aetrix verify that LT3437IDD#TRPBF is sourced from the original manufacturer or authorized distributors?
All LT3437IDD#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 LT3437IDD#TRPBF meets industry standards.
7.What is the process for return or replacement of LT3437IDD#TRPBF?
All LT3437IDD#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3437IDD#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 LT3437IDD#TRPBF part is unused and in its original packaging.
Return procedure for LT3437IDD#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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