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Analog Devices Inc. LT3437EDD#TRPBF
- Part No.:
- LT3437EDD#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 10-WFDFN Exposed Pad
- Datasheet:
-
LT3437EDD#TRPBF.pdf
- Description:
- IC REG BUCK ADJ 500MA 10DFN
- Quantity:
- Payment:
- Shipping:
Inventory:2,886
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Product details
Overview
LT3437EDD#TRPBF from Analog Devices (formerly Linear Technology) is a high-voltage, current-mode monolithic buck switching regulator with integrated 500mA NPN power switch, 0.8Ω on-resistance, and 200kHz fixed-frequency operation. It supports 3.3V–60V input, delivers regulated output down to 1.25V via external feedback, and maintains 100µA quiescent current in Burst Mode for automotive cold-crank and battery-powered systems.
For engineers reviewing the LT3437EDD#TRPBF datasheet, LT3437EDD#TRPBF pinout, LT3437EDD#TRPBF application, or LT3437EDD#TRPBF equivalent, key selection criteria include load-dump transient tolerance (80V), defeatable Burst Mode for ripple-sensitive loads, soft-start control via CSS pin, and thermal performance enabled by its exposed-pad 10-pin DFN package.
Technical Context
The LT3437EDD#TRPBF employs current-mode control with cycle-by-cycle peak current limiting and an internal 200kHz oscillator, enabling fast transient response and stable loop compensation. Its architecture integrates a saturating NPN switch driven by a BOOST capacitor to achieve low VCE(SAT) (400mV at 500mA) across wide duty cycles.
Burst Mode operation reduces quiescent current to 100µA at light loads by disabling non-essential circuitry while maintaining regulation; it can be disabled via logic-high SYNC signal to prioritize low-output-ripple over efficiency. Shutdown draws <1µA, and BIAS pin operation enables >90% efficiency at high VIN/VOUT ratios.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 3.3V to 60V continuous; withstands 80V/100ms transients for automotive load-dump protection |
| Switch Current Limit | 500mA typical peak; maintained across full duty cycle range for consistent overload handling |
| Quiescent Current | 100µA in Burst Mode; enables >1000-hour battery life in always-on 12V automotive modules |
| Feedback Reference | 1.25V ±2.5% over –40°C to 125°C; sets output voltage with standard resistor divider |
| Switching Frequency | 200kHz ±20%; fixed-frequency operation simplifies EMI filtering and avoids audio-band noise |
| Package Thermal Resistance | θJA = 45°C/W; exposed pad soldered to PCB ground plane required for safe 125°C junction operation |
| Shutdown Current | <1µA; enables ultra-low-power system-level sleep states without disconnecting input supply |
Pinout & Package
LT3437EDD#TRPBF uses a thermally enhanced 10-pin (3mm × 3mm) DFN package with exposed GND pad (Pin 11). The package height is 0.75mm, and the exposed pad must be soldered to PCB ground for thermal and electrical integrity.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| SW (Pin 1) | Switch emitter node | Connects to inductor and catch diode cathode; carries full switched current; requires low-inductance layout |
| VIN (Pin 2) | Input power collector | Supplies internal circuitry when BIAS is unconnected; handles high di/dt edges-must be decoupled locally |
| BOOST (Pin 3) | Switch driver boost supply | Accepts external capacitor-diode charge pump; enables saturation of NPN switch for low conduction loss |
| GND (Pin 4) | Main ground reference | Reference for FB, VC, and output regulation; must tie directly to load ground to avoid load regulation error |
| CSS (Pin 5) | Soft-start timing control | Capacitor to output sets dV/dt ramp rate; disables soft-start above 0.9V FB voltage |
| BIAS (Pin 6) | Efficiency-boost bias supply | When connected to regulated output ≥2.7V, shifts internal bias current from VIN to improve light-load efficiency |
| VC (Pin 7) | Error amplifier output | Controls peak switch current; used for loop compensation, current clamping, or forced shutdown when pulled to GND |
| FB (Pin 8) | Feedback input | Senses output via resistor divider; triggers frequency foldback below 0.4V and disables SYNC below 0.9V |
| SYNC (Pin 9) | External synchronization input | Logic-compatible input (25–75% duty); disables Burst Mode and enables external clock sync up to 700kHz |
| SHDN (Pin 10) | Enable/disable control | Logic-high (>1.3V) enables regulator; logic-low places IC in sub-1µA shutdown state |
Key Features
| Feature | Design Value |
|---|---|
| Load-dump tolerant input | Withstands 80V/100ms transients per ISO 7637-2, eliminating need for external TVS in 12V/24V automotive designs |
| Defeatable Burst Mode | SYNC pin logic-high disables Burst Mode, reducing light-load output ripple at cost of higher quiescent current |
| Integrated soft-start | CSS pin capacitor controls output voltage ramp rate, preventing inrush current and input voltage sag during startup |
| BIAS pin efficiency optimization | Diverts internal bias current from VIN to regulated output, improving efficiency by up to 15% at VIN = 48V, VOUT = 3.3V |
| Current-mode control | Enables stable operation with wide input/output ranges and fast line/load transient response without complex compensation |
Applications
| Automotive Infotainment Power Supply | Industrial 24V DC-DC Converter |
|---|---|
Use Scenario: Powering FPGA, DSP, and display controllers in head units with cold-crank (4.5V) and load-dump (80V) conditions. IC Role / Device Role / Timing Role: Primary step-down regulator delivering 3.3V/400mA with Burst Mode active during standby to meet ISO 16750-2 quiescent current requirements. Use Value: Eliminates need for external surge protection and enables single-stage conversion from 12V/24V battery rails, reducing BOM count and board area. | Use Scenario: Converting 24V factory bus to 5V for PLC I/O modules operating in ambient temperatures up to 85°C. IC Role / Device Role / Timing Role: High-reliability buck controller with 125°C rated junction temperature and thermal shutdown, managing continuous 300mA loads. Use Value: Maintains regulation during brownouts (down to 3.3V input) and survives 80V transients without latch-up, ensuring uptime in harsh industrial environments. |
| Powered Ethernet (PoE) PD Interface | Portable Medical Instrument DC-DC Stage |
Use Scenario: Providing isolated 3.3V/200mA bias for PoE-powered IP cameras with IEEE 802.3af/at compliance. IC Role / Device Role / Timing Role: Secondary-side post-regulator accepting 36–57V PoE input, using SYNC pin to align switching with primary-side controller for reduced EMI. Use Value: Enables deterministic switching frequency synchronization and eliminates audible noise in quiet surveillance environments. | Use Scenario: Battery-powered ultrasound probe requiring low-noise 5V rail with <100µA standby draw for multi-day operation. IC Role / Device Role / Timing Role: Main power converter operating in Burst Mode during idle periods, with soft-start preventing sensor bias disruption at wake-up. Use Value: Achieves >1000-hour battery life on two AA cells while meeting medical EMC standards via fixed 200kHz frequency and clean start-up behavior. |
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 |
|---|---|---|---|
| LTC3639EMSE#PBF | 40V max input, 500mA, 3MHz switching, integrated MOSFETs; no BOOST pin; lower IQ (25µA) | Better for space-constrained, high-frequency designs; lacks 80V transient rating and BIAS pin efficiency boost | Select LTC3639 for compact 5V/3.3V point-of-load where input stays ≤40V and ultra-low IQ dominates |
| MAX5033BASA+T | 76V max input, 500mA, 125kHz, no Burst Mode, 2.5mA IQ; SO-8 package | Higher thermal resistance (θJA = 120°C/W); suitable for cost-sensitive industrial use but not automotive transients | Select MAX5033B for legacy industrial designs needing simple drop-in replacement without soft-start or sync capability |
Compared with LTC3639EMSE#PBF and MAX5033BASA+T, the LT3437EDD#TRPBF uniquely combines 80V transient tolerance, defeatable Burst Mode, and BIAS pin efficiency optimization-making it the only choice for automotive-grade 12V/24V systems requiring both robustness and ultra-low standby power.
Availability
LT3437EDD#TRPBF is available at Aetrix Electronics and suitable for automotive infotainment, industrial 24V power systems, and Powered Ethernet device designs requiring stable component supply across extended temperature and transient stress conditions.
Supply support for LT3437EDD#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 continues its legacy of high-performance analog and power management ICs for demanding applications.
The LT3437EDD#TRPBF belongs to Linear's high-voltage monolithic buck regulator product line, designed specifically for automotive, industrial, and telecom power systems where input transients, wide VIN ranges, and low quiescent current are critical.
FAQ
What is the maximum input voltage rating for LT3437EDD#TRPBF during transient conditions?
The LT3437EDD#TRPBF is rated for 80V input transients lasting up to 100ms with duty cycle <15%, per Absolute Maximum Ratings. This allows direct connection to 12V and 24V automotive batteries without external TVS diodes during load-dump events defined in ISO 7637-2. Continuous operation remains limited to 60V.
How does the BIAS pin improve efficiency in LT3437EDD#TRPBF designs?
The BIAS pin on the LT3437EDD#TRPBF allows routing the internal bias current from VIN to the regulated output when connected to ≥2.7V. At VIN = 48V and VOUT = 3.3V, this reduces total input current by ~0.75mA, increasing light-load efficiency by up to 15%. The BIAS pin must not float and should be bypassed with a 0.1µF capacitor.
Can LT3437EDD#TRPBF synchronize to an external clock, and what is the valid frequency range?
Yes, the LT3437EDD#TRPBF accepts external synchronization on the SYNC pin with logic-level inputs (25–75% duty cycle) from 240kHz to 700kHz. Synchronization disables Burst Mode and forces continuous switching. When FB voltage drops below 0.9V, SYNC functionality is automatically disabled to preserve soft-start and fault recovery behavior.
What is the purpose of the BOOST pin in LT3437EDD#TRPBF, and how is it implemented?
The BOOST pin on the LT3437EDD#TRPBF supplies a boosted gate drive voltage to the internal NPN switch, enabling full saturation and minimizing VCE(SAT). It is implemented with an external flying capacitor (e.g., 100nF ceramic) and Schottky diode (e.g., BAS21) from SW to BOOST. Minimum BOOST voltage is 1.8V at 500mA switch current.
Does LT3437EDD#TRPBF support adjustable soft-start, and how is it configured?
Yes, LT3437EDD#TRPBF supports programmable soft-start via a capacitor from the CSS pin to the output. The capacitor value sets the output voltage ramp rate (dV/dt); larger values yield slower ramps. Soft-start is automatically disabled when FB voltage exceeds 0.9V, and CSS threshold current scales with FB voltage per the datasheet's Typical Performance Characteristics.
LT3437EDD#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:
- 0°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 10-DFN (3x3)
LT3437EDD#TRPBF FAQ
1.How can I place an order for LT3437EDD#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3437EDD#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 LT3437EDD#TRPBF reliable?
The price and inventory of LT3437EDD#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT3437EDD#TRPBF is usually 5 days.
3.What payment methods are accepted for LT3437EDD#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3437EDD#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3437EDD#TRPBF?
LT3437EDD#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3437EDD#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 LT3437EDD#TRPBF?
For technical support, including LT3437EDD#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3437EDD#TRPBF requirements.
6.How does Aetrix verify that LT3437EDD#TRPBF is sourced from the original manufacturer or authorized distributors?
All LT3437EDD#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 LT3437EDD#TRPBF meets industry standards.
7.What is the process for return or replacement of LT3437EDD#TRPBF?
All LT3437EDD#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3437EDD#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 LT3437EDD#TRPBF part is unused and in its original packaging.
Return procedure for LT3437EDD#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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