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Analog Devices Inc. LT3437EFE#PBF
- Part No.:
- LT3437EFE#PBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 16-TSSOP (0.173", 4.40mm Width) Exposed Pad
- Datasheet:
-
LT3437EFE#PBF.pdf
- Description:
- IC REG BUCK ADJ 500MA 16TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:1,264
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Product details
Overview
LT3437EFE#PBF 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 LT3437EFE#PBF datasheet, LT3437EFE#PBF pinout, LT3437EFE#PBF application, or LT3437EFE#PBF equivalent, key selection criteria include input transient tolerance (80V load dump), thermally enhanced 16-pin TSSOP package with exposed pad, defeatable Burst Mode, soft-start control via CSS pin, and compatibility with high-side synchronous rectification using external diode.
Technical Context
The LT3437EFE#PBF implements constant-frequency current-mode control with cycle-by-cycle peak current limiting and internal 2.4V bias rail. Its architecture uses BOOST pin voltage (up to 85V transient) to fully saturate the internal NPN switch, reducing conduction loss versus standard bipolar designs.
It integrates Burst Mode operation that reduces supply current to 45µA at light loads while maintaining fast transient response via VC pin clamping; shutdown draws <1µA. Synchronization (240–700kHz) and soft-start (CSS-controlled dV/dt ramp) are implemented without external compensation components.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 3.3V to 60V continuous; withstands 80V/100ms transients (load dump) |
| Switch Current Limit | 500mA typical peak; maintained across full duty cycle range for stable light/heavy load behavior |
| Quiescent Current | 100µA in Burst Mode; enables >10-year battery life in always-on automotive modules |
| Switching Frequency | 200kHz nominal; adjustable via SYNC pin (240–700kHz) for EMI optimization |
| Feedback Reference | 1.25V ±2.5mV over –40°C to 125°C; enables precise output regulation with standard resistor dividers |
| On-Resistance | 0.8Ω typical at ISW = 250mA; reduces conduction loss in high-input-voltage step-down stages |
| Thermal Resistance | θJC(PAD) = 10°C/W; requires soldered exposed pad to PCB ground plane for thermal reliability |
Pinout & Package
LT3437EFE#PBF uses a 16-lead plastic TSSOP package (FE) with exposed pad (Pin 17) tied to GND. The package measures 5mm × 4.4mm × 1.1mm and features low thermal resistance for high-power density applications in constrained automotive and industrial layouts.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN (Pin 4) | Power input collector | Accepts up to 60V continuous; handles 80V/100ms transients; connects to input bypass capacitor and catch diode anode |
| SW (Pin 2) | Switch emitter | Drives external inductor; swings negative during off-time; requires Schottky catch diode cathode connection |
| BOOST (Pin 6) | Switch driver boost supply | Must be ≥3.3V above VIN; supplies gate drive for NPN saturation; clamped at 85V max |
| GND (Pins 8, 17) | Signal and thermal reference | Exposed pad (Pin 17) must be soldered to PCB ground plane; forms primary thermal path and output regulation reference |
| FB (Pin 12) | Output voltage sense | Compares divider output to 1.25V reference; enables frequency foldback below 0.4V and disables SYNC below 0.9V |
| VC (Pin 11) | Error amplifier output | Controls peak switch current; clamped at 1.5–2.1V; driven to ground to force shutdown |
| CSS (Pin 9) | Soft-start ramp control | Current threshold (4–16µA) sets dV/dt limit; disabled when FB > 0.9V; requires capacitor to VOUT |
| SYNC (Pin 14) | External clock input | Logic-compatible (1.5–6V); disables Burst Mode when high; synchronizes oscillator up to 700kHz |
| SHDN (Pin 15) | Enable/disable control | Active-high; 1.1–1.5V threshold; reduces supply current to <1µA when low |
| BIAS (Pin 10) | Efficiency-boost supply | Connects to VOUT ≥2.7V to source internal bias current; improves efficiency at high VIN/VOUT ratios |
Key Features
| Feature | Design Value |
|---|---|
| Load dump protection | Withstands 80V/100ms input transients without derating or external clamping |
| Defeatable Burst Mode | SYNC pin logic-high disables Burst Mode, reducing light-load output ripple at cost of higher IQ |
| Controlled soft-start | CSS pin current threshold (4–16µA) sets output dV/dt; prevents inrush into large capacitive loads |
| Thermally optimized package | Exposed pad (Pin 17) provides θJC = 10°C/W; mandatory soldering ensures 125°C junction operation |
| Frequency foldback | Reduces switching frequency 10:1 when FB < 0.4V; protects IC and external diode during short-circuit faults |
Applications
| Automotive Body Control Module | Industrial 24V DC-DC Conversion |
|---|---|
Use Scenario: Powering microcontrollers and CAN transceivers in door modules under cold-crank (4.5V) and load-dump (80V) conditions. IC Role / Device Role / Timing Role: Primary 5V/3.3V step-down regulator with integrated switch and transient robustness. Use Value: Eliminates need for external TVS and pre-regulator; maintains regulation across full vehicle battery range. | Use Scenario: Converting 24V factory bus to 5V for PLC I/O modules operating in high-noise environments. IC Role / Device Role / Timing Role: High-efficiency buck converter with EMI-controllable 200kHz switching and SYNC capability. Use Value: Reduces thermal footprint vs discrete solutions; exposed pad enables conduction cooling on metal-core PCBs. |
| Battery-Powered Telematics Unit | Powered Ethernet (PoE) Midspan Supply |
Use Scenario: Regulating Li-ion (3.0–4.2V) or lead-acid (9–15V) battery to 3.3V for GPS/GSM modules with multi-year standby. IC Role / Device Role / Timing Role: Ultra-low-IQ buck regulator enabling >10-year battery life in sleep mode. Use Value: 100µA Burst Mode IQ extends runtime; BIAS pin connection to VOUT further improves light-load efficiency. | Use Scenario: Generating isolated 3.3V/5V rails from PoE midspan 48V supply in network switches. IC Role / Device Role / Timing Role: High-input-voltage buck controller supporting wide VIN range and transient immunity. Use Value: Withstands 80V surges common in PoE cabling; BOOST pin enables efficient operation at 48V input. |
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; 1.2MHz switching; integrated MOSFET; no BOOST pin | Lower input voltage range; higher frequency enables smaller magnetics; less suitable for 60V+ automotive | Select LTC3642EMSE#PBF for space-constrained 24V systems requiring higher efficiency at medium loads |
| LM5164QPWPRQ1 | 65V max input; 100V transient rating; integrated MOSFET; 1.5A switch current | Higher peak current; wider temperature range (–40°C to 150°C); AEC-Q100 qualified | Select LM5164QPWPRQ1 for new automotive designs requiring qualification and higher output current |
Compared with LTC3642EMSE#PBF and LM5164QPWPRQ1, LT3437EFE#PBF offers superior load-dump immunity (80V/100ms), lower quiescent current in Burst Mode (100µA vs 120µA), and unique BOOST-driven NPN saturation for reduced conduction loss at high VIN, making it optimal for legacy 14V/42V automotive platforms.
Availability
LT3437EFE#PBF is available at Aetrix Electronics and suitable for automotive body electronics, industrial 24V power systems, and battery-powered telematics requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for LT3437EFE#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-reliability analog and power management portfolio with rigorous automotive and industrial qualification standards.
The LT3437 product line delivers high-voltage monolithic buck regulators targeting harsh-environment applications where input transients, thermal constraints, and ultra-low quiescent current are critical design parameters.
FAQ
What is the maximum input voltage rating for LT3437EFE#PBF during transient conditions?
The LT3437EFE#PBF is rated for 80V input transients with <15% duty cycle and duration ≤100ms, specifically designed to survive automotive load-dump events without external protection circuitry. This rating applies to both VIN and SHDN pins. Continuous operation remains limited to 60V, and exceeding 80V even briefly risks permanent damage per Absolute Maximum Ratings.
How does the BOOST pin function in LT3437EFE#PBF and what external components are required?
The BOOST pin in LT3437EFE#PBF supplies elevated drive voltage to the internal NPN switch base, enabling full saturation and minimizing VCE(sat). It requires an external flying capacitor (typically 10nF ceramic) and Schottky diode (e.g., BAS21) connected between SW and BOOST. BOOST voltage must exceed VIN by ≥3.3V and remain ≤75V during operation; transient rating is 85V/100ms.
Can LT3437EFE#PBF operate with input voltage below 3.3V, and what is the minimum startup voltage?
The LT3437EFE#PBF has a specified minimum continuous input voltage of 3.3V, but can start switching at ~2.5V (per Electrical Characteristics table). However, regulation cannot be maintained below ~3.0V depending on output voltage and load. For reliable operation at cold-crank (e.g., 4.5V), the device functions normally; sub-3V inputs require validation of output stability and dropout behavior per Figure 3437 G19.
What is the purpose of the CSS pin in LT3437EFE#PBF and how is soft-start configured?
The CSS pin in LT3437EFE#PBF controls soft-start by sourcing current into an external capacitor connected to VOUT. When CSS current exceeds 4–16µA (threshold proportional to FB voltage), the VC pin is clamped to limit dV/dt. A typical 10nF capacitor yields ~10ms ramp time. Soft-start is automatically disabled when FB > 0.9V, ensuring normal operation after startup.
Is LT3437EFE#PBF pin-compatible with other variants in the LT3437 family such as LT3437IFE#PBF?
Yes, LT3437EFE#PBF is pin-compatible with LT3437IFE#PBF and LT3437HFE#PBF - all share identical 16-pin TSSOP (FE) package, pinout, and electrical interface. The differences lie solely in guaranteed temperature range (EFE: –40°C to 125°C; IFE: same range with full testing; HFE: –40°C to 140°C) and minor parameter tolerances per datasheet tables.
LT3437EFE#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 16-TSSOP (0.173", 4.40mm Width) Exposed Pad
- Packaging:
- Tube
- 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:
- 16-TSSOP-EP
LT3437EFE#PBF FAQ
1.How can I place an order for LT3437EFE#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3437EFE#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 LT3437EFE#PBF reliable?
The price and inventory of LT3437EFE#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT3437EFE#PBF is usually 5 days.
3.What payment methods are accepted for LT3437EFE#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3437EFE#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3437EFE#PBF?
LT3437EFE#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3437EFE#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 LT3437EFE#PBF?
For technical support, including LT3437EFE#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3437EFE#PBF requirements.
6.How does Aetrix verify that LT3437EFE#PBF is sourced from the original manufacturer or authorized distributors?
All LT3437EFE#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 LT3437EFE#PBF meets industry standards.
7.What is the process for return or replacement of LT3437EFE#PBF?
All LT3437EFE#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3437EFE#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 LT3437EFE#PBF part is unused and in its original packaging.
Return procedure for LT3437EFE#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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