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Analog Devices Inc. LT3437EDD#PBF
- Part No.:
- LT3437EDD#PBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 10-WFDFN Exposed Pad
- Datasheet:
-
LT3437EDD#PBF.pdf
- Description:
- IC REG BUCK ADJ 500MA 10DFN
- Quantity:
- Payment:
- Shipping:
Inventory:1,279
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Product details
Overview
LT3437EDD#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 LT3437EDD#PBF datasheet, LT3437EDD#PBF pinout, LT3437EDD#PBF application, or LT3437EDD#PBF equivalent, key selection considerations include its 80V transient-rated VIN, defeatable Burst Mode, soft-start via CSS pin, synchronous capability, and thermal performance in the 3mm × 3mm 10-pin DFN package with exposed GND pad.
Technical Context
The LT3437EDD#PBF 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 BOOST pin-driven saturated NPN switch, BIAS pin for efficiency optimization at high VIN/light load, and VC pin as error amplifier output and current limit reference.
Burst Mode operation reduces quiescent current to 100µA by disabling control circuitry during light loads, while SYNC pin logic-high disables Burst Mode for lower ripple. Shutdown draws <1µA, and FB voltage foldback below 0.9V disables synchronization and enables soft-start ramp control.
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 |
| Quiescent Current | 100µA in Burst Mode; <1µA in shutdown |
| Feedback Reference | 1.25V ±2.5% over –40°C to 125°C; sets output via resistor divider |
| Switching Frequency | 200kHz nominal; synchronizable from 240kHz to 700kHz |
| On-Resistance | 0.8Ω typical; achieved via BOOST-assisted saturation of internal NPN |
| Package Thermal Resistance | θJA = 45°C/W; θJC(PAD) = 10°C/W with soldered exposed pad |
Pinout & Package
LT3437EDD#PBF is housed in a thermally enhanced 10-pin 3mm × 3mm DFN package (0.75mm height) with exposed GND pad (Pin 11) requiring PCB soldering for thermal and electrical integrity.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN (Pin 2) | Input supply collector | Accepts 3.3V–60V; handles 80V transients; powers internal circuitry when BIAS is unconnected |
| SHDN (Pin 10) | Shutdown control | Logic-high (>1.3V) enables operation; logic-low places IC in <1µA shutdown state |
| BOOST (Pin 3) | Switch drive boost | Provides >VIN voltage to saturate internal NPN; requires external capacitor/diode network |
| VBIAS (Pin 6) | Efficiency bias supply | Connect to VOUT ≥2.7V to source internal bias current, improving light-load efficiency |
| SW (Pin 1) | Switch emitter | Drives external inductor; swings negative during off-time; requires Schottky catch diode |
| CSS (Pin 5) | Soft-start timing | Capacitor to VOUT sets dV/dt ramp rate; current threshold (4–16µA) scales with FB voltage |
| VC (Pin 7) | Error amp output | Controls peak switch current; clamped 0.45V–1.5V; grounding forces sleep mode |
| FB (Pin 8) | Feedback reference | Sets output voltage via resistor divider to 1.25V; triggers frequency foldback and soft-start below 0.9V |
| SYNC (Pin 9) | External sync input | Logic-compatible; disables Burst Mode when high; disables sync function if FB < 0.9V |
| GND (Pins 4, 11) | Power & signal ground | Pins 4 and 11 are internally connected; exposed pad (Pin 11) must be soldered to PCB ground plane |
Key Features
| Feature | Design Value |
|---|---|
| High-Voltage Input Capability | Rated for 60V continuous, 80V/100ms transients-enables direct connection to 14V/42V automotive and industrial rails without pre-regulation |
| Defeatable Burst Mode | SYNC pin logic-high disables low-IQ mode, reducing light-load output ripple at cost of higher quiescent current |
| Integrated Soft-Start Control | CSS pin + capacitor provides programmable output voltage ramp; prevents inrush current and input voltage sag during startup |
| Thermally Optimized DFN | 3mm × 3mm footprint with exposed GND pad achieves θJC = 10°C/W-critical for high-power density in space-constrained automotive modules |
| Current-Mode Stability | Peak-current sensing per cycle enables robust loop compensation and fast line/load transient response without external slope compensation |
Applications
| Automotive Power Management | Industrial DC-DC Conversion |
|---|---|
Use Scenario: Powering infotainment head units and ADAS sensors from 12V battery with cold-crank (4.5V) and load-dump (80V) immunity. IC Role / Device Role / Timing Role: Primary step-down regulator delivering stable 3.3V/5V from wide-input automotive rail. Use Value: 100µA Burst Mode IQ extends battery life during vehicle sleep; 80V transient rating eliminates need for external TVS clamping. | Use Scenario: Converting 24V/48V factory floor power to 5V for PLC I/O modules operating in ambient temperatures up to 125°C. IC Role / Device Role / Timing Role: High-reliability buck converter with guaranteed –40°C to 125°C operation and thermal shutdown protection. Use Value: Exposed-pad DFN package ensures low thermal resistance in sealed enclosures; current-mode control maintains regulation under rapid load steps. |
| Powered Ethernet (PoE) PD | Battery-Powered Instrumentation |
Use Scenario: Providing isolated 3.3V supply for PoE-powered IP cameras, accepting input from IEEE 802.3af/at PSE with up to 57V DC. IC Role / Device Role / Timing Role: Secondary-side DC-DC regulator after PoE interface IC, handling variable input from 37V–57V. Use Value: Wide 3.3V–60V input range accommodates PoE voltage drop and margin; SYNC pin allows system-level clock alignment. | Use Scenario: Powering portable gas analyzers with Li-ion battery (3.0–4.2V) and backup supercapacitor (up to 5.5V), requiring ultra-low standby current. IC Role / Device Role / Timing Role: Efficient buck converter maintaining regulated output during battery discharge and cold temperature operation. Use Value: 100µA Burst Mode IQ minimizes self-discharge; –40°C to 125°C rating ensures functionality in outdoor deployments. |
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 suited for compact, medium-input designs where 60V+ rating is unnecessary | Select LTC3639EMSE#PBF when board space is critical and input stays ≤40V; LT3437EDD#PBF remains preferred for 60V+ automotive/industrial rails. |
| MAX5033BASA+ | 76V max input, 500mA, 250kHz, no BIAS pin, higher IQ (250µA), no SYNC | Offers higher input voltage margin but lacks Burst Mode defeatability and soft-start flexibility | Choose MAX5033BASA+ only if absolute 76V transient tolerance is required and Burst Mode control is not needed. |
Compared with LTC3639EMSE#PBF and MAX5033BASA+, the LT3437EDD#PBF uniquely combines 60V continuous/80V transient input, defeatable Burst Mode, BOOST-assisted saturation for low RCE(SAT), and programmable soft-start-making it optimal for ruggedized 12V/24V/42V systems demanding both efficiency and fault resilience.
Availability
LT3437EDD#PBF is available at Aetrix Electronics and suitable for automotive power management, industrial DC-DC conversion, and Powered Ethernet powered device (PD) applications requiring stable component supply across extended temperature and voltage stress conditions.
Supply support for LT3437EDD#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 legacy of high-performance analog and power management ICs for demanding environments.
The LT3437EDD#PBF 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 range, and low quiescent current are critical.
FAQ
What is the maximum input voltage rating for LT3437EDD#PBF, and how does it handle transients?
The LT3437EDD#PBF is rated for 60V continuous input and withstands 80V/100ms transients-such as automotive load dump-without damage or regulation loss. This is achieved through internal overvoltage protection circuitry and robust process design, eliminating the need for external clamping components in most 12V/24V/42V systems. The LT3437EDD#PBF maintains regulation throughout the transient event when properly decoupled.
How does Burst Mode operation work in LT3437EDD#PBF, and can it be disabled?
Burst Mode in LT3437EDD#PBF reduces quiescent current to 100µA by cycling the control circuitry on/off at light loads. It is automatically enabled below ~10mA output current. Burst Mode can be fully disabled by applying a logic-high (>2V) signal to the SYNC pin, forcing continuous PWM operation with lower output ripple but higher light-load IQ. The LT3437EDD#PBF datasheet specifies this behavior in the Burst Mode Defeated waveform figures.
What is the role of the BOOST pin on LT3437EDD#PBF, and what external components are required?
The BOOST pin on LT3437EDD#PBF supplies a voltage higher than VIN to fully saturate the internal NPN power switch, reducing conduction loss and achieving 0.8Ω typical RCE(SAT). It requires an external flying capacitor (e.g., 100nF ceramic) and Schottky diode (e.g., BAS21) connected between SW and BOOST. The LT3437EDD#PBF datasheet shows this configuration in Figure 1 and specifies minimum BOOST voltage (1.8V) and current (11mA at 500mA SW current).
Can LT3437EDD#PBF be synchronized to an external clock, and what is the valid frequency range?
Yes, LT3437EDD#PBF supports external synchronization via the SYNC pin, which accepts logic-level inputs with 25–75% duty cycle. The valid synchronization range is 240kHz to 700kHz-extending beyond its native 200kHz frequency. Synchronization is disabled when FB voltage falls below 0.9V (e.g., during startup or overload), ensuring reliable soft-start and fault recovery. The LT3437EDD#PBF block diagram confirms SYNC's direct interface to the oscillator.
What thermal design considerations apply to LT3437EDD#PBF in its 10-pin DFN package?
The LT3437EDD#PBF uses a 3mm × 3mm DFN with exposed GND pad (Pin 11) that must be soldered to a PCB copper ground plane to achieve θJC = 10°C/W and θJA = 45°C/W. Thermal vias under the pad are recommended. Junction temperature must stay within –40°C to 125°C; derating is required above 85°C ambient. The LT3437EDD#PBF datasheet specifies thermal resistance values and soldering requirements in the Package/Order Information section.
LT3437EDD#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 10-WFDFN 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:
- 10-DFN (3x3)
LT3437EDD#PBF FAQ
1.How can I place an order for LT3437EDD#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3437EDD#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 LT3437EDD#PBF reliable?
The price and inventory of LT3437EDD#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT3437EDD#PBF is usually 5 days.
3.What payment methods are accepted for LT3437EDD#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3437EDD#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3437EDD#PBF?
LT3437EDD#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3437EDD#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 LT3437EDD#PBF?
For technical support, including LT3437EDD#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3437EDD#PBF requirements.
6.How does Aetrix verify that LT3437EDD#PBF is sourced from the original manufacturer or authorized distributors?
All LT3437EDD#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 LT3437EDD#PBF meets industry standards.
7.What is the process for return or replacement of LT3437EDD#PBF?
All LT3437EDD#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3437EDD#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 LT3437EDD#PBF part is unused and in its original packaging.
Return procedure for LT3437EDD#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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