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Analog Devices Inc. LT3437IDD#PBF
- Part No.:
- LT3437IDD#PBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 10-WFDFN Exposed Pad
- Datasheet:
-
LT3437IDD#PBF.pdf
- Description:
- IC REG BUCK ADJ 500MA 10DFN
- Quantity:
- Payment:
- Shipping:
Inventory:1,490
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Product details
Overview
LT3437IDD#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 LT3437IDD#PBF datasheet, LT3437IDD#PBF pinout, LT3437IDD#PBF application, or LT3437IDD#PBF equivalent, key selection criteria include input transient tolerance (80V load dump), thermally enhanced 10-pin DFN package with exposed GND pad, defeatable Burst Mode for ripple-sensitive loads, and synchronous capability up to 700kHz.
Technical Context
The LT3437IDD#PBF employs current-mode control with cycle-by-cycle peak current limiting and internal 2.4V bias rail, enabling fast transient response and stable loop compensation across wide input/output conditions. Its patented architecture maintains constant peak switch current over full duty cycle range and uses BOOST pin voltage (up to 85V transient) to fully saturate the internal NPN switch.
Burst Mode operation reduces quiescent current to 100µA at light loads by disabling control circuitry, while logic-high SYNC signal disables Burst Mode for lower output ripple. Soft-start is implemented via CSS pin capacitor, with threshold current (4–16µA) proportional to FB voltage and disabled above 0.9V.
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; guaranteed ≥400mA over –40°C to 125°C junction temperature |
| Quiescent Current | 100µA in Burst Mode; <1µA in shutdown; enables >10-year battery life in always-on monitoring systems |
| Switching Frequency | 200kHz nominal; adjustable 140–240kHz over temperature; synchronizable to 240–700kHz external clock |
| Feedback Reference | 1.25V ±1.2% over –40°C to 125°C; sets output voltage via resistor divider with 50nA input bias |
| On-Resistance | 0.8Ω typical at ISW = 250mA; enables high efficiency at 12V→3.3V/400mA conversion (≥85% typical) |
| Package Thermal Resistance | θJA = 45°C/W, θJC(PAD) = 10°C/W; requires soldered exposed pad to PCB ground plane for thermal management |
Pinout & Package
LT3437IDD#PBF is housed in a 3mm × 3mm, 10-pin thermally enhanced DFN package (0.75mm height) with exposed GND pad (Pin 11) that must be soldered to PCB ground for thermal and electrical integrity.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Pin 1 (SW) | Switch emitter | Connects to inductor; swings negative during off-time; requires Schottky catch diode |
| Pin 2 (VIN) | Power switch collector & supply input | Accepts 3.3–60V; handles 80V transients; high di/dt node requiring short PCB trace to input cap |
| Pin 3 (BOOST) | Switch driver boost supply | Requires external capacitor/diode; supplies >35V to saturate NPN switch; 85V max transient rating |
| Pin 4 (GND) | Analog and power ground reference | Reference for FB, VC, and output regulation; must tie to low-impedance ground plane |
| Pin 5 (CSS) | Soft-start current sense | Capacitor to VOUT sets dV/dt ramp rate; current threshold (4–16µA) scales with FB voltage |
| Pin 6 (BIAS) | Efficiency-boost bias supply | Connect to VOUT ≥2.7V to reduce VIN current draw and improve light-load efficiency |
| Pin 7 (VC) | Error amplifier output / current limit control | 0.45V (light load) to 1.5V (full load); clamped at 1.5–2.1V; drives switch current trip point |
| Pin 8 (FB) | Feedback input | Senses 1.25V reference; enables frequency foldback (<0.4V) and soft-start activation (<0.9V) |
| Pin 9 (SYNC) | External synchronization input | Logic-compatible; disables Burst Mode when >2V; accepts 25–75% duty cycle signals up to 700kHz |
| Pin 10 (SHDN) | Shutdown control | Active-high; 1.1–1.5V threshold; reduces supply current to <1µA when pulled low |
| Pin 11 (Exposed Pad) | Thermal & electrical GND | Must be soldered to PCB ground plane; provides primary thermal path (θJC = 10°C/W) |
Key Features
| Feature | Design Value |
|---|---|
| Load dump protection | Withstands 80V/100ms input transients without derating-critical for 12V/24V automotive systems |
| Defeatable Burst Mode | SYNC pin logic-high disables Burst Mode to reduce light-load output ripple at expense of quiescent current |
| Thermally optimized DFN | 3mm × 3mm package with exposed GND pad achieves θJA = 45°C/W-enables compact high-power density designs |
| Current-mode control | Provides inherent cycle-by-cycle current limiting, fast line/load transient response, and simplified loop compensation |
| Wide input range operation | Starts at 2.5V and regulates continuously to 60V-supports 14V/42V automotive, industrial, and PoE applications |
Applications
| Automotive Infotainment Power Supply | Industrial Sensor Node DC-DC Converter |
|---|---|
Use Scenario: Powering 3.3V microcontroller and CAN transceiver in vehicle head unit under cold-crank (4.5V) and load-dump (80V) conditions. IC Role / Device Role / Timing Role: Primary buck regulator providing regulated 3.3V from 12V battery rail with transient immunity and ultra-low quiescent current. Use Value: Maintains system operation during 4.5V cold-crank dips and survives 80V load dumps without external TVS, reducing BOM count and board space. | Use Scenario: Converting 24V industrial bus to 5V for analog sensor front-end and low-power MCU in harsh factory environment. IC Role / Device Role / Timing Role: High-input-voltage step-down regulator delivering stable 5V with minimal heat rise in confined enclosures. Use Value: 0.8Ω switch RDS(on) and thermally enhanced DFN enable >85% efficiency at 500mA, reducing thermal stress in sealed housings. |
| Powered Ethernet (PoE) PD Converter | Battery-Powered IoT Gateway |
Use Scenario: Generating 3.3V/400mA from IEEE 802.3af/at PoE interface (up to 57V) for wireless SoC and RF front-end. IC Role / Device Role / Timing Role: Primary DC-DC converter accepting wide-range PoE input and delivering tightly regulated low-noise output. Use Value: 200kHz fixed frequency simplifies EMI filtering; Burst Mode extends standby time between wake-ups in energy-harvesting nodes. | Use Scenario: Powering cellular modem, GPS, and sensors in remote asset tracker operating from single Li-ion cell (3.0–4.2V) or dual-cell pack (6–8.4V). IC Role / Device Role / Timing Role: Efficient buck regulator supporting wide input range and ultra-low IQ for multi-year battery life. Use Value: 100µA Burst Mode IQ enables >10-year shelf life; soft-start prevents inrush current damage to aging battery cells. |
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 switch, 3MHz switching, no BOOST pin, integrated MOSFETs | Better for compact, high-frequency, medium-current apps; lacks 60V+ input and load-dump robustness | Select when input ≤40V and higher frequency/size reduction outweighs automotive transient requirements |
| MPQ4333HG-AEC1-P | 60V input, 3.5A switch, 100kHz–2.5MHz sync, AEC-Q200 qualified, no Burst Mode | Higher current, automotive-grade; higher IQ (250µA) and no ultra-low-power sleep mode | Select for AEC-Q200 compliance and >500mA loads where 100µA IQ is not mandatory |
Compared with LTC3642EMSE#PBF and MPQ4333HG-AEC1-P, the LT3437IDD#PBF uniquely balances 60V input, 80V transient tolerance, 100µA Burst Mode IQ, and thermally optimized DFN-making it optimal for space-constrained automotive and industrial converters needing both ruggedness and ultra-low standby power.
Availability
LT3437IDD#PBF is available at Aetrix Electronics and suitable for automotive infotainment, industrial sensor nodes, and powered Ethernet power delivery requiring stable component supply, long-term lifecycle support, and guaranteed −40°C to +125°C operation.
Supply support for LT3437IDD#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, Inc. (ADI) is a global leader in high-performance analog, mixed-signal, and power management semiconductors, formed through the acquisition of Linear Technology in 2017.
The LT3437IDD#PBF belongs to ADI's high-voltage monolithic DC/DC converter product line, designed specifically for automotive, industrial, and PoE applications demanding wide input range, transient robustness, and ultra-low quiescent power.
FAQ
What is the maximum input voltage rating for LT3437IDD#PBF during transient conditions?
The LT3437IDD#PBF supports 80V/100ms input transients with <15% duty cycle, enabling direct use in automotive 12V/24V systems subject to load dump events per ISO 7637-2. Continuous operation is rated to 60V. Exceeding 80V-even briefly-risks permanent damage per Absolute Maximum Ratings.
How does the BOOST pin function in LT3437IDD#PBF and what external components are required?
The BOOST pin on LT3437IDD#PBF supplies elevated gate drive to fully saturate the internal NPN switch, reducing conduction loss. It requires an external flying capacitor (e.g., 100nF ceramic) and Schottky diode (e.g., BAS21) from SW to BOOST. BOOST voltage must exceed VIN by ≥3.3V during switch on-time to guarantee saturation.
Can LT3437IDD#PBF operate with input voltage below 3.3V, and what is the minimum startup voltage?
The LT3437IDD#PBF has a minimum input voltage of 2.5V for switching initiation, but regulated output requires sufficient headroom-e.g., 3.3V output needs ≥4.5V input at full load. Startup is guaranteed down to 2.5V; however, sustained regulation depends on output voltage, load current, and BIAS pin configuration.
What is the purpose of the CSS pin on LT3437IDD#PBF and how is soft-start configured?
The CSS pin on LT3437IDD#PBF controls soft-start by sensing current through an external capacitor connected to VOUT. A 10nF–100nF capacitor sets the output voltage ramp rate; CSS current threshold (4–16µA) scales with FB voltage and disables above 0.9V. This prevents inrush current and input voltage overshoot during power-up.
Does LT3437IDD#PBF require external compensation, and what is the recommended approach for loop stability?
Yes, LT3437IDD#PBF requires external compensation via the VC pin. A Type II network (resistor + capacitor from VC to GND, plus series RC from VC to FB) is standard. Compensation values depend on inductor value, output capacitance, and ESR. ADI's LT3437 demo board DC1157A provides validated component values for common 3.3V/5V outputs.
LT3437IDD#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:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 10-DFN (3x3)
LT3437IDD#PBF FAQ
1.How can I place an order for LT3437IDD#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3437IDD#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 LT3437IDD#PBF reliable?
The price and inventory of LT3437IDD#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT3437IDD#PBF is usually 5 days.
3.What payment methods are accepted for LT3437IDD#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3437IDD#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3437IDD#PBF?
LT3437IDD#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3437IDD#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 LT3437IDD#PBF?
For technical support, including LT3437IDD#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3437IDD#PBF requirements.
6.How does Aetrix verify that LT3437IDD#PBF is sourced from the original manufacturer or authorized distributors?
All LT3437IDD#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 LT3437IDD#PBF meets industry standards.
7.What is the process for return or replacement of LT3437IDD#PBF?
All LT3437IDD#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3437IDD#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 LT3437IDD#PBF part is unused and in its original packaging.
Return procedure for LT3437IDD#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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