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Analog Devices Inc. LT3437EFE#TRPBF
- Part No.:
- LT3437EFE#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 16-TSSOP (0.173", 4.40mm Width) Exposed Pad
- Datasheet:
-
LT3437EFE#TRPBF.pdf
- Description:
- IC REG BUCK ADJ 500MA 16TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:3,075
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Product details
Overview
LT3437EFE#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, sustains 80V load-dump transients, features 100µA quiescent current in Burst Mode, and uses a 0.8Ω on-resistance NPN switch in a thermally enhanced 16-pin TSSOP package with exposed pad. It regulates 3.3V/400mA outputs in 14V automotive systems.
For engineers reviewing the LT3437EFE#TRPBF datasheet, LT3437EFE#TRPBF pinout, LT3437EFE#TRPBF application, or LT3437EFE#TRPBF equivalent, key selection criteria include input transient robustness (80V), light-load efficiency (100µA IQ), synchronous capability, soft-start control via CSS pin, and thermal performance enabled by the exposed GND pad.
Technical Context
The LT3437EFE#TRPBF implements fixed-frequency (200kHz) current-mode control with cycle-by-cycle peak current limiting and an internal 1.25V reference. Its architecture integrates a high-voltage NPN power switch, oscillator, error amplifier, slope compensation, and burst-mode logic - all operating from a 2.4V internal bias rail derived from VIN or external BIAS pin.
It employs BOOST pin-driven saturation enhancement to maintain low VCE(SAT) across wide duty cycles, supports external synchronization up to 700kHz via the SYNC pin, and features frequency foldback below 0.4V FB voltage to limit power dissipation during short-circuit conditions.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 3.3V to 60V continuous; withstands 80V/100ms transients - enables direct connection to 12V/24V/42V automotive rails including load dump. |
| Output Current | 500mA peak switch current - supports stable 400mA regulated output with margin for transient loads. |
| Quiescent Current | 100µA in Burst Mode - extends battery life in always-on vehicle modules (e.g., CAN gateways, telematics). |
| Switch On-Resistance | 0.8Ω typical - minimizes conduction loss at high input-to-output voltage ratios (e.g., 14V→3.3V). |
| Feedback Reference | 1.25V ±2.5% over –40°C to 125°C - ensures accurate output regulation across automotive temperature range. |
| Switching Frequency | 200kHz ±20% - balances EMI control, inductor size, and efficiency for compact DC/DC designs. |
| Thermal Resistance | θJA = 45°C/W, θJC(PAD) = 10°C/W - requires exposed pad soldered to PCB ground plane for reliable 125°C junction operation. |
Pinout & Package
LT3437EFE#TRPBF is housed in a 16-lead plastic TSSOP package (FE grade) with exposed thermal pad (Pin 17 = GND). The package measures 5mm × 4.4mm × 1.1mm and is rated for –40°C to 125°C operating junction temperature. Exposed pad must be soldered to PCB ground plane for thermal and electrical integrity.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Pin 1 (NC) | No Connection | Electrically isolated; may be used for mechanical stability or layout routing - no circuit function. |
| Pin 2 (SW) | Switch Emitter | Connects to inductor and catch diode cathode; carries full switched current; clamped externally to prevent negative swing. |
| Pin 3 (NC) | No Connection | Electrically isolated; no internal connection - safe to tie to ground or leave floating. |
| Pin 4 (VIN) | Power Input / Switch Collector | Supplies internal circuitry and powers NPN switch collector; handles high di/dt - requires local 2.2µF ceramic bypass. |
| Pin 5 (NC) | No Connection | Electrically isolated; no internal connection - safe to tie to ground or leave floating. |
| Pin 6 (BOOST) | Boost Drive Supply | Accepts voltage ≥3.3V above VIN to saturate NPN switch; requires external boost capacitor + Schottky diode. |
| Pin 7 (NC) | No Connection | Electrically isolated; no internal connection - safe to tie to ground or leave floating. |
| Pin 8 (GND) | Analog & Power Ground | Reference for FB, VC, and output regulation; must be low-impedance path to load ground to avoid load regulation error. |
| Pin 9 (NC) | No Connection | Electrically isolated; no internal connection - safe to tie to ground or leave floating. |
| Pin 10 (SHDN) | Shutdown Control | Logic-compatible enable; >1.3V activates regulator; <0.8V reduces supply current to <1µA. |
| Pin 11 (SYNC) | External Sync Input | Accepts 25–75% duty-cycle logic-level signal up to 700kHz; disables Burst Mode when high. |
| Pin 12 (FB) | Feedback Input | Senses output via resistor divider; 1.25V reference sets VOUT; triggers frequency foldback and soft-start below 0.9V. |
| Pin 13 (VC) | Error Amplifier Output | Controls peak switch current; used for loop compensation; clamped at 1.5–2.1V; drives to ~0.45V at light load. |
| Pin 14 (BIAS) | Efficiency Boost Supply | Accepts regulated output (≥2.7V) to power internal circuitry - improves efficiency at high VIN/light load. |
| Pin 15 (CSS) | Soft-Start Control | Current-sourced node; capacitor to VOUT sets dV/dt ramp rate; threshold scales with FB voltage. |
| Pin 16 (NC) | No Connection | Electrically isolated; no internal connection - safe to tie to ground or leave floating. |
| Pin 17 (Exposed Pad) | Thermal & Electrical GND | Mandatory solder connection to PCB ground plane; primary thermal path - failure to solder degrades θJA by >30°C/W. |
Key Features
| Feature | Design Value |
|---|---|
| Load-Dump Transient Protection | Withstands 80V/100ms input transients without latch-up or degradation - meets ISO 7637-2 Pulse 5a requirements for 12V automotive systems. |
| Burst Mode Operation | Reduces quiescent current to 100µA at no load while maintaining regulation - critical for always-on vehicle ECUs with strict sleep-current budgets. |
| Defeatable Burst Mode | SYNC pin logic-high disables Burst Mode, eliminating low-frequency output ripple at cost of higher light-load IQ - enables clean power for noise-sensitive analog circuits. |
| Controlled Soft-Start | CSS pin current threshold (4–16µA) scales with FB voltage, enabling programmable dV/dt ramp independent of output voltage - prevents inrush into large capacitive loads. |
| High-Voltage NPN Switch | Integrated 0.8Ω on-resistance switch with BOOST-assisted saturation - achieves >85% efficiency at 14V→3.3V/400mA without external MOSFET. |
| Frequency Foldback Protection | Switching frequency drops to ~20kHz when FB < 0.4V - limits power dissipation in IC and external components during output short-circuit events. |
Applications
| Automotive Infotainment Power | Industrial Sensor Node Supply |
|---|---|
Use Scenario: Powers 3.3V microcontroller, CAN transceiver, and display driver in 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 rail with transient immunity and low-noise Burst Mode operation during vehicle sleep. Use Value: Eliminates need for external TVS and pre-regulator stages; maintains 100µA IQ during CAN bus monitoring to meet UNECE R100 Class 3 sleep-current limits. | Use Scenario: Supplies 5V/200mA to wireless sensor node (LoRaWAN, NB-IoT) operating from 24V industrial rail with brownout risk. IC Role / Device Role / Timing Role: High-input-voltage step-down converter with programmable soft-start and frequency foldback for fault-tolerant field deployment. Use Value: Survives 80V surges on factory floor wiring; soft-start prevents reset during power-up; foldback protects against sensor short-circuits without shutdown. |
| Powered Ethernet (PoE) PD Interface | 14V Battery-Powered Telematics |
Use Scenario: Generates 3.3V/300mA for PoE-powered device (e.g., IP camera) receiving up to 57V from IEEE 802.3af/at PSE. IC Role / Device Role / Timing Role: Secondary DC/DC stage after PoE interface IC, handling wide-input-range conversion with high efficiency. Use Value: Operates across full PoE voltage range (37–57V); 0.8Ω switch and BOOST drive minimize dropout and heat rise in confined enclosure. | Use Scenario: Powers GPS module and cellular modem in vehicle black box during engine-off monitoring (12.8V nominal, down to 9V cold crank). IC Role / Device Role / Timing Role: Main system regulator delivering stable 3.3V with ultra-low IQ and fast transient response to handle modem burst transmissions. Use Value: 100µA Burst Mode IQ extends 12Ah battery life to >1 year in sleep; 200kHz switching enables small 100µH inductor footprint. |
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, 3mm × 4mm MSOP; no BOOST pin; uses MOSFET switch | Lacks 80V transient rating and automotive temp grade; better suited for non-automotive 24V systems | Select if input never exceeds 40V and higher output current is needed; not drop-in for LT3437EFE#TRPBF's 60V/80V use cases. |
| MAX5033BASA+T | 76V max input, 500mA, SO-8; no Burst Mode; 2.5mA IQ; fixed 1.25V ref | Higher quiescent current eliminates battery-backed operation; lacks soft-start and sync capability | Select for cost-sensitive industrial supplies where 100µA IQ is unnecessary and layout space is constrained to SO-8 footprint. |
Compared with LTC3642EMSE#PBF and MAX5033BASA+T, the LT3437EFE#TRPBF uniquely combines 80V transient tolerance, 100µA Burst Mode IQ, and BOOST-assisted saturation in a single TSSOP package - making it the only option qualified for demanding automotive infotainment and telematics power rails.
Availability
LT3437EFE#TRPBF is available at Aetrix Electronics and suitable for automotive infotainment systems, industrial sensor nodes, and powered Ethernet devices requiring stable component supply across extended temperature and high-voltage stress conditions.
Supply support for LT3437EFE#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 its high-reliability analog and power management portfolio. Linear's legacy design ethos emphasizes ruggedness, precision, and automotive-grade qualification.
The LT3437EFE#TRPBF belongs to Linear's high-voltage monolithic buck regulator family, engineered specifically for automotive and industrial environments where input transients, wide temperature ranges, and ultra-low standby power are critical design constraints.
FAQ
What is the maximum input voltage rating for LT3437EFE#TRPBF during transient conditions?
The LT3437EFE#TRPBF is rated for 80V input transients with <15% duty cycle and duration ≤100ms, per Absolute Maximum Ratings. This allows direct integration into 12V automotive systems subject to ISO 7637-2 Pulse 5a load-dump events. Continuous operation remains limited to 60V. Exceeding 80V even briefly risks permanent damage.
How does the BOOST pin function in LT3437EFE#TRPBF, and what external components are required?
The BOOST pin on the LT3437EFE#TRPBF supplies a voltage ≥3.3V above VIN to fully saturate the internal NPN switch, reducing VCE(SAT) to 400mV at 500mA. It requires an external flying capacitor (typically 100nF ceramic) and Schottky diode (e.g., BAS21) connected between SW and BOOST. Without this network, switch losses increase significantly, degrading efficiency and thermal performance.
Can LT3437EFE#TRPBF operate with input voltage below 3.3V, and what is the minimum functional VIN?
The LT3437EFE#TRPBF has a specified minimum input voltage of 3.3V for guaranteed operation, though switching begins at ~2.5V (per Electrical Characteristics). Below 3.3V, regulation cannot be maintained across load and temperature - especially with output voltages ≥3.3V. For 3.3V output, practical minimum VIN is ~3.5V to ensure margin under load and cold temperature.
What is the role of the CSS pin in LT3437EFE#TRPBF, and how is soft-start configured?
The CSS pin on the LT3437EFE#TRPBF controls soft-start by sourcing current into an external capacitor tied to VOUT. The CSS current threshold (4–16µA) scales with FB voltage, enabling programmable dV/dt ramp rates that increase as output approaches regulation. A 10nF capacitor yields ~10ms ramp for 3.3V output; larger values extend ramp time linearly. No resistor is required - only the capacitor.
Is LT3437EFE#TRPBF pin-compatible with other variants in the LT3437 family, such as LT3437EDD#TRPBF?
No, LT3437EFE#TRPBF (16-pin TSSOP) is not pin-compatible with LT3437EDD#TRPBF (10-pin DFN). They share identical functionality and electrical specs but differ in pin count, pin assignment, thermal pad location (Pin 17 vs Pin 11), and NC pin placement. PCB layout, bypassing, and thermal land pattern must be redesigned when switching packages - no mechanical or electrical drop-in replacement is possible.
LT3437EFE#TRPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 16-TSSOP (0.173", 4.40mm Width) 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:
- 16-TSSOP-EP
LT3437EFE#TRPBF FAQ
1.How can I place an order for LT3437EFE#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3437EFE#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 LT3437EFE#TRPBF reliable?
The price and inventory of LT3437EFE#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT3437EFE#TRPBF is usually 5 days.
3.What payment methods are accepted for LT3437EFE#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3437EFE#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3437EFE#TRPBF?
LT3437EFE#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3437EFE#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 LT3437EFE#TRPBF?
For technical support, including LT3437EFE#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3437EFE#TRPBF requirements.
6.How does Aetrix verify that LT3437EFE#TRPBF is sourced from the original manufacturer or authorized distributors?
All LT3437EFE#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 LT3437EFE#TRPBF meets industry standards.
7.What is the process for return or replacement of LT3437EFE#TRPBF?
All LT3437EFE#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3437EFE#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 LT3437EFE#TRPBF part is unused and in its original packaging.
Return procedure for LT3437EFE#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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