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Analog Devices Inc. LT3437HFE#TRPBF
- Part No.:
- LT3437HFE#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 16-TSSOP (0.173", 4.40mm Width) Exposed Pad
- Datasheet:
-
LT3437HFE#TRPBF.pdf
- Description:
- IC REG BUCK ADJ 500MA 16TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:2,017
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Product details
Overview
LT3437HFE#TRPBF from Analog Devices (formerly Linear Technology) is a high-voltage, current-mode monolithic buck switching regulator designed for automotive and industrial power conversion. It operates from 3.3V to 60V input, delivers up to 500mA output current, features 200kHz fixed-frequency operation, 100µA quiescent current in Burst Mode, and includes load dump protection to 80V. It is used in 14V/42V automotive systems for powering infotainment or ADAS subsystems requiring stable low-noise 3.3V or 5V rails.
For engineers reviewing the LT3437HFE#TRPBF datasheet, LT3437HFE#TRPBF pinout, LT3437HFE#TRPBF application, or LT3437HFE#TRPBF equivalent, key selection criteria include its –40°C to 140°C operating junction temperature, 0.8Ω switch on-resistance, 1.25V feedback reference, soft-start capability via CSS pin, and synchronization support up to 500kHz - all critical for high-reliability, transient-immune DC/DC designs.
Technical Context
The LT3437HFE#TRPBF implements constant-frequency current-mode control with cycle-by-cycle peak current limiting and internal slope compensation. Its architecture integrates a 500mA NPN power switch, oscillator, error amplifier, and burst-mode logic on a single die using a proprietary high-voltage process.
It supports dual biasing: VIN powers internal circuitry by default, but connecting BIAS to the regulated output reduces quiescent current and improves efficiency at high VIN-to-VOUT ratios. The BOOST pin enables full saturation of the internal switch via an external capacitor-diode network, maintaining low VCE(SAT) across the duty cycle range.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 3.3V to 60V continuous; withstands 80V transients (load dump), enabling direct connection to 42V automotive battery rails without external TVS. |
| Output Current | Up to 500mA peak switch current; sustained output depends on thermal design and ambient, but supports ≥400mA at 3.3V out with proper PCB copper and exposed pad soldering. |
| Switching Frequency | 200kHz typical (140–240kHz over temp); fixed frequency simplifies EMI filtering and avoids audible noise in sensitive applications. |
| Quiescent Current | 100µA in Burst Mode (no load); enables >1-year battery life in always-on vehicle modules powered from 12V lead-acid or LiFePO4 sources. |
| Feedback Reference | 1.25V ±2.4% (1.212–1.288V) over –40°C to 140°C; allows precise output regulation with standard resistor dividers and minimal drift over extended temperature range. |
| Junction Temp Range | –40°C to +140°C; fully tested and characterized at 140°C, qualifying for under-hood automotive use where ambient exceeds 105°C. |
| Shutdown Current | <1µA when SHDN pin is low; ensures negligible battery drain during vehicle sleep mode or system standby. |
Pinout & Package
LT3437HFE#TRPBF is housed in a thermally enhanced 16-lead plastic TSSOP package (3mm × 4.4mm) with exposed pad (Pin 17) that must be soldered to PCB ground for thermal and electrical integrity. θJA = 45°C/W, θJC(PAD) = 10°C/W.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN (Pin 4) | Input supply collector | Accepts 3.3–60V; carries high di/dt switching current; requires low-inductance path to input capacitor and catch diode. |
| SW (Pin 2) | Switch emitter | Drives external inductor; swings from near GND to VIN during operation; requires Schottky catch diode to clamp negative flyback. |
| BOOST (Pin 6) | Switch drive boost node | Connects to external capacitor-diode network to generate >VIN voltage, ensuring full saturation of internal NPN switch and minimizing conduction loss. |
| GND (Pins 8, 17) | Power and signal reference | Exposed pad (Pin 17) is GND and mandatory thermal path; Pin 8 is signal GND; both must connect to low-impedance ground plane. |
| FB (Pin 12) | Feedback input | Senses output via resistor divider; 1.25V reference sets VOUT; also enables frequency foldback and soft-start when VFB < 0.9V. |
| VC (Pin 11) | Error amplifier output | Controls peak switch current; used for loop compensation; clamped at 1.5–2.1V; driving VC to GND forces shutdown. |
| SHDN (Pin 15) | Enable/disable control | Logic-high (>1.3V) enables regulator; logic-low disables with <1µA supply current; internal pull-down not present. |
| SYNC (Pin 14) | External clock input | Accepts 25–75% duty cycle logic-level signals up to 500kHz; disables Burst Mode when asserted, reducing light-load ripple at cost of higher IQ. |
| CSS (Pin 9) | Soft-start ramp control | Capacitor to VOUT sets dV/dt during startup; current threshold (4–16µA) scales with FB voltage; disabled above 0.9V FB. |
| BIAS (Pin 10) | Efficiency-boost supply | Connect to regulated output (≥2.7V) to source internal bias current externally, improving efficiency at high VIN/VOUT ratios. |
Key Features
| Feature | Design Value |
|---|---|
| Load dump protection | Withstands 80V/100ms transients per ISO 7637-2 Pulse 5a, eliminating need for external TVS in 42V automotive front-end designs. |
| Burst Mode operation | Reduces no-load IQ to 100µA while maintaining regulation, enabling compliance with automotive OEM quiescent current budgets (e.g., <150µA for body control modules). |
| Defeatable Burst Mode | Asserting logic-high on SYNC pin disables Burst Mode, lowering output ripple at light loads without changing PCB layout or component count. |
| Thermally robust packaging | 16-pin TSSOP with exposed pad achieves θJC = 10°C/W, supporting 400mA+ continuous output in compact layouts without heatsinks. |
| Wide temperature qualification | Tested and guaranteed over –40°C to +140°C junction range, meeting AEC-Q100 Grade 0 requirements for under-hood deployment. |
Applications
| Automotive Infotainment Power Supply | Industrial PLC I/O Module Regulator |
|---|---|
Use Scenario: Powers 3.3V microcontroller, CAN transceiver, and display interface in head unit exposed to cold crank (4.5V) and load dump (80V) events. IC Role / Device Role / Timing Role: Primary step-down regulator with integrated switch; provides regulated rail with fast transient response to handle bursty CPU loads. Use Value: 100µA Burst Mode IQ extends battery backup runtime; 140°C rating ensures reliability in sealed enclosures near engine bay heat sources. | Use Scenario: Generates 5V rail for isolated digital I/O circuits in factory automation controllers operating in 0–70°C ambient with 24V DC field bus input. IC Role / Device Role / Timing Role: High-efficiency buck converter delivering stable 5V/400mA; synchronized to system clock via SYNC pin to reduce conducted EMI. Use Value: 200kHz fixed frequency enables predictable filter design; 0.8Ω switch RDS(on) minimizes thermal rise in dense PCB layouts. |
| Powered Ethernet (PoE) Midspan Converter | High-Voltage Battery-Powered Instrumentation |
Use Scenario: Steps down 57V PoE midspan output to 12V for Ethernet PHY and MAC in network surveillance cameras. IC Role / Device Role / Timing Role: Input-stage buck regulator accepting wide-range PoE voltage; handles 100ms surges during cable hot-plug events. Use Value: 60V max continuous input and 80V transient tolerance eliminate need for pre-regulator; soft-start prevents inrush into downstream capacitive loads. | Use Scenario: Powers data acquisition front-end in portable test equipment using 48V Li-ion stack, requiring low-noise, long-life operation. IC Role / Device Role / Timing Role: Main system regulator converting 36–54V battery range to 3.3V for ADC, FPGA, and RF section. Use Value: 100µA quiescent current enables multi-week standby; BIAS pin connection to 3.3V output improves efficiency by >15% 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 MOSFETs, 2.5µA IQ in pulse-skipping mode; smaller 10-pin MSOP package. | Lower voltage range limits use in 42V automotive; higher frequency enables smaller magnetics but increases EMI risk in noise-sensitive analog systems. | Select when board space is constrained and input stays ≤40V; avoid for load dump–exposed automotive front ends. |
| MAX5033BASA+ | 76V max input, 500kHz switching, 1.5mA IQ, no Burst Mode, SO-8 package with no exposed pad. | Lacks Burst Mode and thermal performance: θJA ≈ 120°C/W vs. 45°C/W for LT3437HFE; unsuitable for high-ambient or high-current continuous operation. | Select only for cost-sensitive, non-automotive industrial apps with modest thermal demands and no strict IQ budget. |
Compared with LTC3642EMSE#PBF and MAX5033BASA+, the LT3437HFE#TRPBF uniquely balances 60V/80V ruggedness, 100µA Burst Mode IQ, and 140°C operation - making it the only choice for thermally demanding, battery-backed automotive or industrial systems requiring both ultra-low standby power and transient immunity.
Availability
LT3437HFE#TRPBF is available at Aetrix Electronics and suitable for automotive infotainment, industrial PLC I/O modules, and powered Ethernet midspan converters requiring stable component supply across extended temperature and high-reliability environments.
Supply support for LT3437HFE#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, 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 LT3437 product line was developed by Linear Technology specifically for high-input-voltage DC/DC conversion in harsh environments - targeting automotive, industrial, and telecom applications where wide VIN range, load dump survival, and extended temperature operation are mandatory.
FAQ
What is the maximum allowable input voltage for continuous operation of the LT3437HFE#TRPBF?
The LT3437HFE#TRPBF supports continuous input voltages from 3.3V to 60V. It is rated to withstand 80V transients for up to 100ms with <15% duty cycle, complying with ISO 7637-2 Pulse 5a load dump requirements. Operation above 60V requires adherence to specific derating conditions outlined in the datasheet's Absolute Maximum Ratings table.
How does the LT3437HFE#TRPBF achieve 100µA quiescent current, and under what conditions is this value valid?
The LT3437HFE#TRPBF achieves 100µA quiescent current in Burst Mode operation, which activates automatically at light loads. This value is measured with BIAS = 0V, FB = 1.15V, VC = 0.8V, and SYNC = 2V at TJ = 25°C. At full temperature range (–40°C to 140°C), quiescent current remains ≤300µA in Burst Mode sleep state, as verified in the Electrical Characteristics table.
Can the LT3437HFE#TRPBF be synchronized to an external clock, and what is its synchronization frequency range?
Yes, the LT3437HFE#TRPBF can be synchronized via its SYNC pin (Pin 14). It accepts logic-level inputs with 25–75% duty cycle across a frequency range of 240kHz to 500kHz over temperature. Synchronization disables Burst Mode, reducing output ripple at light loads but increasing quiescent current to ~1.35mA.
What is the purpose of the BIAS pin on the LT3437HFE#TRPBF, and how does it improve efficiency?
The BIAS pin (Pin 10) on the LT3437HFE#TRPBF allows external biasing of internal circuitry from the regulated output voltage (≥2.7V). When connected, it shifts quiescent current sourcing from VIN to VOUT, reducing input supply current by up to 65% at high VIN/VOUT ratios - e.g., from 1.35mA to 0.475mA at VIN = 12V, significantly improving overall system efficiency.
Is the exposed pad on the LT3437HFE#TRPBF package electrically connected, and how must it be handled in PCB layout?
Yes, the exposed pad (Pin 17) on the LT3437HFE#TRPBF is electrically connected to GND and serves as the primary thermal path. It must be soldered directly to a solid PCB ground plane using multiple thermal vias. Failure to do so degrades thermal resistance from θJC = 10°C/W to >30°C/W, risking thermal shutdown or reduced lifetime under continuous 400mA+ loads.
LT3437HFE#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):
- 3.5V
- 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 ~ 140°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-TSSOP-EP
LT3437HFE#TRPBF FAQ
1.How can I place an order for LT3437HFE#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3437HFE#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 LT3437HFE#TRPBF reliable?
The price and inventory of LT3437HFE#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT3437HFE#TRPBF is usually 5 days.
3.What payment methods are accepted for LT3437HFE#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3437HFE#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3437HFE#TRPBF?
LT3437HFE#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3437HFE#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 LT3437HFE#TRPBF?
For technical support, including LT3437HFE#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3437HFE#TRPBF requirements.
6.How does Aetrix verify that LT3437HFE#TRPBF is sourced from the original manufacturer or authorized distributors?
All LT3437HFE#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 LT3437HFE#TRPBF meets industry standards.
7.What is the process for return or replacement of LT3437HFE#TRPBF?
All LT3437HFE#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3437HFE#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 LT3437HFE#TRPBF part is unused and in its original packaging.
Return procedure for LT3437HFE#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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