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Analog Devices Inc. LT3958EUHE#TRPBF
- Part No.:
- LT3958EUHE#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 36-WFQFN, 28 Leads, Exposed Pad
- Datasheet:
-
LT3958EUHE#TRPBF.pdf
- Description:
- IC REG BOOST CUK ADJ 3.3A 36QFN
- Quantity:
- Payment:
- Shipping:
Inventory:7,317
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Product details
Overview
LT3958EUHE#TRPBF from Analog Devices is a wide-input, current-mode DC/DC controller IC with integrated 3.3A/84V N-channel MOSFET, supporting boost, flyback, SEPIC, and inverting topologies. It delivers ±output voltage regulation via a single FBX pin, operates from 5V to 80V input, and features programmable 100kHz–1MHz switching frequency and <1µA shutdown current - ideal for high-voltage industrial power supplies.
For engineers reviewing the LT3958EUHE#TRPBF datasheet, LT3958EUHE#TRPBF pinout, LT3958EUHE#TRPBF application, or LT3958EUHE#TRPBF equivalent, key selection criteria include its dual-polarity feedback architecture, internal LDO-regulated 7.2V gate drive, thermally enhanced 36-lead QFN package, and frequency foldback protection during low-FBX start-up conditions.
Technical Context
The LT3958EUHE#TRPBF implements fixed-frequency current-mode control with slope compensation, enabling stable operation across wide VIN (5V–80V) and VOUT ranges. Its dual-comparator feedback path (1.6V for positive outputs, –0.8V for negative outputs) enables topology-agnostic regulation without external op-amps.
It integrates an internal 7.2V LDO for gate drive, supports external synchronization via SYNC pin (with 20% slower RT programming), and includes dedicated fault recovery: soft-start reset on INTVCC UV/OV, thermal lockout, and EN/UVLO hysteresis control using a 2µA internal current source.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 5V to 80V - supports direct connection to automotive battery, telecom rectified rails, and industrial 48V systems without pre-regulation. |
| Internal Power Switch | 3.3A/84V N-MOSFET - eliminates external high-voltage switch; rated for continuous 3.3A peak current at full temperature range. |
| Feedback Reference | +1.6V or –0.8V - single FBX pin supports both positive and negative output configurations without hardware change. |
| Switching Frequency | 100kHz to 1MHz (programmable via RT resistor) - enables optimization between efficiency (lower fSW) and magnetics size (higher fSW). |
| Shutdown Quiescent Current | <1µA - extends battery life in always-on monitoring or backup power systems. |
| INTVCC Regulator | 7.2V LDO with 3.75V UVLO and 12.8V OVLO - powers internal gate driver and logic; bypass requires ≥4.7µF ceramic to SGND. |
| Operating Temperature | –40°C to +125°C - qualified for under-hood automotive, industrial control, and telecom base station environments. |
Pinout & Package
LT3958EUHE#TRPBF is housed in a thermally enhanced 36-lead (5mm × 6mm) plastic QFN package with two exposed pads: Pin 37 (SGND) and Pin 38 (SW), both requiring soldering to respective PCB copper planes for thermal and electrical integrity.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| SENSE2 (Pin 3) | Current sense input | Receives filtered current-sense signal from SENSE1; sets peak current limit threshold (48mV typical) for cycle-by-cycle protection. |
| SGND (Pins 4,23,24,37) | Signal ground reference | Kelvin return for precision current sensing; must be isolated from power GND externally to avoid noise coupling into control loop. |
| SENSE1 (Pin 6) | Current sense output | Outputs amplified MOSFET source voltage; connects directly or via RC filter to SENSE2 for EMI-reduced current sensing. |
| SW (Pins 8,9,20,21,38) | Power switch drain node | High-side switching node for boost/flyback/SEPIC; exposed pad (38) must connect to SW plane for thermal dissipation and low-inductance routing. |
| GND (Pins 12–17) | Power ground return | Source terminal return for internal MOSFET; internally connected to SGND for Kelvin sensing but kept separate on PCB for noise isolation. |
| EN/UVLO (Pin 25) | Enable & input undervoltage detection | 1.22V falling threshold with programmable hysteresis; resets soft-start on undervoltage, enabling robust brown-out recovery. |
| VIN (Pin 27) | Main input supply | Accepts 5V–80V; powers internal circuitry and charges INTVCC LDO; requires local ceramic bypass to GND (not SGND). |
| INTVCC (Pin 28) | Internal regulated supply | 7.2V output powering gate driver and logic; must be bypassed with ≥4.7µF ceramic to SGND; can be tied to VIN if VIN < 12.8V. |
| VC (Pin 30) | Error amplifier compensation | Connects external RC network to SGND to stabilize voltage loop; determines phase margin and transient response in current-mode control. |
| FBX (Pin 31) | Positive/negative feedback input | Single pin accepts resistor-divider from VOUT; selects 1.6V (positive) or –0.8V (negative) reference automatically based on voltage polarity. |
| SS (Pin 32) | Soft-start control | 10µA pull-up current charges external capacitor; clamps VC during start-up to limit inductor current slew rate and prevent saturation. |
| RT (Pin 33) | Frequency programming | Resistor to SGND sets switching frequency (100kHz–1MHz); open-circuit disables operation - no floating pin allowed. |
| SYNC (Pin 34) | External clock input | Accepts digital clock signal; overrides RT-programmed frequency; ignored when FBX near SGND (e.g., during fault or start-up). |
Key Features
| Feature | Design Value |
|---|---|
| Topology flexibility | Single IC supports boost, flyback, SEPIC, and inverting converters - reduces BOM count and design reuse across multiple power architectures. |
| Dual-polarity feedback | 1.6V/–0.8V reference selection via FBX voltage polarity - eliminates need for external level-shifting or dual-reference circuits. |
| Frequency foldback | Automatically reduces switching frequency when FBX approaches SGND (e.g., short-circuit or cold start) - prevents current runaway without external circuitry. |
| Thermal enhancement | 36-lead QFN with dual exposed pads (SGND and SW) - achieves θJC = 5°C/W, enabling >3W dissipation in compact layouts. |
| Programmable UVLO hysteresis | 2µA internal current source enables precise rising/falling thresholds via external resistor divider - ensures clean power sequencing in multi-rail systems. |
Applications
| Automotive LED Driver | Industrial Telecom Power |
|---|---|
Use Scenario: Driving high-brightness LED strings from 12V–48V vehicle batteries with overvoltage protection during load dump. IC Role / Device Role / Timing Role: Controller for boost converter delivering constant-current LED output; uses FBX feedback and frequency foldback during cold cranking transients. Use Value: Maintains regulated LED brightness across 5V–80V input range while surviving 120V load-dump spikes via 84V SW rating and INTVCC OVLO. |
Use Scenario: Generating isolated ±12V rails from 48V telecom rectifier for analog interface and data acquisition modules. IC Role / Device Role / Timing Role: Flyback controller with synchronous rectification support; leverages dual FBX reference for independent positive/negative regulation. Use Value: Eliminates need for two separate controllers; achieves <1% cross-regulation error between rails using shared current-mode loop and matched timing. |
| Medical Imaging Power Supply | Test Equipment HV Bias |
Use Scenario: Providing stable 200V bias for photomultiplier tubes (PMTs) in portable ultrasound units powered by Li-ion packs. IC Role / Device Role / Timing Role: SEPIC controller enabling step-up from 7.4V nominal battery to 200V output; uses SS pin to limit inrush into large HV capacitors. Use Value: Achieves >85% efficiency at 200V/1mA while maintaining <100ppm/h drift via temperature-stable 1.6V reference and low-drift RT resistor. |
Use Scenario: Generating adjustable –50V to –200V bias for semiconductor parameter analyzers requiring low-noise, low-ripple negative supplies. IC Role / Device Role / Timing Role: Inverting controller with precision –0.8V reference and programmable soft-start; uses SENSE2 filtering to reject EMI from adjacent RF test circuits. Use Value: Delivers <5mVpp ripple at –150V/10mA; FBX-based frequency foldback prevents instability during rapid voltage sweeps. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar DC/DC controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC3789EUF#PBF | 4-switch synchronous buck-boost controller; no integrated MOSFET; supports 4V–36V input; requires external FETs. | Better suited for bidirectional power flow and narrow-input-range applications where efficiency >95% is critical. | Select LTC3789EUF#PBF when input voltage stays within 4V–36V and synchronous rectification is required for high-load efficiency. |
| LM5122MMX/NOPB | Wide-VIN (3V–65V) current-mode controller; no integrated switch; supports boost/flyback/SEPIC; 100kHz–1MHz programmable frequency. | Lacks dual-polarity FBX reference - requires external op-amp for negative output generation. | Choose LM5122MMX/NOPB when cost sensitivity outweighs topology flexibility and dual-reference capability is not needed. |
Compared with LTC3789EUF#PBF and LM5122MMX/NOPB, the LT3958EUHE#TRPBF uniquely integrates an 84V/3.3A MOSFET and supports both positive and negative outputs from one FBX pin - reducing component count and layout complexity in high-input-voltage, multi-topology designs.
Availability
LT3958EUHE#TRPBF is available at Aetrix Electronics and suitable for automotive LED drivers, industrial telecom power supplies, medical imaging bias generators, and test equipment HV sources requiring stable component supply and long-term manufacturability.
Supply support for LT3958EUHE#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 is a global leader in high-performance analog, mixed-signal, and power management semiconductors, serving industrial, automotive, communications, and healthcare markets with precision, reliability, and innovation.
The LT3958EUHE#TRPBF belongs to the Linear Technology DC/DC controller product line, designed specifically for high-input-voltage, multi-topology power conversion in space-constrained, thermally demanding environments.
FAQ
What is the maximum allowable input voltage for the LT3958EUHE#TRPBF?
The LT3958EUHE#TRPBF has an absolute maximum VIN rating of 80V, with guaranteed operation across 5V to 80V. Exceeding 80V may cause permanent damage. The internal 84V-rated MOSFET provides margin for transient spikes, but sustained operation above 80V violates Absolute Maximum Ratings and voids warranty. Always verify input rail transients remain within spec using appropriate clamping or filtering.
Can the LT3958EUHE#TRPBF generate both positive and negative outputs without changing external components?
Yes - the LT3958EUHE#TRPBF uses a single FBX pin that automatically detects polarity: when pulled above 0V, it regulates to +1.6V reference; when pulled below 0V, it regulates to –0.8V reference. No external op-amps, level shifters, or component changes are needed to switch between boost (positive) and inverting (negative) configurations - only the feedback divider orientation changes.
How does the LT3958EUHE#TRPBF handle short-circuit conditions on the output?
During output short-circuit, the LT3958EUHE#TRPBF activates frequency foldback: as FBX voltage drops near SGND, switching frequency decreases to maintain peak current within the 3.3A limit. Simultaneously, the soft-start capacitor discharges, forcing controlled restart after fault clearance. This prevents thermal runaway and inductor saturation without requiring external hiccup or latch-off circuitry.
What is the purpose of the dual exposed pads (Pins 37 and 38) on the LT3958EUHE#TRPBF QFN package?
Pin 37 is SGND and Pin 38 is SW - both are electrically active and thermally critical. The SGND pad must be soldered to the signal ground plane to ensure low-noise Kelvin sensing; the SW pad must connect directly to the high-current switch node plane to minimize parasitic inductance and dissipate heat from the internal MOSFET. Neither pad is optional - omitting either compromises EMI performance, thermal reliability, or current-sense accuracy.
Is the LT3958EUHE#TRPBF pin-compatible with other members of the LT3958 family?
Yes - all LT3958 variants (e.g., LT3958EUHE#TRPBF, LT3958IUHE#TRPBF) share identical pinout, package dimensions, and footprint. The 'E' and 'I' suffixes denote temperature grade (–40°C to +125°C junction for both), not pin or functional differences. Layouts designed for LT3958EUHE#TRPBF are fully compatible with LT3958IUHE#TRPBF and vice versa.
LT3958EUHE#TRPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 36-WFQFN, 28 Leads, Exposed Pad
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Function:
- Step-Up, Step-Up/Step-Down
- Output Configuration:
- Positive or Negative
- Topology:
- Boost, Cuk, Flyback, SEPIC
- Output Type:
- Adjustable
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 5V
- Voltage - Input (Max):
- 80V
- Voltage - Output (Min/Fixed):
- 1.6V
- Voltage - Output (Max):
- 84V (Switch)
- Current - Output:
- 3.3A (Switch)
- Frequency - Switching:
- 100kHz ~ 1MHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 36-QFN (5x6)
LT3958EUHE#TRPBF FAQ
1.How can I place an order for LT3958EUHE#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3958EUHE#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 LT3958EUHE#TRPBF reliable?
The price and inventory of LT3958EUHE#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT3958EUHE#TRPBF is usually 5 days.
3.What payment methods are accepted for LT3958EUHE#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3958EUHE#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3958EUHE#TRPBF?
LT3958EUHE#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3958EUHE#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 LT3958EUHE#TRPBF?
For technical support, including LT3958EUHE#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3958EUHE#TRPBF requirements.
6.How does Aetrix verify that LT3958EUHE#TRPBF is sourced from the original manufacturer or authorized distributors?
All LT3958EUHE#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 LT3958EUHE#TRPBF meets industry standards.
7.What is the process for return or replacement of LT3958EUHE#TRPBF?
All LT3958EUHE#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3958EUHE#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 LT3958EUHE#TRPBF part is unused and in its original packaging.
Return procedure for LT3958EUHE#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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