My Inquiry
My Account
Analog Devices Inc. LT3958IUHE#PBF
- Part No.:
- LT3958IUHE#PBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 36-WFQFN, 28 Leads, Exposed Pad
- Datasheet:
-
LT3958IUHE#PBF.pdf
- Description:
- IC REG BOOST CUK ADJ 3.3A 36QFN
- Quantity:
- Payment:
- Shipping:
Inventory:788
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
LT3958IUHE#PBF from Analog Devices is a wide-input, current-mode DC/DC controller IC capable of configuring as boost, flyback, SEPIC, or inverting converter to generate positive or negative output voltages. It integrates an 84V/3.3A internal N-channel MOSFET, supports 5V–80V input, operates from –40°C to 125°C, and delivers programmable 100kHz–1MHz switching frequency - ideal for high-voltage industrial power supplies and automotive LED drivers.
For engineers reviewing the LT3958IUHE#PBF datasheet, LT3958IUHE#PBF pinout, LT3958IUHE#PBF application, or LT3958IUHE#PBF equivalent, key selection considerations include its dual-polarity feedback capability (±0.8V/1.6V FBX reference), internal 7.2V LDO for gate drive, <1µA shutdown IQ, programmable UVLO with hysteresis, and thermally enhanced 36-lead QFN package with exposed SW and SGND pads.
Technical Context
The LT3958IUHE#PBF implements fixed-frequency current-mode control with slope compensation, enabling stable regulation across wide VIN and VOUT ranges. Its dual-comparator feedback architecture (A1/A2) selects between +1.6V or –0.8V reference based on external resistor divider polarity, allowing single-pin configuration of both positive and negative output topologies.
Internal protection includes frequency foldback during low-FBX conditions (e.g., startup or short-circuit), overvoltage lockout (±8% / ±11% thresholds), thermal shutdown at 165°C, and precise EN/UVLO with 2µA programmable hysteresis current. The RT pin sets switching frequency via resistor-to-SGND, while SYNC enables external clock synchronization with 20% slower RT programming.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 5V to 80V - supports direct connection to 48V telecom, 24V industrial, or 72V battery systems without pre-regulation. |
| Internal Power Switch | 84V breakdown, 3.3A continuous - eliminates need for external high-voltage MOSFET in medium-power converters. |
| Feedback Reference | +1.6V or –0.8V - enables single-pin polarity selection for boost/flyback (positive) or inverting (negative) outputs. |
| Switching Frequency | 100kHz to 1MHz (RT-programmable) - balances efficiency (lower fSW) vs. size (higher fSW) with external resistor tuning. |
| Shutdown Quiescent Current | <1µA - extends battery life in always-on automotive or remote sensor applications. |
| Operating Temperature | –40°C to 125°C - qualified for under-hood automotive and industrial environments with full parameter guarantee. |
| Package | 36-lead 5mm × 6mm QFN with exposed SW and SGND pads - enables high-current routing and low-θJC thermal performance (5°C/W). |
Pinout & Package
LT3958IUHE#PBF uses a thermally enhanced 36-lead plastic QFN (5mm × 6mm) with two exposed pads: Pin 37 (SGND) and Pin 38 (SW). Both must be soldered to dedicated PCB copper planes for signal integrity and thermal management.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| SENSE2 (Pin 3) | Current sense input | Receives filtered voltage from SENSE1 to set peak current limit; connects to RC filter for noise immunity. |
| SGND (Pins 4, 23, 24, 37) | Signal ground | Kelvin-sense reference for internal current sensing; must remain isolated from power GND to avoid measurement error. |
| SENSE1 (Pin 6) | Current sense output | Drives SENSE2 via external RC network; provides amplified switch current signal for control loop. |
| SW (Pins 8, 9, 20, 21, 38) | Internal MOSFET drain | High-current switching node; exposed pad (Pin 38) requires direct connection to SW copper pour for thermal and EMI control. |
| GND (Pins 12–17) | Power ground | Source terminal connection for internal MOSFET; internally tied to SGND but externally isolated to preserve Kelvin sensing. |
| EN/UVLO (Pin 25) | Enable & input UVLO | 1.22V falling threshold with programmable hysteresis; resets soft-start during undervoltage events. |
| FBX (Pin 31) | Feedback input | Dual-reference input: >0V selects +1.6V reference (positive output); <0V selects –0.8V reference (negative output). |
| RT (Pin 33) | Frequency programming | Resistor-to-SGND sets switching frequency; open-circuit disables operation - no pull-up/pull-down allowed. |
Key Features
| Feature | Design Value |
|---|---|
| Single FBX pin for ± output polarity | Eliminates need for separate positive/negative feedback networks - reduces BOM count and layout complexity in dual-rail systems. |
| Programmable soft-start (SS pin) | Capacitor-controlled ramp limits inrush current during startup and fault recovery, preventing inductor saturation and MOSFET overstress. |
| Frequency foldback at low FBX | Automatically reduces switching frequency when output is shorted or during startup, maintaining current limit compliance without external intervention. |
| Internal 7.2V LDO with bypass option | Reduces external component count; INTVCC can be tied to VIN (<12.8V) or VOUT (via diode) to disable LDO and improve efficiency at high input voltages. |
| Synchronization capability (SYNC pin) | Enables EMI reduction by locking switching frequency to system clock - avoids beat frequencies in multi-converter designs. |
Applications
| Automotive LED Headlamp Driver | Industrial 48V-to-12V SEPIC Supply |
|---|---|
Use Scenario: High-brightness LED array powered from vehicle battery (9V–16V) with strict EMI and thermal constraints. IC Role / Device Role / Timing Role: Boost controller generating regulated 60V output with PWM dimming interface and thermal foldback. Use Value: Internal 84V switch withstands load dump transients; programmable frequency avoids AM band; <1µA shutdown preserves battery during parking mode. |
Use Scenario: Isolated 48V telecom rack supply powering legacy 12V subsystems with high reliability requirements. IC Role / Device Role / Timing Role: SEPIC controller providing non-inverting buck-boost conversion with inherent input-output isolation. Use Value: Dual-reference FBX simplifies feedback design; 3.3A switch handles 2A output; –40°C to 125°C rating ensures operation in sealed enclosures. |
| Flyback-Based Medical Isolated PSU | Negative Rail Generator for Op-Amp Bias |
Use Scenario: Compact 24V input, 5V/3A isolated output for patient-connected diagnostic equipment requiring reinforced insulation. IC Role / Device Role / Timing Role: Flyback controller with primary-side regulation using optocoupler-free feedback via auxiliary winding. Use Value: Current-mode control ensures tight regulation across line/load; frequency foldback prevents transformer saturation during overload. |
Use Scenario: Dual-supply op-amp circuit requiring precise –5V rail from existing +12V system rail in test instrumentation. IC Role / Device Role / Timing Role: Inverting converter generating regulated negative output using single FBX pin with –0.8V reference. Use Value: Eliminates need for separate inverting IC; ±0.8% FBX reference accuracy ensures stable bias voltage; QFN package enables compact layout near analog section. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar DC/DC controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LT3758IUHE#PBF | Same pinout and feature set, but rated for –40°C to 150°C junction temperature and higher 100V switch rating. | Better suited for under-hood automotive or high-ambient industrial use where 125°C max is insufficient. | Select LT3758IUHE#PBF only if extended temperature range or 100V switch stress margin is required; otherwise LT3958IUHE#PBF offers identical functionality at lower cost. |
| LM5122MH/NOPB | External MOSFET driver (no integrated switch), 65V max VIN, supports 50kHz–750kHz, requires external current sense resistor. | Used where higher output power (>50W) or discrete FET optimization is needed; lacks integrated switch and dual-polarity FBX. | Choose LM5122MH/NOPB for >3.3A output or custom FET selection; LT3958IUHE#PBF is preferred for space-constrained, medium-power designs needing integration. |
Compared with LT3758IUHE#PBF and LM5122MH/NOPB, the LT3958IUHE#PBF uniquely combines integrated 84V/3.3A switching, dual-polarity feedback, and –40°C to 125°C guaranteed operation in a single 5mm × 6mm QFN - reducing bill-of-materials and PCB area while maintaining design flexibility across boost, flyback, SEPIC, and inverting topologies.
Availability
LT3958IUHE#PBF is available at Aetrix Electronics and suitable for automotive LED drivers, industrial 48V power conversion, medical isolated supplies, and test equipment negative rail generation requiring stable component supply, long-term lifecycle support, and traceable sourcing.
Supply support for LT3958IUHE#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) is a global leader in high-performance analog, mixed-signal, and power management semiconductors, serving industrial, automotive, communications, and healthcare markets.
The LT3958IUHE#PBF belongs to Linear's high-voltage DC/DC controller product line, designed specifically for robust, wide-input power conversion in harsh environments where reliability, thermal performance, and topology flexibility are critical.
FAQ
What is the maximum input voltage supported by the LT3958IUHE#PBF?
The LT3958IUHE#PBF supports an absolute maximum input voltage of 80V on the VIN pin, with guaranteed operation across 5V to 80V. This allows direct connection to 48V industrial buses, 24V automotive systems (including load dump tolerance), and telecom power rails without external pre-regulation stages.
How does the LT3958IUHE#PBF configure for negative output voltage generation?
The LT3958IUHE#PBF configures for negative output by pulling the FBX pin below 0V using an external resistor divider from VOUT to SGND. When FBX < 0V, the internal comparator A2 activates with a –0.8V reference, enabling inverting converter operation - no hardware change or pin reconfiguration is required beyond the feedback network.
Can the LT3958IUHE#PBF synchronize to an external clock, and what are the requirements?
Yes, the LT3958IUHE#PBF supports external clock synchronization via the SYNC pin. To ensure reliable locking, the RT resistor must be selected to program a free-running frequency ~20% slower than the SYNC signal frequency, and the SYNC pulse width must exceed 200ns. The SYNC pin must be tied to SGND if unused.
What is the purpose of the dual exposed pads (Pins 37 and 38) on the LT3958IUHE#PBF QFN package?
Pin 37 is SGND (signal ground) and Pin 38 is SW (switch node drain) - both are exposed copper pads requiring direct soldering to dedicated PCB copper planes. SGND pad ensures low-impedance Kelvin return for current sensing; SW pad provides low-thermal-resistance path for high-current switching, achieving θJC = 5°C/W.
Does the LT3958IUHE#PBF require an external current sense resistor?
No, the LT3958IUHE#PBF does not require an external current sense resistor. It uses internal sensing through the integrated MOSFET's RDS(on), with SENSE1 and SENSE2 pins providing access to the internal sense signal for filtering and loop stability - eliminating external power loss and component count.
LT3958IUHE#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 36-WFQFN, 28 Leads, Exposed Pad
- Packaging:
- Tube
- 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)
LT3958IUHE#PBF FAQ
1.How can I place an order for LT3958IUHE#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3958IUHE#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 LT3958IUHE#PBF reliable?
The price and inventory of LT3958IUHE#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT3958IUHE#PBF is usually 5 days.
3.What payment methods are accepted for LT3958IUHE#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3958IUHE#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3958IUHE#PBF?
LT3958IUHE#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3958IUHE#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 LT3958IUHE#PBF?
For technical support, including LT3958IUHE#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3958IUHE#PBF requirements.
6.How does Aetrix verify that LT3958IUHE#PBF is sourced from the original manufacturer or authorized distributors?
All LT3958IUHE#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 LT3958IUHE#PBF meets industry standards.
7.What is the process for return or replacement of LT3958IUHE#PBF?
All LT3958IUHE#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3958IUHE#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 LT3958IUHE#PBF part is unused and in its original packaging.
Return procedure for LT3958IUHE#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LT3958IUHE#PBF Tags
-
TPS562201DDCR
Texas Instruments
-
MC34063ABD-TR
STMicroelectronics
-
TPS561201DDCR
Texas Instruments
-
MC33063ADR
Texas Instruments
-
MC34063ADR
Texas Instruments
-
TPS560200DBVR
Texas Instruments
-
AP3012KTR-G1
Diodes Incorporated
-
TLV61048DBVR
Texas Instruments
-
AZ34063UMTR-G1
Diodes Incorporated
-
TPS562200DDCR
Texas Instruments
-
AP62300TWU-7
Diodes Incorporated
-
MC34063EBD-TR
STMicroelectronics
Tech Hub
A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.
The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…
The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…
A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…
A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …
An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…
Latch circuits retain one bit through feedback. This technical reference covers SR and D latches, truth tables, transparency, timing limits, latch-versus-flip-flop behavior, applications and common log…
An engineering guide to LED driver operation, constant-current and constant-voltage outputs, linear and switching topologies, dimming, IC selection, calculations, replacement compatibility, and fault c…
Operational amplifier guide covering op amp basics, feedback, ideal vs real op amps, common configurations, buffer circuits, offset, bias current, gain-bandwidth, slew rate, rail-to-rail limits and sel…
Jumper cables guide covering safe connection order, red and black clamp placement, final ground connection, cable gauge, length, clamp quality, copper vs CCA cables, jump starter comparison and battery…
