My Inquiry
My Account
Analog Devices Inc. LT3508HUF#TRPBF
- Part No.:
- LT3508HUF#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 24-WFQFN Exposed Pad
- Datasheet:
-
LT3508HUF#TRPBF.pdf
- Description:
- IC REG BUCK ADJ 1.4A DL 24QFN
- Quantity:
- Payment:
- Shipping:
Inventory:1,486
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
LT3508HUF#TRPBF from Analog Devices (formerly Linear Technology) is a dual monolithic current-mode PWM step-down DC/DC converter with two integrated 1.4A NPN power switches, operating from 3.7V to 36V input and delivering independently regulated 3.3V/5V outputs in anti-phase switching mode. It features programmable 250kHz–2.5MHz frequency, independent soft-start and power-good signals, and is qualified for automotive underhood applications up to 150°C junction temperature.
For engineers reviewing the LT3508HUF#TRPBF datasheet, LT3508HUF#TRPBF pinout, LT3508HUF#TRPBF application, or LT3508HUF#TRPBF equivalent, key selection considerations include its dual-output sequencing capability, thermal grade H (–40°C to 150°C), 24-pin 4mm × 4mm QFN package with exposed GND pad, and internal current limiting with foldback protection during overload.
Technical Context
The LT3508HUF#TRPBF implements dual constant-frequency current-mode control with master-slave oscillator architecture, enabling precise 180° anti-phase switching to minimize input ripple. Each channel uses an internal error amplifier (transconductance 300μS, gain 600V/V) controlling peak switch current via VC pins, with FB regulation at 0.800V ±14mV over temperature.
It integrates cycle-by-cycle current limiting (2.0A–3.2A, duty-cycle dependent), thermal shutdown, and frequency foldback (down to 120kHz under VFB < 0.625V). The BOOST1/BOOST2 pins support external bootstrap capacitor drive for NPN saturation, and TRACK/SS pins enable output tracking or linear soft-start via external capacitor.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 3.7V to 36V - supports automotive battery (cold-crank down to 3.7V), industrial 24V rails, and unregulated wall adapters. |
| Output Current per Channel | 1.4A continuous - enables dual-core DSP or FPGA core/I/O rail generation without external MOSFETs. |
| Switching Frequency | 250kHz to 2.5MHz - adjustable via RT resistor or external SYNC signal; high frequency enables ≤2.2μH inductors and ceramic output caps. |
| Feedback Reference Voltage | 0.800V ±14mV (–40°C to 150°C) - ensures accurate output regulation across full automotive thermal range. |
| Junction Temperature Range | –40°C to 150°C - H-grade qualification allows under-hood deployment without derating below 125°C. |
| Shutdown Current | <2μA - enables ultra-low-power sleep modes in battery-backed systems. |
| Power Good Threshold Accuracy | ±75mV offset from regulation - provides reliable sequencing signal for microcontrollers and FPGAs. |
Pinout & Package
LT3508HUF#TRPBF is housed in a thermally enhanced 24-lead 4mm × 4mm plastic QFN package (UF) with exposed GND pad (Pin 25), requiring soldering to PCB for electrical and thermal integrity. θJA = 40°C/W, θJC = 10°C/W.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| FB1, FB2 | Feedback Input | Regulates each output to 0.800V; connects to resistor divider tap - sets output voltage down to 800mV. |
| TRACK/SS1, TRACK/SS2 | Soft-Start / Tracking Control | Internal 1.2μA current source charges external capacitor for linear ramp; ties to another output for tracking. |
| PG1, PG2 | Open-Collector Power-Good | Active-low signal asserts when respective output reaches ±10% of target - enables safe power sequencing. |
| VC1, VC2 | Error Amplifier Output | Controls peak switch current; can be externally clamped to override regulation or shut down channel individually. |
| RT/SYNC | Oscillator Programming / Sync Input | Resistor-to-GND sets frequency (250kHz–2.5MHz); logic-level SYNC signal overrides for system clock synchronization. |
| SW1, SW2 | Switch Node Output | Drives external inductor and catch diode; requires low-inductance layout due to fast dI/dt edges. |
| BOOST1, BOOST2 | Bootstrap Drive Supply | Accepts ≥2.5V above SW to saturate internal NPN switches - requires external Schottky + capacitor. |
| VIN1, VIN2 | Input Power Supplies | VIN1 powers internal bias and Channel 1; VIN2 powers Channel 2 only - supports split-input configurations. |
| GND (Pins 3–7, 9–14) | Ground Return | Multiple dedicated GND pins + exposed pad minimize ground impedance and improve EMI performance. |
Key Features
| Feature | Design Value |
|---|---|
| Anti-phase dual-channel operation | Reduces RMS input ripple current by ~30% vs. in-phase, lowering required input capacitance and EMI filter size. |
| Independent tracking & soft-start | Enables controlled power-up sequencing between 3.3V and 5V rails - prevents back-driving or latch-up in mixed-voltage systems. |
| Programmable undervoltage lockout | SHDN pin threshold (2.63V ±0.1V) functions as accurate UVLO - prevents erratic startup during brownout conditions. |
| Thermal grade H qualification | Guaranteed operation at 150°C junction temperature - eliminates need for external thermal monitoring in harsh environments. |
| Frequency foldback protection | Automatically reduces switching frequency to 120kHz during overload - limits peak switch current and prevents thermal runaway. |
Applications
| Automotive Infotainment Power | DSP Core & I/O Supply |
|---|---|
Use Scenario: Dual-rail power for automotive head unit SoC requiring 3.3V for interface peripherals and 5V for USB PHY or display backlight driver. IC Role / Device Role / Timing Role: Primary dual-output buck regulator providing sequenced, regulated DC rails with thermal robustness for under-dash mounting. Use Value: Eliminates need for discrete sequencing IC and external MOSFETs; 150°C rating avoids derating in confined enclosures. |
Use Scenario: Powering TI C6000 or Analog Devices SHARC DSPs with separate 1.2V core and 3.3V I/O supplies. IC Role / Device Role / Timing Role: Dual-channel step-down converter generating tightly tracked outputs using TRACK/SS pins for simultaneous voltage ramp. Use Value: Independent soft-start and PG signals ensure safe boot sequence; anti-phase operation minimizes noise coupling into sensitive analog sections. |
| PCI Express Slot Power | DSL/Cable Modem Power |
Use Scenario: Generating +3.3V AUX and +12V (via secondary stage) for PCIe add-in cards in industrial servers. IC Role / Device Role / Timing Role: Primary 3.3V rail generator with PG signal used to enable downstream 12V boost converter after stable 3.3V is established. Use Value: Built-in power-good simplifies inter-rail enable timing; wide 3.7V–36V input accommodates varying server backplane voltages. |
Use Scenario: Powering ADSL line card ASICs and Ethernet PHYs requiring isolated 3.3V and 5V from 12V or 24V wall adapter. IC Role / Device Role / Timing Role: Dual-output buck regulator replacing discrete solutions in space-constrained CPE designs. Use Value: 4mm × 4mm QFN footprint saves >40% board area vs. TSSOP; high-frequency operation allows tiny 1.5μH inductors. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar dual-output buck regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LT3508EUF#TRPBF | Same architecture and pinout, but rated for –40°C to 125°C junction temperature. | Lacks automotive underhood suitability; suitable for commercial/industrial indoor use only. | Select when thermal environment stays below 125°C and cost sensitivity favors E-grade. |
| MP2491DS-LF-Z | Dual 1.2A synchronous buck; 4.5V–36V input; fixed 3.3V/5V outputs; no TRACK/SS or PG; 20-pin QFN. | No output sequencing, no soft-start control, no power-good signaling - requires external circuitry for safe startup. | Choose for cost-driven, non-sequencing applications where simplicity outweighs feature set. |
Compared with LT3508EUF#TRPBF, the LT3508HUF#TRPBF adds guaranteed 150°C operation and tighter thermal margin; versus MP2491DS-LF-Z, it delivers full sequencing, tracking, and fault signaling in a single chip - reducing BOM count and design risk in mission-critical power systems.
Availability
LT3508HUF#TRPBF is available at Aetrix Electronics and suitable for automotive infotainment, industrial DSP power, PCI Express slot power, and DSL/cable modem applications requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for LT3508HUF#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 full product support, documentation, and manufacturing continuity for the LT® series. Linear Technology pioneered high-performance analog and power management ICs with emphasis on precision, reliability, and ruggedness.
The LT3508HUF#TRPBF belongs to Linear's high-voltage dual buck regulator family, designed specifically for automotive, industrial, and telecom applications demanding wide input range, thermal resilience, and integrated sequencing capability without external components.
FAQ
What is the maximum junction temperature specification for the LT3508HUF#TRPBF?
The LT3508HUF#TRPBF is fully specified and guaranteed over a junction temperature range of –40°C to 150°C. This H-grade qualification distinguishes it from E- and I-grade variants and enables direct use in under-hood automotive environments without thermal derating below 125°C. The device incorporates thermal shutdown that activates above 165°C to protect against sustained overload.
Does the LT3508HUF#TRPBF support output voltage tracking between its two channels?
Yes, the LT3508HUF#TRPBF supports precise output voltage tracking using its TRACK/SS1 and TRACK/SS2 pins. By connecting a resistor divider from one regulated output to the TRACK/SS pin of the other channel, the second output will follow the first during startup and transient events. This capability is implemented via an internal 1.2μA current source and comparator architecture - no external op-amps or controllers are needed.
Can the LT3508HUF#TRPBF operate with separate input supplies on VIN1 and VIN2?
Yes, the LT3508HUF#TRPBF supports independent input supplies: VIN1 powers internal bias circuitry and Channel 1, while VIN2 powers only Channel 2. However, Channel 2 requires VIN1 > 3.7V to function - if VIN1 is absent or below UVLO, Channel 2 remains disabled regardless of VIN2 voltage. This architecture enables flexible power domain partitioning while maintaining safety isolation.
What is the purpose of the BOOST1 and BOOST2 pins on the LT3508HUF#TRPBF?
The BOOST1 and BOOST2 pins provide gate drive voltage higher than VIN to fully saturate the internal NPN power switches. Each BOOST pin must be connected through a Schottky diode and capacitor to its respective SW node - forming a charge pump that generates ~VIN + 0.4V. This ensures low RCE(SAT) (<300mV at 1.5A) and high efficiency, especially at low duty cycles or high input voltages.
How does the LT3508HUF#TRPBF handle overload or short-circuit conditions?
The LT3508HUF#TRPBF employs three-tiered protection: (1) cycle-by-cycle current limiting (2.0A–3.2A, duty-cycle dependent), (2) frequency foldback (reducing switching frequency to 120kHz when VFB < 0.625V), and (3) thermal shutdown (>165°C). During sustained overload, foldback reduces peak switch current and power dissipation, preventing thermal runaway while maintaining regulation if possible.
LT3508HUF#TRPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 24-WFQFN Exposed Pad
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Function:
- Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck
- Output Type:
- Adjustable
- Number of Outputs:
- 2
- Voltage - Input (Min):
- 3.7V
- Voltage - Input (Max):
- 36V
- Voltage - Output (Min/Fixed):
- 0.8V
- Voltage - Output (Max):
- 35.28V
- Current - Output:
- 1.4A
- Frequency - Switching:
- 920kHz ~ 1.06MHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- -40°C ~ 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 24-QFN (4x4)
LT3508HUF#TRPBF FAQ
1.How can I place an order for LT3508HUF#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3508HUF#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 LT3508HUF#TRPBF reliable?
The price and inventory of LT3508HUF#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT3508HUF#TRPBF is usually 5 days.
3.What payment methods are accepted for LT3508HUF#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3508HUF#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3508HUF#TRPBF?
LT3508HUF#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3508HUF#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 LT3508HUF#TRPBF?
For technical support, including LT3508HUF#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3508HUF#TRPBF requirements.
6.How does Aetrix verify that LT3508HUF#TRPBF is sourced from the original manufacturer or authorized distributors?
All LT3508HUF#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 LT3508HUF#TRPBF meets industry standards.
7.What is the process for return or replacement of LT3508HUF#TRPBF?
All LT3508HUF#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3508HUF#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 LT3508HUF#TRPBF part is unused and in its original packaging.
Return procedure for LT3508HUF#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LT3508HUF#TRPBF 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…
