My Inquiry
My Account
Analog Devices Inc. LT3504IUFD#TRPBF
- Part No.:
- LT3504IUFD#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 28-WFQFN Exposed Pad
- Datasheet:
-
LT3504IUFD#TRPBF.pdf
- Description:
- IC REG BUCK ADJ 1A QUAD 28QFN
- Quantity:
- Payment:
- Shipping:
Inventory:2,510
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
LT3504IUFD#TRPBF from Analog Devices (formerly Linear Technology) is a quad 40V/1A synchronous step-down switching regulator IC with integrated boost regulator for 100% duty cycle operation. It features four independent 1A buck channels, 3.2V–40V input range, 800mV feedback reference, and programmable 200kHz–2.2MHz switching frequency. Used in automotive battery regulation and industrial distributed power systems where high input voltage tolerance and channel sequencing are required.
For engineers reviewing the LT3504IUFD#TRPBF datasheet, LT3504IUFD#TRPBF pinout, LT3504IUFD#TRPBF application, or LT3504IUFD#TRPBF equivalent, key selection criteria include per-channel RUN/SS control, SKY pin drive capability for internal switch saturation, anti-phase switching to reduce input ripple, and thermal shutdown with –40°C to 125°C operating junction temperature rating.
Technical Context
The LT3504IUFD#TRPBF integrates four independent current-mode buck regulators sharing a single on-chip boost regulator (SW5/SKY) that generates +4.85V above VIN to fully saturate bipolar power switches. Each channel employs cycle-by-cycle peak current limiting and catch diode current limiting for robust short-circuit protection.
It supports output voltage tracking via resistor-divided RUN/SS pins, programmable undervoltage lockout (EN/UVLO threshold = 1.44V rising), and power-good indication (PG) asserting when all FB pins exceed 710mV. Switching phase is fixed at 180° between channel pairs (CH1/CH3 vs CH2/CH4) to minimize input capacitor RMS current.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 3.2V to 40V - supports direct connection to 24V/36V industrial rails and automotive batteries with transient tolerance up to 40V. |
| Output Current per Channel | 1A continuous - enables compact 4-output DC/DC solution without external MOSFETs or gate drivers. |
| Feedback Reference Voltage | 790–816mV (–40°C to 125°C) - tight 800mV nominal reference enables accurate output regulation across temperature. |
| Switching Frequency Range | 200kHz to 2.2MHz - selectable via RT resistor or external SYNC signal; allows optimization of size vs efficiency. |
| Thermal Shutdown Threshold | 125°C junction - protects internal power switches during overload or poor PCB thermal design. |
| Quiescent Current (Shutdown) | ≤2µA - minimizes standby power draw in always-on systems such as telematics or sensor nodes. |
| SKY Pin Drive Voltage | VSKY = VIN + 4.85V - ensures full saturation of internal bipolar switches across full input range. |
Pinout & Package
Tiny 28-lead (4mm × 5mm) thermally enhanced QFN package with exposed pad (Pin 29) soldered to PCB ground plane for optimal thermal performance. Package meets JEDEC MO-220 standard.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| DA1–DA4 (Pins 1,3,6,8) | Catch diode anode sense | Monitors Schottky diode current to prevent inductor current runaway during transients. |
| SW1–SW4 (Pins 2,4,5,7) | Buck switch node | Connects to inductor and diode cathode; internal bipolar switch rated 1.75A typical current limit. |
| VIN (Pins 9,11,26,28) | Main power input | Supplies internal regulator and power switches; must be locally bypassed with low-ESR capacitors. |
| GND (Pins 10,18,27,29) | Ground reference | Exposed pad (Pin 29) is mandatory GND connection for thermal and electrical integrity. |
| RUN/SS1–RUN/SS4 (Pins 12–15) | Channel enable & soft-start | Internal 1.3µA current source ramps voltage; pulling below 0.1V shuts down individual channel. |
| EN/UVLO (Pin 16) | Global enable & UVLO input | 1.44V rising threshold enables startup; also functions as precision undervoltage lockout. |
| RT/SYNC (Pin 17) | Oscillator programming | Resistor-to-ground sets frequency; external clock input synchronizes all four channels. |
| FB1–FB4 (Pins 19–22) | Output voltage feedback | Regulated to 800mV; output voltage set by R1/R2 divider per channel. |
| PG (Pin 23) | Power good indicator | Open-collector output asserts high when all outputs reach ≥710mV (i.e., within regulation). |
| SW5 (Pin 24) | Boost regulator switch | Drives external inductor to generate SKY voltage; 320mA typical current limit. |
| SKY (Pin 25) | Boost output rail | Provides +4.85V above VIN to drive internal buck switches; requires 1µF ceramic capacitor to VIN. |
Key Features
| Feature | Design Value |
|---|---|
| 100% duty cycle operation | Enables output voltages approaching VIN (e.g., 12V→12V LDO replacement) using internal boost-regulated gate drive. |
| Anti-phase switching | Reduces input ripple current by interleaving CH1/CH3 and CH2/CH4, lowering required input capacitance. |
| Independent RUN/SS pins | Allows per-channel soft-start timing and output voltage tracking for controlled power-up sequencing. |
| Integrated boost regulator (SW5/SKY) | Eliminates need for four external charge pumps; reduces BOM count and layout complexity. |
| Short-circuit robustness | Dual current limiting (switch peak + catch diode) prevents damage during output faults or startup into short. |
Applications
| Automotive Battery Regulation | Industrial Control Supplies |
|---|---|
Use Scenario: Powering infotainment head units, ADAS sensors, and body control modules from 12V/24V vehicle battery with load dump transients up to 40V. IC Role / Device Role / Timing Role: Quad buck regulator providing isolated 5V, 3.3V, 2.5V, and 1.8V rails with independent sequencing and fault isolation. Use Value: Eliminates need for discrete pre-regulators or external boost circuits; maintains regulation during cold-crank (down to 3.2V VIN). | Use Scenario: Distributed power in PLC I/O modules, motor drives, and factory automation controllers requiring multiple isolated low-noise supplies. IC Role / Device Role / Timing Role: Centralized multi-rail DC/DC converter delivering four regulated outputs with synchronized switching and thermal monitoring. Use Value: Reduces board area by >40% vs discrete solutions; anti-phase operation cuts input capacitor size and EMI filtering requirements. |
| Wall Transformer Regulation | Distributed Supply Regulation |
Use Scenario: Universal-input AC/DC adapters powering networking equipment (routers, switches) with varying output voltage needs. IC Role / Device Role / Timing Role: Primary DC/DC stage accepting wide-range DC input (e.g., 9–40V from rectified wall transformer) and generating multiple system rails. Use Value: Supports 100% duty cycle for high-VIN/low-VOUT cases (e.g., 36V→3.3V); internal compensation simplifies design validation. | Use Scenario: Point-of-load conversion in telecom base stations and server backplanes where space-constrained boards require dense multi-output regulation. IC Role / Device Role / Timing Role: Compact quad buck controller enabling four independent, trackable power domains on a single IC. Use Value: RUN/SS pin tracking enables precise power-up order (e.g., core before I/O); PG pin simplifies system-level power sequencing logic. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar quad buck regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC3375EFE#PBF | 8-channel configurable buck (1–4×1A, 1–2×2A); lower max VIN (20V); no integrated boost for 100% DC. | Better for lower-input-voltage, higher-channel-count systems needing flexible current allocation. | Select LTC3375 if input <20V and channel current flexibility outweighs 40V tolerance and 100% duty cycle. |
| MPQ4436GL-AEC1-P | Quad 3A buck; AEC-Q200 qualified; 3.3–36V VIN; no internal boost; requires external gate drivers for high-side switches. | Targeted for automotive under-hood use with stricter qualification; lacks SKY-based 100% DC capability. | Choose MPQ4436 for AEC-Q200 compliance and higher per-channel current; avoid if 100% duty cycle or >36V VIN needed. |
Compared with LTC3375EFE#PBF and MPQ4436GL-AEC1-P, the LT3504IUFD#TRPBF uniquely delivers 40V input tolerance, integrated boost for true 100% duty cycle, and independent RUN/SS control-making it optimal for industrial and legacy automotive systems where high VIN and precise sequencing are critical.
Availability
LT3504IUFD#TRPBF is available at Aetrix Electronics and suitable for automotive battery regulation, industrial control supplies, and distributed supply regulation requiring stable component supply across extended temperature ranges.
Supply support for LT3504IUFD#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-performance analog and power management portfolio with rigorous reliability testing and long-term product support.
The LT3504IUFD#TRPBF belongs to Linear's high-voltage monolithic buck regulator family, designed specifically for robust multi-rail power conversion in harsh environments where input transients, thermal stress, and sequencing control are critical.
FAQ
What is the maximum input voltage rating for the LT3504IUFD#TRPBF?
The LT3504IUFD#TRPBF has an absolute maximum VIN rating of 40V, with guaranteed operation from 3.2V to 40V. Exceeding 40V risks permanent damage. During normal operation, it regulates outputs up to 40V input, though constant-frequency operation above ~36V may induce pulse-skipping due to minimum on-time limits.
Does the LT3504IUFD#TRPBF require external components for boost functionality?
Yes - the LT3504IUFD#TRPBF requires two external components for its integrated boost regulator: an inductor connected between SW5 and VIN, and a 1µF ceramic capacitor between SKY and VIN. These are mandatory to generate the +4.85V SKY rail that drives the internal buck switches.
How does the LT3504IUFD#TRPBF achieve 100% duty cycle operation?
The LT3504IUFD#TRPBF achieves 100% duty cycle by using its internal boost regulator to generate SKY = VIN + 4.85V, which provides sufficient gate drive voltage to fully saturate the internal bipolar power switches even when VOUT ≈ VIN. This eliminates the need for external charge pumps or external high-side drivers.
Can all four channels of the LT3504IUFD#TRPBF be synchronized to a single external clock?
Yes - the RT/SYNC pin accepts an external clock signal (250kHz–2.2MHz, >50ns pulse width) that synchronizes all four buck channels and the internal boost regulator. This eliminates beat frequencies and simplifies EMI filtering in noise-sensitive systems.
What is the purpose of the DA pins on the LT3504IUFD#TRPBF?
The DA1–DA4 pins on the LT3504IUFD#TRPBF provide dedicated return paths for Schottky catch diode anodes and enable catch diode current limiting. An internal comparator monitors DA pin current to prevent inductor current runaway during fast load transients or output short conditions.
LT3504IUFD#TRPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 28-WFQFN Exposed Pad
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Function:
- Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck
- Output Type:
- Adjustable
- Number of Outputs:
- 4
- Voltage - Input (Min):
- 3.2V
- Voltage - Input (Max):
- 40V
- Voltage - Output (Min/Fixed):
- 0.8V
- Voltage - Output (Max):
- 40V
- Current - Output:
- 1A
- Frequency - Switching:
- 250kHz ~ 2.1MHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 28-QFN (4x5)
LT3504IUFD#TRPBF FAQ
1.How can I place an order for LT3504IUFD#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3504IUFD#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 LT3504IUFD#TRPBF reliable?
The price and inventory of LT3504IUFD#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT3504IUFD#TRPBF is usually 5 days.
3.What payment methods are accepted for LT3504IUFD#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3504IUFD#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3504IUFD#TRPBF?
LT3504IUFD#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3504IUFD#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 LT3504IUFD#TRPBF?
For technical support, including LT3504IUFD#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3504IUFD#TRPBF requirements.
6.How does Aetrix verify that LT3504IUFD#TRPBF is sourced from the original manufacturer or authorized distributors?
All LT3504IUFD#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 LT3504IUFD#TRPBF meets industry standards.
7.What is the process for return or replacement of LT3504IUFD#TRPBF?
All LT3504IUFD#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3504IUFD#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 LT3504IUFD#TRPBF part is unused and in its original packaging.
Return procedure for LT3504IUFD#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LT3504IUFD#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…
