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Analog Devices Inc. LT3504EUFD#TRPBF
- Part No.:
- LT3504EUFD#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 28-WFQFN Exposed Pad
- Datasheet:
-
LT3504EUFD#TRPBF.pdf
- Description:
- IC REG BUCK ADJ 1A QUAD 28QFN
- Quantity:
- Payment:
- Shipping:
Inventory:816
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Product details
Overview
LT3504EUFD#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 switching frequency from 250kHz to 2.2MHz. It is used in multi-rail industrial power supplies requiring tight output tracking and sequencing.
For engineers reviewing the LT3504EUFD#TRPBF datasheet, LT3504EUFD#TRPBF pinout, LT3504EUFD#TRPBF application, or LT3504EUFD#TRPBF equivalent, key selection criteria include channel independence, anti-phase switching for ripple reduction, SKY pin drive capability for high-side saturation, and robust fault protection including catch diode current limiting and thermal shutdown.
Technical Context
The LT3504EUFD#TRPBF integrates four identical buck regulators sharing a single on-chip boost regulator (Channel 5) that generates SKY voltage at VIN + 4.85V to fully saturate internal bipolar switches. Each channel operates with independent RUN/SS pins enabling per-channel soft-start and output voltage tracking via resistor divider coupling.
Its oscillator supports resistor-programmed constant-frequency operation or external synchronization (350kHz–2.2MHz), with antiphase clocking between Channel pairs (1/3/5 vs 2/4) to reduce input ripple. Protection includes cycle-by-cycle peak current limit, catch diode current limit sensing, and thermal shutdown triggered above 175°C junction temperature.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 3.2V to 40V - supports wide-range industrial and automotive battery inputs without external pre-regulation. |
| Output Current per Channel | 1A continuous - enables compact multi-rail designs powering FPGAs, DSPs, or mixed-signal subsystems. |
| Feedback Reference Voltage | 790–816mV (–40°C to 125°C) - ensures stable regulation across temperature with <±1.5% output error. |
| Switching Frequency Range | 250kHz to 2.2MHz - allows optimization of size (higher fSW) vs efficiency (lower fSW) and EMI filtering requirements. |
| SKY Drive Voltage | VIN + 4.85V - provides sufficient gate drive headroom for full saturation of internal bipolar power switches up to 40V input. |
| Power Good Threshold | FB rising ≥710mV per channel - guarantees all outputs are within regulation before asserting open-collector PG signal. |
| Thermal Shutdown Threshold | 175°C junction - protects internal switches during overload or poor PCB thermal design without latch-up. |
Pinout & Package
Tiny 28-lead (4mm × 5mm) thermally enhanced QFN package with exposed pad (Pin 29) soldered to PCB ground for optimal thermal performance. θJA = 43°C/W.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| DA1–DA4 (Pins 1,3,6,8) | Catch diode anode sense | Enables per-channel diode current limiting to prevent inductor current runaway during transients. |
| SW1–SW4 (Pins 2,4,5,7) | Buck switch node | Connects to inductor and Schottky cathode; supports 1.45–2.1A switch current limit depending on duty cycle. |
| VIN (Pins 9,11,26,28) | Main input supply | Four parallel pins reduce IR drop and improve current handling; must be locally bypassed to GND. |
| 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) | Per-channel enable & soft-start | 1.3µA internal current source ramps voltage; <0.1V forces shutdown; >0.9V enables full 800mV FB regulation. |
| EN/UVLO (Pin 16) | Global enable & UVLO input | 1.44V rising threshold enables startup; hysteresis (110mV) prevents oscillation near trip point. |
| RT/SYNC (Pin 17) | Frequency programming/sync input | Resistor-to-GND sets fSW; external clock (≥50ns pulse width) synchronizes internal oscillator. |
| FB1–FB4 (Pins 19–22) | Output voltage feedback | Regulated to 800mV; resistor divider sets VOUT = 0.8V × (1 + R1/R2); R2 = 10kΩ recommended. |
| PG (Pin 23) | Power good indicator | Open-collector output pulled low until all FB pins exceed 710mV; disabled in shutdown. |
| SW5 (Pin 24) | Boost regulator switch | Drives external inductor to generate SKY voltage; 220–320mA switch current limit. |
| SKY (Pin 25) | Boost output / gate drive rail | Provides VIN + 4.85V to drive internal buck switches; requires 1µF capacitor to VIN. |
Key Features
| Feature | Design Value |
|---|---|
| 100% duty cycle operation | Enabled by integrated boost regulator (SW5/SKY), eliminating need for external charge pumps in low-VIN/high-VOUT applications. |
| Independent channel control | Four dedicated RUN/SS pins allow staggered start-up, individual shutdown, and precise output voltage tracking via resistor networks. |
| Anti-phase switching | Channels 1/3/5 operate 180° out-of-phase with Channels 2/4, reducing input capacitor RMS current and EMI. |
| Catch diode current limiting | Monitors DA pin voltage to detect reverse recovery and prevent inductor current reversal during light-load or transient conditions. |
| Internal compensation | Reduces external component count; eliminates need for external compensation network on each FB loop. |
| Short-circuit robustness | Combined cycle-by-cycle switch current limit and catch diode current limit protect against sustained short-circuit faults without latch-up. |
Applications
| Industrial Control Power Supply | Automotive Body Control Module |
|---|---|
|
Use Scenario: Powering multiple isolated rails (5V, 3.3V, 2.5V, 1.8V) for PLC I/O modules, sensor interfaces, and communication peripherals in factory automation systems. IC Role / Device Role / Timing Role: Quad buck regulator providing independent, sequenced, and tracked outputs with single-board integration and minimal BOM count. Use Value: Eliminates four discrete DC/DC converters, reduces PCB area by >40%, and enables synchronized soft-start to avoid inrush current violations. |
Use Scenario: Generating regulated voltages for microcontrollers, CAN transceivers, LED drivers, and sensor front-ends in 12V/24V automotive body electronics. IC Role / Device Role / Timing Role: Primary multi-output PMIC handling cold-crank (down to 3.2V) and load-dump (up to 40V) conditions while maintaining rail stability. Use Value: Wide input range and 100% duty cycle support uninterrupted operation during battery brownouts; PG pin enables system-level power sequencing. |
| Distributed Telecom Supply | Test & Measurement Equipment |
|
Use Scenario: Local regulation of intermediate bus (e.g., 12V or 24V) into clean, low-noise rails for FPGA, ADC/DAC, and RF front-end ICs in base station radios. IC Role / Device Role / Timing Role: High-efficiency quad converter with anti-phase switching minimizing input ripple and easing bulk capacitor selection. Use Value: Achieves >90% efficiency at full load across 6V–36V input; SKY-driven switches maintain efficiency at high input voltages where MOSFET gate drive is marginal. |
Use Scenario: Precision multi-rail power for benchtop instruments requiring low-noise analog supplies, digital core rails, and isolated auxiliary voltages. IC Role / Device Role / Timing Role: Regulator with tight output tolerance (±1.5%), low load regulation (<±0.5%), and programmable sequencing for calibration-sensitive subsystems. Use Value: Independent RUN/SS pins enable controlled ramp-up of analog and digital domains to prevent latch-up or measurement artifacts during power-on. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar quad buck regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LT3514EUFD#TRPBF | Three-channel 1A/2A/1A configuration; same 28-pin QFN footprint and pin-compatible; lacks fourth 1A channel. | Suitable when only three regulated rails are needed; CH3 delivers 2A instead of 1A, better for higher-current single loads. | Select LT3514EUFD#TRPBF if system requires one high-current rail (>1A) and two standard rails, and fourth rail is unnecessary. |
| MPQ4436GL-AEC1-P | Quad 3A buck with integrated MOSFETs; 3.3V–36V input; no internal boost-requires external gate driver for high-side saturation at high VIN. | Designed for AEC-Q100 automotive qualification; higher per-channel current but larger solution size and no 100% duty cycle capability. | Choose MPQ4436GL-AEC1-P for automotive-qualified designs needing >1A per rail and ISO 26262 functional safety support. |
Compared with LT3504EUFD#TRPBF, LT3514EUFD#TRPBF trades one channel for higher current on CH3 and maintains pin compatibility, while MPQ4436GL-AEC1-P offers AEC-Q100 compliance and higher current but sacrifices 100% duty cycle and increases external component count.
Availability
LT3504EUFD#TRPBF is available at Aetrix Electronics and suitable for industrial control supplies, automotive body electronics, and distributed telecom power systems requiring stable component supply, long-term lifecycle support, and guaranteed parametric performance over –40°C to 125°C.
Supply support for LT3504EUFD#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. (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 LT3504EUFD#TRPBF belongs to Linear's high-voltage monolithic buck regulator product line, designed specifically for space-constrained, multi-rail applications demanding wide input range, fault resilience, and precise output coordination without external complexity.
FAQ
What is the maximum input voltage rating for LT3504EUFD#TRPBF?
The absolute maximum input voltage for LT3504EUFD#TRPBF is 40V on the VIN pins. Operation up to this limit is supported across the full –40°C to 125°C junction temperature range. However, for constant-frequency operation without pulse-skipping, the practical maximum depends on output voltage, switching frequency, and minimum on-time (110ns at 125°C); exceeding it causes skipped pulses and increased ripple but does not damage the LT3504EUFD#TRPBF.
How does the SKY pin function in LT3504EUFD#TRPBF?
The SKY pin in LT3504EUFD#TRPBF is the output of the integrated boost regulator (Channel 5), delivering a regulated voltage equal to VIN + 4.85V. It serves as the gate drive rail for all four internal buck power switches, ensuring full saturation even at high input voltages. A 1µF capacitor must be placed between SKY and VIN; external loading or voltage injection on SKY is strictly prohibited.
Can LT3504EUFD#TRPBF achieve 100% duty cycle operation, and how is it implemented?
Yes, LT3504EUFD#TRPBF supports true 100% duty cycle operation via its internal boost regulator (SW5/SKY). By generating SKY at VIN + 4.85V, the IC ensures sufficient gate-source voltage to fully turn on the internal bipolar switches regardless of input-to-output differential. This eliminates the need for external charge pumps and enables regulation down to VOUT ≈ VIN, critical for low-dropout industrial and automotive applications.
What protection features are built into LT3504EUFD#TRPBF?
LT3504EUFD#TRPBF includes cycle-by-cycle peak switch current limiting, catch diode current limiting (via DA pins), thermal shutdown at ~175°C junction temperature, and undervoltage lockout on both VIN (2.4–3.2V) and EN/UVLO (1.2–1.6V). These protections operate independently per channel or globally, ensuring robust operation under overload, short-circuit, overtemperature, and brownout conditions without latch-up.
Is LT3504EUFD#TRPBF pin-compatible with any other Linear/Analog Devices regulators?
Yes, LT3504EUFD#TRPBF is pin-compatible with the LT3514EUFD#TRPBF in the same 28-lead 4mm × 5mm QFN package. Both share identical pin functions and layout, though LT3514EUFD#TRPBF provides three channels (1A/2A/1A) instead of four 1A channels. This allows direct substitution where fourth rail is not required, simplifying redesign and qualification.
LT3504EUFD#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)
LT3504EUFD#TRPBF FAQ
1.How can I place an order for LT3504EUFD#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3504EUFD#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 LT3504EUFD#TRPBF reliable?
The price and inventory of LT3504EUFD#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT3504EUFD#TRPBF is usually 5 days.
3.What payment methods are accepted for LT3504EUFD#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3504EUFD#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3504EUFD#TRPBF?
LT3504EUFD#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3504EUFD#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 LT3504EUFD#TRPBF?
For technical support, including LT3504EUFD#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3504EUFD#TRPBF requirements.
6.How does Aetrix verify that LT3504EUFD#TRPBF is sourced from the original manufacturer or authorized distributors?
All LT3504EUFD#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 LT3504EUFD#TRPBF meets industry standards.
7.What is the process for return or replacement of LT3504EUFD#TRPBF?
All LT3504EUFD#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3504EUFD#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 LT3504EUFD#TRPBF part is unused and in its original packaging.
Return procedure for LT3504EUFD#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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