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Analog Devices Inc. LTC3605IUF#TRPBF
- Part No.:
- LTC3605IUF#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 24-WFQFN Exposed Pad
- Datasheet:
-
LTC3605IUF#TRPBF.pdf
- Description:
- IC REG BUCK ADJ 5A 24QFN
- Quantity:
- Payment:
- Shipping:
Inventory:7,232
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Product details
Overview
LTC3605IUF#TRPBF from Analog Devices (formerly Linear Technology) is a monolithic synchronous step-down DC/DC regulator delivering up to 5A output current with programmable switching frequency from 800kHz to 4MHz. It features integrated 70mΩ top and 35mΩ bottom N-channel MOSFETs, 0.6V ±1% reference accuracy, and PolyPhase® operation support for up to 12-phase interleaving-used in high-density point-of-load power supplies for FPGA, ASIC, and DSP core rails.
For engineers reviewing the LTC3605IUF#TRPBF datasheet, LTC3605IUF#TRPBF pinout, LTC3605IUF#TRPBF application, or LTC3605IUF#TRPBF equivalent, key selection considerations include its constant-frequency current-mode architecture, phase-lockable oscillator, internal INTVCC LDO, TRACK/SS-enabled output tracking, and thermal performance in the 4mm × 4mm QFN package with exposed PGND pad.
Technical Context
The LTC3605IUF#TRPBF implements a controlled-on-time, constant-frequency current-mode control architecture with dual internal PLLs: one synchronizing the oscillator to an external CLKIN (±30% range), and another servoing the on-time to maintain frequency lock. Its valley-current sensing uses the bottom MOSFET's RDS(ON) as a current sense element, eliminating external sense resistors.
It supports three operational modes via the MODE pin (continuous, discontinuous, or forced CCM), enables output voltage tracking and soft-start via the TRACK/SS pin with 2µA internal pull-up, and provides overvoltage/undervoltage protection with PGOOD monitoring of FB within ±10% of 0.6V. The VON pin allows VOUT-proportional on-time adjustment to stabilize frequency across output voltage changes.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VIN Range | 4V to 15V - supports dual Li-ion battery inputs and 5V/12V intermediate bus systems. |
| Output Current | 5A continuous - sufficient for powering high-performance digital loads like FPGA I/O or CPU cores. |
| Switching Frequency | 800kHz–4MHz (RT-programmable) - enables use of sub-1µH inductors and compact ceramic capacitors. |
| Reference Voltage | 0.6V ±1% (–40°C to 125°C) - ensures tight output regulation across industrial temperature range. |
| Efficiency | Up to 96% at 1MHz - minimizes thermal load and improves power density in space-constrained designs. |
| MOSFET RDS(ON) | 70mΩ (top), 35mΩ (bottom) - reduces conduction losses and eliminates need for external power switches. |
| PolyPhase Support | Up to 12 phases - enables current sharing across multiple LTC3605IUF#TRPBF units with precise phase alignment via CLKIN/CLKOUT. |
Pinout & Package
Package: 24-pin (4mm × 4mm) plastic QFN with exposed PGND pad (Pin 25), rated for –40°C to 125°C operation. Exposed pad must be soldered to PCB ground for thermal and electrical integrity.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| RT (1) | Oscillator frequency programming input | Resistor-to-ground sets switching frequency; determines minimum off-time and duty cycle limits. |
| PHMODE (2) | Phase selector control | Sets CLKOUT phase offset vs CLKIN: INTVCC = 180° (2-phase), SGND = 120° (3-phase), INTVCC/2 = 90° (4-phase). |
| MODE (3) | Operation mode select | INTVCC = forced CCM; SGND = DCM at light load; prevents reverse inductor current and improves light-load efficiency. |
| FB (4) | Feedback voltage input | Compares divider output to 0.6V reference; error amplifier output (ITH) adjusts valley current threshold. |
| TRACK/SS (5) | Tracking & soft-start control | 0–0.6V overrides reference for tracking; capacitor here provides controlled VOUT ramp-up and inrush limiting. |
| ITH (6) | Error amplifier output / compensation node | Directly controls current comparator trip point; tied to INTVCC for simplified internal compensation. |
| RUN (7) | Enable/disable control | >1.2V enables full operation; <1.1V forces shutdown (<15µA IQ); hysteresis prevents chatter near threshold. |
| PGOOD (8) | Open-drain power-good indicator | Pulled low when FB exits 0.54V–0.66V window; includes ~52-cycle blanking to suppress transient glitches. |
| VON (9) | On-time voltage input | Adjusts on-time proportionally to VOUT; maintains constant frequency across output voltage changes when tied to VOUT. |
| PGND (10, 25) | Power ground return | Common return for internal MOSFETs and SW node; exposed pad (25) is mandatory for thermal performance. |
| SW (11–16) | Switch node connection | Drives external inductor; swings from ~–0.3V to PVIN; multiple pins reduce parasitic inductance and improve current sharing. |
| PVIN (17, 18) | Main power input | Supplies top/bottom MOSFETs; dual pins reduce IR drop and enhance thermal dissipation. |
| SVIN (19) | Filtered signal input for INTVCC LDO | Connected to PVIN via RC filter (1–10Ω + 0.1µF) to reject noise and stabilize internal 3.3V regulator. |
| BOOST (20) | Bootstrap supply for top MOSFET gate driver | Swings up to PVIN + INTVCC; requires external bootstrap capacitor between BOOST and SW. |
| INTVCC (21) | Internal 3.3V LDO output | Powers gate drivers and control logic; must be bypassed with ≥1µF low-ESR ceramic capacitor to GND. |
| SGND (22) | Signal ground reference | Separate from PGND to minimize noise coupling into sensitive analog circuitry (FB, ITH, TRACK/SS). |
| CLKOUT (23) | PolyPhase clock output | Drives CLKIN of next stage; phase relationship determined by PHMODE; amplitude = INTVCC to GND. |
| CLKIN (24) | External synchronization input | Accepts external clock (800kHz–4MHz); internal PLL locks oscillator and on-time to rising edge. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated Power MOSFETs | Eliminates external switch components and associated layout complexity while maintaining 96% peak efficiency. |
| Constant-Frequency Current-Mode Control | Delivers fast line/load transient response and stable loop behavior without requiring external slope compensation. |
| PolyPhase® Interleaving Support | Reduces input/output ripple current by up to 12× and enables scalable high-current solutions with minimal capacitance. |
| Output Tracking and Soft-Start | Enables coordinated power-up sequencing with other rails and prevents inrush current damage to input capacitors or source. |
| Internal 3.3V INTVCC Regulator | Provides dedicated low-noise bias for gate drivers and analog circuits, reducing need for external LDOs and simplifying BOM. |
| VIN Overvoltage Protection | Automatically suspends switching if PVIN exceeds 17V, protecting internal MOSFETs from transient spikes without external clamping. |
Applications
| Point-of-Load Regulation | FPGA Core Power |
|---|---|
Use Scenario: Providing tightly regulated 1.2V/3.3V rails directly adjacent to high-speed digital ICs on dense PCBs. IC Role / Device Role / Timing Role: Primary synchronous buck regulator delivering up to 5A with fast transient response and low output impedance. Use Value: Maintains <±1% output accuracy under dynamic load steps up to 5A/µs, minimizing voltage droop during logic switching. | Use Scenario: Powering Xilinx or Intel FPGA core voltages where sequencing, tracking, and low noise are critical. IC Role / Device Role / Timing Role: Core rail controller with TRACK/SS pin enabling precise voltage ramp alignment with auxiliary rails (e.g., I/O, memory). Use Value: Prevents latch-up or configuration errors during power-up by ensuring core voltage tracks within ±2% of reference rail. |
| Battery-Powered Instrumentation | Distributed Telecom Power |
Use Scenario: High-efficiency power conversion in portable test equipment powered by dual Li-ion batteries (8–12.6V). IC Role / Device Role / Timing Role: Main DC/DC converter stepping down battery voltage to 3.3V/1.8V system rails with ultra-low quiescent current in shutdown. Use Value: Draws <15µA in shutdown mode, extending battery life during standby while retaining fast wake-up capability. | Use Scenario: Scalable 12-phase power delivery in 1RU telecom servers requiring >60A total output with low EMI. IC Role / Device Role / Timing Role: One unit in a synchronized PolyPhase array, contributing 5A per phase with precise 30° phase offset. Use Value: Reduces RMS input ripple current by >90%, allowing smaller bulk capacitors and easing EMI filter design. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar synchronous buck regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MP2315DJ-LF-Z | 4.5–24V input, 3A output, fixed 500kHz frequency, no PolyPhase or TRACK/SS support | Lower current, no multi-phase sync or output tracking; suited for cost-sensitive, single-rail applications | Select when 3A output suffices and phase synchronization or rail sequencing is unnecessary. |
| TPS54560QDGQRQ1 | 3.5–60V input, 5A output, adjustable frequency (100kHz–2.5MHz), integrated compensation, AEC-Q100 qualified | Wider VIN range and automotive qualification; lacks PolyPhase clocking and precise 0.6V reference accuracy | Select for automotive environments or high-input-voltage industrial systems where extended temp and reliability certification are required. |
Compared with MP2315DJ-LF-Z and TPS54560QDGQRQ1, the LTC3605IUF#TRPBF uniquely combines 5A capability, 0.6V ±1% reference, PolyPhase clocking, and TRACK/SS functionality in a thermally optimized QFN-making it optimal for high-performance, multi-rail, space-constrained digital power systems.
Availability
LTC3605IUF#TRPBF is available at Aetrix Electronics and suitable for point-of-load regulation, FPGA core power, battery-powered instrumentation, distributed telecom power, and high-density embedded computing requiring stable component supply and long-term production continuity.
Supply support for LTC3605IUF#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. (ADI) is a global leader in high-performance analog, mixed-signal, and power management semiconductors, formed through the acquisition of Linear Technology in 2017.
The LTC3605IUF#TRPBF belongs to ADI's Power by Linear™ family of monolithic DC/DC regulators, engineered specifically for high-efficiency, high-density, and high-transient-performance power delivery in advanced digital systems.
FAQ
What is the operating temperature range for the LTC3605IUF#TRPBF?
The LTC3605IUF#TRPBF is specified for operation from –40°C to +125°C junction temperature and is guaranteed over this full range. Its "I" grade designation confirms industrial temperature qualification, making it suitable for demanding embedded and telecom applications where ambient temperatures exceed commercial limits. Derating curves and thermal resistance (θJA = 37°C/W) are provided in the datasheet to support board-level thermal design.
How does the LTC3605IUF#TRPBF achieve output voltage tracking?
The LTC3605IUF#TRPBF achieves output voltage tracking using the TRACK/SS pin (Pin 5). When an external voltage between 0V and 0.6V is applied to this pin, the error amplifier servo-controls the FB pin to match that voltage-effectively regulating VOUT proportionally to the external reference. An internal 2µA pull-up current enables soft-start when a capacitor is connected, providing controlled ramp-up and preventing input inrush. This function is active only during startup until TRACK/SS exceeds 0.6V.
Can the LTC3605IUF#TRPBF operate in discontinuous conduction mode (DCM)?
Yes, the LTC3605IUF#TRPBF can operate in discontinuous conduction mode (DCM) at light loads when the MODE pin (Pin 3) is tied to SGND. In DCM, the bottom MOSFET turns off when inductor current reaches zero, reducing switching losses and improving light-load efficiency. Tying MODE to INTVCC forces continuous conduction mode (CCM) regardless of load-ensuring constant frequency and predictable ripple but with higher light-load losses.
What is the purpose of the VON pin on the LTC3605IUF#TRPBF?
The VON pin (Pin 9) on the LTC3605IUF#TRPBF sets the on-time comparator threshold and enables VOUT-proportional on-time adjustment. When tied to the output voltage, it makes the on-time linearly proportional to VOUT, stabilizing switching frequency across different output voltages. If VON is below 0.6V or above 6V, frequency regulation is lost. This feature is essential for maintaining consistent performance in multi-output systems where VOUT varies.
Does the LTC3605IUF#TRPBF require external compensation components?
The LTC3605IUF#TRPBF supports both internal and external ITH compensation. Tying the ITH pin (Pin 6) to INTVCC activates internal compensation (30kΩ + 40pF), simplifying design at the expense of loop optimization. For best transient response and minimal output capacitance, external compensation is recommended-using discrete RC networks connected to ITH to tailor the error amplifier's transconductance and pole/zero placement per application requirements.
LTC3605IUF#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:
- 1
- Voltage - Input (Min):
- 4V
- Voltage - Input (Max):
- 15V
- Voltage - Output (Min/Fixed):
- 0.6V
- Voltage - Output (Max):
- 14.85V
- Current - Output:
- 5A
- Frequency - Switching:
- 1MHz
- Synchronous Rectifier:
- Yes
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 24-QFN (4x4)
LTC3605IUF#TRPBF FAQ
1.How can I place an order for LTC3605IUF#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3605IUF#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 LTC3605IUF#TRPBF reliable?
The price and inventory of LTC3605IUF#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC3605IUF#TRPBF is usually 5 days.
3.What payment methods are accepted for LTC3605IUF#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3605IUF#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC3605IUF#TRPBF?
LTC3605IUF#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3605IUF#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 LTC3605IUF#TRPBF?
For technical support, including LTC3605IUF#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3605IUF#TRPBF requirements.
6.How does Aetrix verify that LTC3605IUF#TRPBF is sourced from the original manufacturer or authorized distributors?
All LTC3605IUF#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 LTC3605IUF#TRPBF meets industry standards.
7.What is the process for return or replacement of LTC3605IUF#TRPBF?
All LTC3605IUF#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC3605IUF#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 LTC3605IUF#TRPBF part is unused and in its original packaging.
Return procedure for LTC3605IUF#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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