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Analog Devices Inc. LTC3605AEUF#TRPBF
- Part No.:
- LTC3605AEUF#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 24-WFQFN Exposed Pad
- Datasheet:
-
LTC3605AEUF#TRPBF.pdf
- Description:
- IC REG BUCK ADJ 5A 24QFN
- Quantity:
- Payment:
- Shipping:
Inventory:6,170
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Product details
Overview
LTC3605AEUF#TRPBF from Analog Devices (formerly Linear Technology) is a 20V, 5A monolithic synchronous step-down regulator with phase-lockable controlled-on-time current-mode architecture. It operates from 4V to 20V input, delivers up to 96% efficiency at 1MHz, features integrated 70mΩ/35mΩ N-MOSFETs, and supports PolyPhase® operation up to 12 phases for high-current point-of-load power in portable instrumentation.
For engineers reviewing the LTC3605AEUF#TRPBF datasheet, LTC3605AEUF#TRPBF pinout, LTC3605AEUF#TRPBF application, or LTC3605AEUF#TRPBF equivalent, key selection considerations include its 0.6V ±1% reference accuracy, 800kHz–4MHz programmable switching frequency via RT resistor, ±10% PGOOD window, 40ns minimum on-time, and 24-pin 4mm × 4mm QFN package with exposed PGND pad.
Technical Context
The LTC3605AEUF#TRPBF implements dual phase-locked loops: one synchronizes the internal oscillator to an external CLKIN (±30% range), while the other servos the regulator's on-time to maintain constant frequency under load and input variation. Its current-mode control uses valley-current sensing via the bottom MOSFET's RDS(ON), with ITH pin voltage directly setting the current comparator threshold.
Operation supports both continuous conduction mode (CCM) and discontinuous mode (DCM), selectable via MODE pin; output tracking and soft-start are implemented through the TRACK/SS pin with internal 2.5µA pull-up; VIN overvoltage lockout triggers at 23.5V and recovers at 21.5V without soft-start reinitiation.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VIN Range | 4V to 20V - supports dual/triple Li-ion battery inputs and 5V/12V rail point-of-load conversion |
| Output Current | 5A - delivered continuously with integrated power MOSFETs and thermal design using exposed PGND pad |
| Switching Frequency | 800kHz to 4MHz - set by RT resistor; externally synchronizable within ±30% of programmed value |
| Feedback Reference | 0.6V ±1% - enables precise output voltage setting (e.g., VOUT = 0.6V × (1 + R2/R1)) |
| Efficiency | Up to 96% - achieved at 1MHz, VOUT = 3.3V, VIN = 12V, IOUT = 5A with optimized external components |
| MOSFET RDS(ON) | 70mΩ (top), 35mΩ (bottom) - integrated N-channel devices reduce BOM count and layout complexity |
| PGOOD Threshold | ±10% around 0.6V (0.54V–0.66V) - open-drain output with 12Ω pull-down and 52-cycle blanking delay |
Pinout & Package
Package: 24-pin (4mm × 4mm) plastic QFN with exposed thermal pad (Pin 25), rated for –40°C to 125°C junction temperature. Exposed pad must be soldered to PCB ground for electrical continuity and thermal performance (θJA = 37°C/W).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| RT (1) | Oscillator programming | Resistor-to-SGND sets switching frequency (800kHz–4MHz); determines PLL lock range |
| PHMODE (2) | Phase selector input | Configures CLKOUT phase offset: INTVCC = 2-phase, SGND = 3-phase, INTVCC/2 = 4-phase |
| MODE (3) | Operation mode control | INTVCC = forced CCM; SGND = DCM at light loads; prevents shoot-through in low-IOUT conditions |
| FB (4) | Feedback sense input | Compares resistive divider output to 0.6V reference; regulates VOUT with ±1% accuracy |
| TRACK/SS (5) | Tracking & soft-start control | 0–0.6V overrides reference for tracking; capacitor enables controlled VOUT ramp-up |
| ITH (6) | Error amplifier output | Sets valley current limit; tied to INTVCC enables internal compensation and output voltage positioning |
| RUN (7) | Enable/disable control | >1.2V enables full operation; <1.1V shuts down; draws <15µA in shutdown |
| PGOOD (8) | Power-good status | Open-drain output pulled low if VFB outside 0.54V–0.66V; includes transient blanking |
| VON (9) | On-time voltage input | Programs constant-frequency behavior across VOUT; invalid if <0.6V or >6V |
| PGND (10, 25) | Power ground return | Return path for internal MOSFETs; exposed pad (Pin 25) must be soldered to PCB ground plane |
| SW (11–16) | Switch node | Connects to external inductor; swings from ~–0.3V to PVIN; multiple pins reduce trace inductance |
| PVIN (17, 18) | Main power input | Supplies top/bottom MOSFETs; absolute max 22V; transient rating up to 24.5V |
| SVIN (19) | Signal input supply | Filtered input to 3.3V LDO; requires RC filter (1Ω–10Ω + 0.1µF) to PVIN for noise rejection |
| BOOST (20) | Bootstrap supply | Floating gate drive supply for top MOSFET; connects to bootstrap capacitor positive terminal |
| INTVCC (21) | Internal 3.3V regulator output | Powers gate drivers and bias circuits; requires ≥1µF ceramic bypass to PGND |
| SGND (22) | Signal ground | Reference for analog circuitry; separate from PGND to minimize noise coupling |
| CLKOUT (23) | PolyPhase clock output | Drives CLKIN of next stage; amplitude = INTVCC to GND; phase determined by PHMODE |
| CLKIN (24) | External sync input | Internally terminated to SGND with 20kΩ; locks internal oscillator to external clock source |
Key Features
| Feature | Design Value |
|---|---|
| Controlled-on-time architecture | Enables fast transient response and stable operation at high step-down ratios and high frequencies |
| PolyPhase® capability | Supports up to 12-phase interleaving via daisy-chained CLKIN/CLKOUT, reducing input/output ripple and capacitor stress |
| Integrated power MOSFETs | Eliminates need for external high-side/low-side switches; reduces board area and layout sensitivity |
| Output voltage tracking | Allows coordinated startup with other rails via external voltage applied to TRACK/SS pin |
| VIN overvoltage protection | Automatically suspends switching at 23.5V and resumes at 21.5V - protects internal FETs during transients |
Applications
| Battery-Powered Portable Instruments | Point-of-Load Power Supply |
|---|---|
Use Scenario: Handheld test equipment requiring stable 3.3V/1.2V rails from dual-cell Li-ion (8.4V max) with minimal heat rise and compact footprint. IC Role / Device Role / Timing Role: Primary buck regulator delivering 5A at 1MHz; provides regulated VOUT with tight line/load regulation and fast load-step recovery. Use Value: High 96% efficiency extends battery life; 40ns min-on-time enables high-VIN/low-VOUT conversion without dropout; QFN package supports dense PCB layouts. | Use Scenario: FPGA or ASIC core voltage supply in telecom baseband cards where multiple distributed 1.8V/1.2V rails demand low-noise, high-current delivery. IC Role / Device Role / Timing Role: Synchronous buck controller implementing PolyPhase® interleaving with up to 12 phases for ripple cancellation and thermal sharing. Use Value: Reduced input/output capacitance requirements due to phase interleaving; ±1% reference ensures accurate core voltage compliance per JEDEC spec. |
| Distributed Power Systems | Industrial Embedded Controllers |
Use Scenario: Modular PLC backplane with isolated 12V input powering multiple 5V/3.3V subsystems requiring independent enable/control and fault reporting. IC Role / Device Role / Timing Role: Standalone DC/DC converter with RUN-controlled sequencing and open-drain PGOOD for system-level power monitoring. Use Value: Independent RUN and PGOOD pins allow safe power-up/down sequencing; SVIN/PVIN separation improves noise immunity in noisy industrial environments. | Use Scenario: Ruggedized edge gateway running Linux with DDR3 memory, requiring tightly regulated 1.5V DDR termination and 3.3V I/O rails under wide ambient temperature (–40°C to 125°C). IC Role / Device Role / Timing Role: High-reliability buck regulator operating across full industrial temp range; uses internal 3.3V LDO (INTVCC) to power own gate drivers. Use Value: Guaranteed –40°C to 125°C operation (E-grade); 22V absolute max VIN withstands 24V field wiring transients; exposed PGND pad ensures thermal stability. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar synchronous buck regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC3605EUF#TRPBF | Same pinout and function; rated for 0°C to 85°C (E-grade) vs. –40°C to 125°C (LTC3605AEUF#TRPBF) | Lower-cost option for commercial-temperature applications; not suitable for extended industrial or automotive environments | Select LTC3605AEUF#TRPBF when full –40°C to 125°C operation is required; E-grade lacks guaranteed specs over full range. |
| MP2451DT-LF-Z | 3A output, 4.5V–28V input, fixed 500kHz frequency; no PolyPhase, no external frequency programming, no TRACK/SS | Cost-sensitive, lower-current applications where phase synchronization and output tracking are unnecessary | Choose MP2451DT-LF-Z only for simple 3A point-of-load needs without advanced features; LTC3605AEUF#TRPBF offers 5A, programmability, and multi-phase scalability. |
Compared with LTC3605EUF#TRPBF, the LTC3605AEUF#TRPBF guarantees full –40°C to 125°C operation and tighter parametric limits across temperature; versus MP2451DT-LF-Z, it delivers 67% higher current, full frequency control, PolyPhase support, and precision tracking-making it suitable for demanding embedded and industrial systems where reliability and feature depth are critical.
Availability
LTC3605AEUF#TRPBF is available at Aetrix Electronics and suitable for battery-powered portable instruments, point-of-load power supplies, and industrial embedded controllers requiring stable component supply, long-term lifecycle support, and guaranteed –40°C to 125°C operation.
Supply support for LTC3605AEUF#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 power management portfolio with rigorous characterization and long-term product commitment.
The LTC3605A family was designed for high-efficiency, high-current, multi-phase point-of-load regulation in space-constrained and thermally demanding applications such as portable instrumentation and industrial control systems.
FAQ
What is the absolute maximum input voltage rating for the LTC3605AEUF#TRPBF?
The LTC3605AEUF#TRPBF has an absolute maximum PVIN/SVIN voltage rating of 22V. Transient voltage on SW is rated to 24.5V. Exceeding these values may cause permanent damage. The device also includes VIN overvoltage protection that suspends operation above 23.5V and resumes at 21.5V - this is a protective feature, not an absolute rating.
How does the PHMODE pin affect PolyPhase operation in the LTC3605AEUF#TRPBF?
The PHMODE pin configures the phase offset between CLKIN and CLKOUT: tying PHMODE to INTVCC yields 180° (2-phase), to SGND yields 120° (3-phase), and to INTVCC/2 yields 90° (4-phase). This allows up to 12 phases when cascading multiple LTC3605AEUF#TRPBF units, reducing input/output ripple and improving thermal distribution across converters.
Can the LTC3605AEUF#TRPBF operate in discontinuous conduction mode (DCM)?
Yes, the LTC3605AEUF#TRPBF supports DCM at light loads when the MODE pin is tied to SGND. In this mode, the bottom MOSFET turns off when inductor current reverses, minimizing switching losses. Tying MODE to INTVCC forces continuous conduction mode (CCM) regardless of load - useful for noise-sensitive applications requiring constant frequency.
What is the purpose of the SVIN pin on the LTC3605AEUF#TRPBF, and how should it be connected?
The SVIN pin supplies the internal 3.3V LDO (INTVCC) with a filtered version of PVIN. It must be connected to PVIN through a 1Ω–10Ω resistor and bypassed to PGND with a 0.1µF ceramic capacitor. This RC filter isolates noise-sensitive analog circuitry from power-switching noise on PVIN, ensuring stable INTVCC regulation and accurate feedback control.
Does the LTC3605AEUF#TRPBF support output voltage tracking, and how is it implemented?
Yes, the LTC3605AEUF#TRPBF supports output voltage tracking via the TRACK/SS pin. Applying an external ramp voltage (0–0.6V) to this pin overrides the internal 0.6V reference and forces VFB to follow it, enabling coordinated startup with other rails. An external capacitor on TRACK/SS provides soft-start functionality, limiting inrush current during power-up.
LTC3605AEUF#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):
- 20V
- Voltage - Output (Min/Fixed):
- 0.6V
- Voltage - Output (Max):
- 19.8V
- 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)
LTC3605AEUF#TRPBF FAQ
1.How can I place an order for LTC3605AEUF#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3605AEUF#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 LTC3605AEUF#TRPBF reliable?
The price and inventory of LTC3605AEUF#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC3605AEUF#TRPBF is usually 5 days.
3.What payment methods are accepted for LTC3605AEUF#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3605AEUF#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC3605AEUF#TRPBF?
LTC3605AEUF#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3605AEUF#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 LTC3605AEUF#TRPBF?
For technical support, including LTC3605AEUF#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3605AEUF#TRPBF requirements.
6.How does Aetrix verify that LTC3605AEUF#TRPBF is sourced from the original manufacturer or authorized distributors?
All LTC3605AEUF#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 LTC3605AEUF#TRPBF meets industry standards.
7.What is the process for return or replacement of LTC3605AEUF#TRPBF?
All LTC3605AEUF#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC3605AEUF#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 LTC3605AEUF#TRPBF part is unused and in its original packaging.
Return procedure for LTC3605AEUF#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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