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Analog Devices Inc. LTC3603EUF#PBF
- Part No.:
- LTC3603EUF#PBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 20-WFQFN Exposed Pad
- Datasheet:
-
LTC3603EUF#PBF.pdf
- Description:
- IC REG BUCK ADJ 2.5A 20QFN
- Quantity:
- Payment:
- Shipping:
Inventory:3,051
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Product details
Overview
LTC3603EUF#PBF from Analog Devices (formerly Linear Technology) is a monolithic synchronous step-down DC/DC regulator delivering up to 2.5A at adjustable output voltages from 0.6V to 14.5V, operating from 4.5V–15V input, with 45mΩ top/85mΩ bottom MOSFETs and 1MHz typical switching frequency. It serves as a high-efficiency point-of-load power supply in communications infrastructure and portable instrumentation.
For engineers reviewing the LTC3603EUF#PBF datasheet, LTC3603EUF#PBF pinout, LTC3603EUF#PBF application, or LTC3603EUF#PBF equivalent, key selection considerations include its 20-lead 4mm × 4mm QFN package, OPTI-LOOP® compensation for transient optimization, programmable Burst Mode clamp, Power Good output, and thermal performance with θJA = 37°C/W.
Technical Context
The LTC3603EUF#PBF implements constant-frequency current-mode control with internal N-channel synchronous switches, enabling precise peak-current limiting (3.8A–5.2A) and 99% maximum duty cycle for low-dropout operation. Its error amplifier features 1.7mS transconductance and 0.6V ±1% reference, supporting tight regulation across load and line variations.
It supports three operating modes via SYNC/MODE pin voltage: forced continuous (SYNC/MODE ≥ 1.1V), Burst Mode (0.42V–1.0V), or pulse-skipping (SYNC/MODE = 0V), with external frequency setting via RT resistor (300kHz–3MHz) and synchronization capability to external clock (0.3–3MHz).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 4.5V to 15V - supports wide industrial and telecom input rails without pre-regulation. |
| Output Current | Up to 2.5A - sufficient for FPGA core, DSP, or ASIC point-of-load applications. |
| Switch RDS(ON) | Top: 45mΩ, Bottom: 85mΩ - enables >90% efficiency at 2.5A with minimal conduction loss. |
| Feedback Reference | 0.6V ±1% - allows accurate low-voltage outputs (e.g., 0.8V, 1.0V, 1.2V) with standard resistor dividers. |
| Quiescent Current | 75µA in Burst Mode - extends battery life in always-on portable systems. |
| Switching Frequency | Programmable 300kHz–3MHz - balances inductor size vs. efficiency; 1MHz typical enables compact 2.2µH designs. |
| Power Good Output | Open-drain, ±10% window - provides reliable system-level power sequencing and fault detection. |
| Thermal Resistance | θJA = 37°C/W - requires exposed pad soldered to PCB ground plane for rated thermal performance. |
Pinout & Package
Package: 20-lead (4mm × 4mm) plastic QFN with exposed thermal pad (Pin 21 = SGND). Requires soldering of exposed pad to PCB for thermal and electrical integrity.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| PVIN (Pins 1, 2) | Main power input | Accepts 4.5V–15V; must be decoupled locally to PGND with low-ESR capacitor. |
| SW (Pins 16–19) | Switch node | Connects to inductor; high dv/dt node requiring minimized trace area and proximity to PGND. |
| PGND (Pins 12–15) | Power ground return | Low-impedance path for high pulsed currents; separate from SGND except at single-point connection. |
| BOOST (Pin 20) | Floating gate drive supply | Charged via bootstrap capacitor between BOOST and SW; critical for top MOSFET turn-on. |
| INTVCC (Pin 3) | Internal 5V LDO output | Supplies internal circuitry; decouple with 1µF ceramic capacitor to SGND. |
| VFB (Pin 8) | Feedback input | Senses output via resistor divider; high-impedance (10nA bias) for precision regulation. |
| ITH (Pin 7) | Error amplifier compensation | External compensation network sets loop stability and transient response. |
| RT (Pin 6) | Frequency set | Resistor to ground sets oscillator frequency; 105kΩ yields ~1MHz. |
| RUN (Pin 10) | Enable control | Active-high; 0.4V–1.1V threshold; tie to PVIN for always-on operation. |
| TRACK/SS (Pin 11) | Soft-start / tracking input | 1.2µA pull-up enables external soft-start capacitor or voltage tracking for multi-rail sequencing. |
| SYNC/MODE (Pin 4) | Mode select / sync input | Determines Burst Mode, forced continuous, or pulse-skipping; also accepts external clock. |
| PGOOD (Pin 5) | Power good monitor | Open-drain output asserted high when VOUT within ±10%; requires external pull-up. |
| SGND (Pin 9, Exposed Pad Pin 21) | Signal ground reference | Reference for VFB, ITH, RUN, TRACK/SS; exposed pad must be soldered to PCB ground plane. |
Key Features
| Feature | Design Value |
|---|---|
| OPTI-LOOP® Compensation | Enables stable loop response across wide output capacitor ESR ranges and load conditions without redesign. |
| Adjustable Burst Mode Clamp | External voltage on SYNC/MODE pin sets minimum inductor peak current, allowing ripple vs. efficiency trade-off tuning. |
| Synchronous Switching | Eliminates external Schottky diode, reducing BOM count and improving light-load efficiency by >5%. |
| Overtemperature Protection | Shuts down both switches at ~150°C junction; auto-restarts at ~115°C - prevents thermal runaway in sealed enclosures. |
| 99% Maximum Duty Cycle | Supports ultra-low dropout (e.g., 5.0V out from 5.2V in) while maintaining regulation via periodic bottom-switch refresh. |
| Power Good Output | Provides system-level power sequencing confirmation with ±10% accuracy - essential for FPGA and microprocessor boot reliability. |
Applications
| Baseband Processor Power | Industrial PLC I/O Module |
|---|---|
Use Scenario: Powering ARM-based baseband processors in LTE small cells requiring tightly regulated 1.0V/1.2V core and 1.8V I/O rails with strict sequencing. IC Role / Device Role / Timing Role: Primary point-of-load regulator delivering 2.5A at 1.0V with TRACK/SS-controlled voltage ramp to match companion rail timing. Use Value: OPTI-LOOP® ensures stable transient response during bursty data transmission; PGOOD confirms rail readiness before processor release from reset. | Use Scenario: Supplying isolated analog front-end circuitry (ADCs, DACs, op-amps) in DIN-rail mounted PLC modules operating from 12V or 24V DC input. IC Role / Device Role / Timing Role: High-efficiency 3.3V/2.5A local regulator with low 75µA quiescent current in Burst Mode for standby monitoring functions. Use Value: 45mΩ/85mΩ MOSFETs minimize self-heating in convection-cooled enclosures; overvoltage protection guards against field-wiring faults. |
| Portable Test Equipment | Optical Transceiver Module |
Use Scenario: Battery-powered handheld oscilloscopes or spectrum analyzers needing clean, low-noise 5V and ±12V supplies derived from single-cell Li-ion (3.0–4.2V) via boost + buck stages. IC Role / Device Role / Timing Role: Secondary buck stage generating 5V @ 2.5A from intermediate 12V rail; configured in forced continuous mode to avoid RF interference with sensitive analog signal paths. Use Value: Synchronization to system clock eliminates beat frequencies; low 115ns min on-time supports high VIN/VOUT ratios in compact layouts. | Use Scenario: Providing 3.3V bias to SFP+ transceivers in enterprise switches, where EMI and thermal density are constrained by pluggable module form factor. IC Role / Device Role / Timing Role: Compact 4mm × 4mm QFN regulator placed directly on transceiver PCB; uses external 105kΩ RT for 1MHz operation to minimize inductor size. Use Value: Exposed pad thermal design (θJA = 37°C/W) sustains full 2.5A output in 0.5"² footprint; PGOOD enables hot-plug detection and link initialization handshake. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar synchronous step-down regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MP2315DJ-LF-Z | Fixed 3.3V output; no adjustable feedback; 2.2A max output; no PGOOD or TRACK/SS. | Limited to fixed-output applications; lacks sequencing and monitoring features required for complex SoC power trees. | Select only for cost-sensitive, single-rail embedded systems where flexibility and diagnostics are not needed. |
| TPS54227PWPR | 2.5A, 4.5–18V input, but uses external MOSFETs; no integrated switches; requires more external components. | Higher design complexity and board area; better thermal scalability for >2.5A, but less suitable for space-constrained PoL use cases. | Prefer when thermal management demands discrete FETs or when input exceeds 15V. |
Compared with MP2315DJ-LF-Z and TPS54227PWPR, the LTC3603EUF#PBF uniquely integrates high-current synchronous switches, precision 0.6V reference, PGOOD, TRACK/SS, and OPTI-LOOP® in a thermally optimized 4mm × 4mm QFN - making it optimal for compact, multi-rail, high-reliability point-of-load designs.
Availability
LTC3603EUF#PBF is available at Aetrix Electronics and suitable for communications infrastructure, portable instrumentation, and industrial PLC I/O modules requiring stable component supply with long-term lifecycle assurance.
Supply support for LTC3603EUF#PBF 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 automotive and industrial qualification standards.
The LTC3603EUF#PBF belongs to Linear's monolithic synchronous buck regulator family, designed specifically for high-efficiency, low-noise, and thermally constrained point-of-load applications in telecom, test equipment, and industrial automation.
FAQ
What is the maximum output current capability of the LTC3603EUF#PBF?
The LTC3603EUF#PBF delivers up to 2.5A of continuous output current under typical thermal conditions (θJA = 37°C/W, 25°C ambient, exposed pad soldered). Peak current limit is specified at 3.8A–5.2A, but sustained 2.5A operation requires proper PCB layout, copper area, and airflow per the thermal design guidelines in the datasheet. The LTC3603EUF#PBF achieves this with integrated 45mΩ/85mΩ MOSFETs and optimized thermal pad construction.
Does the LTC3603EUF#PBF support output voltage tracking for multi-rail sequencing?
Yes, the LTC3603EUF#PBF supports voltage tracking via the TRACK/SS pin. Applying a ramp voltage (e.g., from another regulator's output) to this pin causes the LTC3603EUF#PBF output to follow that ramp until it reaches 0.6V, after which regulation transitions to the internal reference. This enables precise core/I/O sequencing for FPGAs and microprocessors. The LTC3603EUF#PBF also supports external soft-start using a capacitor on TRACK/SS, with a 1.2µA internal current source.
How is switching frequency programmed on the LTC3603EUF#PBF?
Switching frequency on the LTC3603EUF#PBF is set by an external resistor (ROSC) connected between the RT pin and ground. The relationship is ROSC = (1.15 × 10¹¹)/f(Hz) – 10kΩ, supporting 300kHz to 3MHz. For example, a 105kΩ resistor yields ~1MHz. The LTC3603EUF#PBF can also synchronize to an external 5V clock applied to the SYNC/MODE pin, with capture range 0.3–3MHz - useful for EMI reduction in dense systems.
What protection features does the LTC3603EUF#PBF include?
The LTC3603EUF#PBF integrates overtemperature shutdown (~150°C trip, ~115°C restart), PVIN overvoltage lockout (~16.5V), output overvoltage protection (via PGOOD and top-FET disable), and short-circuit current limiting (valley current >4.5A triggers cycle skipping). It also includes undervoltage lockout on INTVCC (4.1–4.3V) and robust absolute maximum ratings (e.g., 21V transient on PVIN). These protections ensure robust operation in industrial and telecom environments without external supervision circuits.
Is the LTC3603EUF#PBF pin-compatible with other variants in the LTC3603 family?
No - the LTC3603EUF#PBF uses a 20-lead 4mm × 4mm QFN package, while the eMSOP variants (e.g., LTC3603EMSE#PBF) use a 16-lead eMSOP. Pin functions differ significantly between packages: the QFN has four SW pins, four PGND pins, and dedicated SGND (exposed pad), whereas the eMSOP consolidates pins differently. Layout and thermal design are not interchangeable. Always verify pin mapping and thermal pad requirements using the official LTC3603EUF#PBF datasheet.
LTC3603EUF#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 20-WFQFN Exposed Pad
- Packaging:
- Tube
- Product Status:
- Active
- Function:
- Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck
- Output Type:
- Adjustable
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 4.5V
- Voltage - Input (Max):
- 15V
- Voltage - Output (Min/Fixed):
- 0.6V
- Voltage - Output (Max):
- 14.5V
- Current - Output:
- 2.5A
- Frequency - Switching:
- 1MHz
- Synchronous Rectifier:
- Yes
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 20-QFN (4x4)
LTC3603EUF#PBF FAQ
1.How can I place an order for LTC3603EUF#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3603EUF#PBF 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 LTC3603EUF#PBF reliable?
The price and inventory of LTC3603EUF#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC3603EUF#PBF is usually 5 days.
3.What payment methods are accepted for LTC3603EUF#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3603EUF#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC3603EUF#PBF?
LTC3603EUF#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3603EUF#PBF 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 LTC3603EUF#PBF?
For technical support, including LTC3603EUF#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3603EUF#PBF requirements.
6.How does Aetrix verify that LTC3603EUF#PBF is sourced from the original manufacturer or authorized distributors?
All LTC3603EUF#PBF 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 LTC3603EUF#PBF meets industry standards.
7.What is the process for return or replacement of LTC3603EUF#PBF?
All LTC3603EUF#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC3603EUF#PBF, 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 LTC3603EUF#PBF part is unused and in its original packaging.
Return procedure for LTC3603EUF#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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