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Analog Devices Inc. LTC3633AIUFD-3#TRPBF
- Part No.:
- LTC3633AIUFD-3#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 28-WFQFN Exposed Pad
- Datasheet:
-
LTC3633AIUFD-3#TRPBF.pdf
- Description:
- IC REG BUCK ADJ 3A DL 28QFN
- Quantity:
- Payment:
- Shipping:
Inventory:3,246
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Product details
Overview
LTC3633AIUFD-3#TRPBF from Analog Devices (formerly Linear Technology) is a dual-channel monolithic synchronous step-down regulator delivering 3A per channel across 3.6V–20V input, with 1.5V–12V output voltage sense range, selectable 0°/180° phase shift, and programmable 500kHz–4MHz switching frequency. It serves as a high-efficiency point-of-load power supply in distributed systems requiring tight regulation and fast transient response.
For engineers reviewing the LTC3633AIUFD-3#TRPBF datasheet, LTC3633AIUFD-3#TRPBF pinout, LTC3633AIUFD-3#TRPBF application, or LTC3633AIUFD-3#TRPBF equivalent, key selection criteria include its dual-channel 3A capability, VON sense range (1.5V–12V), phase-shifted operation for reduced input ripple, Burst Mode® vs forced continuous mode trade-offs, and QFN-28 thermal performance at –40°C to 125°C.
Technical Context
The LTC3633AIUFD-3#TRPBF employs a current-mode controlled on-time architecture with internal PLL synchronization, enabling stable constant-frequency operation even at high step-down ratios and low duty cycles (5% at 2.25MHz). Its dual independent channels support out-of-phase switching via PHMODE pin control to minimize input capacitor RMS current.
Each channel features independent RUN enable, TRACKSS soft-start/tracking, ITH loop compensation, and VON-based on-time programming-where VON1/VON2 accept 1.5V–12V inputs to maintain frequency accuracy across the full output range. Overvoltage lockout (22.5V rising) and overtemperature protection are integrated.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 3.6V to 20V - supports Li-ion battery stacks and standard 5V/12V rail inputs without external pre-regulation. |
| Output Current per Channel | 3A continuous - enables dual 3A POL supplies from single IC, reducing board area vs discrete solutions. |
| Output Voltage Sense Range | 1.5V to 12V - matches LTC3633A-3 variant; ensures accurate on-time control for higher-output applications (e.g., 5V, 12V rails). |
| Switching Frequency Range | 500kHz to 4MHz - adjustable via RT resistor; allows optimization of inductor size (e.g., 1µH at 2MHz) vs efficiency. |
| Efficiency | Up to 95% - achieved at mid-load with optimized layout; critical for thermally constrained embedded systems. |
| Phase Shift Control | Selectable 0° or 180° - reduces input capacitance requirements by interleaving channel currents. |
| Operating Temperature | –40°C to 125°C junction - qualified for industrial and automotive under-hood environments. |
Pinout & Package
Package: 28-lead (4mm × 5mm) plastic QFN with exposed PGND pad (Pin 29), requiring soldering to PCB for thermal and electrical integrity. θJA = 43°C/W.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| PGOOD1 / PGOOD2 | Open-drain power-good status outputs | Assert low when respective VFB deviates >±8% from 0.6V reference; filtered (40µs) to avoid transient glitches. |
| PHMODE | Phase select input | Tie to GND for in-phase, INTVCC for 180° out-of-phase operation - directly controls SW1/SW2 timing alignment. |
| RUN1 / RUN2 | Channel enable inputs | Enable channel at >1.22V; shutdown at <1.01V - supports independent sequencing and fault isolation. |
| MODE/SYNC | Mode select & external clock input | Ground = forced continuous; float/INTVCC = Burst Mode®; driven clock = sync + forced continuous. |
| RT | Oscillator frequency program | Resistor to SGND sets fSW (500kHz–4MHz); tie to INTVCC for ~2MHz default - enables precise EMI control. |
| VFB1 / VFB2 | Feedback inputs | Compare output divider voltage to 0.6V reference - sets regulated output (e.g., 3.3V via 10k/5.11k divider). |
| TRACKSS1 / TRACKSS2 | Tracking/soft-start inputs | Accept external voltage <0.6V to force output tracking; internal 1.4µA pull-up enables RC soft-start (e.g., 4.7nF → ~700µs). |
| ITH1 / ITH2 | Error amplifier outputs | Connect external RC network for loop compensation; tie to INTVCC for internal default compensation. |
| VON1 / VON2 | On-time voltage inputs | Set on-time trip point (1.5V–12V range for LTC3633A-3); tying to VOUT enables VOUT-proportional on-time for stable high-VOUT operation. |
| SW1 / SW2 | Switch node terminals | Drive external inductors; swing from ~–0.3V to PVIN - require low-inductance layout and proper bootstrapping. |
| BOOST1 / BOOST2 | Floating gate drive supplies | Connect bootstrap capacitors between BOOSTx and SWx - sustain high-side MOSFET gate drive during 100% duty cycle. |
| PVIN1 / PVIN2 | Independent power inputs | Support separate input rails per channel (e.g., 12V for Channel 1, 5V for Channel 2) - enables flexible multi-rail designs. |
| SVIN | Signal supply input | Powers internal control circuitry and INTVCC LDO - must be ≥3.6V; decoupled with ≥1µF ceramic to PGND. |
| INTVCC | Internal 3.3V regulator output | Powers drivers and logic; disabled when both RUN pins are low - requires ≥1µF low-ESR ceramic bypass. |
| PGND | Power ground (exposed pad) | Return path for input/output capacitors and MOSFET sources - must be soldered to large copper pour for thermal and noise control. |
Key Features
| Feature | Design Value |
|---|---|
| Controlled on-time current mode architecture | Delivers fast load transient response (<10µs recovery) and stable operation at high step-down ratios (e.g., 12V→1.5V @ 2MHz). |
| 180° phase-shifted dual-channel operation | Reduces input capacitor RMS current by ~30% vs in-phase, allowing smaller CIN and lower ESR requirements. |
| Burst Mode® operation | Extends light-load efficiency (e.g., >85% at 10mA) by disabling switching and entering sleep mode - ideal for battery-powered standby states. |
| Independent channel enable and tracking | Enables power sequencing (e.g., RUN1 before RUN2) and output voltage ramp coordination (e.g., 3.3V tracks 5V during startup). |
| Integrated overvoltage and overtemperature protection | Shuts down channels upon PVIN >22.5V or TJ >125°C, then auto-resumes after fault clearance - eliminates need for external supervision circuits. |
Applications
| Distributed Power Systems | Battery-Powered Instruments |
|---|---|
Use Scenario: Dual-rail power delivery in telecom line cards with 12V backplane and isolated 3.3V/5V logic domains. IC Role / Device Role / Timing Role: Dual-channel synchronous buck regulator providing independent, sequenced 3A outputs with phase interleaving to reduce input ripple. Use Value: Eliminates two discrete regulators; 180° phase shift cuts input capacitor count by 50% while maintaining <10mVpp output ripple. | Use Scenario: Portable test equipment requiring long battery life and clean analog/digital supplies. IC Role / Device Role / Timing Role: Primary POL converter generating 3.3V for microcontroller and 5V for display backlight from single Li-ion cell stack. Use Value: Burst Mode® extends runtime >3× at standby; independent RUN pins allow MCU-controlled shutdown of non-critical rails. |
| Point-of-Load Power Supplies | Industrial Embedded Controllers |
Use Scenario: FPGA core and I/O rail generation on compact carrier boards with strict thermal limits. IC Role / Device Role / Timing Role: High-density dual 3A regulator with QFN-28 package and 43°C/W θJA, supporting 1.5V/3.3V outputs. Use Value: Achieves 92% efficiency at 3A/1.5V with 1µH inductors; thermal design fits ≤10cm² footprint without heatsink. | Use Scenario: DIN-rail mounted PLC CPU module operating in uncontrolled ambient (–40°C to 85°C). IC Role / Device Role / Timing Role: Main 5V/3A and 3.3V/3A supply with extended temperature qualification (–40°C to 125°C junction). Use Value: Guaranteed operation across full industrial temp range; PGOOD outputs feed system watchdog for fail-safe reset management. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar dual-channel synchronous buck regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC3633AEUFD-3#TRPBF | Same electrical specs and pinout; differs only in temperature grade (E-grade: 0°C to 85°C vs I-grade). | Suitable for commercial/office environments; not rated for extended industrial temperature extremes. | Select when ambient temperature stays within 0°C–85°C and cost sensitivity outweighs extended temp assurance. |
| TPS543B20RTWT | Single-channel 3A buck with PMBus interface; no dual-channel or phase-shift capability; 4.5V–18V input. | Requires two units for dual-rail; adds digital control overhead but enables real-time telemetry and margining. | Choose when digital monitoring, dynamic voltage scaling, or tighter output tolerance (±0.5%) are required over analog simplicity. |
Compared with LTC3633AEUFD-3#TRPBF, the LTC3633AIUFD-3#TRPBF guarantees full –40°C to 125°C operation, making it suitable for harsh environments where E-grade may derate. Versus TPS543B20RTWT, it offers native dual-channel integration and analog control simplicity but lacks digital configurability and telemetry.
Availability
LTC3633AIUFD-3#TRPBF is available at Aetrix Electronics and suitable for distributed power systems, battery-powered instruments, and point-of-load power supplies requiring stable component supply across industrial temperature ranges and long production lifecycles.
Supply support for LTC3633AIUFD-3#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.
The LTC3633A family was designed for high-efficiency, space-constrained dual-rail DC/DC conversion in industrial, telecom, and portable applications-emphasizing thermal robustness, fast transient response, and flexible sequencing.
FAQ
What is the VON sense range for LTC3633AIUFD-3#TRPBF?
The LTC3633AIUFD-3#TRPBF has a VON sense range of 1.5V to 12V, distinguishing it from the LTC3633A-2 variant (0.6V–6V). This wider range ensures accurate on-time control when regulating higher output voltages like 5V or 12V, preventing frequency deviation that occurs if VOUT falls outside the supported VON window. The LTC3633AIUFD-3#TRPBF uses this specification to maintain stable switching across its full output capability.
How does phase-shifted operation reduce input ripple in LTC3633AIUFD-3#TRPBF?
When configured for 180° phase shift via the PHMODE pin, LTC3633AIUFD-3#TRPBF staggers the switching of its two channels so their input current pulses alternate rather than coincide. This interleaving cuts peak-to-peak input ripple current by up to 50% compared to in-phase operation, allowing smaller input capacitors and lower ESR requirements. The LTC3633AIUFD-3#TRPBF achieves this without external controllers-directly from its integrated PLL and timing logic.
Can LTC3633AIUFD-3#TRPBF operate with different input voltages on each channel?
Yes, LTC3633AIUFD-3#TRPBF supports independent PVIN1 and PVIN2 inputs, enabling operation from separate supply rails-for example, 12V on Channel 1 and 5V on Channel 2. Each channel's power MOSFETs are isolated, and the SVIN pin powers only the control circuitry. This flexibility allows LTC3633AIUFD-3#TRPBF to serve heterogeneous power domains without level-shifting or additional regulators.
What protection features are integrated into LTC3633AIUFD-3#TRPBF?
LTC3633AIUFD-3#TRPBF integrates short-circuit protection on both channels, input overvoltage lockout (22.5V rising threshold), and overtemperature shutdown (125°C junction). Upon fault detection, it disables switching and auto-resumes once conditions normalize-no external circuitry needed. These protections are active across the full –40°C to 125°C operating range and are verified in the LTC3633AIUFD-3#TRPBF datasheet absolute maximum ratings and functional specifications.
Is external compensation required for stable operation of LTC3633AIUFD-3#TRPBF?
No, LTC3633AIUFD-3#TRPBF includes internal compensation and can operate stably with ITH1 and ITH2 tied to INTVCC. External RC networks on ITH pins are optional and used only when optimizing loop bandwidth or phase margin for specific output capacitor ESR/load transient profiles. The default internal compensation ensures robust stability across typical 1µH–2.2µH inductors and ceramic output capacitors, as validated in the LTC3633AIUFD-3#TRPBF typical application circuits.
LTC3633AIUFD-3#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:
- 2
- Voltage - Input (Min):
- 3.6V
- Voltage - Input (Max):
- 20V
- Voltage - Output (Min/Fixed):
- 1.5V
- Voltage - Output (Max):
- 12V
- Current - Output:
- 3A
- Frequency - Switching:
- 500kHz ~ 4MHz
- Synchronous Rectifier:
- Yes
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 28-QFN (4x5)
LTC3633AIUFD-3#TRPBF FAQ
1.How can I place an order for LTC3633AIUFD-3#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3633AIUFD-3#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 LTC3633AIUFD-3#TRPBF reliable?
The price and inventory of LTC3633AIUFD-3#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC3633AIUFD-3#TRPBF is usually 5 days.
3.What payment methods are accepted for LTC3633AIUFD-3#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3633AIUFD-3#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC3633AIUFD-3#TRPBF?
LTC3633AIUFD-3#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3633AIUFD-3#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 LTC3633AIUFD-3#TRPBF?
For technical support, including LTC3633AIUFD-3#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3633AIUFD-3#TRPBF requirements.
6.How does Aetrix verify that LTC3633AIUFD-3#TRPBF is sourced from the original manufacturer or authorized distributors?
All LTC3633AIUFD-3#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 LTC3633AIUFD-3#TRPBF meets industry standards.
7.What is the process for return or replacement of LTC3633AIUFD-3#TRPBF?
All LTC3633AIUFD-3#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC3633AIUFD-3#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 LTC3633AIUFD-3#TRPBF part is unused and in its original packaging.
Return procedure for LTC3633AIUFD-3#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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