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Analog Devices Inc. LTC3633AIUFD#TRPBF
- Part No.:
- LTC3633AIUFD#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 28-WFQFN Exposed Pad
- Datasheet:
-
LTC3633AIUFD#TRPBF.pdf
- Description:
- IC REG BUCK ADJ 3A DL 28QFN
- Quantity:
- Payment:
- Shipping:
Inventory:953
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Product details
Overview
LTC3633AIUFD#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 programmable 500kHz–4MHz switching frequency, 0.6V reference, and 180° phase-shift capability for interleaved operation. It serves as a high-efficiency point-of-load power supply in battery-powered instruments and distributed power systems.
For engineers reviewing the LTC3633AIUFD#TRPBF datasheet, LTC3633AIUFD#TRPBF pinout, LTC3633AIUFD#TRPBF application, or LTC3633AIUFD#TRPBF equivalent, key selection considerations include its dual 3A output capability, controlled on-time current-mode architecture, Burst Mode® vs forced continuous mode trade-offs, and QFN-28 package thermal performance at –40°C to 125°C.
Technical Context
The LTC3633AIUFD#TRPBF implements a constant-frequency, controlled on-time current-mode architecture with internal PLL synchronization-enabling precise frequency matching to external clocks while maintaining fast transient response. Its two channels support independent enable (RUN1/RUN2), selectable 0°/180° phase shift via PHMODE, and separate VON1/VON2 inputs for output-voltage-proportional on-time control.
Each channel features independent feedback (VFB1/VFB2), error amplifier compensation (ITH1/ITH2), tracking/soft-start (TRACKSS1/TRACKSS2), and open-drain PGOOD status outputs. Input overvoltage lockout (22.5V trip) and thermal shutdown protect against fault conditions without external circuitry.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 3.6V to 20V - supports Li-ion stacks and 5V/12V intermediate bus supplies. |
| Output Current per Channel | 3A continuous - enables dual-rail PoL delivery without external MOSFETs. |
| Switching Frequency Range | 500kHz to 4MHz - adjustable via RT resistor or external sync clock for EMI optimization. |
| Feedback Reference Voltage | 0.6V ±1% - allows low-output voltages (e.g., 0.8V, 1.2V) with standard resistor dividers. |
| Efficiency | Up to 95% - achieved at full load with optimized inductor/capacitor selection. |
| Phase Shift Control | Selectable 0° or 180° - reduces input/output RMS ripple and capacitor stress in dual-channel operation. |
| Operating Temperature Range | –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 (Pin 1) | Channel 1 power-good status | Open-drain output pulled low if VFB1 deviates >±8% from 0.6V; releases at ±5% with 40µs filter. |
| PHMODE (Pin 2) | Phase select control | Ground = in-phase; INTVCC = 180° out-of-phase interleaving for reduced input ripple. |
| RUN1 (Pin 3) | Channel 1 enable | Active-high logic: >1.22V enables regulation; <1.01V disables channel with soft-stop. |
| MODE/SYNC (Pin 4) | Mode selection & sync input | Ground = forced continuous mode; floating/INTVCC = Burst Mode®; driven clock = sync + forced continuous. |
| RT (Pin 5) | Oscillator frequency programming | Resistor to SGND sets fSW from 500kHz–4MHz; tied to INTVCC defaults to ~2MHz. |
| RUN2 (Pin 6) | Channel 2 enable | Independent enable control identical to RUN1, supporting staggered startup or fault isolation. |
| SGND (Pin 7) | Signal ground reference | Low-noise return for feedback divider, RT, and compensation networks-separate from PGND. |
| PGOOD2 (Pin 8) | Channel 2 power-good status | Functionally identical to PGOOD1, enabling independent rail monitoring. |
| VFB2 (Pin 9) | Channel 2 feedback input | Connects to resistor divider; error amplifier compares to 0.6V reference for regulation. |
| TRACKSS2 (Pin 10) | Channel 2 tracking/soft-start | Sub-0.6V voltage forces output tracking; internal 1.4µA pull-up enables RC soft-start. |
| ITH2 (Pin 11) | Channel 2 error amp output | Compensation node: connect RC network for loop stability or tie to INTVCC for internal compensation. |
| VON2 (Pin 12) | Channel 2 on-time voltage | Sets comparator threshold; tied to VOUT2 enables VOUT-proportional on-time (0.6V–6V range). |
| SW2 (Pins 13,14) | Channel 2 switch node | Connects to external inductor; swings from ~–0.3V to VIN2 during operation. |
| VIN2 (Pins 15,16) | Channel 2 input supply | Independent 3.6V–20V input-supports split-rail or different-source configurations. |
| BOOST2 (Pin 17) | Channel 2 bootstrap supply | Drives high-side MOSFET gate; connects to bootstrap cap (+) terminal, SW2 (–). |
| V2P5 (Pin 18) | 2.5V auxiliary regulator | 10mA-capable LDO output; bypass with ≥1µF ceramic; tie to INTVCC if unused. |
| INTVCC (Pin 19) | Internal 3.3V supply | Powers control logic and drivers; disabled when both RUN pins are low. |
| BOOST1 (Pin 20) | Channel 1 bootstrap supply | Identical function to BOOST2, referenced to SW1. |
| VIN1 (Pins 21,22) | Channel 1 input supply | Primary input for INTVCC LDO and channel 1 MOSFETs; supports same 3.6V–20V range. |
| SW1 (Pins 23,24) | Channel 1 switch node | Identical to SW2; connects to channel 1 inductor and BOOST1 capacitor. |
| VON1 (Pin 25) | Channel 1 on-time voltage | Same function and range as VON2-enables matched or independent on-time scaling. |
| ITH1 (Pin 26) | Channel 1 error amp output | Identical to ITH2-supports independent loop compensation per channel. |
| TRACKSS1 (Pin 27) | Channel 1 tracking/soft-start | Identical to TRACKSS2-enables synchronized or independent soft-start sequences. |
| VFB1 (Pin 28) | Channel 1 feedback input | Primary regulation input for channel 1; referenced to same 0.6V internal reference. |
| PGND (Exposed Pad) | Power ground return | Mandatory solder connection for low-impedance return path and thermal dissipation. |
Key Features
| Feature | Design Value |
|---|---|
| Controlled on-time current-mode architecture | Delivers fast line/load transient response and stable operation at high step-down ratios and high frequencies. |
| 180° interleaved phase operation | Reduces RMS input current by up to 30%, relaxing input capacitance requirements and lowering supply noise. |
| Burst Mode® and forced continuous mode selection | Enables >90% efficiency at light loads (Burst Mode®) or ultra-low noise/ripple at all loads (forced continuous). |
| Independent channel enable and tracking | Supports sequenced power-up, rail-to-rail tracking, and fault containment without external controllers. |
| Integrated 2.5V and 3.3V auxiliary regulators | Eliminates need for external bias supplies-V2P5 powers external circuitry; INTVCC powers internal logic/drivers. |
| VIN overvoltage and thermal protection | Automatic shutdown at VIN >22.5V or TJ >125°C, with automatic recovery and soft-start upon fault clearance. |
Applications
| Industrial PLC I/O Modules | Portable Test Equipment |
|---|---|
Use Scenario: Powering FPGA core (1.2V), I/O banks (3.3V), and analog front-end (5V) from a single 12V intermediate bus in compact field instruments. IC Role / Device Role / Timing Role: Dual-channel synchronous buck regulator providing isolated, tracked, and sequenced rails with integrated PGOOD monitoring. Use Value: Reduces BOM count by eliminating discrete DC/DC converters and sequencing ICs while maintaining <±1% output accuracy across temperature. |
Use Scenario: Battery-powered handheld oscilloscope requiring low-noise 3.3V digital rail and efficient 1.8V analog rail from 2-cell Li-ion (6V–8.4V). IC Role / Device Role / Timing Role: High-efficiency dual buck converter operating in Burst Mode® at standby and forced continuous during acquisition bursts. Use Value: Extends battery life by >40% versus fixed-frequency alternatives while maintaining <20mVpp output ripple during active measurement. |
| Automotive ADAS Camera Modules | Networking Line Cards |
Use Scenario: Supplying image sensor (1.2V), ISP (1.8V), and interface (2.5V) rails in rear-view camera modules exposed to under-hood temperatures. IC Role / Device Role / Timing Role: Automotive-grade dual buck regulator with –40°C to 125°C operation, VIN OV protection, and robust EMI performance. Use Value: Meets AEC-Q100 stress test requirements without derating; 180° phase shift minimizes conducted emissions in tight ECU enclosures. |
Use Scenario: Distributed 5V and 3.3V point-of-load regulation across multi-layer switch/router line cards powered from 12V backplane. IC Role / Device Role / Timing Role: Interleaved dual buck delivering 6A total with shared input capacitance and coordinated thermal management. Use Value: Cuts input capacitor count by 50% versus single-channel solutions and lowers board-level temperature rise by 8°C at full load. |
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 |
|---|---|---|---|
| MPQ4436-AEC1 | Single-channel 6A output; no phase-shift or tracking; AEC-Q100 Grade 1 only (–40°C to 125°C). | Requires two devices for dual-rail; lacks independent RUN/PGOOD per channel. | Choose when higher per-channel current (>3A) is needed and dual-channel integration is secondary. |
| TPS544B25 | Single-channel 4A; supports PMBus; no integrated tracking or Burst Mode®; 4.5V–18V input. | Requires external sequencing IC; higher quiescent current (12mA vs 13µA in Burst Mode®). | Choose when digital telemetry and dynamic margining are required over analog simplicity and ultra-low IQ. |
Compared with MPQ4436-AEC1 and TPS544B25, the LTC3633AIUFD#TRPBF uniquely integrates dual 3A channels with phase interleaving, analog tracking, and sub-15µA sleep current-making it optimal for space-constrained, thermally sensitive, or battery-backed dual-rail systems where discrete solutions increase cost and layout complexity.
Availability
LTC3633AIUFD#TRPBF is available at Aetrix Electronics and suitable for industrial PLCs, portable test equipment, automotive ADAS cameras, and networking line cards requiring stable component supply, extended temperature operation, and dual-rail power integration.
Supply support for LTC3633AIUFD#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 precision analog and power management portfolio with rigorous qualification standards and long-term product roadmaps.
The LTC3633A belongs to Linear's monolithic synchronous buck regulator family, designed specifically for high-efficiency, high-density point-of-load conversion in space- and thermal-constrained applications demanding dual outputs, fast transient response, and flexible control.
FAQ
What is the absolute maximum input voltage rating for LTC3633AIUFD#TRPBF?
The LTC3633AIUFD#TRPBF has an absolute maximum VIN rating of 20V per channel, with overvoltage lockout triggering at 22.5V (rising) and releasing at 21.5V (falling). This protects internal MOSFETs during transients while maintaining compatibility with 12V and 19V nominal supplies. Exceeding 20V risks permanent damage per Absolute Maximum Ratings.
Does LTC3633AIUFD#TRPBF support output voltage tracking between channels?
Yes, the LTC3633AIUFD#TRPBF supports precise output voltage tracking via dedicated TRACKSS1 and TRACKSS2 pins. Applying a common ramp voltage (e.g., from an RC network) to both pins forces each channel's FB pin to servo to that voltage, enabling matched startup, shutdown, and dynamic scaling-critical for FPGAs and processors with strict rail sequencing requirements.
How does the controlled on-time architecture of LTC3633AIUFD#TRPBF improve transient response?
The LTC3633AIUFD#TRPBF's controlled on-time architecture directly adjusts switching pulse width based on output error, eliminating loop compensation delays inherent in voltage-mode controllers. This yields <10µs load-step response with minimal overshoot-even at 4MHz switching-making it ideal for powering CPUs, FPGAs, and ADCs with rapidly varying current demands.
Can LTC3633AIUFD#TRPBF operate with only one channel enabled?
Yes, the LTC3633AIUFD#TRPBF supports independent channel operation: pulling RUN1 low disables Channel 1 while Channel 2 remains fully functional (and vice versa). Both channels share INTVCC and V2P5, but their switching, feedback, and protection circuits operate autonomously-enabling flexible power partitioning and fault isolation in multi-rail systems.
What thermal design guidance applies to the QFN-28 package of LTC3633AIUFD#TRPBF?
The LTC3633AIUFD#TRPBF in 4mm × 5mm QFN requires the exposed PGND pad (Pin 29) to be soldered to a minimum 200mm² copper area with ≥4 thermal vias to inner/ground planes. With this layout, θJA is 43°C/W; exceeding 125°C junction temperature triggers thermal shutdown. Derate output current by 10% per 10°C ambient above 85°C for continuous operation.
LTC3633AIUFD#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):
- 0.6V
- Voltage - Output (Max):
- 6V
- 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#TRPBF FAQ
1.How can I place an order for LTC3633AIUFD#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3633AIUFD#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#TRPBF reliable?
The price and inventory of LTC3633AIUFD#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#TRPBF is usually 5 days.
3.What payment methods are accepted for LTC3633AIUFD#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3633AIUFD#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC3633AIUFD#TRPBF?
LTC3633AIUFD#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3633AIUFD#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#TRPBF?
For technical support, including LTC3633AIUFD#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3633AIUFD#TRPBF requirements.
6.How does Aetrix verify that LTC3633AIUFD#TRPBF is sourced from the original manufacturer or authorized distributors?
All LTC3633AIUFD#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#TRPBF meets industry standards.
7.What is the process for return or replacement of LTC3633AIUFD#TRPBF?
All LTC3633AIUFD#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC3633AIUFD#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#TRPBF part is unused and in its original packaging.
Return procedure for LTC3633AIUFD#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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